Elastomers special fiber-elastomer

The nomenclature rules say that the trivial names of common polymers need not necessarily be replaced by structural names. Therefore, both trivial and structural names of polymers will be used in this book. Standard abbreviations of trivial names (see Table A1 in the Appendix to this book) will generally only be used in diagrammatic illustrations. For further information, a special table (Table A2 in the Appendix) gives trade names of some important plastics, elastomers, and fibers. 

Polymer science is a specialized field concerned with the structures, reactions, and applications of polymers. Polymer scientists generate basic knowledge that often leads to various industrial products such as plastics, synthetic fibers, elastomers, stabilizers, colorants, resins, adhesives, coatings, and many others. A mastery of this field is also essential for understanding the structures and functions of polymers found in living things, such as proteins and deoxyribonucleic acid (DNA). 

Section B lists, in alphabetical order, the abbreviations and acronyms for thermoplastics, thermosets, fibers, elastomers, and additives. Sections C and D list the abbreviations for polymers, based on their monomeric imits and characteristic groups, respectively. Section E contains abbreviations and acronyms for polymers obtained by chemical transformation of base polymers. Section F contains special abbreviations for blends, reinforced polymers, etc., and Section G the ISO and DIN codes for plastics. Section H lists the special abbreviations connected with the recycling of plastics. Recommended abbreviations and acronyms for elastomers and fibers are given in Sections I and J, respectively. 

Finally, for practical reasons it is useful to classify polymeric materials according to where and how they are employed. A common subdivision is that into structural polymers and functional polymers. Structural polymers are characterized by - and are used because of - their good mechanical, thermal, and chemical properties. Hence, they are primarily used as construction materials in addition to or in place of metals, ceramics, or wood in applications like plastics, fibers, films, elastomers, foams, paints, and adhesives. Functional polymers, in contrast, have completely different property profiles, for example, special electrical, optical, or biological properties. They can assume specific chemical or physical functions in devices for microelectronic, biomedical applications, analytics, synthesis, cosmetics, or hygiene. 

Aqueous systems have been studied by a very large number of investigators. Economy, safety, convenience and quality of product have combined to make this the method of choice for commercial production of copolymers. The industrial importance of such end products as elastomers and acrylic fibers has been a special incentive to related fundamental studies. Furthermore, the relatively high solubility of acrylonitrile monomer in water coupled with insolubility of the polymer make it a convenient test monomer for studies of initiation by redox systems (6, 25, 102). Large numbers of homogeneous chemical initiators and some heterogeneous initiators have been studied as well as initiation by photochemical means, by ultrasonics and by ionizing radiation. It will not be possible here to review the enormous world literature. Several publications (/, 92, 117) refer in some detail to the older papers, and we shall restrict our comments to recent interpretations that have received support from several quarters. 

Block copolymers were developed rapidly in the 1960s when living anionic polymerization was first utilized to synthesize triblock thermoplastic elastomers or elastoplastics. At the same time, step or condensation polymerization to produce thermoplastic polyurethanes, urea-urethane spandex fibers, and later more specialized materials, such as the semicrystalline polyester-polyether copolymers were developed [10]. Imide block or segmented copolymers utilizing... 

A hybrid composite [121,122] can contain more than one type of reinforcement and/or more than one type of matrix, with the objective of improving or lowering the cost of the basic composite [123]. The second reinforcement may be a fiber (continuous or chopped), particles or whiskers. The fiber reinforcement can be in the same laminae and interspersed using any textile process such as weaving, or in different laminae, interspersing plies to obtain the desired mechanical/ physical properties. A sandwich composite is a special case which has an interlayer of a material such as A1 foil or a honeycomb. The matrix may be different for each type of reinforcement, or added to infiltrate the reinforced matrix (e.g. a thermoplastic resin such as PSU) to confer controlled viscosity in the matrix, or an elastomer (e.g. CTBN) for increased toughness. 

MDI is available commercially in several forms. The pure 4,4 -diisocyanatodiphenylmethane is a crystalline solid at room temperature and is used only for fiber and some very special elastomer products. There are forms of MDI that are liquid at room temperature and have a slightly higher functionality, between 2 and 3 (22). A typical liquid MDI is a mixture of MDI and its dimer and trimer and can be represented as follows ... 

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