Cationic photopolymerization of vinyl ether systems: influence of the presence of hydrogen donor additives

Abstract

Several alcohols ( n-butanol, 2-propanol, 2-phenyl-2-propanol) and water were added to diethylene-glycol-divinyl-ether (DVE2) or triethylene-glycol-divinyl-ether (DVE3) in order to investigate their influence on the cationic photopolymerization in the presence of triarilsulfonium hexafluorophosfate as photoinitiator. Until 5% w/w concentration, the alcohols do not show any influence on the rate of polymerization, but they increase the final double bond conversion indicating a plasticization effect. Water causes a decrease of the rate of polymerization and an increase of the final double bond conversion. DSC and DMTA analyses show that the presence of the additives decreases the T g of the UV-cured products. The results are interpreted on the basis of a chain transfer reaction involving -OH groups.