Novel, high molecular weight poly(dimethylsiloxane) / cycloaliphatic polyester segmented copolymers were prepared and characterized. Specifically, polyesters based on dimethyl 1,4-cyclohexane dicarboxylate and 1,4-butanediol were employed. The copolymers were synthesized via a melt process using a high trans content isomer which afforded semi-crystalline morphologies. Aminopropyl terminated poly(dimethylsiloxane) oligonlers of controlled molecular weight were synthesized and then end capped with excess diester to form a diester terminated amide linked oligomer. The latter was then incorporated into the copolymer via melt transesterification step reaction segmented copolymerization. The molecular weight of the polysiloxane and chemical composition of the copolymer were systematically varied to prepare a series of segmented polyester / poly(dimethylsiloxane) copolymers. / Ph. D.