Abstract: A method of improving the stress crack resistance of an impact modified styrenic polymer comprising (a) combining about 95 to about 99.5 wt. % of an impact modified styrenic polymer with about 0.5 to about 5 wt. % of a polymer solution comprising about 25 to about 75 wt. % polyisobutylene and about 25 to about 75 wt. % of a polyolefin comprising one or more C2 to C12 alpha olefins.

Abstract: A rubber modified polystyrene composition that includes the reaction product formed by polymerizing a monomer mixture containing at least 75 weight percent of one or more monovinylaromatic monomers in the presence of rubber particles to form a dispersion of rubber particles in a vinyl aromatic polymer. The dispersed rubber particles have an average particle diameter of from about 6 to about 10 microns. The composition has a gel content of from about 28% to about 36% by weigh. The composition has a swell index of less than 13 and contains no more than 2 wt. % of plasticizers. The present composition can be used as a refrigerator liner material. The liner material can be down gauged while maintaining desirable performance characteristics.

Abstract: A method of improving the stress crack resistance of an impact modified styrenic polymer comprising (a) combining about 95 to about 99.5 wt. % of an impact modified styrenic polymer with about 0.5 to about 5 wt. % of a polymer solution comprising about 25 to about 75 wt. % polyisobutylene and about 25 to about 75 wt. % of a polyolefin comprising one or more C2 to C12 alpha olefins.