Applications of Polymer Alloys and Blends

There is a trend toward specialization in the polymer products industry. Since the industry is expanding globally, a sufficient market is available for these products. Blending is a convenient route to time-efficient and cost-effective upgrading of commodity resins and to tailoring these resins to specific performance profiles for the desired apphcation. The time to commercialization can now be reduced to less than one year for PAB s vs. 8-10 or more years for the synthesis of new polymers. The development of the latter can exceed 10 MM. 

After development, modifications can also be more easily implemented. Lor example, flame retardant (LR) grades of PAB s have been developed for the business machine and electronics markets. These materials combine high modulus, heat resistance, and impact strength in addition to LR. 

Costs can be reduced by blending engineering thermoplastics (ETPs) with less expensive commodity resins. Also, the distinction between plastics and elastomers can be breached by PAB s and is in fact narrowing. 

Advantages of PAB s blends for meeting application requirements can be summarized as follows  

Furthermore, the beneficial PAB properties for general applications include  

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Scobbo, J.J, Jr and Goetder, L.A. (2003) Applications of polymer alloys and blends, in Polymer Blends Handbook (ed. L.A. Utracki), Kluwer Academic Publishers, pp. 951-976. 

Dwyer [51] used a combination of chromatography and IR spectroscopy to provide a versatile tool for characterisation of polymers. HPLC-Fourier-transform IR spectroscopy interface systems deposit the output of a chromatograph on an IR optical medium, which is then scanned to provide data as a time-ordered set of spectra of the chromatogram. Polymer analysis applications described include the identification of polymer additives, the determination of composition/molecular weight distributions in copolymers, the mapping of components of polymer alloys and blends, molecular configuration changes in polymers, and component identification in complex systems. 

D IR spectroscopy has been applied extensively to studies of polymeric materials. A recent review of 2D IR spectroscopy cites numerous applications in the study of polymers by this technique [6]. In this section, some representative examples of 2D IR analysis of polymers are presented. We will start our discussion with a simple homogeneous amorphous polymer then move to more complex multiphase systems, such as semicrystalline polymers. Alloys and blends consisting of more than one polymer components are of great scientific and technical importance. Both immiscible and miscible polymer blend systems may be studied by 2D IR spectroscopy. Analysis of microphase-separated block copolymers is also possible. Finally, the possible application of 2D IR spectroscopy to the studies of natural polymers of biological origin is explored. 

One of the more recent applications of polymer blends and alloys is in plastics recycling. The current solid waste crisis has resulted in public demands for industrial solutions that would result in a reduction of all landfilled solid waste, while minimizing alternate negative environmental impact. It has been perceived by the public that plastic materials account for the overwhelming majority of the landfilled solid mass, when plastics account for only approximately 7 wt% of 18 vol%. 

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 conunerce amenable to polymer blend applications. 

Improving mechanical properties such as toughness usually serve as the main reasons for the development of novel thermoplastic alloys and blends [4]. Other reasons for blending two or more polymers together include (i) to improve the polymer s processability, especially for the high-temperature polyaromatic thermoplastics (ii) to enhance the physical and mechanical properties of the blend, making them more desirable than those of the individual polymers in the blend and (iii) to meet the market force (cost dilution). Most products succeed because of a beneficial combination or balance of properties rather than because of any single characteristic. In addition, a material must have a favorable benefit-to-cost relation if it is to be selected over other materials for a particular application. One key technical issue is whether the blend will exhibit additive properties, or not. In many cases properties are well below additive, while in others they may be above additivity. The property relationships exhibited by blends depend critically on the correct control of their phase behavior [3]. 

From the point of view of the applicability of the iso-free-volume concept, it is of great interest to test it for some systems more complicated than simple polymeric liquids, despite the fact that, as we have already shown, this concept has failed in many cases even for simple polymers. The more complicated cases considered are compositions and polymeric blends and alloys. 

Woddwide sales of poly (phenylene ether)—styrene resin alloys are 100,000—160,000 t/yr (47,96) annual growth rates are ca 9%. Other resin, particulady acrylonitrile—butadiene—styrene (ABS) polymers and blends of these resins with PC resins, compete for similar applications. 

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