Novel thermal initiator systems for radical induced cationic frontal polymerization

Abstract

Frontal polymerization is an extremely efficient and rapid method for producing bulk polymers, characterized by a self-sustaining curing front that propagates throughout the resin. To start this reaction, all that is needed is one initial stimulus in the form of UV radiation or heat. With radical induced cationic frontal polymerization (RICFP) a way has been found to polymerize the industrially important monomer bisphenol A diglycidyl ether (BADGE) using this curing technique. So far, this has only been achieved in combination with the exceptional radical thermal initiator (RTI) tetraphenyl-1,2-ethanediol (TPED), but not with conventional peroxide based RTIs. In this work new initiator systems based on peroxide initiators were developed to polymerize BADGE using RICFP. Different silanes and various oxygen containing hydrocarbon compounds were investigated as coinitiators to accomplish this. Several suitable compounds were found with which a stable frontal polymerization was achieved. Especially in combination with the silane based coinitiator tris(trimethylsilyl)silane (TTMSS), it was shown that several peroxide-based RTIs are suitable for polymerizing BADGE with exceptionally high frontal velocity.