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About this book

This proceedings book presents the main findings of the 13th International Seminar on Polymer Science and Technology ( ISPST 2018), which was held at Amirkabir University of Technology, Tehran, on November 10–22, 2018. This forum was the culmination of more than three decades of academic and industrial activities of Iranian scholars and professionals, and the participation of many notable international scientists, in covering various important polymer-related subjects of concern to Iran and the world at large, including polymer synthesis, processing and properties, as well as issues concerning polymer degradation, stability, and environmental aspects.

For the past half a century, the growing concern for advancing human health, quality of life, and – especially in the last few decades – avoiding and combating environmental pollution have shaped and driven scientific activities geared toward the creation of smart materials that are compatible with the human body, and have prompted scientists and technologists to pursue research using natural and sustainable sources. This book highlights efforts to responsibly address the problems caused by, and which can potentially be solved by, polymers and plastics.

Table of Contents

Frontmatter

Biocompatible and Biodegradable Polymers

Frontmatter

Relationship Between Curing Characteristics and Mechanical Properties of HTV Silicone Rubber

Curing characteristics of rubbers through their effects on crosslinking density affect the final properties of vulcanized rubbers. In this study, compounds of high temperature vulcanized silicone rubber (HTV-SR) containing different amounts of dicumyl peroxide (DCP) as curing agent were prepared and the effect of DCP concentration on the curing characteristics and mechanical properties of the vulcanized SR were investigated. The obtained results showed that by increasing the DCP amount the difference between maximum and minimum torque of rheometry was increased, however the tensile strength was increased for the DCP content up to 1 phr and by further increasing DCP and increasing the crosslink density it was unexpectedly decreased gradually. Increasing the DCP amount increased the hardness and decreased the elongation at break of the compounds.

Hamidreza Heidari, Azam Jalali-Arani

Porous Scaffolds of Polyvinyl Pyrrolidone/Polyethylene Glycol/Nano-Diamond Using Gamma Irradiation

Blends of polyvinyl pyrrolidone/polyethylene glycol (PVP/PEG) along with 1–3% nano-diamond particles (ND) were irradiated by gamma ray at various doses and then subjected to freeze-drying method to render porous scaffolds. At 35 kGy irradiation dose, the gel content was higher than 90%, though the presence of nanoparticles reduced slightly the gel content. It was found that for 10 kGy increase in irradiation dose, there was 15% reduction in pore size. On the other hand, upon the addition of 1% nano-diamond to PVP/PEG blends, the water swelling content of the scaffolds was increased by 10%. Also, the SEM images showed, at 1% nano-diamond level, the pore size was larger than pore size of neat PVP/PEG blends. The scaffolds were also tested for bio-compatibility, bio-degradability and mechanical properties. The results verified the suitability of these scaffolds for bio-medical applications.

Ali Jabbar, Susan Dadbin, Masoud Frounchi

Chitosan and Polyethylene Glycol Nanocomposites Designed to Deliver Anticancer Drug: Molecular Dynamics Simulations

Chitosan (CS) and polyethylene glycol (PEG) nanocomposite systems containing SiO2 nanoparticles and water molecules were designed by molecular dynamics (MD) simulations to deliver pipobromane (PIP) anticancer drug in order to discover more appropriate drug delivery system (DDS) in aqueous medium which was analogous to the human body. The CS system revealed greater fractional free volume (FFV) of 77.232%. The radial distribution function (RDF) data displayed that the PIP molecules had stronger H-bond interactions with the CS chains which reflected the drug molecules would diffuse slower inside the CS nanocomposite. Higher diffusion coefficient (0.0163 × 10−4 cm2/s) was measured for the PEG but lower one was achieved for the CS (0.0154 × 10−4 cm2/s) approving the drug diffusion in the CS was slower, thus providing more controlled and sustained drug delivery in this system.

Zahra Shariatinia, Azin Mazloom Jalali

Molecular Dynamics Simulations on Polycaprolactone Nanocomposite Drug Delivery Systems

Molecular dynamics (MD) simulations were accomplished on polycaprolactone (PCL) nanocomposite systems composed of hydroxyapatite (HA) nanoparticles (0 and 2%) to deliver ifosfamide (IF) anticancer drug in order to achieve the most suitable drug delivery system (DDS). Smaller inter-chain distances measured for the PCL-HA2-IF established that greater intermolecular interactions were occurred in the PCL-HA2-IF as a result of hydrogen bonds formation and electrostatic interactions among the PCL polymeric chains, HA NPs as well as IF molecules. It was found that the drug diffusion was slower/more controlled in the PCL-HA2-IF which would cause a more effective drug delivery.

Zahra Shariatinia, Azin Mazloom Jalali

Fabrication of Antibacterial Electrospun Chitosan-Polyethylene Oxide Nanocomposite Nanofibrous Mats

Antimicrobial chitosan–polyethylene oxide (CS-PEO) nanofibrous mats were developed by electrospinning technique for wound dressing applications. A green method was used to achieve antibacterial mats loaded with 0.25 and 0.50 w/w% of bioactive silver nanoparticles (Ag NPs, ~70 nm diameter) reduced by Falcaria vulgaris herbal extract. All of the nanofibers had an average ~200 nm diameter. Interestingly, both of the CS-PEO mats containing 0.25 and 0.50% bioactive F. vulgaris-Ag NPs revealed 100% bactericidal activities against both S. aureus and E. coli bacteria. The improved properties of CS-PEO-0.50% F. vulgaris-Ag NPs relative to those of the CS-PEO 0.25% F. vulgaris-Ag NPs suggested that the former was superior for biomedical applications.

Zahra Shariatinia, Iraj Kohsari

Biocompatible Electrospun Nanofibrous Mats Designed for Controlled Co-release of Hydrocortisone and Imipenem/Cilastatin Drugs

Antimicrobial chitosan–polyethylene oxide (CS-PEO) nanofibrous mats containing ZnO nanoparticles (NPs) and hydrocortisone-imipenem/cilastatin-loaded ZnO NPs were produced by electrospinning technique. The FE-SEM images displayed that the spherical ZnO NPs were ~70–200 nm in size and the CS-PEO nanofibers were very uniform and free of any beads which had average diameters within the range of ~20–130 nm. The hydrocortisone release increased to 82% within first 12 h while the release rate of imipenem/cilastatin was very much slower so that 20% of the drug was released during this period of time suggesting this nanofibrous mat is very suitable to inhibit inflammation (by hydrocortisone) and infection (using imipenem/cilastatin antibiotic and ZnO NPs) principally for the wound dressing purposes.

Zahra Shariatinia, Yousef Fazli

Peptide Release Behavior from in-Situ Forming Implants: Effect of Multi-walled CNT on Release Profile

The objective was to investigate the role of multi-walled carbon nano-tube MW-CNT as a nucleating agent on the phase inversion process and its effects on the morphology of PLGA in-situ forming implants and release behavior of leuprolide acetate as a model peptide. High performance liquid chromatography (HPLC) was used to measure drug release from implant and scanning electron microscopy (SEM) was conducted to study degradation and morphology of the PLGA implant. Drug release profile showed a remarkable decrease in the first and second stage bursts and a zero-order profile in the second stage which are related to phase inversion rate and implant morphology. Addition of MW-CNT led to changes in the cross sectional morphology from short and closed channels to deep and open channels. Channel depth increased 8 times from 50 μm to 400 μm by the addition of 0.8 wt% carbon nanotubes.

Ehsan Avazverdi, Hamid Mobedi, Hamid Mirzadeh

Drug Release Modeling Through a 3-Stage Model on Hydrophobic Modified Carboxymethyl Chitosan Nanoparticles

In this paper, the mechanism of releasing a small molecule (curcumin) from chitosan nanoparticles was investigated by a three-stage model with constant D. This model takes into account simultaneously initial burst, nanoparticle degradation–relaxation and diffusion with constant diffusion coefficient. Modified chitosan with hydrophobic functional groups is able to make self-assembled nanoparticles in aqueous media which in this study FA modified degraded carboxymethyl chitosan has been synthesized using folic acid, N hydroxy succinimide (NHS), N, N, dicyclohexylcarbodiimide (DCC) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide EDC). The morphology of nanoparticles was observed by scanning electron microscopy which had spherical shape with an average size less than 200 nm. In vitro drug release studies were performed at 37 °C using dissolution medium phosphate buffered saline (pH 7/4). The release profiles exhibited three well defined phases, which were modeled as well by three-phase model with best coefficient of determination (R2 = 0.9649).

Nafise Olov, Hamid Mirzadeh, Shadab Bagheri_Khoulenjani

Skin Tissue Engineering Electrospun Scaffold Based on PCL/PVA/ Aloevera

Artificial skins and skin substitutes are one of the most important areas of tissue engineering. In this work, three dimensional biodegradable nanofiberous scaffolds containing poly(caprolactone) (PCL), poly(vinyl alcohol) (PVA) and aloevera (AV) were successfully fabricated through two nozzles electrospinning process. For this purpose, PVA/AV blend solution was injected from one syringe and poly(caprolactone) solution from the other one. Addition of PVA and PCL improved the electrospinability of AV solution and mechanical properties of the fabricated nanofibers. Scaffolds were evaluated by SEM and FTIR analysis. Scanning electron microscopy (SEM) results showed uniform PVA/AV-PCL blend-hybrid nanofibers with the diameter average about 119.75 ± 11.75 nm. The presence of nanofibers functional groups was evaluated by Fourier transform infrared spectroscopy (FTIR). The sharp peaks observed in the nanofibers could be assigned to the asymmetric and symmetric stretching vibrations of methylene groups and carbonyl groups.

Marjan Shabannejad, Mohammad Sadegh Nourbakhsh, Amir Salati

Fabrication of Biocompatible PLGA/PCL/PANI Nanofibrous Scaffolds with Electrical Excitability

Fabrication of scaffolds with electrical properties plays a key role in neural tissue engineering. This study aimed to prepare aligned electrospun conductive nanofibers by mixing 1, 10, and 18 w/v% doped polyaniline (PANI) with polycaprolactone (PCL)/poly lactic-co-glycolic acid (PLGA) (25/75) solution through the electrospinning process. The fibers diameter and conductivity were measured. In addition, the shape and proliferation of the nerve cells seeded on fibers were evaluated by MTT cytotoxicity assay and scanning electron microscopy. The results revealed that the electrical stimulation enhanced neurite outgrowth compared to those PLGA/PCL/PANI scaffolds that were not subjected to electrical stimulation. As polyaniline ratio increases, electric stimulation through nanofibrous PLGA/PCL/PANI scaffolds results in cell proliferation enhancement. However, a raise more than 10% in polyaniline will result in cell toxicity. It was concluded that conductive scaffolds with appropriate ratio of PANI along with electrical stimulation have potential applications in treatment of spinal cord injuries.

Houra Farkhondehnia, Mohammad Amani Tehran, Fatemeh Zamani

Improved Solubility of Acetamidophenol from PEG-and Witepsol-Based Suppositories via Formation of Inclusion Complex by β-Cyclodextrin with a Controlled Release Profile

Acetamidophenol (ACP) is used to treat moderate pain and reduce fever but poorly dissolution of this compound has restricted its bioavailability. To enhance the solubility of ACP, inclusion complex between ACP and β-cyclodextrin (β-CD) is formed with various mass ratios of β-CD:ACP (1:1, 1:2, 1:4, 1:8) and the effect of complex formation on solubility and release of ACP from PEG (4000,400) and Witepsol (H15) based suppositories is investigated. Inclusion complexes were formed with various ratios of β-CD: ACP and loaded in the formulation of suppositories. FTIR, SEM and XRD results indicate formation of inclusion complex between β-CD and ACP. Physical characteristics and in vitro drug release of the obtained suppositories are determined by several tests such as weight variation, melting point, hardness, and release rate. Results indicate that PEG based suppositories containing β-CD:ACP 1:1 mass ratio show the best in vitro drug release characteristic which released 19.3% of ACP after 8 h.

Faezeh Asgari, Sahar Amiri, Majid Ghiass

Rigid Semi-IPN PVC Foam Modified with Epoxidized Soybean Oil

Semi-IPN rigid poly(vinyl chloride) foam had been prepared by molding and boiling foam process. The chemical structure of foam was modified by epoxidized soybean oil. The cellular structure of obtained foam was characterized. The tensile and compressive properties were also studied and compared to those of commercial foams with similar density. The obtained PVC/IPN foam showed good mechanical properties and higher compression strength than those of commercial foams.

Behnam Khaledi, Farah Salehiravesh

An Investigation on the Effect of Pressure and Temperature on Microcellular Foams of Polylactic Acid (PLA)/Acrylonitrile-Butadiene-Styrene (ABS) Binary Blends

Reducing the weight of petrol-derived plastics is a common way to decrease the environmental impact of several products. Another option consists in using biopolymers instead. However, most of the times, the complete substitution is not possible and partial replacement, usually obtained by blending, appears as a solution. The foaming of these blends combines both strategies and constitutes a further step to reduce the amount of petrol-derived plastics. In this study, PLA/ABS blends were prepared by melt blending without using any type of compatibilizer and were foamed by batch using super critical carbon dioxide as foaming agent. The final morphology of the blends was studied by SEM as a function of pressure and process temperature. Results shows that PLA/ABS blends can be successfully foamed under different conditions to obtain better structures than those known for pure components.

Mohammad Reza Kamrani, Miguel Sanchez-Soto, Alireza Aghili, Amir Ramezannejad

Physical Properties and Antibacterial Activity of Chitosan/Carboxymethyl Cellulose/Starch Biofilms as Natural Bio-Based Polymers

The antibacterial property of food packaging materials plays a key role in improving the safety and shelf-life of the food. The aim of this study was to evaluate the antibacterial activity of chitosan/carboxymethyl cellulose/starch biofilms against S. aureus and E. coli microorganisms by using agar diffusion disc and optical density methods. Investigation on the properties of fabricated biofilms, including water vapor transmission rate, water solubility, tensile strength and thermal resistance was carried out. Results exhibited that the antibacterial activity was enhanced by increasing the chitosan content. Besides, increased carboxymethyl cellulose content resulted in a decline in the permeability of water vapor through samples. Furthermore, the presence of carboxymethyl cellulose improved tensile strength and thermal stability and reduced the degradation rate of biofilms within the self-life period. Also, the increased starch content in biofilms led to increased water solubility. These results suggested that chitosan/carboxymethyl cellulose/starch biofilms could be used as food packaging materials.

Alireza Joorabloo, Zohreh Mansoori-Moghadam, Armaghan Moghaddam, Mohammad-Taghi Khorasani

Effect of Potassium Sorbate on the Mechanical and Thermal Behaviors of Multi-blends Based on LLDPE/LDPE/PLA with PE-g-MA as Compatiblizer

In the present study, the role of potassium sorbate on the mechanical and thermal properties of LLDPE/LDPE/PLA/PE-g-MA modified blends was evaluated. A series of blends of LLDPE/LDPE/PLA with the ratio of (80/20%) LLDPE/LDPE and 10, 20, and 30% PLA was prepared using co-rotating twin screw extrusion followed by extrusion blown film. In the first step, the mechanical properties of the samples were determined and the compositions of 20% PLA were optimized. In the second step, the properties were evaluated again by loading 4 phr potassium sorbate. The tensile strength of the of LLDPE/LDPE/PLA/PE-g-MA film enhanced from 7.93 Mpa to 11.71 Mpa and elongation at break from 282.57% to 551.57%, respectively. Thermal behavior of multi-blends of LLDPE/LDPE/PLA with and without potassium sorbate were studied using Differential Scanning Calorimetry (DSC). The results indicated that the presence of potassium sorbate caused the Tm and Tc of the film decrease from 122.3 ℃ to 111.1 ℃ and 110.32 ℃ to 98.32 ℃, respectively, while the crystallinity increased from 46.7% to 54.3% because potassium sorbate acts as nucleating agent in the blends.

Z. Tolouei Shiviari, Abdulrasoul Oromiehie

Investigation of In Situ Systems of Progesterone in Biphasic Media

Livestock breeding is one of the main concerns for animal owners. Progesterone plays a crucial role in regulating the activity of the reproductive system. In the present study, in situ formed systems that include poly(lactic-co-glycolic) acid (PLGA) as a biodegradable polymer, N-methyl-2-pyrrolidone (NMP) as a bioavailable solvent, and sodium chloride (NaCl) as an additive were provided to treat abortion. The release media was selected as a biphasic that contain 1,2-dichloroethane and buffer phosphate (87:13%) at 37 °C. The high-performance liquid chromatography system was also used to determine the amount of drug release. Degradation of systems was determined by examining the process of pH change. In general, it can be concluded that in situ systems based on PLGA containing NMP with 30 wt% sodium chloride salts showed a linear release profile.

Maryam Armiun, Seyed Mojtaba Taghizadeh, Hamid Mobedi

Fractionation of Poly1-Decene Based Oil Synthesized with AlCl3/Ethanol Cationic Catalyst in the Presence of Toluene Solvent

Polyα-olefin oil (PAO) was synthesized via cationic oligomerization of 1-decene as monomer, aluminum chloride as catalyst, ethanol as coactivator and toluene as solvent. Oligomer product was fractionated by distillation in vacuum and each fraction was characterized using viscometry, HNMR and GPC techniques. Analyses results showed that the fractions with higher boiling point and molecular weights had lower aromatic contents and higher viscosity index (VI).

Amene Rahbar, Naeimeh Bahri-Laleh, Sevda Dehghani, Mehdi Nekoomanesh

Study on Rheology, Crystallinity and Electrical Resistance of Poly(Lactic Acid)/Graphene Oxide Nanocomposites

Poly(lactic acid) (PLA)/graphene oxide (GO) nanocomposites containing 0.5 wt% to 2 wt% GO were prepared via solution mixing and the crystallinity, rheological and electrical properties of them were studied. It was found that the incorporation of GO leads to improve the storage modulus, loss modulus, and complex viscosity of the nanocomposite samples significantly. Also differential scanning calorimetry (DSC) results indicated that GO is an effective nucleating agent for PLA and could increase its crystallinity and decrease the crystallinity temperature. Also it was resulted that by introducing the GO in PLA matrix, the electrical resistance of samples are decreased, especially at low frequencies.

Fatemeh Farhanmoghaddam, Azizeh Javadi

Fabrication of NO-Releasing Silk Fibroin Nanofiber for Wound Dressing Application

The aim of this study was to build a modern system with controlled release to improve the wound healing because sometimes the body alone is not capable of repair and wound closure. Due to evidence for beneficial effects of nitric oxide at any stage of wound healing (for example, induction of inflammation, angiogenesis, cell proliferation, matrix deposition, and reconstruction), treatments based on nitric oxide has been proved to be suitable for wound healing. Different amounts of sodium nitrite (2 and 4 wt%) were added to silk fibroin solution and its effect on the morphology, release profile and fibroblast viability fibers were investigated and compared to those of pure silk fibroin.

