Study On Sulfonated Poly(Phthalazinone Ether) Containing Pendant Phenyl Groups As Proton Exchange Membranes

In this thesis, the synthesis and performance of sulfonated poly(phthalazinone ether) as proton exchange membranes have been studied deeply based on the molecular design principle under the background of the application in proton exchange membrane fuel cells(PEMFC). Two series of sulfonated poly(phthalazinone ether sulfone) containing pendant phenyl groups(SPPES-P) and sulfonated poly(phthalazinone ether ketone) containing pendant phenyl groups(SPPEK-P) were synthesized.Poly (phthalazinone ether sulfone) containing pendant phenyl groups (PPES-P)and poly (phthalazinone ether ketone) containing pendant phenyl groups (PPEK-P) were synthesized respectively by aromatic nucleophilic substitution reaction from 4-(3-phenyl-4-hydroxyphenyl)-2,3-phthalazin-1-one (DHPZ-O) 4-(4-hydroxyphenyl)-2,3-phthalazin-l-one (DHPZ),4,4'-dichlorodiphenyl sulfone (DCS) and 4,4-difluorobenzophenone(DFK). The intrinsic viscosity and molecular weight of polymers have been measured respectively and the result indicated that these polymer had high molecular weight. FT-IR and'H-NMR are used to characterize the structures of polymers. Sulfonated poly (phthalazinone ether sulfone) containing pendant phenyl groups(SPPES-P) and Sulfonated poly (phthalazinone ether ketone) containing pendant phenyl groups (SPPEK-P) with different sulfonation degree are prepared by electrophilic substitution reaction with concentrated sulfuric acid as sulfonating agent, The optimized sulfonation conditions are determined by changing sulfonation temperature and time, and the sulfonated position are controlled successfully. Sulfonated polymers'structures are characterized by FT-IR and'H-NMR, and the result show that ideal polymers are obtained.SPPES-P and SPPEK-P proton exchange membranes are prepared by solution casting method. The water uptake, swelling ratio, proton conductivity, methanol permeability, and oxidative stability of SPPES-P and SPPEK-P membranes were investigated. These membranes have excellent water uptake ratio and low swelling ratio,IEC increased with the increasing SD. When temperature is above 85℃, all membranes with SD more than 0.8 show good proton conductivities (>10-2 S·cm"1), The membranes showed high oxidative stability and good methanol permeability. The two series of membranes are given to make comparison, SPPEK-P membranes have higher break strain and better proton conductivities and better oxidative stability. However, the tensile strength and tensile modulus of SPPES-P membranes are better. The 5%weight loss temperature of SPPES-P and SPPEK-P membranes are above 375℃and 395℃indicated that they all have good thermal stabilities. Besides, these membranes indicated better oxidative stability, mechanical performance and higher proton conductivity compared with sulfonated poly(phthalazinone ether ketone) containing pendant phenyl groups (SPPEK-O) which were synthesized by previous researcher. All properties show that these membranes can be used in PEMFC application.