Molecular simulation of the effect of graft structure on the miscibility of high‐impact polystyrene blends

Abstract High‐impact polystyrene (HIPS) is a kind of thermoplastic with good impact, which is considered to derive from the biphase of microstructure studied with SEM, etc. In this article, the influence of polystyrene (PS)/polybutadiene (PB) graft structure to the behavior of HIPS was studied through molecular simulation. The analysis of Flory‐Huggis parameter χ and radial distribution function (RDF) shows that the blend system of PS/PB has the best miscibility when the mass ratio of PS/PB is 60/40. In the toughening process, however, the graft copolymer PB‐g‐S is formed. For the PS/PB‐g‐S system with the same repeat unit of PS, PB‐g‐S chains with two grafts [PB‐g‐S(G = 2)] are better than PB‐g‐S chains with one graft [PB‐g‐S(G = 1)] in miscibility, which is in accord with the study of Fischer and Hellmann. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers