Effect of antioxidant grafted graphene oxides on the mechanical and thermal properties of polyketone composites

doi:10.1016/j.eurpolymj.2015.06.009

European Polymer Journal

Volume 69, August 2015, Pages 156-167

https://doi.org/10.1016/j.eurpolymj.2015.06.009 Get rights and content

Highlights

•
PK composites were prepared by the polymer powder coating method.
•
The graphene-based materials were found to be more effective nanofillers than CNT.
•
Antioxidant grafted GOs improved both of the thermal and mechanical property of PK.
•
Antioxidant grafted GOs are effective heat stabilizers for thermal stability of PK.

Abstract

Polyketone (PK) composites were prepared by a polymer powder coating method using carbon nanomaterials, such as carbon nanotube (CNT), graphene oxide (GO), and antioxidant grafted GOs as filler materials. The antioxidant grafted GOs were obtained by grafting hindered amine and hindered phenol, respectively, onto the surface of the GOs. The PK composites containing the carbon nanomaterials showed much improved thermal stabilities and mechanical properties compared to PK. In particular, we found that the antioxidant grafted GOs are more effective in increasing the thermal properties of PK than CNT and GO without any antioxidant moieties. The enhanced thermal stability and mechanical property by the antioxidant grafted GOs can be explained by the combined antioxidant ability of the antioxidant functional groups and the rigid conjugated carbon units in the GOs having the ultrathin sheet shapes.

Graphical abstract

Introduction

Carbon nanomaterials, such as carbon nanotube (CNT), graphene, and graphene oxide (GO), have been widely used to improve the performance of polymer composites as filler materials due to their outstanding mechanical, thermal, and electrical properties [1], [2], [3], [4], [5], [6], [7], [8]. Especially, the antioxidant behavior of the carbon nanomaterials in the polymer matrix and their effect on the thermal properties of polymer composites have drawn much attention for scientific interests and industrial purposes [9], [10], [11]. The remarkable improvement in thermal stability by the carbon nanomaterials has been known to be closely related to their inherent radical scavenging ability because they contain lattice defects, such as lattice vacancies, phenol, and other oxygen functional groups that can stabilize the radicals [10], [11], [12]. For example, when 5 wt.% of CNT containing hindered phenol moieties was added to polyethylene (PE), the thermal oxidative stability of PE was found to be improved [13].

However, the application of CNT derivatives for the antioxidant has been limited due to the poor chemical compatibility with polymers forming non-uniform domains, and the effective improvement of the thermal stability could not be easily obtained [9], [10]. On the contrary, GO derivatives have been known to have better compatibility with polymers because various kinds of oxygen functional groups, such as carboxylic acid, hydroxide, epoxide, and ketone groups, in the GO can increase the interactions with polymers. Furthermore, when the oxygen functional groups in the GO were modified with various kinds of chemical moieties including polymers, the compatibility with the polymer matrix was found to be considerably improved and the polymer composites containing such GO derivatives showed much enhanced mechanical strength and thermal stability. For example, when only 0.01 wt.% of the GO derivatives containing polyamide 6 chains were mixed with aliphatic polyketone (PK), the elongation at break was increased by about 100 times and the thermal stability was found to be much improved [14].

PK is an alternating olefin/carbon monoxide (CO) copolymer having various advantageous properties such as good chemical resistance, mechanical properties, and low gas permeability [15], [16], [17]. Accordingly, it has a great potential to use in a wide range of possible applications, while further works on the synthesis, characterization, and process are required for practical applications in the engineering field. In particular, although PK is chemically and physically stable under inert conditions at room temperature, when it is exposed to heat and air, extensive thermal degradation was observed [18], [19], [20]. Therefore, the preparation of PK samples from extrusion or injection molding without deterioration of properties has been known to be very difficult due to the poor thermal stability of PK [19], [21].

In this work, we tried to improve the physical properties including thermal stability of PK by adding CNT, GO, and GO derivatives containing antioxidant groups. The GO derivatives containing hindered phenol moiety as the antioxidant showed most improved mechanical strength and thermal stability. The synthesis of the GO derivatives and the characterization of the PK composites are discussed in this manuscript.

