A novel strategy to construct polybenzimidazole linked crosslinking networks for polymer electrolyte fuel cell applications. (26th June 2020)

• Record Type: Journal Article
• Authors: Duan, Chongxiong; Luo, Haochuan; Li, Jingling; Liu, Cuiyin
• Is Part Of: Polymer. Volume 201(2020)
• Publication Date: 2020-06-26
• Subjects: Polybenzimidazole -- Crosslink -- Benzoxazine; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2020.122555
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: A novel strategy to construct polybenzimidazole linked crosslinking networks (PLCNs) is proposed. A benzoxazine-ended PBI oligomer (BPBI) is prepared, which can react with PBI from the ended benzoxazine groups to form PLCNs. It is proved that the ring-opening reaction of benzoxazine is activated by benzimidazoles mainly from the N–H site in a BIm-rich background and forms phenoxy-type, phenolic-type and crosslinking structures successively under heat. Crosslinked by 15 wt% of BPBI, properties of PBI are remarkably improved with 74% enhancement on tensile strength, 78 °C improvement on sub-Tg transition temperature and 49% increasement on acid uptake. Besides, PBI-Ben(15)-356%PA exhibits a high proton conductivity of 0.122 S cm −1 with a low activation energy of 17.2 kJ mol −1 under 180 °C. As BPBI is thermally stable at room temperature and can crosslink commercial PBI simply by heat, it exhibits promising commercial prospects in the application of polymer electrolyte fuel cells. Graphical abstract: Polybenzimidazole linked crosslinking networks were constructed and displayed excellent mechanical strength, good thermal stability and high acid uptake. Image 1 Highlights: Novel polybenzimidazole linked crosslinking networks were constructed. Benzoxazine was confirmed to react with benzimidazole mainly from the N-H site of benzimidazole. Great improvements on mechanical strength, acid uptake and glass transition temperature were realized by crosslinking. High proton conductivity of 0.122 S cm −1 under 180 °C was achieved.