KINETICS OF PHOTO-CROSS-LINKING REACTIONS OF A DCPA EA MATRIX IN THE PRESENCE OF THIOLS AND ACRYLATES/

The crosslinking efficiency and kinetics of a solid acrylic copolymer DCPA/EA (dicyclopentenyl acrylate/ethyl acrylate) matrix were investig ated in the presence of pentaerythritol tetrakis(2-mercaptoacetate) (P ETMP) or pentaerythritol tri- and tetraacrylates used as multifunction al crosslinking agents. The reaction of thiol and acrylate addition wa s sensitized by benzophenone (BP). The crosslinking efficiency of the DCPA/EA-BP-PETMP copolymer system, illuminated at high wavelengths (la mbda > 310 nm), was compared with that of the DCPA/EA matrix alone and the 2-component system copolymer DCPA/EA-BP. The concentrations of ph otosensitizer and crosslinking agent were varied from 1 to 10 mass %. The kinetics of tetrafunctional thiol addition and cyclopentene (penda nt group of the DCPA/EA matrix) disappearance was followed through Fou rier transform infrared (FTIR) and by determining the gel content. (C) 1997 John Wiley & Sons, Inc.