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2014 | Buch

Polymer Blends Handbook

herausgegeben von: Leszek A. Utracki, Charles A. Wilkie

Verlag: Springer Netherlands

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Über dieses Buch

The Polymer Blends Handbook is a fundamental reference work on polymer blends, covering all aspects: science, engineering, technology and application. It will appeal to anyone working in the field of blends, researchers as well as engineers. The Handbook is designed to be the source of information on all aspects of polymer blends. To this end the Editors have put together an international group of highly respected contributors, each an expert in his chosen subjects.

Inhaltsverzeichnis

Frontmatter

Fundamentals

Frontmatter
1. Polymer Blends: Introduction
Abstract
While this chapter serves as an introduction to all the subsequent chapters, it is quite comprehensive. A brief history as well as information on polymer synthesis, nomenclature, and properties is provided. The need to formulate polymer alloys and blends and the resulting benefits are explained. Since the vast majority of polymer pairs are thermodynamically immiscible, compatibilization and reactive extrusion are necessary to improve interfacial adhesion and to optimize blend performance. How polymer morphology is influenced both by blend composition and the imposed process conditions is discussed first. This provides the theoretical basis for understanding the concept of polymer blending.
The raison d’etre of polymer blending is developing materials having enhanced performance. Performance itself depends on the polymer pair types employed, their relative amounts, extent of miscibility, nature and amount of compatibilizer used, and the method of blending. A key issue is the process of mixing polymers during which blends undergo a complex combination of shear and elongation and the evolution of blend microstructure becomes crucial and requires close attention. Each category of polymer pairs, from commodity resins and their blends, to engineering resins and their blends, and to specialty polymers and their blends is discussed in detail. Pertinent theoretical as well as experimental results are presented and reviewed.
The concern over environmental issues and sustainability has opened up another vibrant research field, namely, biobased and biodegradable polymer blends. An overview of major developments and recent trends in biodegradable blends with an emphasis on PLA blends are also discussed. This chapter closes with an outlook for the future of this important subject.
Leszek A. Utracki, P. Mukhopadhyay, R. K. Gupta
2. Thermodynamics of Polymer Blends
Abstract
This chapter summarizes the thermodynamics of multicomponent polymer systems, with special emphasis on polymer blends and mixtures. After a brief introduction of the relevant thermodynamic principles – laws of thermodynamics, definitions, and interrelations of thermodynamic variables and potentials – selected theories of liquid and polymer mixtures are provided: Specifically, both lattice theories (such as the Flory-Huggins model, Equation of State theories, and the gas-lattice models) and off-lattice theories (such as the strong interaction model, heat of mixing approaches, and solubility parameter models) are discussed and compared. Model parameters are also tabulated for the each theory for common or representative polymer blends. In the second half of this chapter, the thermodynamics of phase separation are discussed, and experimental methods – for determining phase diagrams or for quantifying the theoretical model parameters – are mentioned.
Evangelos Manias, Leszek A. Utracki
3. Crystallization, Micro- and Nano-structure, and Melting Behavior of Polymer Blends
Abstract
When the melt of a crystalline polymer is cooled to a temperature between the glass transition and the equilibrium melting point, the thermodynamic requirement for crystallization is fulfilled.
In a crystallizable miscible blend, however, the presence of an amorphous component, either thermoplastic or thermosetting, can either increase or decrease the tendency to crystallize depending on the effect of the composition of the blend on its glass transition and on the equilibrium melting point of the crystallizable component and also on the curing extent and conditions in case of thermosetting amorphous component. The type of segregation of the amorphous component, influenced by parameters such as crystallization conditions, chain microstructure, molecular weight, blend composition, and curing extent, determines to a large extent the crystalline morphology of a crystallizable binary blend. Separate crystallization, concurrent crystallization, or cocrystallization can occur in a blend of two crystallizable components. The spherulite growth of the crystallizable component in miscible blends is influenced by the type and molecular weight of the amorphous component, the former affecting the intermolecular interactions between both components and the latter the diffusion of the amorphous component. The blend composition, the crystallization conditions, the degree of miscibility and the mobility of both blend components, and the nucleation activity of the amorphous component are important factors with respect to the crystallization kinetics. The melting behavior of crystallizable miscible blends often reveals multiple DSC endotherms, which can be ascribed to recrystallization, secondary crystallization, or liquid-liquid phase separation. Complex crystallization behavior develops in miscible blends containing a crystallizable thermoplastic and a curable thermosetting component. That depends on the temperature and time of curing the thermosetting and also on whether crystallization is initiated before, during, or after the curing process.
