A reactive polystyrene- block-polyisoprene star copolymer as a toughening agent in an epoxy thermoset.

A polystyrene- block-polyisoprene ((PS- b-PI)) star polymer was synthesized by photochemical reversible addition fragmentation chain transfer (RAFT) polymerization. The obtained star polymer was epoxidized and used as a toughening agent in an epoxy thermoset. The incorporation of the epoxidized star polymer resulted in the formation of nanostructures and it was fixed by a crosslinking reaction. The formation of nanostructures in the thermosets follows the mechanism of reaction-induced microphase separation. The mechanical properties such as toughness and tensile strength were considerably increased due to the nanostructures formed by reactive blending. [ABSTRACT FROM AUTHOR]