Mina Vaez Ghasemi, Jhamak Nourmohammadi

Fabrication and Characterization of PCl/Gelatin/Forsterite Nanofibrous Scaffolds Used for Modification of the Implants

Bicomponent nanofibrous scaffold incorporated forsterite nanoparticles were fabricated via facile and cost-efficient electrospinning method for biomedical applications. At the first step, polycaprolactone (PCL) nanofibers were fabricated, concerning to optimize the electrospinning parameters. Afterward, gelatin was added to PCL to provide the nanofibers to be more biocompatible. Subsequently, 1 wt% of forsterite nanoparticles were incorporated in both neat PCL and PCL/gelatin nanofibers. Scanning electron microscopy was employed to investigate the morphology and diameter of the nanofibers and optimize the electrospinning parameters. SEM results showed that incorporation of gelatin to PCL nanofibers led to a significant reduction of the nanofiber’s diameter. In addition, incorporation of forsterite nanoparticles led to an increase in the nanofiber’s diameter for both PCL and PCL/gelatin nanofibrous scaffolds.

Fatemeh Khosravi, Saied Nouri Khorasani, Hamid Zilouei, Rasoul Esmaeely Neisiany

Biodegradable 3D Printed Scaffolds Based on PLA for Bone Tissue Engineering

Fused deposition modelling (FDM) is one of the additive manufacturing techniques that offers the potential to fabricate natural tissue constructs. The aim of this study is to fabricate biocompatible and biodegradable scaffold with good mechanical properties for tissue engineering. FDM allows to design and fabricate highly porous 3D scaffolds with interconnected network. At first, filament with the use of poly lactic acid (PLA) was fabricated. Utilizing computer aided design software the scaffolds structures were designed then using fused deposition modeling, scaffolds with controlled pore size and pore structure were printed. To determine the optimum structure, the effect of several parameters, such as nozzle size, raster angle and different interior fill of software were investigated. Specimens with different nozzle sizes of 0.3, 0.4, and 0.5 mm in various raster angles of 0°/90°, ±45° and 0°/60°/120° and in various interior fill percentages were printed. Specimens were characterized with SEM and compression testing. Pore size and porosity were calculated.

Shaghayegh Kaviani-Samani, Shadab Bagheri-Khoulenjani, Hamid Mirzadeh, Soheil Dariushi

Synthesis and Characterization of Biodegradable and Nontoxic Water Borne Copoly(Ether-Urethane-Urea)s Based on Amino Acid Derivatives

Biodegradable and biocompatible polyurethanes are a class of polymers that are useful in medical industry. In this study, new biodegradable and nontoxic water dispersed co-poly(ether-urethane-urea)s (PEUU)s were synthesized based on amino acid and peptide moiety. These polymers were prepared via the reaction of L-leucine anhydride cyclopeptid (LAC), polyethylene glycol (PEG), hexamethylene diisocyante (HDI) and serine (S) as dispersing agent. These polymers were characterized by FT-IR, NMR, TGA, DSC, AFM, and DLS. PEUU polymers were synthetized with three different structural architectures and block sequence. The polymer’s particle size dispersions are around 300 nm. The degradation test was carried out in PBS at 37 °C and evaluated by weight loss, viscosity and particle size decrement as well as by AFM. In order to determine cytotoxicity of the polymers, in vitro toxicity of final polymer was assessed using L929 mouse fibroblast cell line. The results showed no cytotoxicity of these polymers.

Shayesteh Tafazoli, Fatemeh Rafiemanzelat

In Situ Forming Hydrogels Based on Clickable Star-PEG for Biomedical Applications

Four-arm polyethylene glycol (star-PEG) macromeres are known as building blocks of homogenous hydrogels, known as tetra-PEG gels, which show excellent elasticity for load-bearing applications. However, biomedical application of the convectional tetra-PEG gels has been limited by weak bioorthogonality of the crosslinking reaction, non-biodegradability of the crosslinks, or complexity of the synthetic methods. Michael addition between simple groups of thiol and maleimide is a click reaction which is fast under physiological conditions, cytocompatible, and bioorthogonal. However, thiol-maleimide crosslinks are not biodegradable. Herein, we hypothesized that biodegradable, yet clickable tetra-PEG derivatives might be achieved by introduction of a hydrolyzable ester bond before thiol end groups. Upon mixing the degradable tetra-PEG-SH and tetra-PEG-Mal in less than 10 s, a biodegradable PEG hydrogel was produced that showed potential for loading and sustained release of proteins and encapsulation of live cells.

Mohammad Hossein Ghanian, Hamid Mirzadeh, Hossein Baharvand

Influence of Polyolefin Elastomer Content on Morphology, Rheology and Thermal Behavior of Toughened Polylactic Acid/Polyolefin Elastomer Blends

Improving the processability and melt strength of sustainable bio-based polymers using elastomers is essential to preserve their biodegradability making them suitable for many applications. Hence, different blends based on polylactic acid (PLA)/polyolefin elastomer (POE) were prepared by the melt mixing. The droplet-matrix morphology of blends was observed by the Field Emission Scanning Electron Microscopy. Structural development of PLA/POE blend was examined depending on the POE content (10–30 wt%). The droplet size of the dispersed POE phase initially decreased and then increased as the POE content increased. The rheological test results indicated that the incorporation of polyolefin elastomer could enhance the storage modulus and the melt complex viscosity of PLA/POE blends. Within all the compositions prepared, the blend containing 20 wt% of POE showed significant increase in the melt strength compared to neat PLA. The thermal behavior showed two different PLA crystal structures after the cooling cycle. The thermograms analysis also exhibited that the glass transition temperature was slightly decreased with the increased content of POE in PLA/POE blends. The results of structural development and the rheological properties of the blends showed that the blend performance was strongly dependent on the composition of POE in the blend.

Nadia Jalalifar, Babak Kaffashi

Electrospinning of Polycaprolactone (PCL)/Poly(Lactic Acid) (PLA)/Ferula Gummosa Boiss Extract (Galbanum)

Electrospinning is one of the most efficient, cost effective and straightforward methods for fabricating nanofibers. Nanofibers with special characteristics such as high surface to mass (or volume) ratio and high porosity are best candidate for simulating the extracellular matrix structure. In this research, polycaprolactone (PCL), poly(lactic acid) (PLA), and F. gummosa extract were electrospun. Electrospinning was performed using solutions containing 10% PCL and 8% PLA and varying amount of F. gummosa extract. Extracts of F. gummosa with ratios of 15, 20, and 25% were added to the polymer solution and stirred for 1 h. The morphology changes of nanofibers were studied by Scanning Electron Microscopy (SEM). The antibacterial properties of nanofibers were examined against a gram positive and gram negative bacteria. SEM results showed that average diameters of nanofibers without extract of F. gummosa and with extract were 497 ± 30 nm and around 642 ± 35 nm, respectively. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed that extract of F. gummosa was loaded in nanofibers structure properly. Hydrophilicity of nanofibers was also examined by water contact angle measurements.

Mohaddeseh Sharifi, Melika Sharahi, Sara Labbafi, S. Hajir Bahrami, Nahid Hemmati Nejad

Synthesis of Biodegradable Unsaturated Polyester Resin Using Soybean Fatty Acid as an Acidic Monomer

In recent years, many researches have been performed on issues that affect human life. Polymers, despite of huge applications in different industries, have been considered for their long-term degradation and their negative effects on environment. Many efforts have been performed to produce environmentally friendly resins. One of the newest types of these materials are biodegradable resins. In this research, biodegradable unsaturated polyester resin was synthesized. For this purpose, soybean oil, a natural fatty acid, was selected to be used as partial replacement of acidic monomer (i.e. maleic and/or phthalic anhydride). The replacing content changed from 0 wt% to 20 wt% and its effect on the mechanical properties of the cured resin was assessed. FTIR and NMR analysis were used to characterize chemical structure of the produced biodegradable resins. For better understanding, a general purpose unsaturated polyester resin as control sample was produced and its mechanical properties compared to the biodegradable samples.

Nika Parsi, Masoud Jamshidi, Mohsen Sarrafi

Fabrication of Gelatin 3-D Nanofibers via Wet Electrospinning Method

In this study, ultrafine gelatin fibers were successfully produced with the use of the wet spinning technique. Gelatin is an exceptional and versatile biopolymer with applications in various fields of medicine and biochemistry. Distilled water and acetic acid was used as solvents. The morphology of the gelatin fibers was found to be dependent on the voltage of wet spinning process. The SEM results showed that 20 kV is an inappropriate voltage because it formed beaded nanofibers but the 26 kV was the best voltage for successful wet spinning of gelatin and 3D nanofibrous structure formation.

Sarah Karimi, Mohamad Pezeshki-Modaress, Najmeh Najmoddin

Fabrication and Characterization of Hybrid Scaffolds Based on β-TCP/PCL-HAp/Gel Nanofibers for Bone Regeneration

Design and production of nanofibrous scaffolds for medical application especially tissue engineering have attracted considerable interest in last 2 decades. Recently, 3D bioactive scaffolds have been made to repair human bone tissue. They should contain a mineral phase such as bioceramics with synthetic or natural polymers. Here, we report fibrous scaffolds made of a combination of 20% PCL and 15% gelatin with acetic acid as a co-solvent. In order to produce fibrous scaffolds, β-tricalcium phosphate loaded PCL and hydroxy apatite-Gel solutions were electrospun. For this, HAp with different weight percentages (5, 10%) were added to gelatin polymeric solution and the HAp/Gel blend was injected from one syringe. The other syringe was included 5% and 10% of β-TCP in PCL solution. After producing nanofibrous webs, their surface morphology was examined by SEM images. These results showed that PCL/β-TCP-Gel/HAp nanofibers have some features such as random arrangement with agglomeration of particles and proper porosity. Also, hydrophilicity and mechanical properties of hybrid webs were investigated. These scaffolds not only possess properties such as biocompatibility and tensile modulus, but also sufficient water absorption that will improve the adhesion process and proliferation of osteoblasts cells. Besides, cell culture studies showed good adhesion and proliferation.

Melika Sharahi, Mohaddeseh Sharifi, Sara Labbafi, S. Hajir Bahrami, Nahid Hemmati-Nejad

Surface Modification of Polyurethane Films with Chitosan and Collagen Biomolecules, Using Layer by Layer Self-Assembly Method to Improve Biocompatibility Properties

Recently biocompatible polymer films have received the great attention in tissue engineering applications. One of the material surface modification methods is use of the layer-by-layer self-assembly process (LbL), especially the electrostatic self-assembly process controlled by the adsorption and desorption equilibrium in anionic and cationic solutions. In this research, the polyurethane (PU) film obtained from the reaction of hexamethylene diisocyanate and castor oil was initially functionalized by the low-pressure nitrogen plasma treatment and then grafted with acrylic acid. Acrylic acid grafted PU film was modified in three LbL ways (A, B, and C) with three layers and five layers. Each layer first consisted of collagen containing positive electrical charge, anionic sodium polystyrene sulfonate (PSS) and cationic chitosan, which was stained with quantum particles. The modified three-layer and five-layer films obtained from all three methods were characterized and analyzed with results from field emission scanning electron microscopy (FESEM) images, confocal microscopy and HGF fibroblast cell culture. The results confirmed that the method (C), firstly contained positive charge by hexamethylenediamine, was the best method through the LbL techniques.

Narges Bahrami, Saied Nouri Khorasani, Hamid Mahdavi

Green Coatings and Engineering in Polymer Science

Frontmatter

Performance of Room Temperature Cross-Linkable Acrylic Latexes Synthesized Using DAAM and AAEMA Functional Monomers

Different acrylic latexes were synthesized using acetoacetoxy ethyl methacrylate (AAEM) and diacetone acrylamide (DAAM) functional monomers (in concentration of 0.5 wt% of monomers) through seeded semi-continuous emulsion polymerization. Adipic acid dihydrazide (ADH) and 1,3-diaminopropane (DAP) were added as crosslink agents to the synthesized DAAM-acrylic and AAEM-acrylic, respectively to prepare two components in one-pot latexes. Crosslink reactions were carried out at room temperature during the process of latex film formation. Mechanical properties of the crosslink films were evaluated via pendulum hardness measurements and dynamic mechanical thermal analysis (DMTA). Cross-linking was proved through increase in hardness, storage modulus at rubbery plateau, and Tg values. In addition, the results showed improved mechanical properties in latex films formed from DAAM-acrylics in comparison to those formed from AAEM–acrylics.

Saba Goharshenas Moghadam, Shahla Pazokifard, Hamidreza Parsimehr

Effect of Curing Conditions on the Surface and Bulk Properties of High Solid Silicone-Epoxy Coatings

This work reports the effect of curing at ambient conditions and elevated temperature on the properties of epoxy-silicone coatings cured by amino functional hardeners in two different weight ratios of 100:40 and 100:60. FTIR spectroscopy was used to evaluate curing process and crosslinking reaction in the coating samples. Hardness and water contact angle measurements were carried out on the coatings as the indications for bulk and surface properties of the coatings, respectively. The results revealed that increasing the curing temperature leads to higher water contact angle and lower hardness. It reason can be assigned to surface roughness of the coating caused by shrinkage or thermal stress occurred during heating the coating.

Mohammad Yasin Mollajavadi, Shahla Pazokifard, Seyed Mojtaba Mirabedini

Synthesis of UV-Curable Urethane Acrylate Zirconium Oxide Nanocomposites as Thermal Insulator

Synthesis of polyurethanes through UV-curing process contributes to the environmental protection by removing the hazardous organic solvents. At first, UV-curable urethane acrylate (UA) ZrO2 nanocomposites with different weight percentages of ZrO2 were synthesized and then thermal conductivity of the nanocomposites was measured by infrared thermography. Infrared thermography results showed that adding ZrO2 nanoparticles to the urethane acrylate matrix increased surface reflection coefficient and decreased thermal conductivity in the urethane nanocomposites. Consequently, urethane acrylate ZrO2 nanocomposites (3 and 5 wt%) acted as strong thermal insulators.

Abbas Madhi, Behzad Shirkavand Hadavand, Ali Amoozadeh

Antibacterial Performance of Biomimetic Modification of Polymeric Surfaces: Rice-like and Lotus Pattern

Significant research effort has been devoted to understanding surface modification methods to achieve antibacterial surface due to the growing prevalence of antimicrobial resistant strains. In this way, the biomimetic patterning approach has considered as modification approach because of improving surface to prohibit bacteria growth in the absence of antibiotic agents. In this study, we present two biomimetic microstructures from the rice-like pattern and a lotus structure to consider their ability in reducing bacterial adhesion. Two inspired structures have developed on the polydimethyle siloxane and polypropylene surface. The results of the attachment behaviors have examined on two bacteria strains of gram-negative Escherichia coli (E. coli) bacteria and gram-positive Staphylococcus aureus (S. aureus). Bacteria adhesion function on these roughness surfaces is demonstrated by the prevention of growth on our structured plastic surfaces. The bacteria attached to the surfaces have also offered the important role of bacterial species and material type to prevent bacterial adhesion.

Masoumeh Ayazi, Nadereh Golshan Ebrahimi

Fabrication of Ag/TiO2-Coated Textile Fabric via a New Photoreduction Method as an Eco-Friendly Technique

A new facile in situ synthesis coating method was utilized to improve the photocatalytic activity of the textile fabric. An eco-friendly method of photoreduction was used to synthesize Ag/TiO2 nanoparticles. The synthesis and coating approaches were performed simultaneously. The elemental analysis of the X-ray photoelectron spectroscopy showed a pair of separated peaks with a binding energy of 6 eV between two states which confirmed the creation of silver metallic on the fabric surface. The field emission scanning electron microscope images and map analysis showed an even distribution of coating with nanoparticle size of 27 ± 5 nm. The self-cleaning properties were estimated by measuring the discoloration of reactive blue stain under UVA, UVC, and daylight irradiation and showed a significant increase in photocatalytic activity. The anti-bacterial property showed an excellent activity after Ag-doping in TiO2.

Zahar Moridi Mahdieh, Shahla Shekarriz, Faramarz Afshar Taromi

Fabrication of Super-Hydrophobic Fabric by Eco-Friendly Plasma Technique

A facile method was used to create a super-hydrophilic polyester/cellulose blended fabric. The fabric was exposed to air plasma treatment under different input powers and exposure times without any extra chemical modification. The wettability test showed the maximum hydrophobic properties for an input power of 300 W and exposure time of 10 min. The static contact angle of 167° was indicated for the super-hydrophobic sample. The decrease of intensity of active functional groups and the increase of roughness with a nano-scale pattern presented a super-hydrophobic surface that confirmed by ATR-FTIR and FESEM analysis.

Zahar Moridi Mahdieh, Shahla Shekarriz, Faramarz Afshar Taromi

Nano-Silica Extracted from Rice Husk Ash: Effect on the Thermal Properties of Hydroxyethyl Cellulose

Thermal resistance and thermal stability of cellulose film are of particular importance in different applications. In this work, the effect of nanosilica extracted from rice husk ash on the thermal properties of hydroxyethyl cellulose has been investigated using thermal analysis test (Differential Scanning Calorimeter, DSC). Morphology and nanosilica dispersion and distribution were investigated using Scanning Electron Microscopy (SEM). The results of this work show that by increasing the amount of nanosilica from 0 wt% to 8 wt% to the hydroxyethyl cellulose, the heat of degradation increases to about 127%. The thermal degradation temperature also increases by about 33 K. Also, the burning time increased from 84 s to 300 s.

Niloofar Bakhtiari-Nasr, Ahmad Reza Bahramian

Spectroscopic Study of Waterborne Polyurethane/Acrylate Hybrids Based on Acrylate Monomers Contents

A series of waterborne polyurethane/acrylate hybrids were synthesized using different values of acrylic monomers (butyl acrylate, methyl methacrylate, and acrylic acid). The samples were synthesized via prepolymer mixing method and followed by radical polymerization. The crucial parameters were temperature, viscosity, and rate of stirring for obtaining the stable dispersions. Here, the IR spectroscopy of waterborne polyurethane and synthesized waterborne polyurethane/acrylate hybrids is investigated.

Ghazal Minoofar, Hengameh Honarkar, Mehdi Barikani

Enhancing Corrosion Resistance of Alkyd Coatings Using Cerium Nitrate Hexahydrate Treated Ceria Nanoparticles

Cerium-based compounds have been considered as effective inhibitors in corrosion resistance coatings for many years. In this study, corrosion inhibition behavior of alkyd coatings containing either cerium nitrate or cerium oxide was evaluated. In order to use cerium nitrate in the coatings, cerium oxide nanoparticles were first treated with cerium nitrate hexahydrate. Then treated and untreated nanoparticles were loaded into the alkyd coating. Surface treatment of nanoparticles was studied using FTIR spectroscopy. Dispersion of nanoparticles in polymeric matrix was assessed via EDAX analysis. Corrosion performance of the coatings applied on steel substrates was evaluated using EIS technique. The results showed that presence of cerium nitrate on cerium oxide nanoparticles leads to improve corrosion resistance of alkyd coatings.

