초록 |
Poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole]-lithium hydrazinium sulfate (PBI-LiHzS) composite membranes were prepared by casting N,N'-dimethylacetamide solutions containing PBI and LiHzS, where the contents of LiHzS in the composite membranes were controlled from 2.5 to 10 wt.-%. LiHzS was obtained by reacting hydrazine sulfate with lithium carbonate in water. PBI-LiHzS composite membranes were thermally stable up to approximately 300°C and their acid absorbing capabilities were comparable to those of pure PBI membranes. The proton conductivities of PBI-LiHzS composite membranes (2.12×10-2 S cm-1 at 180°C and 0% relative humidity) were higher than those of pure PBI membranes when used at the same acid doping levels. The mechanical stabilities of the composite membranes having less than 5 wt.-% of LiHzS were found to be close to those of pure PBI membranes. |