THE STUDY OF VARIOUS STYRENE-BUTADIENE COPOLYMERS AS COMPATIBILISERS IN BULK BLENDS OF POLYSTYRENE POLYBUTADIENE/

blends, produced by compositional quenching, were used to examine the effectiveness of different styrene-butadiene copolymers as interfacial agents in blends of polystyrene (PS) with polybutadiene (PB). Each po lymer blend was compression molded for various times to allow particle ripening and was then tested for impact strength. The most effective compatibiliser proved to be a long, asymmetric diblock, which could en tangle in both homopolymer phases. Diblocks with short PS segments wer e inadequate as interfacial agents, presumably because their short PS blocks were easily pulled from the matrix. Random copolymers with a co mposition near 50/50 were successful as interfacial agents, but the im pact strength declined with a decrease in PS composition of the copoly mer. A commercial multiblock copolymer, Phillips K-Resin(R), also prov ed to be reasonably effective compatibiliser, giving better impact str ength than the HIPS control. (C) 1998 Elsevier Science Ltd. All rights reserved.