Curing behavior and final properties of nanostructured thermosetting systems modified with epoxidized styrene-butadiene linear diblock copolymers

Nanostructured thermosetting materials based on thermosetting matrices were prepared by modification of an epoxy system with linear PS-block-PB copolymers. The nanostructured thermosets were obtained through PS block segregation. Depending on the block-copolymer content in the thermosets and its epoxidation degree, the PS domains can display micellar, worm-like or hexagonally-packed cylinder structures, retaining the stiffness of the epoxy matrix, where the hexagonally cylindrical morphology lead to a significant increase in fracture toughness. The rheokinetics of micro-phase separation during network formation was investigated. Nanostructures are judged to be formed by polymerization-induced microphase separation, in marked contrast to equilibrium self-organized structures that are preformed, with the microphases fixed via a curing reaction.