Photoinitiated cationic polymerization of urethane vinyl ether crystalline monomers

Photoinitiated cationic polymerization of crystalline monomers based on urethane vinyl ether has been investigated by means of differential photocalorimetry (DPC). The crystalline monomers in the melt state polymerized rapidly by exposure to UV light in the presence of a cationic photoinitiator such as an iodonium salt, sulfonium salt or iron arene salt. The kinetics of the cationic photopolymerization process were studied by following k(p)[M+] as a function of conversion. High conversions, of around 90%, were obtained for most of the systems investigated. The efficiency of the cationic photoinitiators in initiating the polymerization of the vinyl ether monomers was in the order: iodonium. salt>iron arene salt>sulfonium salt. Monomers modified with different saturated alcohols had different activities in photopolymerization, although they all carry the same functional group, i.e. vinyl ether. (C) 2005 Society of Chemical Industry.