Toughened blends of polystyrene and ethylene-styrene interpolymers

Ethylene-styrene interpolymer (ESI) resins prepared using a constrained geometry catalyst have been found to make toughened blends with polystyrene (PS). At a low level in the blend, an ESI resin forms dispersed micro-domains of sub-micron size in polystyrene. At 40 %, an ESI resin makes a co-continuous blend that is both stiff and ductile. The toughening effect increases as the styrene content in the ESI resin increases peaking at an approximately 70 wt % of styrene. The results indicate that ESI resins are compatible with polystyrene and the compatibility increases as the styrene content in the resin increases.