SYNTHESIS OF SILICON-CONTAINING VINYL ETHER MONOMERS AND OLIGOMERS AND THEIR PHOTOINITIATED POLYMERIZATION

Silicon-containing divinyl ether monomers were synthesized by the addi tion reaction of glycidyl vinyl ether (1) with various silyl dichlorid es using tetra-n-butylammonium bromide (TBAB) as a catalyst. The react ion of 1 with diphenyl dichlorosilane gave bis-[1-(chloromethyl)-2-(vi nyloxy)-ethyl]diphenyl silane (3a) in 89% yield. Polycondensations of 3a with terephthalic acid were also carried out using 1,8-Diazabicyclo [5.4.0]-7-undecene (DBU) to afford silicon-containing polyfunctional v inyl ether oligomers (5). A multifunctional Si-monomer with both vinyl ether and methacrylate groups (7) was prepared by the reaction of 3a with potassium methacrylate using TBAB as a phase transfer catalyst. P hotoinitiated cationic polymerizations of these vinyl ether compounds proceeded rapidly using the sulfonium salt, bis-[4-(diphenyl-sulfonio) phenyl] sulfide-bis-hexafluorophoshate (DPSP), as the cationic photoin itiator in neat mixtures upon UV irradiation. Multifunctional monomer 7 with both vinyl ether and methacrylate groups showed ''hybrid curing properties'' using both DPSP and the radical photoinitiator, 2,4,6-tr imethylbenzoyl diphenylphoshine oxide (TPO). (C) 1997 John WiIey & Son s, Inc.