Thermoplastic blends of physically crosslinked multiblock copolymers and copolymers with uniform grafts

Abstract Two multiblock copolymers of styrene and propylene oxide and four acrylate copolymers with uniform polystyrene grafts were prepared and blended. The blends are melt processable and their properties varied from thermoplastic elastomers to toughened plastics. The relationship between mechanical properties and composition of the thermoplastic blends indicated that all the blends exhibited a synergism, which is probably due to the increase of miscibility between the components caused by the same physical crosslinks — the glassy domains aggregated from both the polystyrene grafts and polystyrene blocks. The synergistic effect seemed more evident when two different graft copolymers were blended together than when one multiblock copolymer was blended with one graft copolymer. In all cases a maximum tensile strength appeared at the blend with 90 wt.‐% of the component, possessing higher tensile strength and ultimate elongation.