Synthesis And Application Of Polymerizable And Polymer Photoinitiators

To reduce the toxicity of the traditional small molecule benzophenone photoinitiator, unsaturated double bond was introduced into the benzophenone structure, and a series of polymerizable and polymer benzophenone photoinitiators were synthesized in this paper.By acylation, reduction, dehydration and distillation of chlorobenzene, p-Chlorostyrene was gained. When the acetylation reaction was at 40℃for 2.5 h, then was refluxed for 8 h with the molar ratio of isopropanol aluminum to p-Chloroacetophenone being 1.2:1, and when the temperature of cracking reaction was at 220℃, the total yield of p-Chlorostyrene was up to 82.4%.The impacts of the temperature, time, and solvent of preparing the Grignard reagent, the molar ratio of Grignard reagent to p-chloro benzonitrile, the temperature and time of addition reaction, the condition of hydrolysis, on the yield of 4-vinyl-4'-chloro benzophenone (4-VCBP) were studied in this paper. The results showed that the optimum preparation conditions was as followed: when volume ratio of tetrahydrofuran to toluene was 2:1, volume ratio of solvent to p-Chlorostyrene 4:1, p-Chlorostyrene reacted with excessive Mg at 35℃for 10h, and Grignard reagent reacted with p-chloro benzonitrile at 50℃for 10h with the molar ratio of 1.4:1, then the product was added with moderate benzene and refluxed in the sulfuric acid for 8 h, the yield of 4-VCBP was up to 70%. When Grignard reagent of p-Chlorostyrene was reacted separately with 4-methoxy-benzonitrile or 4-methoxy benzonitrile or 2-methoxy benzonitrile or benzonitrile, 4-vinyl-4'-methoxy benzophenone, 4-methyl-4'-vinyl benzophenone, 2-methyl -4'- vinyl benzophenone and 4-vinyl benzophenone would be gained.The maximum UV absorption wavelength of polymerizable photoinitiator shifted toward long wavelength, and the residues of light-cured were far less than benzophenone. The impacts of monomer type, the concentration of photoinitiator, amine type, the concentration of amine, curing methods, oxygen resistance, thickness of coating, distance of light ,on the curing time and conversion rates of monomers, were studied in this paper.