Sepideh Parchami, Seyed Mojtaba Mirabedini, Shahla Pazokifard, Morteza Behzadnasab

Surface Modification of BOPP Film Using a Gliding Arc Plasma and Low Pressure Atmospheric Plasma

Increasing the surface energy of polymer is one of the most essential needs of industries such as battery industry, printing, textiles, etc. In this article, we present a study into the mechanisms underpinning surface energy increase of BOPP and hydrophilic using gliding arc plasma (GAP) and low-pressure atmospheric plasma (LPP). Measurements of contact angle indicate an increase in surface energy to 63 mNm−1. The effect of the plasma was studied at different durations of treatment 10–120 s. The OES analysis confirms the presence of air molecules in the plasma. Atomic force microscopy (AFM) showed that plasma etching occurs in stages and may be related to the reach of the species. To analyze the chemistry on the surface, attenuated total reflectance–Fourier transforms infrared spectroscopy (ATR-FTIR) was used. Plasma is an eco-friendly process because it does not produce any pollution and is safe.

Fahime Darvish, Mohammadreza Khani

Effect of Low-Functionalized Graphene Oxide on the Rheological and Electrical Properties of Water-Based Epoxy Coatings

In the present work, rheological and electrical properties of epoxy-based nanocomposite coatings containing low-functionalized graphene nanosheets are studied. The low-functionalized, highly concentrated graphene nano-sheets in water were synthesized using a non-dispersion mechanism, which made them to be stable in water. The rheological investigations show a transition from a viscous response to a solid-like response at low frequency region, which indicates formation of nanofillers network structure in these samples at low filler contents. In addition, electrical conductivity as high as 1.34×10−1 S/m is achieved for the epoxy based nanocomposite coatings, which indicates a good electrical network formation through the epoxy matrix.

Amir Rezvani Moghaddam, Milad Kamkar, Zahra Ranjbar, Uttandaraman Sundararaj, Ali Jannesari

Environmentally Friendly Hybrid Polysilsesquioxane-Poly(Butyl Acrylate) Nanocomposite: Film Properties

Inorganic-organic core-shell polysilsesquioxane-poly(butyl acrylate) hybrid latex nanoparticles were synthesized via emulsion polymerization. FTIR spectroscopy and dynamic light scattering (DLS) confirmed core-shell structure of the resultant hybrid latex nanoparticles. Hybrid core-shell nanocomposite film underwent drying in a shorter period of time in comparison with the polysilsesquioxane latex, due to the lower Brownian diffusivity of its latex nanoparticles. It also revealed less hydrophilicity and higher resistance to water whitening, compared to the seed latex film.

Ali Ahmadi Dehnoei, Somayeh Ghasemirad

Protection of Structural Buildings Against Dirt Adsorption: Photoactive Cements vs. Photoactive Coating

In this study, TiO2 nanoparticles (Aeroxide P25) and synthesized TiO2/SiO2 nanocomposite were used to provide a photoactive concrete and water based acrylic façade coatings. For this purpose, TiO2 nanoparticles (1 wt%) were loaded into a mixture of cement and sand (weight ratio 5:12) compared to acrylic coatings containing either 1 wt% Aeroxide P25 or synthesized TiO2/SiO2 nanoparticles. Photo-catalyst activity of the nanoparticles embedded samples was evaluated by color data measurements of photo-degradation of rhodamine B dyestuff implemented on the sample’s surface, during exposure to the sun light for 18 days. The results showed that in spite of improving photo-activity of acrylic coatings using TiO2/SiO2 nano-composites, the highest photo-activity arised from concrete loaded by commercial TiO2 nanoparticles.

Fatemeh Mohammadi, Seyed Mojtaba Mirabedini, Khosro Khodabakhshi, Shahla Pazokifard

Nanoassemblies for Sustainable Energy and Environment Applications

Frontmatter

Improved Conductivity and Film Forming of Transparent PEDOT:PSS Electrodes Using Non-ionic Surfactants

We could successfully design and prepare transparent conductive electrodes for optoelectronic applications. The optimized electrode was formulated based on PEDOT:PSS and PVA as non-ionic surfactant. Conductivity and film forming were improved after the addition of optimum amounts of PVA to PEDOT:PSS to reduce the ionic interaction between PEDOT and PSS. UV-Vis spectroscopy, four-point probe and profilometer were used to monitor transparency, conductivity and film thickness, respectively. We could reach the conductivity of 10.12 S/cm after adding 0.625 g/L PVA to PEDOT:PSS solution, which is 15 times higher than that of bare PEDOT:PSS film. Transparency remained more than 85% after addition of less than 1 g/L PVA. The proposed electrode is a promising candidate for use in high conductive optoelectronic devices.

Milad Kianpisheh, Bahareh Rezaei, Faramarz Afshar-Taromi

Sol–Gel Preparation and Characterization of Antibacterial and Self-cleaning Hybrid Nanocomposite Coatings

ZnO-TiO2, SiO2-TiO2, and SiO2-TiO2-ZnO hybrid nanocomposite coatings based on sol-gel precursors using tetra methoxysilane (TMOS), 3-glycidoxypropyl trimethoxysilane (GPTMS), tetra-n-butyl orthotitanate (TBT) and zinc acetate dihydrate were synthesized and characterized. Hybrid network was characterized by FTIR, FESEM and EDAX. The results indicated that inorganic particles sizes were in nano size range (20–30 nm) with a very uniform distribution and dispersion. Photocatalytic and self-cleaning activities of these coatings were investigated by degradation of 2-methylene blue in aqueous solution (20 ppm) at visible light irradiation which indicated photo-catalytic performance of coating containing ZnO and TiO2. The antibacterial effect of coating was investigated for inhibition and inactivation of cell growth, and the results showed that the antibacterial activity of ZnO-TiO2 and SiO2-TiO2-ZnO coating against E. coli and S. aureus was the same and higher than that of SiO2-TiO2 hybrid nanocomposite coating.

Sahar Amiri, Seyed Armin Zare Estekhraji

Synthesis of Au@GO Core-Shell Structure for Solar Cell Application

Stable Au NPs were synthesized with Turkevich method and graphene oxide was prepared using improved Hummer method for better functionalization of graphite sheets. Core shell structure of Au@GO was synthesized by changing zeta potential of Au NPs. Band gap of Au NPs was tunable at different concentrations of GO. The Au2@GO UV-Vis absorption peak of Au NPs shifted to a higher wavelength and the energy of band gap was determined by optical absorption of Au NPs. Tauc analysis was used for calculation of optical band gap of Au NPs. The results revealed high applicability of this structure for solar cell fabrication.

Bahareh Rezaei, Milad Kian Pisheh, Zahra Babaei, Bahareh Nasrollahi, Faramarz Afshar Taromi

Effect of Monomer Concentration in Primary Sol on the Colloid like Particle Size of Novolac Aerogel

Three various novolac aerogels with different monomer concentrations of 10, 15, and 20 wt% were prepared by sol-gel polymerization method. In order to investigate structure-properties relation, morphology and physical measurements were done. By increasing monomer concentration from 10 wt% to 20 wt% in initial sol, size distribution peak of aerogel colloids was moved from 120 nm to 60 nm. In addition, porosity was declined by as much as 10.8%, whereas density of ultimate aerogel was increased.

Golnoosh Abdeali, Ahmad Reza Bahramian, Mahdi Abdollahi

Synthesis of Paraffin Wax Phase Change Material Nanoencapsulated by Polyurethane via Interfacial Polymerization

This work deals with the synthesis and physico-chemical characterization of nanoencapsulated paraffin wax with polyurethane (PU) via interfacial polymerization method. In synthesized nanocapsules, the paraffin wax has a function of phase change material, while PU acts as a shell material. The nanoencapsulated PCMs were characterized chemically and morphologically by using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The results of morphological study showed that the particle size distribution of the nanocapsules were 80–400 nm by digimizer analysis.

Hediyeh Nikpourian, Ahmad Reza Bahramian, Mahdi Abdollahi

Adsorption of Acid Red 1 onto Functionalized Silica by Amine-Terminated Dendritic Polymers: Isotherms and Kinetic Models

Pristine silica was functionalized by amine-terminated dendritic polymers via divergent synthetic routes in first generation. The chemical structure analyzed by Fourier Transform Infrared Spectroscopy (FTIR) confirmed the presence of amine terminated group on silica. The pristine and functionalized silica were investigated for adsorption capacity of acid red 1 (AR1). The results showed that the removal was enhanced from 0% to 94.8% by functionalization. It seems that this modification improved significantly the adsorption capacity of this adsorbent. Moreover, their adsorption isotherms and kinetics were further investigated to explore the application in the industrial operating system. The adsorption kinetics fitted pseudo-second order model well. Furthermore, the adsorption isotherms fitted the Freundlich model well and with the modification of pristine silica, R2 of this model was 0/98.

Samane Goftari, Somaye Akbari

Effect of Waste Paper Extracted Cellulose on the Structure and Properties of Resorcinol Formaldehyde Aerogel

Hydrophilicity properties of polymeric aerogels have an effective role in water filtration applications. In this work, the effect of cellulose extracted from the waste paper on the structure and properties of resorcinol formaldehyde aerogel was investigated. The density and porosity of resorcinol formaldehyde aerogels were decreased and increased with the addition of cellulose, respectively. Fragility and shrinkage also decreased with increasing cellulose content. The results showed an increase of 10% in porosity by adding 13 wt% of cellulose extracted from waste paper.

Parisa Hakimi, Ahmad Reza Bahramian

PVA Electrospun Hollow Nanofibers via One-Pot Coaxial Electrospinning

Uniform and beadless PVA hollow nanofibers with a mean shell thickness of less than 100 nm were successfully prepared by one-pot coaxial electrospinning technique. The morphology and diameter of nanofibers were characterized by scanning electron microscopy (SEM). The micrographs indicated that the air flow rate could control the morphology of electrospun hollow nanofibers. Also, they showed that nanofiber diameter increased with increasing air flow rate. To obtain PVA hollow nanofibers, the ratio of air flow rate to the solution feed rate was adjusted at 75.

Niloufar Ghaedi Dehaghi, Sobhan Sharafkhani, Mehrdad Kokabi

A Molecular Dynamics Approach to Study Polymer/Nano-Filler Interactions

There is a common knowledge that the dynamic and structural behavior of polymer chains in the vicinity of nano-fillers is rather different from the bulk. Despite the extensive literature on this topic, this phenomenon is not yet fully understood. Apart from several experimental methods to study it, molecular simulations, in particular molecular dynamics (MD) methods, are good candidates for such study. In other words, MD simulation techniques give us a remarkable ability for mechanistic studies of dynamic and structural properties of polymer chains in nano-scales and they are proved to be highly reliable methods for estimating such properties. Therefore, in this study, we developed a time and spatially-resolved molecular dynamic method by which the structural and dynamic properties of two polymers, i.e., polypropylene (PP) and polyvinyl alcohol (PVA), are studied as a function of distance from graphene (G) and graphene oxide (GO) nano-layers.

Hesam Makki, Farhad Sharif, Morteza Ebrahim

Curing Characteristics of Phenolic Syntactic Foams Based on Oxygen Plasma Treated Hollow Glass Microspheres

Curing behavior of syntactic foams based on phenolic resins and hollow glass microspheres treated by oxygen plasma was investigated through differential scanning calorimetry (DSC) analysis. Plasma treatment was carried out and the existence of carbonyl group was approved by Fourier-transform infrared spectroscopy (FT-IR) via the appearance of an extra peak at 1730 cm−1 wavenumber. The composites were prepared by solution mixing and the results revealed that by using treated particles within phenolic resins, the curing temperature shifted to lower temperatures from 160 °C to 152 °C. This accelerated effect was endorsed by Flynn-Wall-Ozawa model by which the extent of reaction was traced with variations of activation energy.

Milad Karbalaei-Bagher, Rasool Amirkhani, Mohammad-Hassan Omidi

Optimization of Methylene Blue Dye Batch Adsorption by Carboxylic Acid Functionalized Halloysite Nanotubes

The adsorption behavior of methylene blue from aqueous solution was investigated to identify the ability of functionalized halloysite nanotubes (HNTs) to remove colored textile dye from simulated wastewater. For this purpose, carboxylic acid groups were synthesized into the halloysite as the mineral adsorbent. The synthesis process was investigated by X-ray photoelectron spectroscopy (XPS) which confirm functionalization. The statistics parameter was used to optimize the methylene blue dye batch adsorption by carboxylic acid functionalized HNTs. The optimum adsorbent dosage and pH for dye removal were obtained to be 0.3 and 9 g/L, respectively

Mohammad Hassan Kanani-Jazi, Somaye Akbari

Natural Bio-based Polymers and Composites

Frontmatter

Effect of Crosslinking Agent Concentration on Swelling Behavior of Acrylic-Nanocellulose Hydrogels

In this study, composite hydrogels with interpenetrated polymer networks (IPNs) based on cellulose nanofibrils (CNFs) and poly(acrylic acid) comprising low amount of CNFs were synthesized through radical polymerization for agricultural applications. N,N′-Methylene-bis-acrylamide (MBA) was used as crosslinking agent. The formation of this IPN structure was studied with thermogravimetric analysis (TGA). The onset of PAA dehydroxylation began at higher temperature in the presence of cellulose nanofibrils. The MBA concentrations of 0.05, 0.1, 0.2, 0.3, and 0.4 wt% were used to investigate its influence on the swelling degree and strength of the samples. The absorption capacities measured in distilled, drinking and saline (0.9%) water showed an increase upon increasing crosslinking agent concentration. Absorptions under load (AUL) data presented higher strength (ranged from 17 g/g to 21 g/g) with increasing the network crosslink density up to 0.3 wt% MBA concentration. The absorption rate data also followed the same trend as AUL data.

Mahnaz Shahzamani, Navid Naseri, Fariba Safaei

Swelling Behavior of Acrylic-Cellulose Hydrogels for Agricultural Applications: Effect of Reactants Concentration

Effect of reactants concentration on swelling properties of cellulose-acrylic hydrogels was investigated in this study. The composite hydrogels with interpenetrated polymer networks (IPNs) comprising low amount of cellulose nanofibrils (CNFs) were synthesized through radical polymerization. Cellulose concentration was changed from 0.5 wt% to 2.5 wt% by using different amounts of water. The swelling behavior was measured in different aqueous media and fertilizers such as urea and ammonium sulfate solution. The absorption ranges of hydrogels in saline water (0.9 wt%) and ammonium sulfate (0.12 mol/L) are significantly lower than those in other absorption media (<25 g/g). The equilibrium absorption of the prepared hydrogels in urea solution, drinking water and distilled water changed from 62 g/g to 64 g/g, 54 g/g to 68 g/g, and 71 g/g to 79 g/g, respectively. Absorptions under load (AUL) data presented a slight decrease in strength at low cellulose concentration (0.5 wt%).

Mahnaz Shahzamani, Navid Naseri

Preparation of a New Antioxidant for Polypropylene Based on Quercetin

Quercetin, a naturally occurring antioxidant, was converted to quercetin stearate through an esterification reaction with stearic acid. The occurrence of the esterification reaction was examined by FT-IR spectroscopy. The synthesized ester was then incorporated into polypropylene via melt mixing. Determination of oxidative induction time (OIT) and oxidation onset temperature (OOT) of the samples with the aid of differential scanning calorimetry (DSC), proved that the modified quercetin enhances the stability of the polymer outstandingly in the melt state, so that, the stabilization efficiency of quercetin stearate is higher than that of Songnox 1010, a commercially used antioxidant for polypropylene.

Afarin Rahmati, Reza Jahanmardi, Sahar Amiri

Controlling the Adsorption of Scleroglucan Polymer on the Surface of Carbonate Particles by Grafting Acyl Chlorides with Different Chain Lengths

Scleroglucan (Sclg) polymer possesses unique properties making it especially attractive for enhanced oil recovery (EOR) applications. However, the hydrophilic nature of Sclg is a major constraint in EOR applications. Fortunately, its hydroxyl groups render it prone to different chemical reactions. In this study, Sclg is grafted by three modifying molecules with different hydrophobic chain lengths: stearoyl chloride (C18), decanoyl chloride (C10) or hexanoyl chloride (C6) and the effects of the alkyl chain length of the modifier on the adsorption of Sclg, from its saline solutions, on carbonate rock surfaces are studied. The pristine Sclg showed the lowest adsorption amount on the rock surfaces and the adsorption amounts of the modified Sclgs were increased by increasing the hydrophobic chain length of the modifier. Actually, by increasing the hydrophobic chain length in the modified samples, from hexanoyl chloride to stearoyl chloride, the possibility and strength of hydrophobic interactions among the hydrophobic sections were increased that, eventually resulted in higher adsorption amounts. Finally, the experimental results can be described by the well-known Langmuir model.

Behnam Davoodi, Alireza Sharif, Jamal Aalaie

Chemical Modification of Polyfurfuryl Alcohol Resin Using Maleic Anhydride: FTIR Study of a Diels-Alder Reaction

In this study, furan bio-resin (PFA) was modified with maleic anhydride (MA) via Deils-Alder reaction. With this reaction, the number of carboxylic groups of the resin is increased and, as a result, its reactivity with polyamine-based curing agent is facilitated. The modification of PFA was performed using various wt% of MA (1, 2, 3, 5, and 15) at 40 °C. Reaction kinetic of different samples was studied using FTIR spectroscopy. The results showed that PFA modified with 1, 2, and 3 wt% of MA can be cured using 30 wt% polyamine curing agent. Higher amount of MA (5 and 15 wt%) remains intact and unreacted in the systems which is not suitable for modification.

Roghayyeh Marefat Seyedlar, Mohammad Imani, Seyed Mojtaba Mirabedini

Hardness and Chemorheological Properties of Chemically-Modified Polyfurfuryl Alcohol Resin

Polyfurfuryl alcohol (PFA) is cured with amine-based curing agent via carbonyl functional groups of the resin. In this study, PFA was chemically modified via Deils-Alder reaction with different wt% of maleic anhydride (MA). Curing behavior of the modified resins was investigated in the presence of the polyamine curing agent using chemorheological and hardness techniques. According to the results, increasing MA wt% from 1 to 5, leads to increase of viscosity and storage modulus ($$ G^{\prime} $$) of the mixture. However, the rate of viscosity increasing is higher than the increasing rate of $$ G^{\prime} $$ for resins with higher MA content. In these systems, viscosity increases faster due to higher concentration of MA which results in reduction in chains mobility and crosslinking reaction which affects $$ G^{\prime} $$ increasing rate. Hardness of the formulations increases with MA content and time progression up to 72 h.

Roghayyeh Marefat Seyedlar, Mohammad Imani, Seyed Mojtaba Mirabedini

Influence of Cut-Out Shape on Buckling Behavior of Composite Beams

In this study, the buckling behavior of orthotropic composite beams with circular, elliptic and square cut-out shape under compression loading has been studied. A simulation based on finite element method has been developed to evaluate critical buckling load and predict the failure around the holes with different shapes. In order to obtain empirical results, specimens were manufactured with symmetric lay-up and different hole shapes. Several key findings and behavioral characteristics are discussed. The results show that specimens without cut-out have the highest critical buckling load and specimens with circular hole have the lowest critical load. The experimental results are well matching with that of FEM solution.