Section snippets

Materials

Multi-walled carbon nanotubes (CNTs) were purchased from Nanocyl (Belgium). The purity, outer diameter, and length of CNT are ⩾95%, 10–20 nm, and 10–20 μm, respectively. Graphite powders were received from BASF (Germany). Aliphatic polyketone (PK, glass transition temperature = 10 °C, melting temperature = 225 °C, melt index = 60 g/10 min) was kindly provided by Hyosung (Korea) and used as received. The PK used in this study is an alternating olefin/carbon monoxide copolymer prepared by olefins (ethylene

Preparation of GO grafted with hindered phenol (HP-GO) and GO grafted with hindered amine (HA-GO)

GOs grafted with hindered phenol and hindered amine group, named as HP-GO and HA-GO, respectively, were prepared by the reactions of GOs with hindered phenol or hindered amine, respectively, as shown in Fig. 1. These antioxidant grafted GOs were used as fillers to impart the antioxidant property to the PK composites. HP-GO was synthesized by the esterification between the acyl chloride group in hindered phenol and the hydroxyl groups in GO. HA-GO was prepared by the ring-opening reaction

Conclusion

The thermal stabilities and mechanical properties of PK were found to be much improved by adding a small amount of antioxidant (hindered amine and hindered phenol) grafted GOs. The antioxidant grafted GOs in the PK composites can increase the mechanical properties because organic functional groups in the GOs can increase the interfacial interactions between the fillers and the polymer matrix, then the homogeneously dispersed rigid conjugated carbon units in GOs can increase the mechanical

Acknowledgements

This research was supported by a grant from the Fundamental R&D Program for Technology of World Premier Materials funded by the Ministry of Trade, Industry and Energy, Republic of Korea and the National Research Foundation of Korea funded by the Korean Government (NRF-2010-C1AAA01-0029061).

References (47)

R.J. Young et al.
Compos. Sci. Technol.
(2012)
R. Sengupta et al.
Prog. Polym. Sci.
(2011)
J.R. Potts et al.
Polymer
(2011)
Z. Spitalsky et al.
Prog. Polym. Sci.
(2010)
X. Shi et al.
Carbon
(2012)
N.T. Dintcheva et al.
Carbon
(2014)
X. Shi et al.
Polymer
(2013)
M.-Y. Lim et al.
Carbon
(2014)
A. Sommazzi et al.
Prog. Polym. Sci.
(1997)
F. Garbassi et al.
Polymer
(1998)

J.C.W. Chien et al.

Polym. Degrad. Stab.

(1993)

G. Conti et al.

J. Mol. Struct.

(1993)

K. Kalaitzidou et al.

Compos. Sci. Technol.

(2007)

J. Dong et al.

Carbon

(2013)

M. Cano et al.

Carbon

(2013)

S. Stankovich et al.

Carbon

(2007)

X. Jiang et al.

J. Power Sources

(2012)

B.X. Du et al.

Polym. Degrad. Stab.

(2011)

M. Schmid et al.

Polym. Test.

(2003)

Y. Cao et al.

Carbon

(2010)

R. Gensler et al.

Polym. Degrad. Stab.

(2000)

X. Shen et al.

Carbon

(2014)

X. Wang et al.

Carbon

(2013)

Cited by (50)

