Preparationof Proton Exchange Membranes And Its Properties Under High And Low Temperature Conditions

The shortage of non-renewable energy is seriously and the problem of environmental pollution is imminently.The fuel cell is a device which converts chemical energy into electrical energy.The Chemicalreaction products are low contamination and environmental friendly.The main content of the second chapter of this thesis is to introduce the freeze-drying technology to prepare proton exchange membranes and determine the proton exchange capacity and other properties of the proton exchange membranes at different operating temperatures.The freeze-drying technology can ensure the drying of the proton exchange membranes.The spatial structure is not easy to collapse,which is conducive to subsequent drug doping.Chloro 1-butyl-3 methylimidazole(bmimCl),thioglycolic acid-cadmium telluride(CdTe-tga)and polyacrylamide(PAM)were introduced into the composite film prepared by freeze-drying method,which can significantly improve the performance of the film Kevlar/PAM/bmimCl(fd)/PA composite membrane has a proton conductivity of 2.64×10-1S/cm at a temperature of 180℃.The third chapter of this thesis mainly introduces the preparation of proton exchange membranes working at low temperature by solution casting method.For the experimental materials,a Kevlar nanofiber dispersion and a polyvinyl alcohol(PVA)aqueous solution from which potassium hydroxide(KOH)was removed were selected.The electrical conductivity was measured by low-temperature cycling and the mechanical properties were measured at room temperature.Suitable for long-term applications of low temperature proton exchange membranes.The fourth chapter of this paper introduces the PVA40%/SPEEK60%/PA100%membranes prepared by solution casting method.When the temperature reaches 30℃,the proton conductivity reaches 0.123S/cm,and when the temperature is-30℃,the proton conductivity is 0.049S/cm,the conductivity is stable within 1000h,the tensile strength at break is 0.39MPa,and the conductivity is stable after 7 cycles.After passing the performance test,the composite film was found to have excellent performance in a low temperature environment.