Multicomponent Polymeric Materials

Multicomponent polymeric materials consist of polymer blends, composites, or combinations of both. A polymer blend has two definitions The broad definition includes any finely divided combination of two or more polymers. The narrow definition specifies that there be no chemical bonding between the various polymers making up the blend. Table 2.5 and Section 2.7 summarize the basic types of polymer blends based on the broad definition primarily these are the block, graft, star, starblock, and AB-cross-linked copolymers (conterminously grafted copolymers), interpenetrating polymer networks, as well as the narrow definition of polymer blends. More complex arrangements of polymer chains in space can be shown to be combinations of these several topologies. 

Basically a polymer composite contains a polymer and a nonpolymer. While polymer composites include such compositions as foams and some types of gels, this chapter will be restricted to compositions of one or more polymers and one or more nonpolymers in the bulk state. There are a few points of overlap between blends and composites polymer-impregnated wood (where wood itself is a natural polymer blend), and organic fiber (e.g., polyester) reinforced plastics constitute examples. Compositions of special interest to this chapter include glass fiber reinforced plastics, carbon black reinforced rubber, and mineral-pigmented coatings. 

Since no multicomponent polymeric material can exist without interfaces, the reader s attention is called to Chapter 12. In brief, the nature and extent of bonding between the various phases critically determines the mechanical strength and other properties of the material. 

Introduction to Physical Polymer Science, by L.H. Sperling ISBN 0-471-70606-X Copyright 2006 by John Wiley Sons, Inc. 

Types of overall properties include mechanical behavior, electrical conductivity, diffusion coefficients, and biomedical compatibility, among many others, not the least of which is price. While this last will not be emphasized in this text, many blends and composites are manufactured because they contain one or more very low price components. If a product can be produced with 90% of the properties with 50% of the cost, that product has a very important advantage in today s world. 

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For convenience, multicomponent polymeric materials based on cellu-losics may be grouped into three classes, namely (a) combinations of wood with plastics (WPC), (b) mechanical mixtures in the form of fibers, such as cotton/polyester staple-mixed fibers and cellulosic fiber-filled polymer sheets, and (c) incorporations of cellulosics at a hyperfine structural level. The latter can be further ramified, for instance as follows ... 

Multicomponent polymeric materials with microheterogeneous mophologies include a number of polymer blends and block copolymers, however, an especially easy way to bring about the desired morphology is through interpenetrating polymer networks. Several papers in the symposium are concerned with IPN s and related materials. 

It is often necessary to convert between the mole fractions (m), weight fractions (w) and volume fractions () of the components in dealing with multicomponent polymeric materials such as copolymers, blends and composites. The equations needed to make these conversions are listed below, for the i th component of an n-componcnt system. In these equations, p is the density, M is the molecular weight per mole, and V is the molar volume. 

In the last 10 years a new very interesting and actual subject was approached, namely—multicomponent polymeric materials. The development of modem... 

Paul, D.R. (1985) Polymer blends. Phase behavior property relationship in Multicomponent Polymeric Materials (Eds D.R. Paul, LH. Sperling), AtAmices in Chemistry Series, 211, American Chemical Society, Washington D.C.,... 

Quantitative prediction of the dependence of elastic moduli on the properties of constituents and the material composition for multicomponent polymeric materi-... 

Nomenclature. The IPNs have a well-developed nomenclature (9), as do most multicomponent polymeric materials (10). Thus, a cross-linked polymer network is indicated by the prefix net-, and an IPN is indicated by the connective -ipn-. Thns, an IPN of polybutadiene and polystyrene is written as... 

THE MODULUS OF MULTICOMPONENT POLYMERIC MATERIALS 701 Integrated composite analyzer (ICAN)... 

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