| Abstract: | Block copolymers were synthesized by the condensation of dihydroxyl-terminated poly-(α-methylstyrene) oligomers and bisdimethylamino-terminated poly(dimethylsiloxane) oligomers. Manipulation of block molecular weight produced copolymers ranging in composition from 21% to 73% poly(dimethylsiloxane). Compression moldablity was found to be good. Physical properties were dependent upon siloxane content, varying from high modulus, low elongation to low modulus, high elongation materials. High siloxane-content compositions exhibited elastomeric properties due to the two-phase morphology of these systems. Glass transition temperatures were observed as low as ?120°C for the poly(dimethylsiloxane) block and as high as + 140°C for the poly(α-methylstyrene) block. Even higher poly(α-methylstyrene) transition temperatures may be possible by using higher molecular weight oligomers. |