For the discussion of the crystallization and melting behavior in immiscible polymer blends, a division into three main classes is proposed.
In blends with a crystallizable matrix and an amorphous dispersed phase, both the nucleation behavior and the spherulite growth rate of the matrix can be affected. Nucleation of the matrix always remains heterogeneous; however, the amount of nuclei can be altered due to migration of heterogeneous nuclei during melt-mixing. Blending can also influence the spherulite growth rate of the matrix. During their growth, the spherulites can have to reject, occlude, or deform the dispersed droplets. In general, the major influence of blending is a change in the spherulite size and semicrystalline morphology of the matrix.
A completely different behavior is reported for blends in which the crystallizable phase is dispersed. Fractionated crystallization of the dispersed droplets, associated with different degrees of undercooling and types of nuclei, is the rule. The most important reason is a lack of primary heterogeneous nuclei within each crystallizable droplet. An important consequence of fractionated crystallization may be a drastic reduction in the degree of crystallinity.
When two crystallizable components are blended, a more complex behavior due to the influence of both phases on each other is expected. In general, the discussion for matrix crystallization and droplet crystallization can be combined. However, crystallization of one of the phases can sometimes directly induce crystallization in the second phase. As a consequence, the discussion of blends of this type has been subdivided with respect to the physical state of the second phase during crystallization. The special case of “coincident crystallization,” in which the two phases crystallize at the same time, is discussed. Finally, the effect of compatibilization of crystalline/crystalline polymer blends is briefly reviewed.
A new section has been added, introduced to deal with crystallization phenomena in immiscible polymer blends containing nanoparticles. Recent reports, although few, discuss the effect of nanoparticles on crystallization and melting in immiscible polymer blends.
G. Groeninckx, C. Harrats, M. Vanneste, V. Everaert
4. Interphase and Compatibilization by Addition of a Compatibilizer
Abstract
Polymer blends are mixtures of at least two macromolecular species, polymers and/or copolymers. For practical reasons, the name blend is given to a system only when the minor component content exceeds 2 wt%. Depending on the sign of the free energy of mixing, blends are either miscible or immiscible. In a general sense, the polymer/polymer miscibility does not exist – it is always limited to a “miscibility window,” a range of independent variables, such as composition, molecular weight, temperature, pressure, etc. More than 1,600 of these “miscibility windows” have been identified for two-, three-, or four-component blends. The immiscibility dominates the field (Utracki 1989). For more details on the thermodynamics of mixing and phase diagrams, the reader is referred to Chap.​ 2, “Thermodynamics of Polymer Blends” in this volume. This chapter is an updated version of the 1998 version and addresses the aspects related to the interphase in immiscible polymer blends and their compatibilization by the addition of a compatibilizer. In the first part, theoretical aspects treating on the prediction of the distribution profiles, interface thickness, and interfacial tension are presented for immiscible homopolymer blends, copolymers, copolymer/homopolymer blends, and finally copolymer-added homopolymer blends. The second part deals with experimental aspects such as measurement techniques and comparisons of experimentally measured results with theory for the interfacial tension and thickness for the systems mentioned above. Finally, some information on patented polymer blends is presented in table form. The first two parts are updated at their end with related information from recent literature.
Abdellah Ajji
5. Reactive Compatibilization
Abstract
Reactive compatibilization of immiscible polymer blends by in situ copolymer formation is reviewed using approximately 1,100 examples taken from both journal articles and patents. Selected references in English through approximately 2013 to early 2014 are included. Important chemical reactions are illustrated which are useful for copolymer formation across a melt-phase boundary during melt processing of the immiscible blends. Focus is on irreversible chemical reactions taking place within typical extrusion residence times for polymer processing. Examples of block, graft, cross-linked, and degradative copolymer formation are shown. The illustrated chemical reactions and processes are also generally useful for compatibilization of immiscible polymer blends either not illustrated or not yet conceived.
S. Bruce Brown
6. Interpenetrating Polymer Networks
Abstract