Soheil Dariushi

Tensile Properties of Jute/Epoxy/Aluminum Hybrid Laminates

In this research, tensile properties of hybrid laminates consist of layers of thin aluminum sheets and jute/epoxy composite are investigated and compared with those of jute/epoxy laminates. The main objective of this research is to study the effect of combining aluminum layers and laminated jute/epoxy composite to improve the mechanical properties. Two groups of specimens were made and tested according to ASTM D3039. The first group of specimens contained Jute/epoxy [0/90/90/0] and the second group was made up of 2024-T3 aluminum sheets and jute/epoxy laminates, the stacking sequence was set as [Al/0/90/90/0/Al]. The results show that adding aluminum layers to composites laminates caused an enhancement in modulus, maximum stress, and elongation at break point for jute/epoxy composites.

Sara Alirezaei, Soheil Dariushi, Mohammad Hosain Beheshty

Adsorption Behavior of Cyclodextrin-Triazole-Titanium Based Nanocomposite for Heavy Metal Ions from Aqueous Solution

A cyclodextrin-triazole-titanium based nanocomposite (CD.COM) was successfully synthesized and fully characterized. CD.COM exhibited a good adsorption performance for removal of Zn+2, Cd2+, and Pb2+ ions from aqueous solutions by batch technique. The adsorption parameters such as pH, contact time, adsorbent dosage, temperature, metal ions concentration, coexisting ions and the regenerability of CD.COM were investigated. The Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models were evaluated using adsorption equilibrium data. The Langmuir model showed the best agreement with the experimental data, resulting in the maximum adsorption capacities of 147.1, 158.7, and 200.0 (mg . g−1) for Zn+2, Cd+2, and Pb+2 ions, respectively. Among the pseudo-first order, pseudo-second order, intraparticle diffusion and Elovich models, the kinetic data was well fitted with the pseudo-second order model. Thermodynamic parameters indicated a spontaneous and endothermic adsorption process. The bioadsorbent showed high selectivity for Pb(II) ions in the presence of other coexisting metal ions.

Zari Fallah, Hossein Nasr Isfahani, Mahmood Tajbakhsh

Study on Tensile Properties of Nanocomposites Based on PLA Reinforced by Nanoclay and Nanocalcium Carbonate

In this study, binary nanocomposites of poly lactic acid (PLA) containing 3 wt% of nanoclay (NC) and 7 wt% of nanocalcium carbonate (NCC), also hybrid nanocomposite of PLA/NC/NCC containing 3 wt% of NC and 7 wt% of NC were prepared via melt mixing using an internal mixer. The effect of each nanoparticle and also both of them on the mechanical properties of nanocomposites was investigated and compared with those of pure polymer. The results showed that the modulus and tensile strength of all nanocomposites were improved in comparison with those of pure polymer. The highest increase in tensile strength was 37% for hybrid sample (PLA-NC3-NCC7). Also it was found that the highest improvement in elongation at the break was 68% and the least reduction in impact resistance was 6% which both belonged to the binary PLA-NCC containing 7 wt% of NCC.

Zahra Asadi, Azizeh Javadi

Biodegradation and Thermal Properties of Biocomposites Based on Poly(Lactic Acid)/Thermoplasticized Rice Straw

Poly(lactic acid) as a biodegradable aliphatic polyester has some drawbacks that limit its marketability such as high cost and low biodegradation rate. In this work, these drawbacks were overcome by adding an abundant agricultural residue, rice straw, to PLA. Rice straw was thermoplasticized by using alkali pulping and benzylation processes. The benzylated rice straw pulp and pulping liquor considerably improve the biodegradation rate of PLA about 20 times faster after 128 days burying in soil. In addition, these lignocellulosic fillers can increase the PLA crystallinity degree, Vicat softening point and thermal stability comparing with untreated rice straw.

Asa’ad Zandi, Amirhossein Zanganeh, Shayan Hosseini, Farkhondeh Hemmati, Jamshid Mohammadi-Roshandeh

Vancomycin Loaded Silk/Pectin Hydrogel for Bone Tissue Engineering

Designing a biomaterial with efficient drug delivery has great importance in bone tissue engineering. In the present study, based on Schiff mechanism, a self-crosslinking hydrogel of oxidized pectin (OP) and silk fibroin (SF) was synthesized and vancomycin, a small charged molecule was loaded into hydrogel precursor by electrostatic interactions. The hydrogels with 1:1 and 3:1 ratio of SF and OP were screened with respects to swelling ratio, internal morphology and cell interactions. The hydrogels were well able to preserve cell viability and proliferation toward mesenchymal stem cells.

Akbar Karkhaneh, Fereshteh Ahadi, Sajedeh Khorshidi

Fabrication of Hybrid Suture Yarn Containing Chitosan/Poly(Vinyl Alcohole)-Poly(Lactic Acid) Micro and Nanofibers and Investigation of Their Mechanical Properties

The low diameter of nanofibers, high specific surface, flexibility, desirable mechanical properties, and the porous nature of nanofibers, make such nanostructures as a suitable choice for many medical applications. Suture yarn as a biodegradable material is one of the mechanical methods for closing and healing of wounds. Suitable suture should have some characteristics such as making the least tissue reaction, antibacterial properties, non-sensitivity, non-carcinogenicity, low price, comfortable handling, proper tensile strength and suitable binding ability. In this paper, hybrid nanofiberous yarns containing chitosan/poly(vinyl alcohole) (PVA/CS) with the blend ratio of (75:25) and poly(lactic acid) (PLA) were fabricated by electrospinning process. For this, CS/PVA and PLA solutions were injected from two different syringes. These two different syringes had positive charge, and the collector for assembling fibers had negative charge. In the composition of produced micro and nano fibrous yarn, both PLA and PVA/CS exist with the blend ratio of 75:25. Fabricated yarns were assessed for their morphological, surface, mechanical characteristics. However, the hydrophilicity nature of produced mat was analyzed by reporting contact angle measurements. The SEM images exhibited porous and smooth fibers with parallel arrangement. The mechanical strength of produced yarn was about 79.26 MPa. The presence of chitosan/PVA component in yarn composition changed the hydrophilic/hydrophobic balance. The results of this paper showed that these yarns are a good candidate for application as wound sutures.

Vida Saa’di, Marzieh Ranjbar Mohamadi, Meysam Moezzi, Reza Sghafi

Benzylated Products of Rice Straw as Effective Fillers for Starch Biocomposites

Rice straw is an abundant biomass that can be used as filler in biodegradable polymers like starch. In this study, different microfillers based on rice straw including untreated rice straw, alkali pulp of rice straw, benzylated rice straw and benzylated pulp and pulping liquor were incorporated in plasticized starch with glycerol. The findings show that the benzylated products of rice straw having stronger interaction with starch are more effective fillers than untreated rice straw in starch biocomposites.

Maryam Shoja, Farkhondeh Hemmati, Jamshid Mohammadi-Roshandeh

Extrusion Foaming of PLA-Based Nanocomposites: Effects of Different Nanofillers and Chemical Reagents on Foam Morphology

Poly(lactic acid) (PLA) foams have great potential for replacing synthetic polymer foams owing to their special properties such as biodegradability, biocompatibility and good mechanical performance. However, PLA has some drawbacks in common foaming processes to gain marketability. In this work, the PLA melt strength in extrusion foaming process was improved by adding different nanofillers, i.e. nanosilica, expanded graphite, pristine nanoclay and organoclay as well as chemicals including benzoyl peroxide and maleic anhydride grafted polyethylene. The morphological results and void content measurements show that the incorporation of the chemicals into PLA matrix comparatively causes better foam structural characteristics than nanofillers.

Mohammad-Hasan Khademi, Sirwan Ghavami, Farkhondeh Hemmati, Mohammad-Ali Aroon

Effect of Microorganisms on Rheological Behavior of Polymer Fluids

The presence of microparticles in polymeric fluids increases their viscosity. Here, we experimentally investigated the effect of the presence of the bacterium E. coli which has flagellates behind the cell body. We found that even a small amount of bacteria reduces viscosity in the polymeric solutions.

Behtab Montaser Kouhsari, Nadereh Golshan Ebrahimi

Fabrication of Antibacterial PVP/Keratin Hydrogel Embedded with Lavender Extract

In this research, chicken feathers as the source of keratin and polyvinyl pyrrolidone (PVP) as the synthetic polymer were used to produce composite hydrogel by UV irradiation. The results revealed that adding hydrogen peroxide accelerated the formation of crosslinking during the irradiation process. Swelling and mechanical analysis were performed on the produced samples with different formulations. To induce antibacterial properties to the hydrogel, herbal lavender extract was embedded in the hydrogels. The antimicrobial activity was finally assessed against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria and the incorporated hydrogels exhibited excellent antibacterial properties.

Faezeh Tajik, Niloofar Eslahi, Aboosaeed Rashidi

Soybean Oil Derived Non-isocyanate Polyurethane with In Situ Formed Nano-silver as Antimicrobial Wound Dressing

Reaction of a carbonated soybean oil (CSBO) with a multifunctional amine curing agent containing both primary and secondary amine groups led to the formation of a non-isocyanate polyurethane network (NPU) with free secondary amine groups chemically anchored to the polymer network. The resulting NPU shaped as free standing membrane was immersed into a solution containing silver salt. Silver nanoparticles (AgNPs) were simply prepared and loaded into dressing membrane through a redox reaction between silver ions and free amine groups. Evaluation of the physical, mechanical and biological properties for this nanocomposite showed its high utility for using as an antimicrobial wound dressing for low exuding wounds.

Hoshyar Gholami, Hamid Yeganeh

Diameter-Tuning of Electrospun Pectin-Based Nanofibers

There is an increasing interest to fabricate natural nanofibers with tunable structures using electrospinning. Pectin (PEC), an anionic hetero-polysaccharide present in plant cell-walls, is biodegradable and biocompatible so it can be used in biomedicine and food industry. In this study, various blends of pectin and polyethylene oxide (PEO) solutions were prepared. The viscosities of the samples containing Triton-X-100, as a nonionic surfactant, were measured prior to electrospinning. The electrospinning parameters, PEC: PEO ratio and molecular weight (Mw) of PEO were assessed using SEM, and ATIR-FTIR spectroscopy in order to improve the spinnability of pectin with appropriate morphological appearance and mechanical properties. SEM micrographs implied that higher Mw of PEO is a feasible way to apply higher ratio of PEC: PEO, leading to bead-free fiber formation. In addition, it was also found that higher ratio of PEC: PEO resulted in thinner nanofibers.

Shahrzad Zirak Hassan Kiadeh, Azadeh Ghaee, Addie Bahi, Mehdi Farokhi, Jhamak Nourmohammadi, Frank K. Ko

Synthesis of Chitosan/Zeolite/Silver Nanoparticles Composites: Antibacterial Activity Against Aquatic Bacteria

This study was conducted to develop novel chitosan nanocomposites and to investigate the antibacterial activity of chitosan/zeolite/silver nanoparticles composites for the aquaculture application. Novel chitosan/zeolite/silver nanoparticles composites were prepared via the method of solution blending. Streptococcus iniae bacteria was used to test antibacterial activity of the obtained chitosan/zeolite/silver nanoparticles composites by disc diffusion method. Finally, it was found that composites B, C, and D exhibited good antibacterial activity and composite C had the highest antibacterial activity. The above analysis suggested that these composites could be used as potential candidates for the aquaculture hatcheries systems.

Fatemeh Salar Hosseini, Navid Ramezanian, Zoheir Shokouh Saljoghi

Other Aspects of Polymer Science and Technology

Frontmatter

Effect of Nanoclay Concentration on the Curing and Mechanical Behavior of Chlorobutyl Rubber Nanocomposites

Chlorobutyl rubber (CIIR) as a special grade of rubbers is widely used in tire industries thus, the reduction in its consumption by decreasing the products thickness/weight along with improvements in mechanical properties of the composite has economic significance. In this work, samples containing different amounts of organoclay (OC, cloisite 30B) were prepared on a two-roll mill and characterized. The rhometry test of the samples, which was performed by an oscillating disk rhometer, showed slightly increase in scorch and cure times by addition of OC and increasing its amount, which this behavior was in contrast to what was reported for the other elastomers. Measuring mechanical properties of the samples indicated an increase in tensile strength and elongation at break in the presence of OC and increasing its amount up to 3 phr. This was attributed to the dispersion of the OC, the presence of OC modifier and increase in crosslink density.

Matin Khamseh-Kajoori, Azam Jalali-Arani

Effect of Hydroxyl Value of Acrylic Resin on the Anti-graffiti Properties of Acrylic-PU Nanocoating

In this study, the effect of hydroxyl value of acrylic resin on the anti-graffiti properties of a silica nanoparticles embedded polyurethane coating was evaluated. Hardness property of different coating samples was determined using pendulum hardness (Persoz). Hydrophobicity and graffiti resistances of the coatings were studied through water contact angle measurements and removability of permanent ink marker from the surface of the coatings, respectively. The results showed that using high hydroxyl value acrylic resin in combination with applying hydrophilic silica nanoparticles (0.7 wt%) and hydroxyl-functional silicone-containing surface additive (2.0 wt%) improves easy-cleaning and mechanical properties of resulted PU coatings. This can be related to the synergic effects of crosslinking reaction of hydroxyl acrylic resin with IPDI in presence of hydrophilic silica nanoparticles along with hydrophobic character of silicone-based additive on the surface of the coating.

Saba Nemati Mahand, Shahla Pazokifard, S. Mojtaba Mirabedini

Microstructure and Mechanical Properties of Nanocomposite Based on PA6/NBR/Graphene

Polyamide 6 (PA6)/nitrile butadiene rubber (NBR) thermoplastic elastomers (TPEs) reinforced with graphene oxide were compounded by a two-step melt mixing process via an internal mixer. The effect of graphene oxide on tensile and impact strength was investigated. Samples containing 30 wt% of NBR, 0.5, 1.25, and 2 wt% of graphene oxide were produced. Increasing the graphene oxide content from 0.5 wt% to 2 wt%, increased the tensile strength from 63.6 MPa to 69.3 MPa, whereas impact strength decreased from 78.1 MPa to 75.3 MPa when graphene oxide content increased. The morphology study of prepared nanocomposites with scanning electron microscopy (SEM) shows that the size of NBR droplets in TPE nanocomposites reduces by adding of graphene oxide into the PA6 phase.

Mohammad Reza Nakhaei, Ghasem Naderi, Mir Hamid Reza Ghoreishy

Numerical Simulation of Mixing Polymeric Fluids in Rotating Cylinder Rheometer

In this study, mixing of non-Newtonian polymeric fluids was simulated three dimensionally using a power-law rheological model in a rotational rheometer with coaxial cylinders. The simulation was performed by obtaining 3D components of velocity for each grid point using finite volume method and tracking the grid points in specified time intervals. To generalize the method to immiscible polymers, a modification was done by introducing interfacial tension and viscosity ratios of two fluids in solving velocity equations. The developed simulation method can be used to simulate the mixing of immiscible polymers.

Ebrahim Khalaj, Mohammad Hossein N. Famili, Faezeh Ghodratpour

Numerical Simulation of Mixing Polymeric Fluids in Twin Screw Extruder

In this study, mixing of non-Newtonian polymeric fluids was simulated three dimensionally using a power-law rheological model in a twin screw extruder. The simulation was performed by obtaining 3D components of velocity for each grid point using finite volume method and tracking the grid points in specified time intervals. To generalize the method to immiscible polymers, a modification was done by introducing interfacial tension and viscosity ratios of two fluids in solving velocity equations. The developed simulation method can be used to simulate the mixing of immiscible polymers.

Ebrahim Khalaj, Mohammad Hossein N. Famili, Faezeh Ghodratpour

3D Simulation of Velocity Field for Polymeric Fluids in Twin Screw Extruder by Finite Volume Method (FVM)

In this research, the velocity field of polymeric fluids is simulated in twin screw extruder by finite volume method (FVM). The simulation was three dimensional and the discretization performed using central difference method. For optimizing of the simulation, an Under Relaxation Factor (URF) parameter was considered. It was found that by using URF equal to 0.3, simulation had more rapid convergence. Considering a lower power law index (n) also had a similar effect.

Ebrahim Khalaj, Mohammad Hossein N. Famili, Faezeh Ghodratpour

Study on Rheology, Morphology and Mechanical Properties of PLA/Nanoclay Nanocomposites

In this research, nanocomposites of polylactic acid (PLA)/nanoclay (NC) containing 1–3 wt% of Cloisite 30B were prepared via melt mixing. The mechanical properties, rheology and morphology of resulted nanocomposites were studied. It was observed that the addition of nanoclays led to increase in modulus and tensile strength and decrease in the impact resistance of the neat PLA. The maximum increase in tensile strength was 33% corresponded to sample containing 3 wt% of Cloisite 30B. X-ray diffraction results showed an increase in the interlayer spacing of Cloisite 30B, which indicates the intercalation of this nanoparticle in the PLA matrix. Rheological assessments on nanocomposites containing Cloisite 30B displayed that the elastic modulus, loss modulus and complex viscosity of poly lactic acid were increased by increasing the amount of nanoclay and this increase is much higher at lower frequencies.

Fatemeh Mohammadzadeh, Romina Esmailzadeh, Azizeh Javadi

Investigation on the Effects of Nanoclay and Nano Calcium Carbonate on Properties of Binary and Hybrid Nanocomposites Based on PLA

Polylactic acid (PLA)/nanoclay, PLA/nano calcium carbonate (NCC) and PLA/nanoclay/NCC binary and hybrid nanocomposites were prepared via melt mixing containing 1, 2, and 3 wt% nanoclay and 5, 7 wt% NCC. It was observed via X-ray diffraction that nanoclay interlayer distance was enhanced from 1.8 nm to 3.26 nm indicating intercalation in binary samples. Interlayer distance was increased more in presence of NCC comparing to binary PLA/nanoclay samples. Rheological studies showed an increase in the storage modulus of samples at low frequencies comparing to neat polymer. Modulus was less increased in NCC containing binary and hybrid samples at higher amounts of NCC. An improvement in complex viscosity of all samples was observed and the highest increase was witnessed for hybrid sample containing 5 wt% NCC. According to Differential Scanning Calorimetry results, crystalline temperature of hybrid sample containing 7 wt% NCC was about 8 °C higher than that of neat sample.

Kosar Alavi, Zahra Asadi, Fatemeh Mohammadzadeh, Azizeh Javadi

Qualitative Characterization of Branches in Various Polyethylene Species via Fourier Transform Spectroscopy

In this paper the microstructure of different polyethylenes was characterized via FTIR spectroscopy. Two commercial low density polyethylenes (PE) (L1 and L2) and one commercial high density polyethylene were characterized. For comparison, one branched metallocene-PE and one linear metallocene-PE were also used. Test specimens were prepared in the form of film through hot compression molding of the polymers. Based on the FTIR spectra the exact position of the methyl deformation band for L1 and L2, was located at 1379.1 cm−1, which has a position between the ethyl branch (1379.1 cm−1) and the butyl (1377.8 cm−1) and for mLCB-PE, the absorbance band is at 1377.5, which indicates that most of its branches are of the hexyl type. Absorbance bands in the 790–700 cm−1 region correspond to the branches of ethyl, butyl and hexyl or longer groups, indicating the presence of ethyl branches in LDPE samples, butyl but not any ethyl branch in mLCB-PE, and no ethyl and butyl branches in the HDPE. According to the absorption bands of 888 and 910 cm−1 unsaturated species in the microstructure of polyethylene samples, mainly vinylidene and vinyl end groups, were investigated.

