| 초록 |
A series of poly(aryl ether benzimidazole) copolymers bearing different aryl ether linkage contents were synthesized by condensation polymerization in polyphosphoric acid by varying the feed ratio of 4,4’-dicarboxydiphenyl ether to terephthalic acid. As the ether unit content in the copolymer increased, the solubility of the copolymer in PPA and N,N’’-dimethylacetamide/LiCl improved. XRD studies revealed that the incorporation of flexible aryl ether linkages increased the chain d-spacings of the polymer backbones and decreased the crystallinity of the copolymers. Still, these copolymers having ether linkages showed reasonably good thermal/mechanical stability and high proton conductivity. For example, the copolymer with 30 mol% ether linkage had a tensile strength of 43MPa (at 26 oC and 40% relative humidity) at an acid doping level of 7.5 mol H3PO4 and a proton conductivity of 0.098 S cm1 (at 180 oC and 0% relative humidity) at an acid doping level of 6.6 mol H3PO4. |
