Miscibility of some chlorinated poly(hydrocarbons) with ethylene-acrylic rubber

The compatibility of an ethylene-acrylic rubber (R) with poly (chloroprene) (CR) and two chlorinated poly-ethylenes, containing 48 (CPE 48) and 25 (CPE 25) wt.-% chlorine, was investigated. Blends with the latter polymer were studied in the complete composition range. The techniques used were phase-contrast microscopy, differential scanning calorimetry, dynamic mechanical and stress-strain testing. The single T_g relaxation of blends and its almost linear variation with composition, together with results obtained using the techniques mentioned, support the view that the systems are miscible at the segmental level. At low rubber contents an antiplasticisation effect was observed for the R/CPE 25 system. At high rubber compositions a small reduction of crystallinity and a melting point depression of the PE phase in CPE were observed. Various equations proposed to predict the T_g of blends and their modulus using pure component data were also tested at varying compositions and temperatures.