Block copolymers of diene having their terminal end blocks of a random copolymer of styrene or alkylstyrene and an alpha-methylstyrene, and their preparation

摘要

Block copolymers are prepared having end blocks with random copolymer of styrene and/or alkyl substituted derivatives and α-methylstyrene ranges from 1:0.5 to 1:2.5, a central block of a polydiene polymer joins the terminal blocks. The block copotymers contain from 10 to 90 weight percent of polydiene, the remaining portion being of random alkylstyrene-α-methylstyrene copolymer. The polymers range from medium impact polystyrene type polymer of low polydiene content to thermoplastic elastomers of high polydiene content.