Stabilization efficiency of graphene in γ-irradiated styrene-isoprene-styrene copolymer
2024, Radiation Physics and Chemistry
The stabilization efficiency of reduced graphene oxide (rGO) on the γ-irradiated styrene-isoprene-styrene copolymer (SIS) matrix is studied by chemiluminescence. The relevant protection effects of polymer against oxidation are obtained, when the inorganic phase is present in low concentrations (1, 2 and 3 wt%). The values of the characteristic kinetic parameters of degradation, namely oxidation induction time (OIT) and onset oxidation temperature(OOT) keep their figures in respect with pristine polymer. The γ-exposure of modified SIS probes to various doses up to 100 kGy demonstrates the appropriate ability of rGO to delay thermal and radiochemical oxidation. Because the oxidation strength increases as the rGO loading is greater, these stabilization formulations may be recommended as the appliable versions in the manufacture of long life polymer products. The coupling rGO with rosemary extract for the extension of polymer durability proves the favorable association between the two stabilization mechanisms: the interlayer scavenging shown by rGO and the proton substitution operated by the polyphenolic compounds existing in rosemary extract.
Impacts of polyketone-grafted carbon nanotube on the thermal, mechanical, and electromagnetic shielding performance of polyketone composites
2023, European Polymer Journal
We report the impacts of polyketone-grafted multiwalled carbon nanotube (CNT-g-PK) on the thermal, mechanical, electrical, and electromagnetic interference (EMI) shielding performance of polyketone (PK) composites. For this purpose, a masterbatch of 10 wt% hydroxylated CNT (CNT-OH) with 90 wt% glycidyl methacrylate-grafted PK (PKGMA) is manufactured by solution mixing and drying. It is then composited with neat PK to fabricate a series of PK/CNT-g-PK composites with varying CNT amounts of 0.5–5.0 wt% via reactive melt-compounding. Infrared spectral results confirm the successful formation of CNT-g-PKs in the melt-compounded composites through the reaction between the hydroxy group of CNT-OH and the epoxy group of PKGMA. Electron microscopic images of PK/CNT-g-PK composites reveal that CNTs are evenly distributed and tightly encapsulated in the composite matrices, indicating good interfacial adhesion between the reinforcing CNT filler and the PK matrix. Accordingly, the melt-crystallization temperature of the PK/CNT-g-PK composites increases as the CNT content increase owing to the nucleating agent role of CNTs, while the melt-crystallization/melting enthalpies decrease due to the mobility hindrance in the PK chains anchored by CNTs. The elastic storage modulus and tensile strength of PK/CNT-g-PK composites are significantly enhanced with increasing CNT content. The 1-mm-thick PK/CNT-g-PK composite with 5.0 wt% CNT exhibits high electrical conductivity of 6.98 × 10⁻⁴ S/cm and EMI shielding effectiveness of ∼22.4 dB in the X-band radio frequency range.
Enhancement in thermal stability and mechanical performance of modified polyketone/aramid short fiber composites with controlled interface
2023, Composites Part A: Applied Science and Manufacturing
The influence of aramid short fiber (ASF) on the rheological, thermal, and mechanical properties of thermoplastic polyketone (PK)-based composites is investigated. To attain improved interfacial adhesion between the ASF filler and the PK matrix, glycidyl methacrylate-grafted PK (PKGMA) is prepared by in situ melt-blending. The modified PK-based composites with various ASF contents of 0.5–10.0 wt% are manufactured via melt-compounding and injection-molding. The electron microscopic images show that ASFs at 0.5–7.0 wt% loadings are dispersed uniformly in the PKGMA-based composites and they have good interfacial bonding with the PKGMA matrix. The infrared spectroscopic analysis confirms the effectual modification of PKGMA and the presence of hydrogen bonding interactions as well as chemical reactions between the amide group of ASFs and the GMA group of the PKGMA matrix in the PKGMA/ASF composites, unlike a PK/ASF composite. The melt-rheological data support the existence of chemical grafting reactions of PKGMA on the ASF filler. As a result, the crystallization of the PKGMA matrix in the composites is hindered by the presence of the ASF filler. However, the thermal stability of PKGMA/ASF composites is improved noticeably. In addition, the tensile and dynamic mechanical moduli of PKGMA are improved most significantly with the addition of 7.0 wt% ASFs.
Understanding the molecular origin of the superior toughness of polyamide-6/polyketone blends by solid-state NMR spectroscopy
2022, Polymer
