Preparation And Properties Of Proton Exchange Membrane By Irradiation-induced Grafting Of PVDF Film

As an important material of proton exchange membrane fuel cells,proton exchange membranes play a role in transporting protons without allowing fuels crossover,and sulfonated proton exchange membrane is a kind of ion exchange membrane with high chemical stability,thermal stability and excellent mechanical properties,having extremely broad application prospects.In this paper,a new proton exchange membrane at different does rate was prepared based on polyvinylidene fluoride films using ?-irradiation,numerous free radicals acted as active sites for the styrene monomer,the grafted membranes were sulfonated by chlorosulfonic acid.Firstly,the grafting of styrene into the polyvinylidene fluoride membranes was proved by FT-IR spectroscopy analysis,compared with the original PVDF membranes.There are many parameters,which strongly affect radiation-induced graft copolymerization process And this paper discusses the main parameters,including the total does,does rate,monomer concentration and additive.The effect of each one of these parameters on the conductivity of the membrane is discussed in the following sections.In the end,the condition of irradiation was obtained with 30 KGy total does,30 Gy·min-1 does rate,4 mol·L-1 monomer concentration with 5 % crosslinking agent.And then,a series of PEM at the suitable parameters were prepared and their properties were measured.The result showed that at the 30 Gy·min-1,IEC was 1.97 mmol·g-1,ionic conductivity was 224.24 mS·cm-1,water uptake was 72 %,Swelling ratio was 26 %,TGA test showed that sulfonic acid groups start to decomposed at 215 ?,tensile tests show that the tensile strength of PEM was improved and meets performance requirements of the PEMs for proton exchange membrane fuel cells.At the same time,SEM-EDX proved that irradiation reaction can not only occur on the surface of the films,but also can be used to achieve uniform membranes under the appropriate irradiation conditions.Finally,membrane electrode assemblies(MEA)are prepared with the method of gas diffusion electrode(GDE).We discussed the influence of the hot press and binder on the single fuel cell performance.When we used the Nafion as the binder,the maximum power density of the single fuel cell was 198.3 mW·cm-2 at 60 ?.