Sulfonated Poly (ether Sulfone) Proton Exchange Membrane Synthesis And Performance Research

Preparation conditions of 3, 3'-disulfonated-4, 4'-difluorophenyl sulfone (SDFDPS) and purification of 4, 4'-difluorophenyl sulfone (DFDPS) was studied. On the basis of synthesis of sulfonated poly(arylene ether sulfone)(SPAES) and crosslinked sulfonated poly(arylene ether sulfone)(CSPAES), we prepared two types of blend membranes by blending SPAES or CSPAES with sulfonated polyimide (SPI), and investigated the various properties of blend membranes in detail. The results shows that the two types of blend membranes have good stability and high proton conductivity. The approach to preparation of post-crosslinking SPAES membranes was preliminarily researched.A systematic study of the synthesis and characterization of SDFDPS was conducted by varying reactant stoichiometries, reaction temperature and reaction time. The raw material of DFDPS was industrial grade and purified by sublimation. The purity of products was detected by HPLC and the optimum synthesis bacth process variables were 3.0:1 reactant molar ratio (DFDPS:SO₃) at 110℃for 20h. High purity SDFDPS was purified by recrystallization treatment.A series of SPAES/ SPI blend membranes were prepared by solution casting method. Compared with pure SPAES, the blend membranes displayed the larger dimensional stability, higher water stability and better mechanical properties. As the result of combinding from two sulfonated polymer composites, the blend membranes maintained some high IEC level and showed high proton conductivity. They showed higher proton conductivity than Nafion112 in water. The blend memebrane (SPAES/SPI-4/6) displayed the swelling rate in the plane direction and thickness direction of 0.30 and 1.14 respectively, and the toughness of V after aging in 130℃water for 24h, while showed the conductivity in the water of 178.6mS/cm.Higher stability CSPAES was selected to blend with SPI in order to further improve the performance of the blend membranes. The toughness of CSPAES/SPI blend membranes (sulfonation degree of CSPAES is 50% and 60%) all reached V after aging in 130℃water for 24h. The blend membranes displayed greatly larger dimensional stability and water stability compared with pure CSPAES, and higher proton conductivity in the entire range of humidity compared with the SPI.A facile approach was successfully developed for the preparation of a series of cross-linked SPAES membranes by adding different proportions of phosphorus pentoxide to SPAES. The cross-linked SPAES membranes showed higher dimensional stability in comparison with the uncross-linked ones, while maintained high proton conductivity (>100mS/cm, 60℃100%RH)...