An interpenetrating polymer network, IPN, can be defined as a combination of two polymers in network form, at least one of which is synthesized and/or cross-linked in the immediate presence of the other. This chapter presents the synthesis, morphology, and properties of IPNs made in different ways emphasizing bulk syntheses and latex syntheses. Some of the most interesting materials have a glassy polymer and a rubbery polymer combined. Usually, polymer I is synthesized, followed by polymer 2. If the reactions are noninterfering, both monomers can be mixed with their respective cross-linkers and initiators and polymerized simultaneously. Applications of IPN technology are broad, including sound and vibration damping, biomedical applications, coatings, adhesives, and golf ball components.
The morphology of IPNs has been widely investigated via electron microscopy and dynamical mechanical spectroscopy. Many IPNs have dual-phase continuity, with phase domain sizes of the order of several hundred angstroms. For sound and vibration damping over broad temperature ranges, the two polymers are mixed in different extents in different parts of the material, usually in the submicron range.
As examples of the biomedical materials, films to cover serious skin burns are used because of their capability of transporting moisture away from the burn site by diffusion while simultaneously transporting in oxygen to help keep the still living tissue cells alive and multiplying. The films are transparent, so that the doctors can see how the healing is progressing. Quite different materials make up false teeth, which are hard and tough and very crack resistant.
Structured latex particles were also introduced to provide multifunctional properties. Three component latexes with IPN cores as impact and damping improvers were prepared by three-stage emulsion polymerization. The IPN cores were composed of one impact part and one damping part.
L. H. Sperling, R. Hu
7. Rheology of Polymer Alloys and Blends
Abstract
This chapter presents an overview of some of the important principles and characteristics associated with the rheological behavior of polymer blends. Initially, the chapter reports the observations and the scientific laws that illustrate and govern the rheological behavior of classical suspensions and emulsions of simple non-polymeric liquids. It is indicated that one of the main characteristics that differentiates the rheological behavior of polymer blends from that of simpler liquids is the viscoelastic nature of polymers and their blends. The discussion also points out the relationship between blend morphology and rheology and the importance of surface energy effects, such as interparticle and interfacial interactions. The general rheological characteristics of miscible polymer systems are considered. However, since the majority of polymers are immiscible, the rheological behavior of immiscible polymer blends is considered in more detail, with allowance for both thermodynamic and morphological factors. The influence of flow on morphology, as in phase separation, drop deformation, breakup, and fiber formation are discussed. Both viscous and viscoelastic characteristics of blend behavior are described, under the influence of shear and elongational flow fields. Various examples are presented, based on the study of rheological behavior of blends in both rheological testing devices (parallel plate, rotational, steady state, oscillatory, capillary, elongational, etc.) and processing equipment (extruders, mixers, molds, dies, etc.). In many cases, the observed rheological behavior is compared to the predictions of theoretical, computational, or empirical models.
Musa R. Kamal, Leszek A. Utracki, A. Mirzadeh
8. Morphology of Polymer Blends
Abstract
In this chapter, as a guideline to control the phase separation morphology, the morphology formation mechanism is primarily explained. First the phase diagram and the phase separation mechanism are briefly explained to provide basic knowledge on controlling the morphology of polymer blends. Then, the effect of the shear flow on the phase diagram as a factor that influences the formation of the phase separation morphology is explained and the relation to the morphology control is shown. This is especially important in the polymer processing of polymer blends. Finally, as a control of the phase separation morphology using reactions, reaction-induced phase separation and reactive blending are explained. Because most polymer blends are immiscible, it is necessary to use some methods to obtain polymer blends that show good physical properties. Therefore, these are powerful tools for controlling the morphology in the polymer blends.
Toshiaki Ougizawa, Takashi Inoue
9. Compounding Polymer Blends
Abstract
In processing polymer blends, equipment selection, conditions, and formulation are highly important to control the final morphology. In this chapter, a review of the fundamentals in mixing (laminar, chaotic, dispersive, and distributive) is given before presenting the main limitations/problems related to interfacial properties, coalescence, and measure of mixing quality. Then, different methods and equipments are presented for lab-scale and industrial applications. A special focus is made on reactive system and phase compatibilization to improve the properties of the final blends. Also, nonmechanical techniques (solutions) are presented.
Leszek A. Utracki, G. Z. -H. Shi, D. Rodrigue, R. Gonzalez-Núñez

