Commercial Applications of Polymer Blends

Several reviews of commercial applications involving polymer blends will provide a more complete discussion than possible in this book [ 1—3 ]. The more recent review by Akkapeddi [3 ] provides a comprehensive overview and the book edited by Utracki [2] provides a listing of the commercial blends available as of 1994. The most comprehensive review is given by Utracki [4], which lists commercial blends and presents a detailed analysis of the patent literature involved with polymer blends. 

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The commercial application of polymer blend technology has grown significantly such that, today, compositions are available with properties that once were substantially unattainable with homopolymers. To date, polymer blends have been applied in optical fibers [13,14], microlenses [15], liquid crystal display components [16,17], solar cells [18-20], nonionizing radiation detection [21] and polymer light-emitting diodes [22-24]. In particular, the use of developed polymer blends in optoelectronics applications appears unlimited. Polymer blends may also provide model systems in statistical physics when studying the fundamental aspects of equilibrium and nonequilibrium properties [3], optical properties [25], and mechanical and electrical properties [26]. 

Applications of Polymer Blends Commercial Polymer Blends Compounding Polymer Blends... 

The primary motivation for the commercial development of polymer blends has been to adjust the cost-performance balance and tailor-make products for specific end-use applications. Thus the commercial growth of polymer blends in the last several decades outpaced the growth rate of existing polymers by at least 2 %. The demand for polymers and the polymer blends will continue to increase as the global economy continues to grow. Several key factors contribute to the commercial success and continued interest in the polymer blends, such as those listed below ... 

Tihe technological properties and the commercial application of several polymer blends have been studied extensively. Investigations of the basic principles, however, relating the phase structure of the blends to the properties of the individual components have not been carried out to an extent justified by the industrial value of these materials. Several methods have been used, the most successful being optical and electron microscopy and dynamic-mechanical measurements. Critical factors and difficulties in the morphological studies of polymer blends have been... 

Examples of Commercial Blends. In this subsection we will review some of the commercial activity in polymer blends. We find it interesting and informative to categorize examples into specific areas that relate to both technical issues associated with these mixtures, such as miscibility or crystallinity, and the intended commercial applications, such as rubbers or fibers. Other schemes of classification could be used, and the present one is not intended to be exhaustive. Likewise, there is no intent to mention all of the commercially interesting polymer blends, but rather, the present purpose is to illustrate some of the possibilities. Information about the examples used here was obtained from product literature supplied by the companies who sell these blends and from various literature references that have attempted to review commercial developments in polymer blends (70-76). 

Polymer blends have become a very important subject for scientific investigation in recent years because of their growing commercial acceptance. Copolymerizalion and blending are alternative routes for modilications of properties of polymers. Blending is the less expensive method. It does not always provide a satisfactory alternative to copolymerization, of course, but polymer blends have been successfully used in an increasing number of applications in recent years. Such successes encourage more attempts to apply this technique to a wider range of problems in polymer-related industries. 

Ternary blends that comprise two immiscible polymers and a copolymer are of a particular interest. They not only represent an ideal model for studying compatibilization of polymer blends, but also they have found direct commercial applications. Phase diagram information can be found in reviews by Ajji and Utracki [1996, 1997] and in Chapter 2 in this Handbook. 

The worldwide commercialization of polymer blends has been directed at the replacement of traditional materials, such as metals and ceramics. Even though plastics can be more costly than other types of materials on a weight basis, they are often more economical in terms of production and manufacturing cost, mainly attributed to the less complex assembly of plastic parts that can be easily formed in complex-finished shapes [1, 21-26], Blending is a convenient route to the time-efficient and cost-effective upgrading of commodity resins and to the tailoring of these resins to specific performance profiles for the desired application. The most common polymer blends and their applications are described below. 

Polymer blends, i.e. mixtures of two or more polymeric components, are of increasing commercial importance for a number of applications. The advantage of polymer blends is the useful combination of the properties of the components without creating chemically new polymers. This approach in many cases is more feasible than developing new tailor-made polymer structures. 

The concept of transesterification of polyesters has been previously discussed in detail . Application to commercial polymers, however, has only begun recently, partly because of limited industrial development of new polymers. Moreover, as most pairs of polymer blends are incompatible, partially or completely reacted polymer pairs, i.e., block or random copolymers, could well exhibit better properties than the corresponding polymer blends because of the homogenizing effect of new copolymers made by coreaction. 

However, no single material possesses all of these qualities. Those that are chemically resistant are difficult to process, and vice versa. These limitations have been overcome by the formation of polymer blends for membrane application. Polymer blends of many types have become the dominant material class of polymers in commercial practice over the last 30 years with much research in this area. 

This chapter will divide the advancements in rubber nanocomposites as a function of polymer type. One should be aware that polymer blending is very prevalent in commercial applications of rubber. For example, a tire can contain eight different polymer types. 

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