Change of mixing state of polybutadiene rubber–polyolefin resin blend by remilling and heat treatment

Abstract

AbstractThe change of the mixing state of polybutadiene rubber–polyolefin resin blend resulting from remilling and heat treatment was studied. Polyolfin resins studied here were high‐pressure polyethylene, low‐pressure polyethylene, and polypropylene. As in case of polybutadiene rubber–general purpose polystyrene resin blend, we made use of the results obtained through hardness and compression modulus measurement and microscopic observation. Even in case of polybutadiene rubber–polyolefin resin blend, the change of mixing state and the softening phenomenon by remilling were observed. The hardening phenomenon by heat treatment of the sample softened by remilling was also observed at high polyolefin resin content. But at low polyolefin resin content, the hardness which had increased once often decreased as the heat treating time increased, and in some cases the nonremilled sample was observed to soften with heat treatment. These phenomena attendant on heat treatment show that the intrinsic nature of a heterogeneous blend system also appears in a microheterogeneous polymer blend system.