Properties

Frontmatter
10. Properties and Performance of Polymer Blends
Abstract
This chapter presents an overview of properties and performance of polymer blends. It is structured into nine sections dealing with aspects required for assessing the performance of a polymer blend. These are mechanical properties comprising of both low-speed and high-speed popularly studied properties; chemical and solvent effects; thermal and thermodynamic properties; flammability; electrical, optical, and sound transmission properties; and some special test methods which assumed prominence recently because of their utility.
Each section opens up with standard test methods such as ASTM, BS, DIN, and ISO for each property evaluation and is summarized. Since presentation of all test methods for each property is beyond the scope of this chapter, one popular test method is described in detail while others are discussed with reference to it. The factors controlling each property are also examined. Each section concludes with an outline of the state of the art pertinent to the aspect in focus. Definitions of all terms from each section are grouped together in Table 10.36.
Toughening plays an important role in designing polymer blends. Due emphasis has been given to this aspect by presenting the different methods of determining blend toughness, specially using ductile fracture mechanics; the mechanisms of toughening; and also the factors influencing toughness. Flammability aspect assumed a great deal of interest ever since the US Federal Trade Commission’s (FTC) action in 1972. Commercial exploitation of a polymer blend is regulated, since then, by its flammability characteristics. A brief review on factors affecting flammability is presented, and a list of fire-retardant chemicals is provided in Table 10.37.
The recent advances in optical properties, sound transmission properties, and certain “special testing methods” are presented at the closing of the chapter. These “special test methods” are not yet matured into international test methods but, nevertheless, are popularly used for meeting the requirements of certain applications. Hence, awareness of these methods is considered to be essential. The chapter concludes with perspectives for the future developments.
S. F. Xavier
11. Mechanical Properties of Polymer Blends
Abstract
Mechanical properties of polymer blends, including strength and toughness, are described in terms of morphology, resulting texture, and elementary deformation mechanisms and cavitation. Basic principles of toughening of blends based on glassy, crystalline, and thermoset polymers are described. Toughening strategies involving crazing, cavitation, crystal plasticity, and other micromechanisms involving energy dissipation are presented. Cavitation during deformation arising from mechanical mismatch between differently oriented stacks of lamellae in a semicrystalline polymer, decohesion at interfaces, as well as internal rubber cavitation contribute to the toughness by activation of other mechanisms of plastic deformation of the surrounding matter. Internal cavitation, although augmenting the toughness, greatly reduces the strength of the material. Micromechanisms that are engaged in rubber-toughened blends were characterized with significant attention. Matrix and dispersed-phase properties, as well as interfacial effects, were considered in the interpretation of structure–property relationship for incompatible and partially compatible polymer blends. The dispersion of the second component of the blend and its influence on stress concentrations around inclusions were discussed. The concept of easy deformation paths connected with interparticle distances and shear orientation was considered.
The function of the interfaces, including compatibilizers, in plastic response of polymer blends, is also analyzed.
Z. Bartczak, A. Galeski
12. Broadband Dielectric Spectroscopy on Polymer Blends
Abstract
