MOLECULAR DESIGN OF MULTICOMPONENT POLYMER SYSTEMS .18. EMULSIFICATION OF HIGH-IMPACT POLYSTYRENE AND LOW-DENSITY POLYETHYLENE BLENDS INTO HIGH-IMPACT ALLOYS

The interfacial activity of a hydrogenated polybutadiene‐polystyrene tapered diblock copolymer, (HPB‐b‐PS) is investigated in blends of a low density polyethylene (LDPE) with a high impact polystyrene (HIPS) prepared in the melt state on a two‐roll mill. Optical and scanning electron microscopy examinations of smoothed or fracture surfaces and also surfaces obtained after THF‐extraction of PS phases demonstrate that the copolymer promotes the dispersion and interfacial adhesion of the components, whatever the composition and is able to create and stabilize particular dispersions of the rubber particles in these blends. Tensile and Charpy impact properties are also very significantly improved. All these features demonstrate that the ductility and toughness of PS and LDPE/PS blends can be closely controlled by adequate combinations of rubber particles and a HPB‐b‐PS copolymer. Copyright © 1990 Society of Plastics Engineers