Study On Synthesis And Properties Of Sulfur-Containing Resin With High Refractive Index

A new sulfur-containing epoxy acrylate resin for UV-curing has been synthesized. The sulfur-containing epoxy resin has been prepared based on the reaction of4,4’-thiodiphenol (TDP) with epichlorohydrin.Then esterified with acrylic acid to form sulfur-containing epoxy acrylate resin.It was observed that the sulfur-containing epoxy acrylate resin when used with (4-phenylthio)phenyl diphenyl sulfonium hexafluoroph-osphate salt which was designed and synthesized and reactive diluent can be cured in few seconds.The optimum technological conditions of sulfur-containing epoxy resin,sulfur-co-ntaining epoxy acrylate resin,(4-phenylthio) phenyl diphenyl sulfonium hexafluoroph-osphate salt and the curing of prepared prepolymer were studied by single-factor optimization method.Structural characterization of sulfur-containing epoxy resin,sulfu-rcontaining epoxy acrylate resin,(4-phenylthio) phenyl diphenyl sulfonium hexafluoro-phosphate salt were determined by FT-IR,1H NMR,TG,DSC.The best conditions of preparation of the sulfur-containing epoxy resin were got as follows:the molar ratio n(4,4’-thiodiphenol):n(epichlorohydrin)=1:20, the molar ratio n(4,4’-thiodiphenol):n(sodium hydroxide)=1:6,the dropping time of alkali liquor is180min,the reaction temperature of65℃.In these conditions,the yeld of sulfur-containing epoxy resin is91.8%.The melting point of sulfur-containing epoxy resin is between35℃to37℃.The best conditions of preparation of sulfur-containing epoxy acrylate resin were got as follows:n(sulfur-containing epoxy resin):n(acrylic acid)=1:2～1:2.1,the catalyst is triphenyl phosphate,the amount of triphenyl phosphate is2.5%(to sulfur-containing epoxy resin),the inhibitor is hydroquinone,the reaction temperature of95℃.In these conditions,the acid value of sulfur-containing epoxy acrylate resin is less than5mgKOH/g.The best conditions of preparation of (4-phenylthio) phenyl diphenyl sulfonium hexafluorophosphate salt were got as follows:n(dphenyl sulfide):n(diphenyl sulfoxide)=1:1.1.The amount of acetic anhydride is7%(to the sum amount of diphenyl sulfide and diphenyl sulfoxide).In these conditions,the yeld of (4-phenylthio) phenyl diphenyl sulfonium hexafluorophosphate salt is93.5%.The best curing system were got as follows:the photoinitiator is (4-phenylthio)phenyl diphenyl sulfonium hexafluorophosphate salt,the diluent is benzyl glycidyl ether.The radiation distance is20cm.The amount of photoinitiator is4%(to sulfur-containing epoxy acrylate resin),the amount of benzyl glycidyl ether is15%(to sulfur-containing epoxy acrylate resin). In these conditions,the comprehensive properties of cured products are still good.