GB1336005A - Process for the production of butadiene-styrene-butadiene block copolymers - Google Patents

Abstract

1336005 Block copolymers and their preparation FIRESTONE TIRE & RUBBER CO 13 Nov 1970 [26 Nov 1969] 54245/70 Heading C3P Block copolymers of the formula B(SB) 1 to 3 , where each B is a butadiene polymer and each S is a styrene polymer, where each B block is equivalent to a molecular weight of at least 3000 and the total polystyrene present has a molecular weight of at least 4500, and where the S block(s) comprises 15 to 60% and the B blocks 40 to 85% of the polymer, and the B blocks comprise at least 50% 1,2-configuration, are obtained by sequential polymerization in the presence of difunctional anionic radical initiator reaction products of alkali metals with contiguous or fused ring aromatic hydrocarbons, 1,1-diphenyl ethylene or certain ketyls, and in the presence of certain polar (ether) compounds. The polymer may be cured with peroxides, optionally in the presence of fillers. The polymers may be used for moulding or in the production of laminates, particularly from prepregs of glass fibre mat, fabric or paper. In examples, butadiene-styrene three-(BSB), five-(BSBSB) and seven (BSBSBSB) block copolymers are formed in the presence of lithium or sodium biphenyl, sodium or lithium naphthyl, potassium anthracyl, lithium 1,1-diphenyl ethylene, sodium pyrene, potassium dihydrophenanthryl, lithium fluorene, sodium benzophenone, tetrahydro-furan or -pyran, dioxan, dimethyl ether, methyltetrahydrofuran, or the dimethyl ethers of ethylene glycols, and the products cured with dicumyl-, di-t-butyl-, di-t-amyl-, bis-(1,1-diphenylethyl) - or bis - (1,1 - dicyclohexylethyl)-peroxide. The monomers may be purified before use, e.g. styrene washed with NaOH and H 2 O, stored over CaSO 4 , refluxed over CaH 2 , distilled at 51‹ C. and 25 mm. of Hg. and stored over CaH 2 , and butadiene distilled over sodium/ fluorene, and then flash distilled.