Introduction of end groups into cyclic poly(ether sulfone) by means of transetherification with bis(aryloxyphenyl) sulfone

Abstract

AbstractEnd‐functionalized linear poly(ether sulfone) (PES) free from cyclic PES (CPES) was obtained by reversible transetherification of CPES with bis(aryloxyphenyl) sulfone 1 in the presence of base catalyst. Initially, transetherification of CPES with bis(phenoxyphenyl) sulfone 1a in the presence of a catalytic amount of CsF in N‐methylpyrrolidone (NMP) at 145 °C afforded not the desired linear PES (LPES), but CPES with decreased molecular weight. However, when PhOSiMe3/K2CO3 was used instead of CsF at 180 °C, the desired LPES with a phenoxy group derived from 1a at both ends was obtained. Under the established conditions, the transetherification of CPES with bis(bromophenoxyphenyl) sulfone 1b instead of 1a afforded not only LPES with a bromophenoxy group at both ends, but also LPES with a bromophenoxy group at one end and a phenoxy group at the other. Since the phenoxy group might be introduced from PhOSiMe3, the reaction was conducted with BrPhOSiMe3 instead of PhOSiMe3 along with K2CO3 as a catalyst, and in this case, the desired LPES with a bromophemoxy group at both ends was obtained.