Mohsen Mohammadi, Alireza Azizi

Investigation of Thermal Stability of Polyethylene/Silica Aerogel Compounds

To investigate the effects of adding silica aerogel (SA) nanoparticles to low density polyethylene (LDPE) on the thermal stability and thermal degradation of their compounds, SA/LDPE composites were prepared. Silica aerogel and low density polyethylene were mixed via melt mixing method using an internal mixer and then compression molded to sheets. The composites had different weight percent of silica aerogel. Thermal stability and thermal degradation of these composites were examined using thermal gravimetric analysis. It was observed that increasing the silica aerogel content, shifted Tmax to higher temperature that shows increase of thermal stability.

Mohammad Amin Abbas-Zadeh, Amir Hesam Arab Sorkhi, Mohsen Mohammadi

Novel Polysulfone and Related Sepiolite Nanocomposites for Water Desalination

In this study new types of polysulfone, related sulfonated polysulfones, and also nanocomposites were prepared and investigated for desalination application. For this purpose, a novel monomeric diol was prepared and identified. Through its reactions with bis(4-fluorophenyl)sulfone monomer, the related polysulfones were prepared and characterized. In the second step by the aim of improving the hydrophilic nature of the polymer, the sulfonated groups were introduced into the polysulfone structure by direct sulfonation of dihalide, and in this way copolymers with 20–50 wt% sulfonation content were prepared. Another strategy for improving the hydrophilicity of the polysulfones was applied via the addition of hydrophilic nanoparticles to the polymeric matrix. In this part, by addition of 1, 3, 5, 7, and 10 wt% of sepiolite nanoparticles to the polymeric matrix, the related nanocomposites were prepared. Finally, membranes with 30 wt% of the samples were produced by phase inversion method and the operation tests of the prepared membranes were done and compared.

Samaneh Khodami, Samal Babanzadeh, Shahram Mehdipour-Ataei

Synthesis and Characterization of Novel Poly(Arylene Ether Sulfone) for Desalination Application

Poly(arylene ether sulfone)s are known as high performance thermoplastic polymers which are broadly used in membrane technology. In this study, a novel poly(arylene ether sulfone) was synthesized through condensation polymerization of 4,4’-thiodiphenol and dichlorodiphenyl sulfone. 1H-NMR and IR spectroscopies were used to determine the chemical structure of polymer. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), gel permeation chromatography (GPC), and scanning electron microscopy (SEM) were employed to characterize thermal properties, molecular weight, and morphologies of the polymer. The static contact angle measurement was demonstrated hydrophilicity of the polymer. Polymer films and related membranes were prepared by means of phase inversion method. The obtained results confirmed that these membranes had potential applications for water desalination process.

Rahil Nahvi, Shahram Mehdipour-Ataei, Samal Babanzadeh

Low Compression Set VMQ/XNBR Rubber Blends with Improved Aging Properties

The supply of consumable parts has always been a limiting factor for diverse industries. Sealings are considered as vital consumable parts in industry. Vinyl Methyl Siloxane (VMQ) is mainly used in the sealing industry, which needs improved mechanical and aging properties. Furthermore, compression set is a crucial property needed in this industry. In this research, the effect of blending VMQ with XNBR was studied to improve mechanical and aging properties especially compression set of VMQ. VMQ blends containing 0 phr to 20 phr Carboxylated Acrylonitrile Butadiene Rubber (XNBR) were prepared. Optimum cure conditions were obtained by a moving die rheometer. Samples were produced by compression molding. The results of tensile and hardness tests on the initial samples; showed a peak. Blend containing 10 phr of XNBR has showed a great improvement in compression set. Moreover, blending improved mechanical properties after aging than the non-blended sample. Thus, ultimately increases service life.

Mustafa Azizi, Ghodratollah Hashemi Motlagh

Morphology, Rheology and Impact Resistance of PS/EOC/SEBS Ternary Blends

Immiscible polystyrene (PS)/ethylene-octene copolymer (EOC) blends with different amounts of styrene-ethylene–butylene-styrene copolymer (SEBS) as compatibilizer were prepared by melt mixing method and the morphology, rheology and impact resistance of the blend samples were investigated. The scanning electron microscopy (SEM) micrographs revealed that incorporation of SEBS into PS/EOC blend leads to change the shape of EOC dispersed phase from droplet to fibrillar. From the melt linear viscoelastic rheological studies, the interaction between SEBS and each of PS matrix and EOC dispersed phases in the ternary blends was confirmed. Moreover, the micelle formation of the compatibilizer in PS matrix phase of the ternary blends with relatively high amounts of SEBS was founded by the rheological analysis. The impact resistance of PS/EOC blend enhanced with increasing the SEBS quantity.

Hasti Pourmadadkar, Mehdi Entezam, Hossein Ali Khonakdar, Seyed Hassan Jafari

Acidic Dye Removal by Chitosan Treated Membrane Containing Spacer Fabric/Nylon6 Nanofibers/TiO2 Nanoparticles

The major aim of this paper was to assess the capability of polymeric nanofibers membranes containing nylon 6/titanium which were electrospun onto both sides of the spacer fabric and then was treated with chitosan for removing acidic dyes from textile waste water. The prepared compositions were characterized by SEM analysis. Chitosan treated nylon/TiO2/spacer (CNTS) compositions showed the highest amount of discoloration for acidic dyes at pH = 6. The results of this study exhibited CNTS structures could be used as a great absorbent in removing azoic dyes of wastewater.

Ehsan Yousefi, Marziyeh Ranjbar Mohammadi, Mohammad Nouri Taba

Preparation of Fe3O4/Polymethyl Methacrylate Composite Particles from Monolayer Oleic Acid-Modified Fe3O4

Mono disperse magnetic nanocomposite particles with high saturation magnetization have wide applications in biomedical fields. In this article, we have studied the structure of Fe3O4 nanoparticles with polymethyl methacrylate shell. First of all Fe3O4 nanoparticles were synthesized by co-precipitation method and then they were modified by oleic acid in order to put the poly methyl methacrylate layer via mini emulsion method. The surface properties of OA modified magnetite nanoparticles have great effects on preparation of composite particles. The monolayer OA modified Fe3O4 nanoparticles are more hydrophobic than the multilayer coated ones and by multilayer OA coated Fe3O4, there was a large amount of free poly methyl methacrylates in the solution of product. After coating, the monolayer nanocomposite particles formed monodisperse nanoparticles as it was demonstrated by DLS tests. The PMMA/Fe3O4 nanoparticles have spherical core shell structure with a proper size distribution. The VSM tests have showed that the Fe3O4/PMMA nanoparticles have high magnetic power. High saturation magnetization demonstrates the super paramagnetic property.

Roxana Moarref, Saeed Pourmahdian

A Silicone-Based Macro-Initiator for RAFT Polymerization

Reversible addition-fragmentation chain transfer (RAFT) polymerization is an efficient technique for synthesis of polymers with well-defined architecture. Here, a macro-initiator based on dihydroxy-terminated polydimethylsiloxane (PDMS) and 4-Cyano-4-(phenylcar-bonothioylthio) pentanoic acid as a chain transfer agent (PDMS-macro CTA) were prepared via esterification reaction promoted in the presence of dicyclohexylcarbodiimide (DCC) coupling agent and 4-(dimethylamino) pyridine (DMAP) as a catalyst. PDMS-macro CTA was purified and characterized by FTIR spectroscopy. According to the FTIR findings, absence of hydroxyl functional groups, a broad peak in the region of 3340 cm−1 and appearance of carbonyl ester groups at 1743 cm−1 supported the performance of the esterification reaction.

Saeed Hanifi, Farhid Farahmand, Mohammad Imani

Synthesis of Silicone-Based Amphiphilic Copolymer via RAFT Polymerization

Reversible addition-fragmentation chain transfer (RAFT) polymerization has been used to prepare amphiphilic silicone-based copolymer via copolymerization of 2-hydroxyethyl methacrylate (HEMA) at the end of activated polydimethylsiloxane (PDMS). PHEMA-b-PDMS-b-PHEMA copolymer synthesized using direct polymerization of PDMS-macro CTA (macro chain transfer agent) and HEMA monomer in the presence of AIBN as an initiator. After completion of reaction, the prepared copolymer was successfully purified. The chemical structure characterization was assessed by FTIR spectroscopy. According to the FTIR results, the appearance of new broad peak in the region of 3200–3700 cm−1 was attributed to the hydroxyl groups. Also presence of high-intensity sharp peak at 1743 cm−1 related to the carbonyl functionalities and PDMS finger print peaks in the product spectrum, showed that copolymerization reaction was successfully performed.

Saeed Hanifi, Farhid Farahmand, Mohammad Imani

Toughening Mechanism of Polyetheramine-Modified Epoxy Resins

In this research polyetheramine (PEA)-modified epoxy was prepared and the toughening mechanism of the modified networks was studied. According to the mechanical test results, incorporation of PEA into epoxy networks can significantly toughen the epoxy matrix. The addition of 15 phr PEA increased the critical stress intensity factor (KIC) and critical strain energy release rate (GIC) of the epoxy from 0.85 MPa.m1/2 to 1.86 MPa.m1/2 and from 0.38 kJ.m−2 to 2.27 kJ.m−2, respectively. The toughening and failure mechanisms were discussed based on microscopy of the crack tips. As a result, shear yielding as a possible toughening mechanism was proposed based on microscopical investigations. These in-depth studies could uncover underlying structure-property relationships in a relevant class of PEA-like modifiers, shedding light on the future design of top-performing homogeneous tough polymer networks.

Hossein Abdollahi, Ali Samadi, Somayyeh Hosseini Rad

Investigation of Encapsulation of 1-Methylimidazole Latent Curing Agent Using Solid Epoxy Resin

Encapsulation of 1-methylimidazole (1-MI) was investigated to prepare the latent 1-MI curing agent by using solid epoxy resin as the wall materials. The morphology of 1-MI/solid epoxy microcapsules was investigated by SEM. The thermal behavior of the prepared microcapsule was investigated using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). According to the TGA and DSC results, the weight loss of 1-MI/solid epoxy microcapsules although not showing the actual value of the encapsulated 1-MI, but it can be thought-out as the weight of 1-MI that participates in the reaction with the matrix liquid epoxy resin.

Sayed Morteza Mozaffari, Mohammad Hosain Beheshty, Sayed Mojtaba Mirabedini

Using the Rheo-Dielectric Method in Analyzing the Effect of System Dynamics on the Dispersion State of CB/PS Nanocomposites

Simultaneous dielectric and dynamically mechanical investigations have a tremendous number of impressive accomplishments on microscopic properties of polymeric systems containing dipoles, specially nanocomposites. So far, a huge amount of research has been carried out to analysis such properties of nanocomposites by using dielectric and rheo-dielectric method. In this research we traced the percolation threshold and the changes in dielectric properties of nanocomposites of CB/PS through rheo-dielectric tests. We observed the remarkable differences of dielectric properties and also percolation threshold between before and after of imposing the oscillatory shears on CB/PS nanocomposites with three different volume fractions of nanoparticles.

Mona Janipour, Mohammad Hossein Navid Famili

Analyzing and Comparing the Effect of System Dynamics on Agglomerations of CB/PS and TiO2/PS Nanocomposites Through Rheological Dielectric Method

Various particles containing dipoles have different dielectric properties which would be applicable in varied industries like electronics, aerospace, food and etc. Carrying out dielectric and rheological experiments called “Rheo-dielectric” would result in dramatic achievement in macro and micro structures of polymeric composites. In this study we used TiO2 (as a ceramic material) and CB (as a conductive material) nanoparticles in PS (which is neutral) as a matrix to investigate the dispersion and agglomeration of each kind of nanocomposite and then compare them together. The dielectric experiments have been done at the frequency of 100 Hz and a sweep of shear strain has been imposed to the nanocomposites at the constant shear rate of 1 rad/s. We observed the breaking down of agglomerations, resulting in changes in dielectric data which were different in each nanocomposite.

Mona Janipour, Mohammad Hossein Navid Famili

Improving Polypropylene Sediment Filter by Nano Surface Coating to Reduce Biomass Infection

Polypropylene sediment filter which is made from multi-layers of tissues with fine pore of polypropylene yarn and high filtering efficiency that can remove dirt, rust, dust, silt, algae and the other, could not prevent bacterial growth and remove harmful bacteria and microorganisms unless being coated by nano silver coating. So, physical vapor deposition, as a special technique to coat a thin layer of nano silver with an average of arbitrary thickness on the filter surface, was used. It improved the polypropylene sediment filter application with 40 nm thickness of silver coating in specific temperature (up to ten degree more than 25 ℃), evaporation rate (0.1 nm/s) and vacuum condition (3 × 10−5 Torr). As a result, both the filter pore size reduction and anti-microbial nano silver thin layer caused harmful bacteria and biomass affection to decline.

Farzaneh Ghorab, Zarrin Es’haghi

Microwave Curing of Epoxy Resin by Embedding Core-Shell Structure Particles

Magnetite particles with a polymeric shell were synthesized and used for heat generation and curing of an epoxy resin. The synthesized particles were characterized using several analysis methods. Samples containing particles, epoxy resin, and curing agent were cured by microwave and thermal oven and were then investigated. DSC measurements showed an increase in degree of conversion and Tg by increasing the microwave irradiation time. Using high contents of particles led to improved mechanical properties. The identified chemical groups of cured samples through FTIR analysis approved the occurrence of curing reactions.

Sara Akbarpour Esfahlani, Jalil Morshedian, Habibollah Baharvand

Enhancing In-plane Mechanical Properties of Carbon/Epoxy Composite Using Poly(methyl methacrylate) Nanofibers

In this study, poly(methyl methacrylate) (PMMA) nanofibers were employed to enhance the in-plane mechanical properties of a conventional carbon/epoxy composite. The optimized PMMA nanofibers were straightly deposited on the conventional carbon fiber fabric surfaces via the electrospinning process. Vacuum assist resin transfer molding (VARTM) was used for the preparation of the carbon/epoxy composite. Evaluation of in-plane mechanical properties of the composites revealed that incorporation of PMMA nanofibers between carbon layers led to 14% and 8% improvement in tensile strength and tensile strain at break, respectively in comparison with the results obtained for the control composite. T-test analysis was also carried out and confirmed that incorporation of PMMA nanofibers significantly increased the in-plane mechanical properties of the composite. Finally, fractographical analysis of the composites cross-sections, investigated by field emission scanning electron microscope (FE-SEM), revealed that incorporating PMMA nanofibers in the hybrid composite led to a tougher fracture in resin rich-area.

Rasoul Esmaeely Neisiany, Saied Nouri Khorasani, Jeremy Kong Yoong Lee, Alireza Safdari, Seeram Ramakrishna

Preparation and Characterization of Novel Polyureas Containing Amide Units with High Thermal Stability

A novel diamine with built-in ether and amide structure was prepared via two-step reactions. Nucleophilic reaction of 4,4′-oxydianiline with 6-chloronicotinoyl chloride led to preparation of N,N′-(oxybis(1,4-phenylene))bis(6-chloronicotinamide) (OPCN). OPCN was reacted with 4-aminophenol to provide a novel diamine (EADA). After complete characterization, the prepared diamine (EADA) was used to prepare related polyureas by reaction with different diisocyanates. The obtained poly(ether-amide- urea)s were characterized and their properties were studied. Improved thermal stability was observed for the prepared polyureas in comparison to the common ones. This modification extends application of these polyureas in various industrial purposes.

Fatemeh Sadat Siadatian-Haghighi, Shahram Mehdipour-Ataei

Synthesis and Properties of Novel Pyridine-Based Polyamides with Improved Solubility

A novel aromatic diamine containing pyridine unit was prepared via two-step reactions. Nucleophilic substitution of oxydianiline with 6-chloronicotinoyl chloride led to preparation of a dichloro-diamide compound. Subsequent reaction of this compound with 3-aminophenol resulted in synthesis of a particular diamine. After complete characterization, polycondensation reaction of the diamine with terephthaloyl chloride and isophthaloyl chloride led to preparation of related polyamides. The polymers were characterized and their physical and thermal properties were studied.

Milad Lotfnejad-Moghimi, Amir Ahmad Latifi, Shahram Mehdipour-Ataei

Nicotinic-Based Poly(ether-amide-imide)s: Preparation and Properties

A novel aromatic diamine containing pyridine units, amide, and ether groups was generated via two-step reactions: nucleophilic substitution reaction of oxydianiline with 6-chloronicotinoyl chloride led to preparation of a dichloro compound. Subsequent reaction of this compound with 4-aminophenol resulted in synthesis of the particular diamine. After characterization, polycondensation reaction of the diamine with different dianhydrides led to preparation of related poly(ether-amide-imide)s. The nicotinic-based poly(ether-amide-imide)s showed high heat resistance and improved solubility in polar solvents.

Sattar Gholamrezaei Boshehri Nejad, Mehrdad Hasani, Shahram Mehdipour-Ataei

Synthesis and Characterization of Core/Shell Titanium Dioxide Nanoparticle/Polyacrylamide Nanocomposite

Core/shell titanium dioxide (TiO2) nanoparticle/poly(Acrylamide-2-Acrylamido-2-methylpropane sulfonic acid) [P(AM-AMPS)] nanocomposite was successfully synthesized via in situ emulsion polymerization. TiO2 nanoparticles were firstly modified by silane coupling agent, 3-(Triethoxysilyl) propyl Methacrylate (MPS), to increase the dispersibility of TiO2 nanoparticles into the polyacrylamide matrix. The core/shell TiO2/polyacrylamide nanocomposite was then synthesized by in situ emulsion polymerization. The MPS-modified TiO2 nanoparticles and the synthesized core/shell nanocomposite were characterized by Fourier transform infrared spectra (FTIR) and X-Ray Diffraction (XRD). The results showed that MPS coupling molecules was chemically bonded on the TiO2 nanoparticles surface. According to XRD patterns the copolymer composite was formed.

Erfan Rezvani Ghomi, Saied Nouri Khorasani, Mohammad Dinari, Shahla Ataei, Rasoul Esmaeely Neisiany

Electrochemical Conversion of Heavy Residues to Bitumen and Other Light Products by Silver (II) Mediator

Ag (II) ions generated by Mediated Electrochemical Oxidation (MEO) was employed to convert a heavy residue feed (mazut) to a porous solid polymer and some other valuable products. At atmospheric pressure, conversion of the heavy residue was carried out at 50–60 °C for 2 h. The obtained liquid and solid products were then separated and analyzed by FTIR and simulated distillation (Sim-Dist) analysis. FTIR results specified that the reactions between Ag (II) and heavy residue resulted in a decrease in methylene groups and an increase in aromatics, branched aliphatic hydrocarbons and carbonyl groups. Also, Sim-Dist results proved that during this process the heavy hydrocarbons of the feed were cracked and changed into lighter hydrocarbons and bitumen; however a liquid product was formed which comprises gasoline, kerosene and atmospheric gasoil.

