Preparation of sulfur-containing polycarbonates through melt ester-exchange copolymerization of bisulfhydryl and bisphenol A monomers utilizing ionic liquid catalysts

In this study, 4,4 '-thiobisbenzenethiol and bisphenol A monomers were utilized to incorporate sulfur-containing structures into the polycarbonate backbone through melt transesterification employing imidazole-based ionic liquid catalysts. The catalytic reactivity of a series of imidazole-based ionic liquid catalysts in the copolymerization of sulfhydryl and hydroxyl groups was investigated, along with determining the optimal process conditions for the melt transesterification reaction. By optimizing the process parameters, a range of sulfur-containing polycarbonates with main chains were successfully synthesized, exhibiting molecular weights (Mn) ranging from 2.46x104 to 3.17x104, glass transition temperatures between 118 degrees C and 146 degrees C, refractive indices up to 1.623, and Td-5 % temperatures reaching as high as 428 degrees C.