Versatility of Pyrylium Salt/Vinyl Ether Initiating System for Epoxide Dual-Cure Polymerization: Kick-Starting Effect of the Coinitiator

Abstract

Pyrylium salts combined with vinyl ethers are shown to act as new versatile dual-cure initiating systems for both photochemical and thermal initiation of oxirane monomers. The combination of both possibilities allows the curing of thick samples through photoinduced frontal polymerization. On the basis of quantum calculations and photochemical experiments, some clues are given about the reaction mechanisms involved. Interestingly, a sequential kick-starting effect is observed in the presence of vinyl ether enabling the curing of oxetane monomers. Thereby, this communication presents a short overview of potential of pyrylium salts in cationic polymerization of oxiranes.

Keywords: cationic polymerization; dual-cure; epoxides; kick-starting; pyrylium salt.