Shahrnaz Mokhtari, Fereidoun Mohammadi, Zahra Panahi

Synthesis of Polycarboxylate Superplasticizer: Influence of Temperature of Polymerization

In this study, Polycarboxylate (PC) superplasticizers based on acrylic acid (AA) were synthesized via free-radical copolymerization with an ethylene glycol monomer and characterized. The temperature of polymerization (ranging from 50 °C to 70 °C) appeared to be the key operating factor governing the chemical structure of the superplasticizers. The chemical structures of the products were analyzed by gel permeation chromatography, Fourier transform infrared spectroscopy and nuclear magnetic resonance. The results showed that the PCs synthesized at different polymerization temperature have similar functional groups but the temperature has affected on the molecular weight (MWs) and MW distribution. By increasing of temperature of polymerization the MW of PC has increased.

Maryam Mohammadi, Alireza Redaei, Mohammad Ali Karimizarchi, Mohammad Ali Mohammad Mirzaei

Effect of Silane Curing Conditions on Properties of the Metallocene-Based Polyethylene-Octene Copolymers Compound

A compound was prepared from crosslinking of blend from two type of metallocene-based polyethylene-octene copolymers by different octene content through a two-step silane grafting method (Sioplas process) in a twin-screw extruder. The silane grafted compound was used as wire and cable coatings. The curing condition and specimen preparation method (injection molding and/or extrusion) were factors influenced the hot-set test results at 200 °C. The results of tensile and elongation studies showed a maximum value of 9 MPa for tensile strength and 397% for elongation-at-break after 6 h curing.

Mehri Dana, Gholam Hossein Zohuri, Saeid Asadi

The Relationship Between Adhesion and Electrochemical Parameters of Epoxy Resin on Mild Steel

Electrochemical impedance spectroscopy (EIS) has been employed in the investigation of the corrosion characteristics of epoxy polymeric film both coated and attached as a free film without adhesion on mild steel panels during immersion in 3.5 wt% NaCl solution. Meanwhile gravimetric liquid sorption experiments were used to evaluate water uptake inside the coating. The results of impedance spectroscopy indicate that epoxy resin shows greater anticorrosion protection characteristics when applied on mild steel than attached as a free film. Attached Free films present higher value of water uptake compared with coated samples. Adhesion seems to play a major role in the protection of the metals. The first step of electrolyte penetration through the coating is related to water uptake and after that a different process occurs, that could be either the penetration of the water in the bulk of the polymer, or the slow diffusion of ions.

Amir Hossein Jalali Kandeloos, Mohammad Reza Mohammadzade Attar

Dielectric Properties of Polydimethylsiloxane (PDMS) Composites Containing Hybrid Silica-Decorated Reduced-Graphene Oxide (SiO2@rGO)

The aim of this study is to investigate the effect of a new hybrid graphene-based filler, namely silica-decorated reduced-graphene oxide (SiO2@rGO) nano-plates on dielectric characteristics (dielectric constant, dielectric loss, and dielectric breakdown strength) of PDMS composites. The SiO2@rGO hybrid was synthesized using tetraethylorthosilicate (TEOS) and chemical reduction by hydrazine solution. Dielectric results revealed that by replacing rGO with SiO2@rGO in PDMS composites, a significant improvement in dielectric performance of the final composites was achieved. Such improvement was explained and quantified by “dielectric efficiency” concept which will introduce in this study. In comparison of rGO/PDMS with SiO2@rGO/PDMS composites, later ones have higher dielectric efficiency and greater dielectric breakdown strength. This achievement provides a simple and efficient approach in relation to high performance dielectric smart polymer composites, especially in electric energy storage devices and dielectric elastomer actuators applications.

Mohsen Sadroddini, Mehdi Razzaghi-Kashani

Effect of Ethylene Monomer Pressure on BCE Ziegler-Nata Catalyst Fragmentation in the Early Stage of Polymerization

In order to investigate ethylene monomer pressure on fragmentation and in the morphology of the BCE Ziegler-Nata catalyst particles (TiCl4/MgCl2) in the early stages of polymerization reaction, polymerization was carried out at a 3.0 bar to 4.5 bar of the ethylene monomer pressure. Scanning electron microscope (SEM) has been used to investigate the effect of ethylene monomer pressure on morphology of the catalyst particles. SEM images show that with increasing pressure size of pores and cracks of the catalyst increases. Meanwhile activity of the catalyst was linearly increased from 16.0 to 18.6 (gPE.mmolTi−1.h−1) with increasing of the monomer pressure.

Mohammad Mansouri, Gholam Hossein Zohuri, Navid Ramezanian

Evaluation of Mechanical Properties of Polylactic Acid/Nanoclay Nanofibers Using Taguchi Method

In this study, nanofibers based on polylactic acid (PLA)/nanoclay were produced using electrospinning method. The mechanical properties of the nanofibers were studied by ANOVA method. The effects of formulation parameters as nanoclay contents 0 wt% to 6 wt%, and processing parameters such as spinning voltage, solution concentration and feeding rate on modulus and strength of PLA/nanoclay nanofibers were studied.

M. Aloushi, Marziyeh Ranjbar-Mohammadi, Ali Vahidifar, Elnaz Esmizadeh, Golshan Hajizadeh

Creating Gas Lenses Using Polymer in a Minimum Pressure Range of 0.01 to 0.1 Bar

Given the increasing importance of lenses, this study has focused on designing and introducing gas lenses by putting forward the question “Is it possible to compress gas using pressure at the ambient temperature so that it forms a gas-like lens with a defined focal length?” Poly methyl Methacrylate (PMMA) and carbon dioxide were used to create the lenses. In this study, the model was simulated using ANSYS (Ver.11). This work has been done for the first time in the world. Due to the specifications of the polymer and the gas used, the focal length of the lenses was calculated at various pressures of 0.01 bar to 0.1 bar.

Soheila Shojaei, Mohammad Bohloul, Zhila Shah Ali

Effect of Polymers on the Damping Capacity of Automotive Bitumen Anti-vibration Insulators

Sound and vibration damping in automobile industry cause manufacturers to use insulators in automobile parts. High performance polymers are the best choice for noise reduction application. The addition of commercial polymers to bitumen base insulators of Ayegh Khodro Toos (AKT) Co. improved their performance. Effect of polymers such as styrene-butadiene-styrene (SBS), styrene butadiene rubber (SBR) and butyl rubber with different weight percentages (2, 4, 6, and 8 w%) was studied in laboratory scale (3.5 kg product). Butyl rubber showed the highest vibration absorption (about 27%) among the polymers studied. Generally, the higher the concentration of the polymer used, the lower tensile strength, elongation at break and also the higher of damping was obtained.

Haniyeh Miranmousavi, Gholamhossien Zohuri, Mohammad Nourmohammadi

Effect of Nanoclay on the Morphological Properties of Ternary PA6/POE-g-MAH/LDPE Blend

In recent years, polymer blends have gained more attention because of their applications and extra ordinary properties. Blending in polymers has been divided in two groups: miscible and immiscible blends. Immiscible blends are usually used to improve the properties of blends because of taking advantage of diverse polymers with different characters. It is more probably to achieve specific goals. In this type of polymers, it is necessary to use compatibilizers. Nowadays, nanoparticles play a crucial role as compatibilizer in immiscible polymers because they are able to improve the properties of blends. In this case, nano particles should be located in interface. The effect of nanoclay Cloisite15A on the ternary blend PA6/POE-g-MA/LDPE was investigated. The XRD results demonstrated that nano particles were exfoliated completely. The SEM results showed that average diameters of particles firstly decreased and after reaching of the minimum of average diameters, improved with increasing nano particles.

Tahere Keramati, Shervin Ahmadi, Ali Salimi

Optical Properties of PMMA Nanofibers with Different Fiber Diameters

Electrospinning is an effective method for fabrication of nanofibers. Polymethyl methacrylate (PMMA) was electrospun to prepare nanofiber. For investigation of effect of diameter on the optical properties of fibers, fibers were electrospun with different diameters by changing in polymer concentration, needle inner diameter, and flow rate. Fibers with the same morphology were selected. It was observed that in the studied range of diameter by increasing fiber diameter, the reflectance of fibers increased.

Fatemeh Ahmadkhani Khari, Saeideh Gorji Kandi, Maryam Yousefzadeh, Farhad Panahi

Effect of Compatibilizers on Polyamide 6 and Styrene-Butadiene Rubber Blend: Graphene Oxide and Glycidyl Methacrylate

In this study, two types of compatibilizer were used for improving the mechanical and morphological properties of polyamide 6 (PA6)/Styrene-butadiene rubber (SBR). Glycidyl methacrylate (GMA) was grafted onto SBR chain through a free radical polymerization for improving its miscibility with PA6 because epoxy groups of the GMA can be cured by the amine groups of PA6 chains, so that these two polymers can be strongly connected by covalent bonds. As GMA has less activity toward SBR, styrene was used as a co-monomer according to the fact that styryl macroradicals have better activity toward GMA than SBR chain. 0.25, 0.5, and 1% of graphene oxide (GO) were used as another compatibilizer for reaching higher mechanical properties because of its amphiphilic properties. The toughness of polymer was investigated by tensile test and increased by 83.04% in 0.5% GO. The degree of grafting was measured by titration and Fourier-Transform Infrared Spectroscopy (FTIR).

Ramin Mirzaee, Ahmad Aref Azar

Investigation of Tensile Strength and Impact Strength of Nanocomposites Based on PP/NBR/HNT

The object of this paper is to study the effect of different levels of halloysite nanotubes (HNTs) loading on tensile strength and impact strength of PP/NBR/HNT nanocomposite in presence of PP-g-MA as compatibilizer. Samples containing 20 wt% of NBR, 1, 3, and 5 wt% of HNTs and 10 wt% of PP-g-MA were produced using counter-rotating twin-screw extruder. HNTs enhanced both of the mechanical properties. At all levels of loading, tensile strength plot showed an ascending trend, however in case of impact strength, the optimum level of HNTs was achieved at 3 wt%. Scanning electron microscopy was utilized to figure out the effect of HNTs loading on the way the elastomer phase dispersed into the continuous phase or the matrix.

Amir Bakhtiari, Faramarz Ashenai Ghasemi, Ghasem Naderi, Mohammad Reza Nakhaei

Synthesis and Characterization of Fe3O4 Magnetite Nanoparticles Coated by Polyvinylpyrrolidone

The purpose of this study was to synthesize polyvinylpyrrolidone (PVP) coated with iron oxide nanoparticles (Fe3O4@PVP NPs) and to evaluate the effect of PVP content on its properties. The Fe3O4@PVP nanoparticles were synthesized by co-precipitation method and characterized by field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectra (FT-IR) and vibrating sample magnetometer (VSM). Results indicated successful synthesis of coated nanospheres with supermagnetic properties. The core size of the nanoparticles was about 17 nm and the overall size was around 40 nm. The magnetization of NPs was also changed with PVP content and the highest saturation magnetization was observed for Fe3O4@PVP 0.32.

Alireza Heiran, Shadi Hassanajili, Mehdi Escrochi

Cathodic Disbondment of Unpigmented Epoxy Coatings: Effect of Thickness, pH, and Curing Conditions

Due to increasing usage of metals, it is very important to protect them against corrosion and increase the service life of the components. This paper examines the cathodic disbondment of unpigmented epoxy resin. Disbondment of coating occurs when coatings in a cathodic protection system interact either chemically or physically, ultimately causing corrosion beneath the coating. In this paper, the cathodic disbondment of epoxy resin applied on steel sheets, which starts from around a fixed-diameter cavity, is studied through a sacrificial magnesium anode and an electrolyte with 3% salt in a fixed amount of time. Thickness, pH, and curing condition are considered as variable parameters. During the experiment, it was observed that the cathodic disbonding rate of this resin will be increased with a decrease in the pH of the electrolyte, thickness reduction, and also incomplete curing of epoxy resin. Due to importance of corrosion control in the industry, especially pipelines, in this paper, we examined the factors affecting cathodic disbondment.

Shirin Ardeshirian Sharifabadi, Bahar Hassanpour, Mohammadreza Mohammadzadeh Attar

Effect of Ultrasound Stimulation on the Chondrogenic Activity of MSCs on a Hybrid Hydrogel Scaffold

The objective of this study was to determine the effects of low-intensity pulsed ultrasound (LIPUS) on chondrogenic activity and gene expression of mesenchymal stem cells (MSCs) seeded on alginate oxide (AD) -carboxymethyl chitosan (CMC) – polyethylene glycol (PEG) hydrogel for cartilage tissue engineering. DAPI staining for evaluating cell viability of groups was done. DMMB and real-time PCR analysis for assaying cartilage-specific extracellular matrix (ECM) gene markers were carried out. According to the results, LIPUS at a resonant frequency of 40 kHz for 7 days with 5 min has the most effect on GAG secretion and SOX9 expression compared other times.

Ziba Naghizadeh, Akbar Karkhaneh, Arash Khojasteh

Effect of Relative Energy Difference (RED) of Coagulation Bath on the Structure of Polysulfone Membrane

Phase inversion is one of the favorite methods for preparation of polysulfone (Psf) membranes. Some main factors such as: solvent and non-solvent exchange rate, phase inversion process, thereby, they can influence membrane structure. This study focused on the relative energy difference (RED) of coagulation bath which extracted from Hansen solubility parameters. Ethanol and water were selected as coagulant and effect of RED in different composition of ethanol/water was investigated. Results showed that at high concentrations of ethanol in coagulation bath, morphology of membranes declined to a sponge like structure and size of macrovoids was decreased due to the reducing of RED. On the other hand, precipitation time and porosity of membranes were increase accordingly.

Rahim Dehghan, Jalal Barzin, Zahra KordKatooli, Shahla Mahdavi

Improvement of Delamination Resistance in Glass/Phenolic Composite Laminates with Nano-interlayers

Generally, phenolic multi-layered composites are not resistant to delamination and that is because of the brittle matrix in their composition. One of the best ways for toughening the multi-layered composites is the use of interleaved thermoplastic flexible polymers. In this research, PVB (Polyvinyl Butyral) electro-spun nanofiber (average diameter = 400 nm) has been used as interleaving in various thicknesses. The results showed that a 30 µm thickness is the optimal value for these glass fiber composites.

Hossein Ipakchi, Masoud Esfandeh, Amir Masoud Rezadoust, Mohammad Rezaei

Biological and Antibacterial Properties of Catechin-Incorporated PLA/Gelatin Hybrid Microfibers

The main purpose of this study was fabrication of catechin (green tea extract) loaded PLA/gelatin microfibers and investigation about antibacterial and cell culture behavior of produced fibers. For this, catechin was loaded in gelatin or PLA or both polymeric solutions and electrospinning with two different nozzles was used for scaffold production. SEM analysis showed smooth fibers with no cracks for catechin incorporated fibers. Loading catechin increased hydrophilic nature of mat. Antibacterial analysis against gram positive and gram negative bacteria confirmed that fibers with catechin can inhibit bacteria growth.

Marziyeh Ranjbar Mohammadi, Mohammad Nouri-Taba, Ehsan Yousefi

Janus Fiber Fabrication Using Electrospinning Process

Arguably, one of the most versatile approaches toward anisotropic particles, cylinders, fibers, and fiber scaffolds is based on electrohydrodynamic (EHD) co-jetting. Electrospraying and electrospinning processes have been applied to polymer solutions to establish straightforward methods for the preparation of nano-/microparticles using high electrical voltages as driving forces for the transport of polymer solutions [1]. In this study, we have obtained the electrohydrodynamic method of Janus fiber. The precursor solutions of these fibers include polyvinylpyrrolidone (PVP) in blue and yellow, with a flow rate of 0.3 mL/h at 8 kV.

Khadijeh Keshavarz Bahaghighat, Mohammad Hossein Navid Famili

Polymer Recycling to Protect Environment

Frontmatter

Mechanical Properties of Poly(Lactic Acid)/Ethylene-Vinyl Acetate Copolymer/Nanoclay Composites as Biodegradable Packaging Films

To improve flexibility of poly(lactic acid), PLA, different amounts of ethylene-vinyl acetate copolymer, EVA, with 28% vinyl acetate monomer were added as a toughing agent. The optimum composition of EVA in EVA/PLA blends was determined for preparing the nanocomposites. Nano-sized clay (DK4) was used to improve mechanical and barrier properties of PLA. PLA/EVA blends and PLA/EVA/DK4 nanocomposite films were prepared by solvent casting method. Resultant nanocomposites and blends were characterized by tensile tests. It was found that by adding just 3 wt% of EVA to PLA, elongation at break of PLA increased by approximately 300% while tensile strength decreased only 4%. Then PLA/EVA3 blend was chosen for producing nanocomposite with 1, 3, and 5 pph of nanoclay. Introducing 1 pph nanoclay compensated for the strength decrease due to adding EVA. The elongation at break for the nanocomposites was still higher than that of pure PLA (about 225%). These results show success in toughening PLA.

Mahdieh Zaji, Masoud Frounchi

Catalytic Degradation of Linear Low-Density Polyethylene Over USY Catalyst: Effect of Catalyst to Polymer Ratio

Catalytic degradation of linear low-density polyethylene (LLDPE) has been investigated using non-isothermal thermogravimetric analyses of the polyolefin samples mixed with different amounts of ultra-stable Y (USY) zeolite catalyst to assess the effect of catalyst to polymer ratio (0, 0.2, 0.6, and 1) on several events of catalytic decomposition, reflected as the onset, maximum rate and completion temperatures. The obtained results revealed that upon increasing of catalyst to polymer ratio from 0 to 1, the onset temperature decreased by more than 150 K while the decrease for the maximum-rate and completion temperatures were approximately 80 and 70 K, respectively. The results presented useful data for the reactor design of the plastic waste degradation process.

Mohammad Ghashghaee, Mohammad Reza Omidkhah, Samira Shirvani

Effects of Black Content and Type on the Biodegradability of Natural Rubber

In this study, biodegradability of compounds based on natural rubber filled with different black content and type, has been investigated. By increasing the amount of black reinforcement, the degradation percent decreased. Furthermore, the blends with the smaller filler were less degraded than that of the larger filler at the same amount of black. The unfilled sample (reference) had the highest final degradation and the highest percentage of extracted sole fraction. While the lowest percentage of sole fraction was seen in the compounds filled with highest amount of the black with the greater surface area. In the same amount of black, the compounds filled with the smaller black, showed the lower sole fraction in comparison with compounds containing bigger black particle size.

Somayyeh Mohammadian, Mohammad Barghamadi, Mehri Alimohammadi

Recycling of Polyethylene Terephthalate (PET) via Glycolysis Method for Synthesis Waterborne Polyurethane

Due to the several applications and widespread use of polyethylene terephthalate (PET) in the world and the resulting waste, recycling of this material has a particular importance. In this work, glycolysis of PET waste was carried out using excess ethylene glycol in the presence of zinc acetate as catalyst at 195 °C for 2 h. Weight ratio of catalyst to PET (0.01) and molar ratio of PET to ethylene glycol (1:7.6) have been considered as suitable conditions for depolymerization process. The main products of the glycolytic reaction were bis (2-hydroxyethyl) terephthalate (BHET) and its oligomers or asymmetrically substituted terephthalates. The obtained product was purified then its structure was analyzed by Furrier Transform Infra-Red (FTIR) spectroscopy and the melting point was measured. It is important to point out that this product was used as polyol to produce waterborne polyurethane.

