Poly(sulfonium cation) for the Synthesis of High-Molecular-Weight Poly(phenylene sulfide)

Abstract

High molecular weight poly(phenylene sulflde)(PPS), Mw > 2 x 10 5 , was synthesized via a poly(sulfonium cation) through oxidative polymerization of methyl 4-(phenylthio)phenyl sulfoxide. Polymerization proceeds in protic acid homogeneously. The poly(sulfonium cation) was soluble in common solvents such as acetonitrile, acetone, formic acid and dimethyl sulfoxide. The poly(sulfonium cation) was available as a soluble intermediate for the synthesis of high molecular weight poly(phenylene sulfide). It was feasible to convert high molecular weight poly(arylene sulfide) through the Sn 2 reaction with pyridine as a nucleophile. This polymerization is applicable to the synthesis of new block copolymers such as, poly(phenylene sulfide)-block-[poly(tetrafluoroethylene-co-per fluoro (propylvinyl ether)]}-block-poly(phenylene sulfide). The poly sulfonium cation is isolatable as a stable salt which acts as an unique polymeric reagent for the methylation of aromatic compounds having mobile hydrogen.High molecular weight poly(p-phenylene sulfide) (PPS) has received much attention as a high-performance engineering plastic due to its excellent chemical, thermal, and mechanical properties which are a result of its high crystallinity(i-6) These properties make it difficult to synthesize high molecular weight PPS. Normally, the preparation of PPS employs high-temperature and high-pressure processes in order to overcome poor solvent solubility, e.g. commercial preparations of PPS are often carried out at temperature in excess of the boiling point of NMP, and require the use of pressure vessels. To overcome these difficulties a large amount of effort has been put into the formation of high molecular weight poly(arylene sulfide) (PAS)(Eq. l)(7-75). PPS can also be obtained by other reaction mode, e.g. electrophilic reaction and