Fremgangsmåde til forbedring af polystyrens styrkeegenskaber

1,153,205. Polystyrene/elastomer compositions. PHILLIPS PETROLEUM CO. 6 Sept., 1966 [7 Sept., 1965; 5 Jan., 1966], No. 39771/66. Heading C3P. Polystyrene is blended together with a rubbery polymer comprising at least one polymer of a conjugated diene, an inorganic or organic peroxy compound is incorporated in the blend in an amount sufficient to provide 0À25-6 millimoles of peroxy oxygen/100 g. of polymerized conjugated diene in the blend and the blend is heated to thermally decompose the peroxy compound. In examples, (1) the elastomer is a block copolymer of butadiene and styrene formed by first polymerizing styrene in cyclohexane and then the butadiene, using n-butyllithium as initiator, terminating the polymerization with liquid epoxidized polybutadiene and stabilizing the polymer with 2,6 - di - tert. - butyl - 4 - methylphenol and the peroxide is dicumyl peroxide which crosslinks the elastomer; (II) as (I) but also containing tris-(nonylphenyl) phosphite; (III) as (I) but using as the peroxide tert.-butyl peracetate or perbenzoate, 2,5-dimethyl-2,5-di- (tert.-butylperoxy) hexane, di-tert.-butyl peroxide, p-methane hydroperoxide, cumene hydroperoxide or tert.-butyl hydroperoxide; (IV) the elastomer comprises two different butadiene/ styrene block copolymers, the peroxide is bis-(α,α-dimethylbenzyl) peroxide, and the composition also contains thio-bisphenol; (V) the elastomer is a butadiene/styrene random copolymer produced by polymerizing in nhexane with n-butyllithium as catalyst with tetrahydrofuran as the randomizing agent or an emulsion copolymer of butadiene and styrene made using a rosin acid soap as emulsifier; and (VII) the elastomer comprises polybutadiene and a styrene/butadiene block copolymer, the polybutadiene being made in n-hexane using n-butyllithium as initiator which was inactivated with a mixture of C 16-18 fatty acids.