Rubber, polybutadiene, uses

According to the mass process, polybutadiene rubber is dissolved in the mixed solution of styrene and acrylonitrile monomers, and then the reaction proceeds to prepare the ABS resin. For polybutadiene rubber, the method for grinding and then adding the rubber is utihzed. Contrary to the emulsion process, the particles of polybutadiene rubber are not present before the reaction, and therefore, the shape and distribution of particles appear to be different from those of the emulsion process. The molecular weight of polybutadiene rubber to be used is about 200,000, with the cis-1,4 ratio being about 40%. The amoimt of polybutadiene rubber used should be kept to 20% due to the problem related to a viscosity of polymerization solution. 

Let us consider the determination of molecular characteristics S and for butadiene-styrene rubber. As it is known [15], the value of macromolecule diameter square is equal to for polybutadiene - 20.7 and for polystyrene - 69.8 A. Calculating the macromolecule, simulated as cylinder, cross-sectional area for the indicated polymers according to the known geometrical formulae, let us obtain 16.2 A and 54.8 A, respectively. Further, accepting as S for butadiene-styrene rubber mean value of the cited above areas, let us obtain S=35.5 A. Further the characteristic ratio can be determined, which is a polymer chain statistical flexibility indicator [16], with the aid of the following empirical formula [14] ... 

In recent years, chemically modified polymers have gained an increasing importance in the manufacture of rubbers and plastic materials. Unsaturated polymers are particularly suitable for such transfomiations. It seemed to us in 1990 that a complementary approach to radical-initiated copolymerization of ethylene-carbon monoxide would be the reaction of polybutadiene with carbon monoxide under free radical conditions (eq 3). Due to the entropy factors, which are favorable in unimolecular reactions, it was expected that mild experimental conditions would be suitable, i.e. relatively low reaction temperature and pressure. Furthermore, it was hoped to find some special properties in this material containing polycyclopentanonic units. From the chemical point of view, the expectation turned out to be partidly correct. 

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