Mehran Dadash Ziyaei, Mehdi Barikani, Hengameh Honarkar

Feasibility Study on Producing of Side-by-Side Bicomponent Filament Yarns Produced from Recycled and Fiber Grade PET

Side by side bicomponent filament from recycled poly(ethylene) terephthalate from post-consumer bottles and fiber grade PET was extruded. The bicomponent fibers were produced in a melt spinning machine and drawn to improve their mechanical properties. The effects of conditions on the fiber structure and physical properties of resultant fibers were evaluated by the following methods: differential scanning calorimetric (DSC), scanning electron microscopy (SEM), optical microscopy, intrinsic viscosity (IV) and tensile testing. The mechanical properties, such as tensile strength and initial modulus for bicomponent filament showed improvement compared to those for FG-PET. Furthermore, degradation of R-PET molecular structure leads that the viscosities of two polymers are of comparable value.

Marjan Abbasi, Richard Kotek

Effect of Chemical Composition of Vinyl Acetate/Dibutyl Maleat Copolymers on the Permeation Properties of Blend Membranes Based on Poly(Ethylene Oxide-B-Amide6) Block Copolymer for Carbon Dioxide Separation

Pebax1657, poly(ethylene oxide-b-amide6) block copolymer and blend membranes containing 30 wt% P(VAc-co-DBM) copolymers with different chemical compositions were prepared by solution casting method. Effect of chemical composition of P(VAc-co-DBM) on the structure and permeation properties was studied. Formation of hydrogen bonding between NH groups of the PA6 chains and carbonyl groups of VAc-based copolymer chains was confirmed by FT-IR analysis. The permeation results showed that permeability and selectivity increased for all blend membranes simultaneously. Selectivity of blend membranes was increased significantly by increasing the DBM content of VAc-based polymer. Increase in the selectivity can be attributed to the increased solubility of CO2 gas without any significant solubility change in the CH4 solubility.

Marzieh Shirinia, Mahdi Abdollahi, Mohammadreza Omidkhaha

Synthesis of Pyrolytic Carbon from Polyethylene Terephthalate on Graphite Substrate

Pyrolytic carbon is a type of carbon that has many uses in the aerospace, nuclear, electrical and medical industries due to its unique properties. Usual raw materials for producing it, are mainly hydrocarbon gases and require high temperatures for their thermal decomposition, which consume high cost and energy. In this research, pyrolytic carbon is produced by using polyethylene terephthalate (PET) with the objective of recycling non-degradable plastics and environmental protection. In this study, pyrolytic carbon was synthesized at lower temperatures and without using catalyst. Also, the effect of process factors such as residence time, carrier gas flow and temperature on pyrolytic carbon morphology was investigated. SEM analysis showed pyrolytic carbon structures were made by using PET in the range of 800 ℃ to 1000 ℃. The formation of pyrolytic carbon structures was confirmed by Raman test (presence of D and G peaks) and X-ray diffraction analysis. The optimum residence time was 452 s.

Mitra Oliaei, Mohammad Yousefi

Polymers for Smart and Sustainable Future

Frontmatter

Alkanolamine-Based Adduct as Latent Accelerator for Epoxy/Dicyandiamide: Statistical Approach to the Relationship Between Adduct Ingredients and Cure Characteristic of One-Pot System

Through the addition reaction of epoxy, phthalic anhydride and different types of alkanolamine, we developed adducts as latent accelerators for one-pot epoxy/dicyandiamide system. The analysis of variance (ANOVA) technique was employed to evaluate the relationship between the adduct ingredients, namely alkanolamine type, alkanolamine and phthalic anhydride content, and cure peak temperature (Tp) of one-pot system. Results showed that the Tp was affected by all three factors while the degree of influence of alkanolamine type on accelerating the curing reaction was higher than that of the others. Moreover, increasing the alkanolamine amount promoted while higher amount of phthalic anhydride demoted the accelerating ability of accelerator.

Mohammadnabi Hesabi, Ali Salimi, Mohammad Hosain Beheshty

Fixation of Carbon Dioxide Using Epoxy Resin: A Thermodynamics and Molecular Simulation Study

Carbon dioxide is a non-polar chemical compound which is seriously suspected for global warming. Fixation of CO2 using epoxy resin results in cyclic carbonate compounds. On the other hand, cyclic carbonate compounds react with diamines to provide non-isocyanate polyurethanes in response to the environmental concerns about polyurethanes made of isocyanates. In this study, CO2 fixation using epoxy resin to form cyclic carbonate and its subsequent reaction with diethylene triamine (DETA) to form non-isocyanate polyurethane is simulated molecularly. Calculated enthalpies and Gibbs free energies of the reactions revealed that CO2 fixation is thermodynamically possible using epoxy resin and product became more viscos, but the reaction with DETA may result in incomplete curing.

Mahtab Shabani, Seyed Tahmoures Keshavarz, Farhid Farahmandghavi, Mohammad Imani

Preparation of Polyether Sulfone Ultrafiltration Membrane and Investigation of Factors Affecting Its Performance for Hospital Wastewater Treatment

Hospital wastewater may contain high levels of pathogen microorganisms, drug and laboratory residues, metabolites from medicinal substances, radioactive elements, or other hazardous chemicals. Such pollutants has made hospital wastewater one of the most dangerous materials for the health of humans and the environment. In this research, the construction and evaluation of the function of poly-sulfone ultrafiltration membrane in the treatment of hospital wastewater were discussed and evaluated. In the first part of this study, the poly-sulfone ultrafiltration membrane was constructed by phase inversion method, using water-soluble and N-methyl-pyrrolidone (NMP) solvent. In the second part, an ultrafiltration system was designed and developed, then the membrane was evaluated by this system. The flux passing through the membrane was measured at pressures of 3 and 5 bar with ultrafiltration system. The effect of concentration, thickness, coagulation bath temperature and opacity on flux was discussed in this research after the measurement.

Seyed Hasan Maghoul, Ali Niatouri

Study on the Viscoelastic Behavior of Nitrile Rubber/Polyvinyl Chloride Compounds Modified with Different Levels of Nanolayered Silicate

In this study, the effects of nanolayered Silicate and acrylonitrile content on the viscoelastic behavior of NBR/PVC based nanocomposites were investigated. By increasing the nanoparticle and acrylonitrile content in the samples, the maximum elastic ($$ {\text{S}}^{{\prime }} $$) and viscous ($$ {\text{S}}^{{\prime \prime }} $$) vulcanization torques were increased. In the samples containing higher acrylonitrile groups, the peak of $$ {\text{S}}^{{\prime \prime }} $$ shifted to the shorter times, while by adding the nanoparticles to the compound, this peak shifted to the longer times. Drop in $$ {\text{S}}^{{\prime \prime }} $$ ($$ {\text{DS}}^{{\prime \prime }} $$) declined by raising nanoparticle content. Samples with higher acrylonitrile content, showed the lower $$ {\text{DS}}^{{\prime \prime }} $$. Elastic torque at $$ {\text{S}}_{\hbox{max} }^{{\prime \prime }} $$ ($$ {\text{S}}^{{\prime }} $$ @ $$ {\text{t}}_{{{\text{S}}^{{\prime \prime }} { \hbox{max} }}} $$), increased by increasing nanoparticle content. In the stress relaxation test, the ratio of the long time drops in modulus (DGl) to the short term drop in modulus (DGs) was corresponded with declining in the $$ {\text{DS}}^{{\prime \prime }} $$ of cure test.

Mohammad Barghamadi, Mohammad Karrabi, Mir Hamid Reza Ghoreishy, Somayyeh Mohammadian

Temperature Dependency of the Payne Effect in NBR/PVC Blends

In this study, the effects of temperature and also the presence of PVC on the Payne effect of NBR based compounds were investigated. Increasing the temperature, served to decrease the drop of the shear storage modulus (ΔG′) in the strain sweep test. The ΔG′ for the sample containing PVC show higher value than that for the rubber compound. The slop of modulus drop after Payne effect (Ad) declined by raising the temperature, especially in blend sample. Critical strain (Sc) increased by increasing temperature. In other words, less dependency of modulus on the strain is decreased at higher temperatures. Blend samples due to the presence of PVC phase are more sensitive to the shear than rubber compound and non-linearization occurs in lower strains.

Mohammad Barghamadi, Mohammad Karrabi, Mir Hamid Reza Ghoreishy, Somayyeh Mohammadian

Numerical Evaluation of Effective Properties of PZT-5A/Epoxy Smart Piezoelectric Composite

Here, finite element method (FEM) has been employed to determine the effective properties of the active fiber composite (AFC) consists of a circular cross-section piezoelectric fiber (PZT-5A) in a non-piezoelectric polymeric matrix (epoxy) as a representative volume element (RVE). Six simulation runs with adjusted boundary conditions and appropriate mechanical-electrical loading were executed. Boundary conditions firmly control the simulation process. Homogenization approach was used to obtain the average value of the coefficients in the whole of RVE. Finally, eleven electromechanical coefficients including; six stiffnesses ($$ {\text{C}}_{11}^{\text{eff}} $$, $$ {\text{C}}_{12}^{\text{eff}} $$, $$ {\text{C}}_{13}^{\text{eff}} $$, $$ {\text{C}}_{33}^{\text{eff}} $$, $$ {\text{C}}_{44}^{\text{eff}} $$, and $$ {\text{C}}_{66}^{\text{eff}} $$), three piezoelectric ($$ {\text{e}}_{13}^{\text{eff}} $$, $$ {\text{e}}_{33}^{\text{eff}} $$, and $$ {\text{e}}_{66}^{\text{eff}} $$) and two dielectric constants ($$ {\upvarepsilon }_{11}^{\text{eff}} $$, $$ {\upvarepsilon }_{33}^{\text{eff}} $$) were evaluated. The adequate accuracy of the analysis was approved by comparing the calculated coefficients with the reported analytical and numerical data.

Sobhan Sharafkhani, Mehrdad Kokabi

Prediction of a Typical Amorphous Shape Memory Polymer Behavior Considering Both Glassy and Rubbery Phases

In this study, mathematical prediction and validation of shape memory thermomechanical behavior of a typical amorphous polymer was formulated considering both rubbery and glassy phases. The constitutive model with different hyperelastic functions for rubbery and glassy phases was developed using continuum mechanics approach. A typical uniaxial cycle of deformation was considered. The theoretical results exhibited a good agreement with experimental data.

Ghazaleh Alamdarnejad, Mehrdad Kokabi

Preparation of PVDF Nanowire by Infiltration Method into Lumina Nanopores

Poly(vinylidene fluoride) (PVDF) homopolymer nanowire array with the desired ferroelectric β-phase is fabricated in an anodic alumina porous (AAP) template. The results indicate that the hydrogen bonds between the AAP surface hydroxyl groups and PVDF molecules promote the formation of the β-phase. The mechanism of polymer infiltration into the pores is also very important in order to obtain the desired one-dimensional nanostructures and to control their final morphology. In this study, infiltration method was explored with the aim to obtain different 1DPNs. It was shown that, with these infiltration methods, it is possible to obtain nanowire composed of poly(vinylidene fluoride).

Hosna Soleymani, Mohamad Mehdi Abolhasani, Mohamad Normohamadi, Mohsen Ashjari

Comparison Study of Carbon Nanotube and Carbon Black Filled Polyamide6/Polyethylene as a Tissue Equivalent Material

Tissue equivalent polymeric materials should be electrically conductive like the real tissue. Composites based on polyamide 6/polyethylene filled with two different conductive additives, carbon nanotubes (CNT) and carbon black (CB), were prepared. Electrical conductivity measurements revealed that the PA/PE/CNT composite has been reached to percolation threshold with 3% CNT which is much lower than 16% CB in PA/PE/CB composite. After percolation, the CNT filled composites showed lower electrical conductivity than CB filled ones because of the low tunneling effect in narrow cylindrical CNTs in comparison with spherical CB. However, electrical conductivity of both composites is in the range of semi conductive materials which are suitable for using as a tissue equivalent material. Lower amount and high strength of CNT offered better mechanical properties for the PA/PE/CNT composite.

Farah Khoylou, Azam Akhavan, Faranak Naimian

Producing Porous Polyacrylonitrile Fibers Using Wet-Spinning Method for Making Carbon Fibers

Investigation of the increment in the porosity and diameter of polyacrylonitrile (PAN) fibers during the wet-spinning process has great importance in producing carbon fibers and textile industries. In this study, the influence of several factors such as stretching and flow rate and also the presence of non-solvent on the porosity and diameter of the fibers have been investigated. PAN used in certain quantity as polymer, with DMF (dimethylformamide) as solvent and distilled water as non-solvent were combined under certain temperature to make dope wet-spinning process. At the final stage, the PAN fibers were ejected from the spinning machine under the various flow rates and porosity was generated in the fibers and then the fibers related to a sample were stretched by pulling device.

Ehsan Samimi, Mohammad Mehdi Abolhasani, Shahram Arbab

Shape Memory Behaviour of Waterborne Polyurethane-Based Aerogel

In this work, shape memory behaviour of waterborne polyurethane-based aerogel was investigated using dynamic mechanical analysis technique. The porosity and pore-size distribution of polyurethane aerogel also determined by a mercury porosimetry test. The results showed the prepared aerogel had 81% porosity with average pore diameter around 10 nm, also a shape fixing ratio and shape recovery ratio of 98% and 48%, respectively.

Mohsen Teymouri, Reza Akbari, Mehrdad Kokabi

Surface Modification of Cellulose Nanocrystal Through Dendrimer with Amine End Groups

Cellulose nanocrystal with the presence of a large number of chemical functionalities within its structure, provides a unique platform for significant surface modification through various chemistries. Using dendrimer for this purpose is a unique choice that not only does shield hydroxyl groups and change surface charge but also introduce several functional groups on its surface. In this work surface modification of cellulose nanocrystal through dendrimer with amine end groups by physical adsorption technique was conducted to decrease its negative charge while increasing surface functional groups and its antibacterial properties. The result was analyzed by Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) and Zetasizer instrument. It was found that due to strong hydrogen bonds the result of physical adsorption reaction is comparable with chemical grafting and is an efficient route for surface modification of cellulose nanocrystal.

Ali Mianehro, Somaye Akbari, Atefeh Solouk, Seid Ali Ahmadi

Effect of Surface Treatment on Polyethylene Separator’s Properties of Lithium-Ion Batteries

In the current research, polyethylene and alumina coated polyethylene (AC-PE) Li-ion battery separators were studied and the effect of surface treatment on the properties of polyethylene separator was investigated. Tensile test, contact angle measurement and thermal shrinkage investigation were done to clarify the role of ceramic coating on the mechanical and thermal properties, and wettability of PE separator surface. Results showed that the contact angle of modified polyethylene separator was obtained much lower (69°) with respect to unmodified one (118°), which showed better wettability of PE surface with the incorporation of Al2O3. Tensile strength of PE and AC-PE was also obtained 156.2 and 142.4 MPa, respectively, and alumina coated polyethylene showed much brittle mechanical behavior. Finally, Al2O3 coated separator had obvious thermal shrinkage resistance with respect to PE separator, as shrinkage changed from 60.3% to 12.4% of separators original size.

Mohammad Hadi Moghim, Ashkan Nahvi Bayani, Abdol Majid Ghasemi, Rahim Eqra

Copolymerization of Styrene and 1-Hexene via Ziegler-Natta and Atom Transfer Radical Polymerization Methods

Polymerization of 1-hexene and its copolymerization with styrene were done via Ziegler-Natta catalyst in bulk medium at 60 ℃. The results showed that 1-hexene was well polymerized with this type of catalyst, but increasing the molar ratio of styrene in the reaction feed led to decrease the catalyst activity and, consequently, a reduction of the overall conversion. Compared to this catalytic reaction, the atom transfer radical copolymerization of styrene and 1-hexene was carried out with CCl4 initiator and CuCl/N, N, N′, N′, N″-pentamethyldiethylenetriamine (PMDETA) catalyst system in bulk at 80 ℃. The results of conversion showed that styrene has a high activity in the atom transfer radical polymerization. By increasing the molar ratio of styrene monomer in the feed, the overall conversion of the reaction increased. Thus, increasing the concentration of 1-hexene can decrease the activity of macroradicals. The structure of various synthesized copolymers was characterized by 1H NMR method. Thermal properties of the synthesized poly 1-hexene and its copolymers with styrene were determined by DSC method. The results showed that the synthesized polymers via Ziegler-Natta have glass transition temperature in the range of −40 ℃ to −45 ℃.

Mohammad Reza Rostami Darounkola, Naeimeh Bahri-Laleh, Mehdi Nekoomanesh-Haghighi, Sanaz Rahmatiyan

A Multi-objective Optimization Strategy for Controlling the Structural Properties of Lightweight Mutiphasic PE/EVA Foams

In this work, a mathematical approach based on the combination of response surface methodology and desirability function was applied to optimize the foaming extrusion process of polyethyelene/ethylene vinyl acetate copolymer blends in order to control the structural properties of them, which is of great importance for their applications in sectors like energy management. Continuous foaming extrusion of these blends has complexity due to the mutual effects of material and processing parameters as well as the phase separation phenomena. The findings show that the employed mathematical strategy can be a useful tool for muti-objective optimization of these parameters.

Sirwan Ghavami, Mohammad-Hasan Khademi, Farkhondeh Hemmati, Ali Fazeli, Jamshid Mohammadi-Roshandeh

Fabrication of Photonic Crystal Heterostructures Free of Interface Imperfection Based on Plasma Assisted Versatile Deposition

In this study, we proposed a facile one-step thermal self-assemble method for depositing a photonic crystal heterostructure (PCH) on a flexible polymer substrate which can filter a determined wavelength band from a broad spectrum illumination and provide transmission of an adjustable wavelength. Method includes improving surface hydrophilicity property of the polymer substrates using the application of cold plasma treatment and using one-step thermal treatment for deposition of PCH. The plasma treatment successfully increased the hydrophilicity of the surface of the heat-sensitive polymer substrates. The device resulting from the method has defect-free junction structure that contains at least two photonic crystals with different photonic crystal lattice constants. The PCHs led to a broadband reflection as well as creating low-loss waveguides, high-performance filters, frequency selectors, and chemo/biosensors.

Zahra Sadat Azizi, Mohammad Mehdi Tehranchi, Saeed Pourmahdian

Shape Memory Behavior of Polyacrylamide Hydrogel

In this work, polyacrylamide hydrogel prepared by free radical polymerization and its shape memory behavior are investigated using dynamic mechanical analysis technique. The switch (transition) temperature of the amorphous hydrogel containing 85% water was obtained around ~−7 ℃. The results indicated that the shape fixing ratio and shape recovery ratio of the system were 99% and 82%, respectively.

