Highly porous rigid polybenzoxazole (PBO) network films were prepared using a precursor-mediated fabrication method. The obtained PBO network films possessed high porosities of ~40%, as calculated from their apparent densities. In addition, the 5%-weight-loss temperatures of the films were ≥570°C under nitrogen atmosphere, demonstrating an excellent thermal stability. The electrical conductivities of the obtained PBO network films and phosphoric-acid-doped PBO network films were also evaluated. In addition, PBO network films containing pyridine rings were prepared and subjected to phosphoric acid doping. The resultant films were found to exhibit the highest conductivities of the films considered in this study owing to proton conduction both between phosphate groups and between the pyridine rings. The highest conductivity was found for a film prepared from a phosphoric-acid-doped PBO network containing pyridine rings, that is, 2.09 × 10⁻¹ S/cm at 150°C, which was higher than that of Nafion™. Therefore, these films can be used at higher temperatures than that of Nafion™.

中文翻译：

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高多孔耐热聚苯并恶唑网络薄膜的制备及其导电性

使用前体介导的制造方法制备了高度多孔的刚性聚苯并恶唑 (PBO) 网络薄膜。根据表观密度计算，获得的 PBO 网络薄膜具有约 40% 的高孔隙率。此外，薄膜在氮气氛下的5%失重温度≥570°C，表现出优异的热稳定性。还评估了获得的 PBO 网络膜和磷酸掺杂的 PBO 网络膜的电导率。此外，制备了含有吡啶环的 PBO 网络薄膜并进行磷酸掺杂。由于磷酸基团之间和吡啶环之间的质子传导，发现所得薄膜表现出本研究中考虑的薄膜的最高电导率。^-1  S/cm at 150°C，高于 Nafion ™。因此，这些薄膜可以在比 Nafion ™更高的温度下使用。