Polybenzoxazole (PBO) has long suffered the compromised thermal and mechanical stability due to hydrolysis in humid environment caused by phosphoric acid residues, which further leads to performance degradation. Nanoparticle (NP) catalysts are potentially promising to address this issue as they have been widely applied in the green chemistry synthesis of organic molecules under mild conditions. However, nanocatalysts have rarely been studied in polymerization reaction. Here we report that copper-based NPs to efficiently catalyze tandem reactions of ammonia borane, diisopropoxy-dinitrobenzene, and terephthalaldehyde to prepare PBO polymer. The polymerization reaction exhibits size- and oxidation state-dependent catalytic properties, making 13 nm Cu2O NPs the best catalysts for PBO synthesis and yielding a molecular weight (Mw) of 19 kDa. Owing to the improved purity of polymer prepared by our green chemistry method, obtained PBO thin film shows enhanced mechanical and thermal stability after simulated seawater treatment when compared with commercial Zylon. Our study demonstrates the use of non-noble metal based nanocatalysts in the synthesis of PBO polymer, which could pave a new way for exploring green chemistry synthesis in producing high-performance polymers.

Cu2O nanoparticle-catalyzed tandem reaction for polybenzoxazole synthesis

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.