Synthesis And Properties Of Photosensitive Polysulfone For High Temperature Proton Exchange Membrane

In this article, two chloromethylated polysulfones（CMPSF） with140%and160%chloromethylation ratios were prepared by chloromethylation of polysulfone usingchlorine methyl ether as the chlorine methylation reagent and ZnCl₂as catalyst. Thentwo CMPSF were reacted with a certain amount of acrylic acid （AA） and singlehydroxy chalcone ketone （HC） to obtain photosensitive chloromethylatedpolysulfones CMPSF-AA and CMPSF-HC which contain a part of acrylic structureand chalcone structure in the side-chain respectively. The polymers werecharacterized by FT-IR and1H-NMR. The CMPSF-HC and CMPSF-AA exhibitedhigh photosensitivity，the maximum crosslinked degree of CMPSF-HC was up to68%after UV light irradiating15min without photoinitiator.Quaternized CMPSF-HC （QNPSF-HC） membranes with chalcone and quaternaryammonium structure in the side chain were prepared by reaction of CMPSF-HC withtrimethylamine. The crosslinked quaternized membrane （QNPSF-HC） exhibited bestperformance when quaternization temperature was40℃, the amount oftrimethylamine was5times of chloromethyl, the reaction time was8h andpoto-crosslink under without stem and swelling. The quaternization level reached90%.Photosensitive polysulfone membrane （QNPSF140-HC45） with45%chalcone and95%quaternary ammonium and photosensitive polysulfone membrane（QNPSF160-HC45） with45%chalcone and115%quaternary ammonium werephosphorylated to obtain PAPSF140-HC45and PAPSF160-HC45. Thephosphorylated membranes were characterized by XPS, FT-IR and TGA tests. Theresults showed that acid doping level of the crosslinked and non-crosslinkedmembranes of PAPSF140-HC45and PAPSF160-HC45increased with the increasingphosphate concentration and reaction time and finally reached saturation. Phosphoricacid doping levels of the crosslinked and non-crosslinked membranes ofPAPSF140-HC45and PAPSF160-HC45were12.5,7.5and18.3,23, respectively.The results showed that non-crosslinked membranes of PAPSF140-HC45andPAPSF160-HC45welled in THF, NMP, DMSO, DMAc, DMF and chloroform, whilethe crosslinked membranes did not swell. The initial decomposition temperature ofPAPSF140-HC45and PAPSF160-HC45were216℃，while that of the crosslinkedPAPSF140-HC45and PAPSF160-HC45improve to224℃and220℃，respectively. Mechanical strength of non-crosslinked membranes of PAPSF140-HC45å'ŒPAPSF160-HC45were31.1MPa and27.4MPa and increased to55.6MPa and50.4MPa for crosslinked the membranes. The oxidation resistance stability of thecrosslinked membranes of PAPSF140-HC45and PAPSF160-HC45increased to60min and51min from24min and15min for non-crosslinked the membranes.Dimensional stability of the membranes have also been significantly increased aftercrosslinked, indicating that crosslinked could improve the performance of protonexchange membrane, such as thermal stability, mechanical properties, oxidationresistance and dimensional stability and so on.