Nanostructured thermoplastic elastomers based on SBS triblock copolymer stiffening with low contents of epoxy system. Morphological behavior and mechanical properties

摘要

We report an approach for the design of nanostructured thermoplastic elastomeric materials consisting of poly(styrene-b-butadiene-b-styrene) and epoxy. This approach consists in the epoxidation of PB block and further mixing with low contents of the DGEBA:MCDEA system. Morphological behavior as well as thermal and mechanical properties have been investigated. The modification of epoxidized SBS with 10, 20, and 30 wt % epoxy system induces microphase separation at nanoscale from a poorly to well-ordered self-assembled morphology where the shape of these structures depends greatly on the mixture compositions, showing a transition from worm-like to lamellae. The generated nanostructures are accessible owing to the miscibility between the epoxidized PB block and the epoxy system that have been confirmed by an increment on the T_g (before and after curing) of this block in the mixture. The mixing produces a significant increase on strength and stiffness being more relevant in the system with 30 wt % epoxy and well-ordered lamellar morphology.