Redox initiated cationic polymerization: The unique behavior of alkyl glycidyl ethers

Abstract

Redox systems composed of a diaryliodonium or a triarylsulfonium salt together with a silane bearing Si-H groups were used for the in situ generation of strong Brønsted acids at room temperature in the presence of alkyl glycidyl ether monomers. Secondary oxiranium intermediates are generated with lifetimes from minutes to hours at room temperature. These systems undergo rapid, exothermic cationic chain polymerization when the temperature is raised. Metastable monomer-redox initiator systems were also observed to undergo frontal polymerizations when a localized heat source is applied to the sample. The application of these delayed cationic ring-opening polymerization systems for the development of one-component structural adhesives that undergo rapid thermosetting at low temperatures are discussed. © 2011 Wiley Periodicals, Inc.