In this chapter broadband dielectric spectroscopy (BDS) is employed to polymeric blend systems. In its modern form BDS can cover an extraordinary broad frequency range from 10−4 to 1012 Hz. Therefore, molecular and collective dipolar fluctuations, charge transport, and polarization effects at inner phase boundaries can be investigated in detail including its temperature dependence. In the first part of the chapter, the theoretical basics of dielectric spectroscopy are briefly introduced covering both static and dynamic aspects. This section is followed by short description of the various experimental techniques to cover this broad frequency range. To provide the knowledge to understand the dielectric behavior of polymeric blend systems, the dielectric features of amorphous homopolymers are discussed in some detail. This concerns an introduction of the most important relaxation processes observed for these polymers (localized fluctuations, segmental dynamics related to the dynamic glass transition, chain relaxation), a brief introduction to the conductivity of disordered systems as well as polarization effects at phase boundaries. Theoretical models for each process are shortly discussed. In the last paragraph the dielectric behavior of polymer blends is reviewed where special attention is paid to binary systems for the sake of simplicity. In detail the dielectric behavior of binary miscible blends is described. The two most important experimental facts like the broadening of the dielectric relaxation spectra and the dynamic heterogeneity of the segmental dynamics are addressed in depth. Appropriate theoretical approaches like the temperature-driven concentration fluctuation model and the self-concentration idea are introduced.
Huajie Yin, Andreas Schönhals
13. Physical Aging of Polymer Blends
Abstract
The selection of polymers and polymer blends for use as specific materials requires the consideration of how these will withstand the environmental conditions to which these will be subjected. The long-term stability of a polymer will depend on its aging characteristics both physical and chemical.
Physical aging is the term used to describe the observed changes in properties of glassy materials as a function of storage time, at a temperature below the glass transition, T g . This phenomenon is important mainly when the materials have a substantial amorphous content. For these materials, a quench from above T g into the glassy state introduces a nonequilibrium structure which, on annealing at constant temperature, approaches an equilibrium state via small-scale relaxation processes in the glassy state. The aging process can be detected through the time evolution of thermodynamic properties such as the specific volume or enthalpy or mechanical methods such as creep, stress-relaxation, and dynamic mechanical measurements. Here, the fundamental principles of physical aging will be described, and models that quantitatively describe the aging process are briefly described.
Physical aging effects have practical implications and need to be considered when assessing the long-term stability of polymers and polymer–polymer mixtures. This chapter focuses on a discussion of the effect of blending on physical aging and gives a review of the different experimental methods that can be used to compare aging rates in blends to those of the individual components.
J. M. G. Cowie, V. Arrighi
14. Degradation, Stabilization, and Flammability of Polymer Blends
Abstract
The thermal degradation and fire retardancy of polymer blends is covered in this chapter. Blends of PVC, polystyrenes, polyolefins, and polyamides are covered. The component parts of the blend may have the same stability as does its homopolymer or it may be less or more thermally stable. In some cases the relative amounts of the polymers may cause a change from a less thermally stable polymer to one which is more thermally stable. Thus, one can only determine through experimentation how making a blend will affect the thermal stability of its constituent parts.
Zvonimir Matusinovic, Charles A. Wilkie

