Polycondensation Engineering Plastics

The additive analysis reported has been largely confined to conventional polymers (polyolefins, polycondensates, PS, PVC, etc.) Very little work, if any, has been reported on advanced engineering plastics. Similarly, also relatively little research activity has focused on additives in acrylics or blends. 

Maleic anhydride is an important intermediate in the chemical industry [8-9]. It is used in polycondensation and addition reactions. The end products of these reactions are polyesters, alkyd resins, lacquers, plasticizers, copolymers and lubricants. For example, the copolymer of styrene and maleic anhydride is an engineering plastic. 

Poly(phenylene-sulfide) has proven over several decades to be an important and versatile high performance engineering plastic and particularly useful as matrix of composites containing glass fiber, carbon fiber, electro conductive particles, etc. The classical syntheses are based on the polycondensation 1,4-dichlorobenzene with Na2S or on the polycondensation of 4-chlorothiophenol salts (220). In this connection intensive studies... 

Polyamides (PAs, except for those that are fully aromatic) represent a versatile group of plastics that have been successful for 70 years in the market of fibers, engineering plastics and specialties. Aliphatic polyamides and copolyamides (Scheme 7.1), obtained by a classical polycondensation of diamines and diacids, or a-amino acids (PA 66, PA 612, PA 610, PA 46, PA 11) or by the hydrolytic polymerization of lactams (PA 6, PA 12), belong to the group of highly valued semicrystalline plastics that are widely used in most branches of industry in some applications they are, as yet, irreplaceable. 

Figure 5.9 Effect of crystallinity on the solid-state polycondensation of PET, shown as the number-average molecular weight as a function of time. Conditions fluidized bed polymerization at 230°C particle size, 35-48 mesh superficial velocity of nitrogen, 43cm/s [6]. From Chang, T. M., Polym. Eng. Sci., 10, 364 (1970), and reproduced with permission of the Society of Plastics Engineers...

PolyQ>phenylene sulfide) (PPS) deserves much attention as an engineering and a conductive plastic and in some cases as a specialty polymer with excellent performance. Lenz first reported that PPS is synthesized by the polycondensation of / -halothiophenolate alkali-metal salts at high temperature [83], Commercially PPS is produced by the polycondensation of -dichlorobenzene and sodium sulfide in A-methyl-2-pyrrolidone [84]. These polymerizations proceed only at high temperature and pressure, and it is difficult to remove the metal halides such as sodium chloride as by-products in order to obtain pure PPS salt contamination degrades the electric performance and moldability. 

Throne, J. L., Plastics Process Engineering, Marcel Dekker, New York, 1979. Solomon, D. H. (ed.). Step Growth Polymerization, Marcel Dekker, New York, 1978. Kuchanov, S. 1., M. L. Keshtov, P. G. Halatur, V. A. Vasnev, S. V Vingradova, and V V Korshak, On the Principle of Equal Reactivity in Solution Polycondensation, Macro-mol. Chem., 184, 105-111, 1983. 

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