Cationic photocuring of polydimethyl siloxane .1. Synthesis and photocuring of polydimethyl siloxane with epoxy norbornene groups

This paper deals with the synthesis of photocurable polysiloxanes bearing epoxy norbornene groups. Two reactive schemes were used. The first one was an hydrosilylation of 5-vinyl-2-norbornene on hydrogeno chlorosilane followed by a condensation with alpha,omega-dihydroxy polydimethylsiloxane and completed by an epoxydation. The second way was an hydrosilylation of polysiloxane bearing Si-H groups with 2,3-epoxy-5-vinyl norbornene previously prepared by selective epoxydation of 5-vinyl-2-norobornene. All the compounds were characterized by 2D NMR (H-1-H-1 and H-1-C-13), FTIR, etc., and the first results on cationic photopolymerization with triaryl sulfonium hexafluoroantimonate as initiator are reported. As the temperature increases, the yield passes through a maximum at about 50-60 degrees C. (C) 1997 Elsevier Science Ltd.