Applications

Frontmatter
15. Applications of Polymer Blends
Abstract
This chapter builds on the information contained on the same subject in Chap. 13 of the first edition of the Polymer Blends Handbook by providing an overview of current applications of polymer blends and alloys with an outlook towards developing areas. A dual approach employed herein to portray the field covers both a description of polymer blend technologies directed toward solving application issues related to societal megatrends, as well as the generic performance/testing specifications required for products in broad areas of commerce amenable to polymer blend applications.
Lloyd A. Goettler, James J. Scobbo
16. High Performance Polymer Alloys and Blends for Special Applications
Abstract
This chapter discusses blends that are based on the use of high performance polymers. Both miscible and immiscible mixtures of such polymers are discussed and advantages that are provided by both types of blends are highlighted. It is pointed out that due primarily to the molecular conformation of high performance polymers the criteria for obtaining miscible mixtures of these type of polymers are different than for more flexible type polymers and the influence of the entropic energy of mixing is emphasized. The continued need for in-depth structure–property studies of blends that contain high performance polymers is stressed so that a better understanding of the molecular features that lead to miscibility can be obtained. In addition, the requirement of improved theoretical models that explicitly consider the molecular conformation of the two polymers in a mixture is discussed in detail.
Mark T. DeMeuse
17. Polymer Blends Containing “Nanoparticles”
Abstract
This chapter discusses the role of various nanoparticles in immiscible polymer blends for control of the size of the dispersed polymer phase particles, phase inversion and rheological behavior, impact strength, and mechanical performance. Various issues such as the effect of nanoparticle dimensions on the polymer particle size and properties, blending sequence, location of nanoparticles in the blend components, mechanism behind improvement in properties, individual effect of various fillers on the blend properties, and future trends are also discussed in detail. Since the literature on polymer nanocomposites is vast and the utilization of nanoparticles in blends has significantly increased in recent years, this chapter is designed to review the current state of knowledge in this area. To do so, various examples of polymer blends and nanofillers relevant to the abovementioned factors are discussed.
D. R. Paul, R. R. Tiwari
18. Polyethylenes and Their Blends
Abstract
Several books offer information on various aspects of polyolefin (PO) synthesis, technology, performance, as well as on the preparation, fundamentals, and degradability and recyclates of polymer alloys and blends (PAB) [Utracki and Weiss, Multiphase Polymers: Blends and Ionomers. ACS Symposium Series, vol. 395 (Washington, DC, 1989); Utracki Polymer Alloys and Blends (Hanser, Munich, 1989); J. Rheol. 35(8), 1615–1637, 1991; Encyclopaedic Dictionary of Commercial Polymer Blends (Chem Tec Pub., Toronto, 1994); Makromol. Chem. Macromol. Symp. 118, 335–345, 1997, Commercial Polymer Blends (Chapman & Hall, London, 1998); Zweifel, Stabilization of Polymeric Materials (Springer, Berlin, 1998); Moeller, Progress in Polymer Degradation and Stability Research (Nova Sci. Publ., New York, 2008); Anand (ed.), National Seminar on Emerging Trends in Plastic Recycling Technologies and Waste Management (Goa, India, 1995); Recycling and Plastics Waste Management, Proceedings of National Seminar (CIPET, Chennai, 1997); Akovali et al., Reprocessing of Commingled Polymers and Recycling of Polymer Blends. NATO ASI, vol. 351 (Kluwer, Dordrecht, 1998)]. There are also encyclopedic editions on PAB, e.g., Utracki [Encyclopaedic Dictionary of Commercial Polymer Blends (Chem Tec Pub., Toronto, 1994, 2013); Isayev (Encyclopedia of Polymer Blends (Wiley-VCH, Weinheim, 2010–2014)].
The first patent on PAB was granted to Parkes in 1846 for two natural polymers co-vulcanized during blending in the presence of CS2, i.e., a natural rubber (NR = amorphous cis-polyisoprene, IR) with gutta-percha (GP = semicrystalline trans-polyisoprene, IR). Thus, rubber PAB predates that of synthetic polymers by ca. 80 years (PMA/PVAc 1929). Notably, while the early plastics were bio-based, their usage fell to <5 wt% nowadays slowly recovering from the absolute dominance of synthetic, petroleum-based plastics.
PO is a part of the commodity resin category, where the continuous use temperature (CUT) ≤ 75 °C. Specifically, to this category belong polyethylenes (PE), polypropylenes (PP), styrenics (PS), acrylics (PMMA), and vinyls, such as poly(vinyl chloride) (PVC). The relative importance of commodity resin is evident from the data displayed in Fig. 18.1.
In the 1900s, world plastic production was about 30 kt, increasing to 300 Mt by the year 2010. Figure 18.1 shows the growth after 1960, extrapolated to 2020. Accordingly to Pardos Marketing [Pardos Marketing] plastic consumption is dominated by the commodity resins to the extent that the total consumption of plastics on the plot is indistinguishable from that of commodity resin. Notably, within the commodity resin category, PE contribution is 45–55 wt%.
The 75th anniversary of the invention of the first commercial PE seemed to be an appropriate occasion for summarizing in a (relatively) short chapter the factors that create such a vast spectrum of materials often having unexpected properties. Considering the character of the Polymer Blends Handbook – 2 (PBH-2), the Chapter provides concise, fundamental information in a historical perspective, starting with single PE resins before addressing PE blends. It also offers extensive tabulated data, useful for readers.
The chapter is divided into 19 parts, including classification of PE resin, their discovery and historical evolution, and methods and equipment of PE characterization, and then PE blends preceded by greatly abbreviated fundamentals and followed by description of various mixtures. In view of the importance of miscibility for processability and performance of PE blends, this aspect is particularly stressed.
Leszek A. Utracki
19. Commercial Polymer Blends
Abstract
In this chapter, an overview of the commercially important polymer blends is presented with a particular emphasis on the rationale for their commercial development, the compatibilization principles, their key mechanical properties, and their current applications and markets. To facilitate the discussion, the commercial polymer blends have been classified as follows into 13 major groups depending on the type of the resin family they are based on.
(i)
Polyolefin blends
 
