Heterocoagulation of polychloroprene on natural rubber latex particles for use in the preparation of toughened polystyrene

The toughness of high‐impact polystyrene based on γ‐radiation‐vulcanized natural rubber (NR) was effectively enhanced by the addition of a block copolymer at the NR/polystyrene interface. An NR/polychloroprene (CR) composite latex particle was produced by the heterocoagulation technique for its use as a model in a compatibilization study. A nonionic surfactant (Tween 80), whose molecule bore poly(ethylene oxide) (PEO), was adsorbed onto the CR particle and allowed to form a complex between PEO and an indigenous surfactant (protein–lipid) on the NR particle surface. The presence of CR–Tween on the outer layer of the obtained composite polymer particle was characterized by the particle size, ζ potential, and glass‐transition temperature. That the film cast from the heterocoagulated latex showed better oil resistance than the NR film confirmed the NR/CR core–shell structure. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 9–13, 2003