EFFECT OF BLOCK COPOLYMER ARCHITECTURE ON COMPATIBILITY .1. EPOXIDIZED STYRENE BUTADIENE COPOLYMERS WITH CHLORINATED POLYMERS

The compatibility behaviour of epoxidized styrene-butadiene (SB) block copolymers of varying architecture with chlorinated polyethylene at two degrees of chlorination (36 and 48 wt%) and with poly(vinyl chloride) was investigated over the complete composition range. The copolymers were two diblock (SB) copolymers differing in their degree of purity and a multiarm block copolymer (SB)n. For comparison, data obtained previously with an epoxidized (E) triblock (ESBS) were also used. Other parameters examined were the degree of epoxidation to attain miscibility and the degree of chlorination. The techniques used were dynamic mechanical analysis, differential scanning calorimetry and tensile testing. It was demonstrated that epoxidized SB (ESB) is more miscible with chlorinated polymers than ESBS or E(SB)n with the same degree of epoxidation. Also E(SB)n is better in this respect than ESBS. The level of impurities (homopolymers and SBS) accompanying commercial samples of SB did not impair the tensile properties of these blends. The degree of chlorination was found to determine the required degree of epoxidation to obtain a miscible system.