Preparation of high temperature resistant polycarbonate via ionic liquid activation of bisphenol fluorene under mild conditions

Abstract

In this study, the melt polycondensation reaction of 9,9’- bis(4-hydroxyphenyl)fluoride (BHPF) and diphenyl carbonate (DPC) was catalyzed using three ionic liquids (ILs) and a conventional alkali metal as catalysts. The optimal IL catalysts were determined to be [BMmim][BF4] ionic liquid catalysts, and the catalytic mechanism was investigated. Furthermore, the optimum process conditions were identified: the optimal amount of [BMmim][BF4] was 0.05 mol% based on DPC, the polycondensation temperature was set at 200°C for a duration of 3 h, followed by polymerization at 280°C for another 3 h. As a result, the Mn value of poly(9,9-bis(4-hydroxyphenyl) carbonate) (PFC) reached up to 41387 g/mol with a glass transition temperature band of approximately 254°C and Td-5% value of around 436°C.