(ii)
Styrenic blends
 
(iii)
Vinyl resin blends
 
(iv)
Acrylic blends
 
(v)
Elastomeric blends
 
(vi)
Polyamide blends
 
(vii)
Polycarbonate blends
 
(viii)
Poly(oxymethylene) blends
 
(ix)
Polyphenyleneether blends
 
(x)
Thermoplastic polyester blends
 
(xi)
Specialty polymer blends
 
(xii)
Thermoset blend systems
 
(xiii)
Biodegradable polymer blends
 
Within each major category, the individual polymer blends of industrial significance have been described with relevant data. Since the discussion is limited only to those blends that are actually produced and used on a commercial scale, the relevant cost and performance factors that contribute to the commercial viability and success of various types of blends have been outlined.
In comparing the different blends, the specific advantages of each type, as well as any potential overlap in performance with other types of blends have also been discussed. The fundamental advantage of polymer blends, viz., their ability to combine cost-effectively the unique features individual resins, is particularly illustrated in the discussion of crystalline/amorphous polymer blends such as the polyamide and the polyester blends. Key to the success of many commercial blends, however, is the selection of intrinsically complementing systems or the development of effective compatibilization methods. The use of reactive compatibilization techniques in commercial polymer blends has also been illustrated under the appropriate sections such as the polyamide blends.
In many commercial blends, rubber toughening plays an important and integral part of the blend design. Combining high impact strength with other useful properties such as heat and solvent resistance can significantly enhance the commercial value of a blend. Hence, the nature of the impact modifiers used and the role of morphology on properties have been discussed under the appropriate cases of commercial blends. The chapter concludes with an outline of the potential trends in the commercial polymer development.
M. K. Akkapeddi
20. Recycling Polymer Blends
Abstract
Starting with the second half of the 1970s, polymer recycling was extensively adopted to reuse plastics otherwise destined for landfills with the goal to avoid the consequent net loss of money and energy. The simple idea to reintroduce scraps or post-consumer plastics in the processing lines actually revealed complications because even adding the recycled polymer to the same virgin material often led to secondary materials due to differences in the molecular weight, branching, and difference of density. The situation appeared more complicated in the recycling of commingled plastics. In this case, the chemical nature and structures of the different components produce secondary materials with poor properties, thus inhibiting any possible practical application. Nevertheless, enforcement of the law about mandatory collection of post-consumer plastic and the repeated economic crises pushed toward the implementation of recycling of polymer blends in industrial processes, especially if the same processing equipments/methods used for virgin materials can be adopted. In this chapter a review of the recycling technologies of plastic blends is presented. In particular, the mechanical recycling of single polymers in the same virgin materials (the so-called “homopolymer” blends), typical in the on-site reuse of industrial scraps, and, in another section, the strategies that can be pursued to recycle directly a stream of commingled post-consumer plastics to obtain secondary materials with properties suitable for practical applications are analyzed.
Francesco Paolo La Mantia, Roberto Scaffaro
21. Miscible Polymer Blends

Miscible polymer blends were once considered a rarity. However, extensive research has led to the discovery of a large number of miscible polymer blends. This Chapter is a compilation of miscible polymer blends reported in literature up to 2012.

Suat Hong Goh
Backmatter
Metadaten
Titel
Polymer Blends Handbook
herausgegeben von
Leszek A. Utracki
Charles A. Wilkie
Copyright-Jahr
2014
Verlag
Springer Netherlands
Electronic ISBN
978-94-007-6064-6
Print ISBN
978-94-007-6063-9
DOI
https://doi.org/10.1007/978-94-007-6064-6

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