Synthesis and Properties of Silphenylene-containing Epoxy Resins with High UV-stability |
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| Authors: | Xin Yang Xiaojuan Zhao Ying Zhang Wei Huang Yunzhao Yu |
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| Institution: | 1. Institute of Chemistry, Chinese Academy of Sciences , Beijing, P. R. China;2. Graduate University of Chinese Academy of Sciences , Beijing, P. R. China;3. Institute of Chemistry, Chinese Academy of Sciences , Beijing, P. R. China |
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| Abstract: | Two novel silphenylene-containing cycloaliphatic epoxy resins, 1,4-di 2-(3, 4-epoxycyclohexylethyl) dimethylsilyl] benzene (DEDSB) and 1,3,5-tri 2-(3, 4-epoxycyclohexylethyl) dimethylsilyl] benzene (TEDSB) were synthesized through in situ Grignard reaction and hydrosilylation, and characterized by FT-IR and 1H-NMR. They were colorless transparent viscous liquids. Methyhexahydrophthalic anhydride (MeHHPA) was used to cure the epoxy resins to give glassy solids with high optical clarity. Differential scanning calorimetry (DSC) results indicated that DEDSB and TEDSB showed similar curing reactivity. The cured TEDSB had a higher glass transition temperature, a higher storage modulus and a lower coefficient of linear thermal expansion than the cured DEDSB due to a higher crosslink density. The cured silphenylene-containing epoxy resins exhibited a much higher resistance to discoloration under UV irradiation than the commonly used epoxy resins diglycidyl ether of bisphenol-A (DGEBA). XPS analysis revealed that they were much less susceptible to photo-oxidation than DGEBA. |
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| Keywords: | Silphenylene epoxy resin curing UV resistance light-emitting diodes (LED) encapsulation |
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