THERMOPLASTIC VULCANIZATES BY REACTION-INDUCED PHASE SEPARATION OF A MISCIBLE POLY(ε-CAPROLACTONE)/EPOXY SYSTEM

摘要

A new method for the preparation of thermoplastic vulcanizates (TPVs) was successfully applied. Starting with a miscible system of a semi-crystalline thermoplastic polymer and an elastomer precursor, phase separation was induced by the increase in molecular weight during crosslinking of the elastomer precursor. Poly(ε-caprolactone) (PCL) and an epoxy resin based on poly(propylene oxide) (PPO) were used as a model system. This approach enables the dispersion of up to 80 wt% of crosslinked rubber in a thermoplastic matrix, providing morphologies that are typical for TPVs. A range in rubber particle size of 0.5 to 3 μm was obtained, without the need of blend compatibilization or dynamic processing. The materials exhibit mechanical and rheological properties typical for TPVs and the rubber particles feature a high crosslink density. At high curing temperatures and low PCL contents, connectivity of the rubber particles was observed, which was attributed to the phase separation mechanism. Connectivity of the rubber particles has a negative influence on both the mechanical properties and the rheological behavior.