Preparation of highly porous heat‐resistant polybenzoxazole network films and their electrical conductivities

Highly porous rigid polybenzoxazole (PBO) network films were prepared using a precursor-mediated fabrication method. The obtained PBO network films possessed high porosities of similar to 40%, as calculated from their apparent densities. In addition, the 5%-weight-loss temperatures of the films were >= 570 degrees 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 x 10(-1) S/cm at 150 degrees C, which was higher than that of Nafion (TM). Therefore, these films can be used at higher temperatures than that of Nafion (TM).

This is the peer reviewed version of the following article: [Uchida, T, Onishi, Y, Goto, A. Preparation of highly porous heat-resistant polybenzoxazole network films and their electrical conductivities. Polym Adv Technol. 2021; 1- 7. doi:10.1002/pat.5494], which has been published in final form at [https://doi.org/10.1002/pat.5494]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-ArchivedVersions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wileyor by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked toWiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof bythird parties from platforms, services and websites other than Wiley Online Library must be prohibited.
This fulltext is available in Sep. 2022.