Synthesis and degradable property of novel sulfite-containing cycloaliphatic epoxy resins

Liquid cycloaliphatic diepoxide containing sulfite group (Epoxide-S) was designed and synthesized through the two-step reactions: the nucleophilic substitution between thionyl chloride and cyclohex-3-1-methanol, and the subsequent epoxidation. The chemical structures of the epoxidized product and its olefin precursor were confirmed by FTIR and 1H NMR spectra. Different from conventional thermosetting epoxy resins, the cured Epoxide-S started to decompose at 185 °C. The apparently lower degradable temperature is desirable for reworkable electronic packaging materials because the dismantlement of waste electronic products or the replacement and repair of faulty chips become convenient. Moreover, after co-curing between Epoxide-S and the commercial cycloaliphatic diepoxide ERL-4221, the thermal degradation temperatures of the copolymers were tunable in the range from 185 to 323 °C by varying the ratio of two monomers. The unique degradation behaviors were investigated by means of computer calculation, thermogravimetric analysis, and FTIR spectra.