42 - STEREOSPECIFIC CATALYSIS AND STEREOISOMERIC POLYMERS. PREPARATION OF FIBRES, PLASTICS AND NEW ELASTOMERS

Abstract

This chapter discusses stereospecific catalysis and stereoisomeric polymers, and the preparation of fibers, plastics, and new elastomers. The stereospecific polymerization processes are of great advantage because one can obtain long linear chains by poly addition of vinyl monomers. These chains consist of sequences of monomeric units with tertiary carbon atoms with the same steric configuration. The discovery of the processes of stereospecific catalysis has brought a revolutionary initiative in macromolecular chemistry. In the case of diolefins, the newly-discovered processes of stereospecific polymerization not only made possible by synthesis the obtainment of crystalline polymers corresponding to two types of geometric stereoisomery, which are present in natural rubber and guttapercha, but also have led to other stereoisomers which do not exist in nature. The importance of stereospecific catalysis in the field of plastics is because of the fact that said catalysis makes it possible to investigate a vast new branch of macromolecular chemistry and to produce new classes of linear and highly crystalline polymers. Furthermore, the discovery of the highly crystalline isotactic polymers has shown that very high tenacity fibres can be obtained from macromolecules of pure hydrocarbons, free of hydrogen bonds, and polar groups.