以NMP为溶剂,通过溶液浇铸法,将主链含杂萘联苯结构的聚苯并咪唑(PPBI)铺制成膜.采用不同磷酸浓度、掺杂温度和掺杂时间,对PPBI膜进行磷酸掺杂,得到不同掺杂程度的膜.PPBI膜的磷酸掺杂程度分别随着磷酸浓度、掺杂温度和掺杂时间的增加而呈现增大的趋势.当掺杂时间超过20 h,掺杂程度趋于最大值而不再随时间的增大而增大,较优掺杂时间为30 h.在180℃温度条件下14.7 M的浓磷酸中掺杂能够得到最高掺杂度(15.2 mol H3PO4)的PPBI膜.将不同掺杂度的膜进行力学性能、质子传导率和耐氧化性的测试,发现膜的力学性能、传导性能和耐氧化性均依赖于掺杂程度.PPBI膜的质子传导率随着磷酸掺杂程度的增大而增大,尤其在高掺杂程度下这种趋势更加明显.PPBI膜的机械强度和耐氧化性随着掺杂程度的增大而降低,此系列PPBI膜的机械强度和耐氧化性均能够满足燃料电池质子交换膜的要求.%The PPBI polymers was cast into membranes using NMP as solvent, doped with phosphoric acid and fur?ther investigated as proton exchange membranes. To investigate the doping conditions, the PPBI membranes were doped in PA with different concentration, at different doping temperature and for different time. The doping level increased with PA concentration and doping temperature, remaining the high value after doping for 30 h. Mem?branes with the highest doping level were obtained by doping at high temperature. The mechanical properties and proton conductivity of PPBI membranes with different doping levels were carried out. With the increasing of doping level, the mechanical strength was reduced while the proton conductivity was enhanced. The proton conductivity in?creased sharply at high doping level above 13 mol H3PO4 especially at high temperature. The mechanical strength of membrane with the highest doping level was still sufficently high for proton exchange membrane fuel cell use. High performance acid doped PPBI membrane could be obtained by the high?temperature doping process.
展开▼