Sonia Norouzi Esfahany, Ghazaleh Alamdarnejad, Mehrdad Kokabi

Determination of Entangled Supramolecular Polymer Networks Dynamics by High-Order Associations of Strong Hydrogen Bonding Groups

Dynamics of entangled polymer chains in the melt state are deliberately excluded in most of the studies on supramolecular polymer networks by utilizing non-entangled precursor chains. Relaxation of the system mainly depends on the dissociation of the associative groups in latter case and non-entangled chains deliver nothing to resist afterwards. Conversely, in an entangled system relaxation of polymer chains and dissociation of associative groups can occurred parallel. Supramolecular networks based on an entangled precursor polymer with different levels of strong associating ureidopyrimidinone, UPy, groups are synthesized to screen the corresponding effects on the dynamics of the system. Binary-associated UPy groups phase separate into collective assemblies by stacking and form high-order, needle-like domains at higher UPy contents. Relaxation of polymer chains is significantly hindered due to the trapping of polymer segments between UPy stacks. Above a certain threshold of UPy content (~4 mol%), the plateau level as well as final relaxation time of networks show a significant jump, which is attributed to the onset of high-order association of UPy groups.

Amir Jangizehi, Seyed Reza Ghaffarian, Mostafa Ahmadi

Investigating the Physico-Mechanical Properties of Elastomers Based on EPDM/Kevlar/Silica: Effect of Cork Filler and Curing Condition

Fiber filled ethylene propylene diene (EPDM) elastomers are widely used as internal insulator in aerospace industries. Kevlar fibers, silica and flame retardants are used in most heat insulators. In this study, in order to prepare lightweight EPDM based composites, the effect of adding Cork into EPDM compound was investigated. The results showed that the addition of Cork into EPDM compounds reduced the density and elasticity of cured elastomer. On the other hand, Cork content and curing condition (time and temperature) affected the tensile strength and elongation at break. Therefore, through investigating the effect of different proportions of the Cork in the compound, it became clear that the compound filled with 15 phr Cork had optimum physical and mechanical properties. Tensile and density test results showed that the density, tensile strength and elongation of mentioned sample were 1.1951 g/cm3, 6.3 MPa and 272%, respectively.

Tohid Farajpour, Mohamad Javad Babaei-Velin, Hadi Rezaei-Vahidian, Ghodratoallah Mohammadzamani, Saeed Moradi

Effect of Peroxides Mixtures on the Molecular Structure of Ethylene-1-Octene Copolymer in Reactive Blending

Various methods have been examined to achieve high performance polymers, among them, chain branching method has shown excellent potential for production of polymers suitable for new applications. This work aims at investigating the effects of different mixtures of peroxides on the molecular structure of ethylene-1-octene copolymer during reactive blending. The torque of mixing has been applied as an indicative of a change in the molecular structure. Moreover, the gel content test is used to investigate the partial crosslinking of the samples. In this research, the response surface method (RSM) according to a box Behnken statistical design was applied to investigate the effect of three peroxides mixtures with different half-life times and radical stability on the molecular structure. The method suggests the optimized formulation for maximum branching with little gel content.

Mahdi Mahmoodabadi, Shervin Ahmadi, Hossein Ali Khonakdar

Effect of Nanographene on the Curing Behavior and Rheological Properties of NBR/Phenolic Compounds

In the recent years, many researchers have attended to reinforce rubbers by nanographene. The aim of this work is to study the effect of nanographene on the curing behavior and rheological properties of NBR/phenolic blends. Nanocomposites containing NBR, novolac resin and nanographene as reinforcing agent (0.5, 1, and 1.5 phr) were prepared on a two-roll mill. Curing behavior and rheological properties are investigated by Rubber Processing Analysis (RPA) and strong role of nanographene on these properties was demonstrated. So, the results showed that nanographene increased the scorch time of the samples in comparison with blends without nanographene. Moreover, the difference between the highest and the lowest torque (MH-ML) increased with addition of nanographene. Interestingly, it was observed that by increasing nanographene content, viscosity reduced.

Sara Shafiee, Mohammad Karrabi, Mir Hamid Reza Ghoreishy

Encapsulation of Epoxy Resin Within Nanocapsules via Facile and Cost Efficient Electrospray Method

Corrosion of metals is an important issue in various industries, causing heavy maintenance costs and other problems which have always attracted researchers’ attention to minimization of these expenses. Polymer coatings are used for corrosion prevention; however, these coatings face practical difficulties and lose their functionality after any damages. Therefore, self-healing coatings have been proposed. In this research, a self-healing agent was encapsulated in core-shell nanocapsules via electrospray method. For this purpose, low viscosity epoxy resin was stored in styrene acrylonitrile nanocapsules using emulsion electrospray. The morphology of the prepared capsules was studied by scanning electron microscopy (SEM), confirming the fabrication of capsules with the average size of 870 ± 320 nm. Furthermore, Fourier-transform infrared spectroscopy (FTIR) results confirm the successful encapsulation of epoxy within the nanocapsules without any chemical reaction between core and shell.

Alireza Safdari, Saied Nouri Khorasani, Rasoul Esmaeely Neisiany

Solvathochromism Effect of a New Synthesized Conjugated Organic Compound in Different Environments and Types of Polymers

Fluorescence is widely used in optical sensors and cellular imaging to detect cancer types and security issues. The effect of the environment, including the effect of the solvent, the protonation, the polarity of the conjugate fluorescence organic compounds, and the addition of the donor-acceptor substitutions to the derivatives of distyrylbenzene and the polymers combined with conjugated organic compounds, change the behavior of the optical behavior. Distyrylbenzene derivatives have fluorescence properties. Adding the various substitutions of the electron-donor and the electron withdrawing to these derivatives changes the emission spectrum. These compounds have a different color in different polarity solvents and polymers, which can be seen solvathochromism effect. By increasing polarity, the emission spectrum will have a shift toward red colors.

Fateme Miri, Saeideh Gorji Kandi, Farhad Panahi

MWCNT/PDMS Mixed Matrix Membrane for Oxygen Enriched Air Production

Mixed matrix membranes (MMMs) composed of MWCNT and a rubbery polymer, polydimethylesiloxane, were prepared by priming method. Investigation by FESEM showed that agglomeration of carbon nanoparticles increased with its weight fraction exceeding 0.7 wt%. The O2/N2 gas separation performance by using the PDMS/MWCNT membranes has also been carried out. In consequence, the optimized membrane sample contains 0.6 wt% MWCNT with 3.13 as selectivity.

Mohammad Fazel Hasanzade, Fereidoon Mohammadi, Seyed Ali Ghadimi, Maryam Jalaei

Modeling of Shape Memory Behavior of Semi-crystalline Polymer Considering Both Amorphous and Crystalline Phases

Shape memory polymers easily form different temporary shapes and recover their permanent shape even after undergoing large deformation. In this work, shape memory behavior of a typical semi-crystalline polymer is modeled and the constitutive equations for the original amorphous and the semi-crystalline phases are derived. The amorphous and crystalline phases were characterized by an Ogden and a neo-Hookean response, respectively. The model was used to simulate a typical uniaxial cycle of deformation. The results demonstrated very good agreement between simulation and experimental data.

Reza Akbari, Mehrdad Kokabi

Synthesis and Characterization of Linseed Oil Microcapsules with Poly(Melamine-Urea-Formaldehyde) Shell

In this project, it has been attempted to encapsulate linseed oil by in-situ polymerization as the core of the poly (melamine-urea-formaldehyde) which is capable to be used in smart self-healing coatings. Sodium lauryl sulfate had the role of anionic emulsifier and polyvinylpyrrolidone with molecular mass of 40000 g/mol was used as stabilizer with electrostatic and steric hindrance functions. In this work, various factors and conditions were studied on the morphology of the obtained microcapsules by optical microscopy. These factors and conditions include change in stabilizer amount, reaction time, process temperature, mechanical mixer blade type, emulsifier and stabilizer type.

Ashkan Karami, Atiyeh Adelinia

Bio-Based Self-healing Thermoset Polyurethane Based on Pseudo-Tannin

In this research, we have produced a thermoset polyurethane that has self-healing properties above 110 ℃. The reaction of hydroxyls bonded to the benzene ring, with isocyanate, is capable of being isolated from isocyanate at high temperature and rejoin at low temperatures. We used bio-based pseudo-tannin material that comes from walnut trees and gives us the ability to self-healing. This mechanism led us to reach about 70% of the initial strength and 80% of the initial elongation at break after healing.

Adel Soleimani, Mobina Khakbaz, Negar Tavakoli, Gity Mirmohamad Sadeghi

Effect of Chain Extender on the Properties of Polysulfone-Based Membrane as a Candidate for Fuel Cell Proton Exchange Membrane

Proton exchange membrane is a key component in fuel cell system with major impact on the performance. So tuning polymer structure to obtain the best properties and performance has been attracted many attentions. In this research two types of sulfonated polysulfone (sPSU) based on bisphenol AF, bisfluorophenyl sulfone (BFPS), and sulfonated bisfluorophenyl sulfone (sBFPS) in the presence or absence of decafluorobiphenyl (DFBP) as chain extender with 30 wt% degree of sulfonation (DS) were synthesized. FTIR and 1H NMR analyses, DSC, TGA, and tensile tests confirmed successful synthesis and acceptable properties of sulfonated monomer and polymers. Suitable membranes were obtained from the prepared polymers. Water uptake and IEC measurements, MEA preparation, and performance of membranes were evaluated. Besides these, presence or absence of DFBP in two synthesized structures was compared.

Maryam Mohammadi, Maryam Oroujzadeh, Shahram Mehdipour-Ataei

A Novel Polysulfone-Based Proton Exchange Membrane: From Polymer Synthesis to Membrane Preparation, MEA Fabrication, and Fuel Cell Performance

Polymer electrolyte membrane is one of the key components in fuel cell systems. Finding a competitive alternative to commercial membranes to decrease cost and improve their properties is one the most interesting subjects in fuel cell field research. In this study, a novel category of proton exchange membrane (PEM) was prepared from a thermally stable chain-extended sulfonated polysulfone (sPSU) with 45 wt% degree of sulfonation. After membrane preparation, optimizing ink formulation and membrane electrode assembly (MEA) condition, performance assessment in a fuel cell system was done successfully. Based on the results in the typical test condition (T = 80 °C, RH = 100%) it was revealed that this type of synthetic membrane could be an acceptable alternative for commercially available PEMs.

Maryam Mohammadi, Maryam Oroujzadeh, Shahram Mehdipour-Ataei

Microencapsulation of 2-Ethylhexyl Acrylate with Potential Application in Thread Locking Adhesives

The main objective of this research was to synthesize polyurethane/polyuria-formaldehyde (PU/UF) microcapsules containing 2-ethylhexyl acrylate (EHA). Bi-layer microcapsules containing EHA monomers were synthesized via interfacial polymerization in an oil/water emulsion. The surface morphology and shape of synthesized microcapsules were evaluated using optical microscopy (OM) and scanning electron microscopy (SEM). FTIR spectroscopy was carried out for characterization of the microcapsule. The results showed that the prepared microcapsules were spherical, with an average diameter about 20-140 and thickness of about 1.5 μm, without any inter-capsule bonding and had a smooth surface. The microcapsules synthesized in this way offer an interesting prospect for applications in thread locking adhesives.

Elahe Adibzade, Seyed Mojtaba Mirabedini, Morteza Behzadnasab

Processing and Reactive Processing of Environmental Polymers

Frontmatter

Synthesis, Characterization and Thermal Stability of UV-Curable Hydrogel

In this research, the synthesis, characterization and thermal stability of UV curable hydrogels have been investigated. To this end, urethane acrylate was initially synthesized with isophorone diisocyanate, polyethylene glycol and hydroxyethyl methacrylate. In the next step, the UV curable hydrogel was synthesized with acrylamide, acrylic acid and the urethane acrylate. FTIR spectra proved the structure of urethane acrylate and hydrogel. The study of thermal behavior showed that the synthesized hydrogel is stable to 327 ℃.

Zahra Rahmani, Saeed Pourmahdian, Behzad Shirkavand Hadavand

Effect of Polyolefin Addition on the Heat Seal Strength of HDPE Blown Films

Heat seal strength and quality of HDPE blown films with addition of 4 different polyolefins (LLDPE-g-MAH, LDPE-g-MAH, POE-g-MAH, and PP) were investigated. HDPE contained 1 wt% to 5 wt% of each polyolefin was passed though film blowing process followed by heat sealing temperature as low as 140 ℃. The sealing time ranged from 1 s to 5 s. Peeling test on films led to seal strength and type of failure considered as seal quality. Type and content of added polyolefin affected both of them. Different thermal properties of polyolefin, as a function of corresponding microstructure, is a key parameter which determined the way in which sealing quality of HDPE was influenced. Besides that, dwell time was found to be a critical parameter specially for sealing quality. All additives improved the heat seal properties, but in their special conditions.

Ayat Mehdipour, Hossein Abedini, Majid Habibelahi, Morteza Ehsani

Preparation of Novel Liquid, Solvent-Free, Polyalfaolefin-Based Adhesives

An innovative approach for functionalization of polyolefins was developed and newfound polyolefins end-capped with trimethoxysilane (silylated polyolefins) was discovered as a material which can be applicable as an extraordinary polyolefin-based adhesive. For synthesizing mentioned materials, 1-octene as a higher α-olefin was cooligomerized with linear, non-conjugated (1,5-hexadine and 1,7-octadiene) by the metallocene catalyst system of Cp2HfCl2/MAO at room temperature. Then, amine-terminated trimethoxysilane (3-aminopropyltrimethoxy silane) in the presence of palladium(II) acetate was reacted with unsaturated bonds containing of synthesized cooligomers by nucleophilic addition. The adhesion properties of resultant adhesives were subjected to different substrates. Obtained adhesives indicated greater tendency to Al substrate. Furthermore, the tensile shear strength of the synthesized adhesives on polar substrates was 2.21% to 2.84% more than that on polar substrates.

Ahad Hanifpour, Naeimeh Bahri-Laleh, Mehdi Nekoomanesh-Haghighi

Evaluation of the Mechanical Properties of Poly(Lactic) Acid/ABS Bio-Blend Foams

Foaming is a powerful method that allows lightening of products and reducing the amount of material used. Poly(lactic) acid (PLA) is considered a promising thermoplastic for the replacement of traditional non-biodegradable polymers. In this study, PLA was modified with an epoxide chain extender via reactive extrusion and blended with Acrylonitrile – Butadiene – Styrene (ABS) in the presence of a compatibilizer. The MuCell® process was applied to obtain foams from the previous prepared blends. Results shows that the presence of the epoxide and ABS inhibit the degradation during processing making foaming possible. Under flexural conditions where foamed are designed to work, the mechanical properties of the foamed blends were very similar to the solid counterparts.

Miguel Sánchez-Soto, Mohammad Reza Kamrani, Maria Lluisa Maspoch, Orlando Santana, Jonathan Cailloux

PET/PLA Blends Crystallization Kinetics

The crystallization behavior and mechanical properties of PET/PLA blends with various amounts of PLA were investigated using wide angle X-ray diffraction (WAXD), differential scanning calorimeter (DSC) and tensile analyses. The crystallization rate and relative crystallinity of the PET/PLA blends were studied by theoretical models of Kissinger, Avrami, Ziabicki and Ozawa. The WAXD analysis showed that the PLA phase was wholly amorphous in all blends after cooling from the melt to ambient temperature. Crystallization behavior assessments on PET/PLA blends suggest that PLA acts as a nucleating agent for PET phase leading to an increase in the initial and peak crystallization temperatures. Kissinger’s model showed a rise in activation energy up to 72% for the PET/PLA blends containing 30 wt% PLA. Ziabicki’s model gave a minimum value for kinetic parameter in PET/PLA (70/30 w/w) due to the nucleating action of PLA. On the other hand, PLA acted as a retarder for chain segments of PET tending to diffuse through the surface of growing crystals. Therefore, at an optimal composition of PET/PLA, crystallization occurs appropriately. However, an increase in PET content leads to fall in ductility, tensile strength, modulus, elongation-at-break, and fracture toughness of PET/PLA blends.

Hasan Azizi Topkanlo, Zahed Ahamadi, Faramarz Afshar Taromi

Microstructure and Mechanical Properties of Compatibilized Polylactide/Thermoplastic Starch Blends

Biodegradable polymer blends of polylactic acid/thermoplastic starch (PLA/TPS) were prepared via direct melt blending varying order of mixing of ingredients fed into the extruder. The effect of interface interactions between PLA and TPS in the presence of maleic anhydride (MA) compatibilizer on the microstructure and mechanical properties was then investigated. The prepared PLA/TPS blends were characterized by scanning electron microscopy, differential scanning calorimetry (DSC), tensile, and rheological measurements. Morphology of PLA/TPS shows that the introduction of MA into the polymer matrix increases the presence of TPS at the interface region. The DSC results revealed the reduction of glass transition of PLA with contributions from both TPS and MA. The crystallization temperature was decreased by the addition of MA leading to reduction of overall crystallization of PLA/TPS blend. The mechanical measurements show that increasing MA content up to 2 wt% enhances the modulus of PLA/TPS more than 45% compared to the corresponding blends free of MA compatibilizer.

Seyed Ali Nezamzadeh, Zahed Ahamadi, Faramarz Afshar Taromi

Solvent Effect in 1-Decene Oligomerization Using Silica Supported AlCl3 Catalyst

In this research, poly1-decene was synthesized by Silica/AlCl3/H2O catalytic system in the presence as well as absence of toluene as a solvent. The effect of solvent amount on the final product properties was explored. The obtained oligomers were characterized with GPC, TGA, Kinematic Viscosity at 40 and 100 ℃ (KV40, KV100), Viscosity Index (VI) and 1H NMR methods. The results showed that the molecular weight and kinematic viscosity of 1-decene oligomer decreased as the toluene amount increased. TGA analysis demonstrated that thermal stability of the synthesized oil decreased in the poly1-decene samples synthesized in the presence of toluene. 1H NMR spectroscopy revealed the presence of aromatic ring in the structure of oligomer chains synthesized in the presence of toluene while that for the chains without solvent, the characteristic peaks of aliphatic and alkene type hydrogens were detected.

Sevda Dehghani, Mehdi Nekoomanesh-Haghighi, Samahe Sadjadi, Naeimeh Bahri-Laleh

Predicting Droplet Size by Rheometry Analysis for PBAT/EVOH Blend

The aim of the present article is to predict the morphology and droplet size of the PBAT/EVOH blend. PBAT is a biodegradable polymer which is usually used in packaging, however to improve its barrier properties, the blending with EVOH was proposed. Thus, predicting the final morphology can achieve a good look. By combination of the theories and rheological data, the volume average radius of droplets was calculated and compared with those extracted from the FE-SEM images. The models of Palierne, Gramespacher and Meissner, and Bousmina fitted the rheological data and the volume average radius calculated by these models were 0.29, 1.01, and 0.40 µm, respectively. On the other hand, the FE-SEM images showed a volume average radius of about 1.1 ± 0.3 µm. Thus, the good compatibility between theory and experimental results was observed which could be useful to adjust the final morphology.

Mehdi Elhamnia, Ghodratollah Hashemi Motlagh

Backmatter

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