Polymer blending is a typical and conventional approach for integrating the excellent physical/chemical properties of individual polymer components. Specifically, the mechanical toughness and strength of polyamide-6 (PA6)/polyketone (PK) blend are substantially enhanced compared to either PA6 or PK individual component. Nevertheless, there are few atomic-level insights into such mechanical property enhancement. In this study, solid-state nuclear magnetic resonance (NMR) is utilized as a main tool to understand the molecular origin of the mechanical enhancement of PA6/PK blends. The proton relaxation times are used to evaluate the miscibility and domain sizes in PA6/PK blends, and to determine the crystallinity of each component, where both conventional DSC and WAXD experiments fail because of similar crystallization/melting behaviors of PA6 and PK components. 2D ¹H–¹³C WISE (wideline separation) and HETCOR (heteronuclear correlation) solid-state NMR spectroscopy were performed to further reveal the nano-heterogeneous structures and hydrogen bonding interactions in PA6/PK blend. With further combination with FTIR and SEM results, the previous characteristic morphological model for elucidating the toughening mechanism for PA6/PK blends is refuted, and it is proposed that the superior performance of PA6/PK blend is resulted from the synergistic effects of enhanced interfacial adhesion and interconnected interphase percolated in the bulk PA6/PK blends via hydrogen bonds. We envisage the detailed molecular level insights provided by solid-state NMR spectroscopy could assist in the bottom-up design of high performance polymer blend materials.
Lithium dendrite suppression by single-ion conducting gel polymer electrolyte cross-linked with graphene oxide
2022, Journal of Power Sources
This study presents a preparation of single-ion conducting gel polymer electrolytes (SPGEs) and their application for lithium metal battery systems. SGPEs are prepared by an in-situ cross-linking reaction of methacrylate-graphene oxide (MGO) and lithium cation conducting monomer (LiMTFSI) using poly(vinylidene fluoride-co-hexafluoropropylene) (PVH) as a matrix polymer. The SGPEs prepared by the in-situ cross-linking reaction with MGO are found to have highly porous structure leading to the high liquid electrolyte uptake and high ionic conductivity. The cross-linked SGPEs show improved mechanical strength, thermal and electrochemical stability compared with the SGPE without any MGO cross-linker. In addition, lithium dendrite growth is successfully suppressed by the cross-linked SGPE because it contains single ion conducting LiMTFSI moiety and MGO cross-linker having 2D structure with many lithiophilic moieties. As a result, lithium metal batteries assembled with SGPE show much improved cycle performance compared to the conventional Celgard-liquid electrolyte system.
Chapter 3: High-performance fibers based on flexible polar polymer molecules
2022, Advanced Industrial and Engineering Polymer Research
Polyethylene (PE) fibers based on ultra-high-molecular-weight polyethylene, UHMW-PE, have been developed successfully with outstanding specific values for strength and stiffness, at least at ambient temperature, as discussed in the previous chapters. But this relatively new class of high-performance PE fibers also possesses some limitations notably a relatively low melting temperature, appr. 150 °C, and relatively poor long-term properties viz. pronounced creep. The questions to be asked is whether other flexible polymer molecules as possible candidates for high-performance fibers are preferably available with stronger intermolecular interactions, i.e. hydrogen bonding or other polar interactions, than the weak Van der Waals interactions prevailing in between the polyethylene chains. In this chapter this question will be addressed and potential polymer candidates will be discussed.

View all citing articles on Scopus

View full text

Macromolecular NanotechnologyEffect of antioxidant grafted graphene oxides on the mechanical and thermal properties of polyketone composites

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Materials

Preparation of GO grafted with hindered phenol (HP-GO) and GO grafted with hindered amine (HA-GO)

Conclusion

Acknowledgements

Compos. Sci. Technol.

Prog. Polym. Sci.

Polymer

Prog. Polym. Sci.

Carbon

Carbon

Polymer

Carbon

Prog. Polym. Sci.

Polymer

Polym. Degrad. Stab.

J. Mol. Struct.

Compos. Sci. Technol.

Carbon

Carbon

Carbon

J. Power Sources

Polym. Degrad. Stab.

Polym. Test.

Carbon

Polym. Degrad. Stab.

Carbon

Carbon

Macromolecular Nanotechnology
Effect of antioxidant grafted graphene oxides on the mechanical and thermal properties of polyketone composites