Preparation And Properties Of Cross-linked PBI High Temperature Proton Exchange Membranes

In this paper, IronIIIsulfophenyl phosphate bonding with phosphotungstic acid(PWA) compound (FeSPP-PWA) is synthesized using IronIIIchloride, m-sulfophenylphosphonic acid (msPPA) and PWA by in situ polymerization methods until washingwater to the neutral. The microtopography, element composition, crystal structure andthermal stability are characterized by SEM、TEM、EDX、XRD and TG-DTA. Resultsshow that FeSPP-PWA has a typical lamellar structure and good thermal stability. Athigh humidity (RH), Vehicle mechanism plays the leading role. At low RH, theGrotthuss mechanism plays the major role. At100%RH and180℃, the conductivityof FeSPP-PWA is0.13S/cm. At50%RH and180℃, the proton conducticity is6.1×10-2S/cm. In a drying oven, the conductivity is4.22×10-3S/cm at180℃.Polybenzimidazole (mPBI) was prepared by3,3-diamino benzidine andisophthalic acid through melt polymerization. Sulfonated poly (aryl ether ether ketone)(SPEEK) was synthesized by H2SO4and PEEK. SPEEK/PBI composite membranewas prepared by blending method. SEM indicates PBI disperses well and uniformly.IR shows the hydrogen bond formed between SPEEK and PBI. TG-DTA reveals thatthe composite membrane has good thermal stability. SPEEK/PBI compositemembrane has good mechanical strength, dry and wet deformation, resistance tooxidation stability and low methanol permeability.100%RH and170℃，the protonconductivity of SPEEK/PBI(20wt%) is0.1985S/cm.Bisphenols Aepoxy resin (DGEBA) was synthetized by bisphenol A, NaOH andepichlorohydrin. The epoxy value is0.54. Cross-linked membrane was prepared bylow polymerization degree mPBI and DGEBA through thermal crosslinking method.SEM shows that the cross-linked membrane is smooth and density. TG-DTA revealsthat the cross-linked membrane has good thermal stability and does not decompose at200℃. The cross-linked membrane has good resistance to oxidation stability, goodmechanical strength. In order to enhance the proton conductivity, phosphoric acid (PA)and FeSPP are added into the crosslinked membrane.100%RH and170℃, the protonconductivity of PBI/DGEBA/PA(10wt%) is0.1052S/cm；100%RH and180℃, theproton conductivity of PBI/DGEBA/FeSPP (20wt%) is0.0952S/cm.