Organosilicon sulfides as co-initiators in photoinduced free radical polymerization

Summary Three sulfur-containing silanes (organosilicon sulfides) were investigated as electron donors in photoinduced free radical polymerization, in conjunction with xanthene dye (5,7-diiodo-3-butoxy-6-fluorone, DIBF) as sensitizer. The results were compared with the nonsulfur-containing silane, N-((trimethylsilyl)methyl)aniline (K1) and thiophenoxyacetic acid (TPAA). The kinetic studies clearly showed that the DIBF-organosilicon sulfides exhibit a significant increase in the efficiency of free radical polymerization of TMPTA compared to nonsulfur-containing silane and that the efficiency of all tested electron donors is only slightly dependent on the structure of the sulfur-containing co-initiators.