| abstract |
1,264,741. Alphamethylstyrene block copolymers. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. 31 March, 1970 [1 April, 1969], No. 15180/70. Heading C3P. A block copolymer of the formula in which each A is a random copolymer block of styrene and alphamethylstyrene and each B is a conjugated diene polymer block, an alpha olefin polymer block or a hydrogenated conjugated diene polymer block, is obtained by (a) sequential polymerization using a mono- or difunctional lithium compound as initiator or (b) forming a two-block copolymer and coupling, using a polar additive in the alpha-methyl styrene polymerization. The product may be hydrogenated. In examples, B is formed from butadiene, the initiator is a s-butyl lithium or lithium-alphamethylstyrene reaction product, the polar additive is tetrahydrofuran, and the coupling agent in the former case is phenyl benzoate. |