High-performance, intrinsically fire-safe, single-component epoxy resins and carbon fiber reinforced epoxy composites based on two phosphorus-derived imidazoliums

• Published in: Polymer degradation and stability Vol. 208; p. 110261
• Main Authors: Wang, Jingsheng, Chen, Xi, Wang, Jun, Yang, Shuang, Chen, Kaiwen, Zhu, Lu, Huo, Siqi, Song, Pingan, Wang, Hao
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2023
• Subjects: Carbon fiber reinforced epoxy composite; carbon fibers; degradation; epoxides; fire safety; Flame retardancy; flammability; gels; imidazole; One-component epoxy resin; oxygen; polymers; shelf life; smoke; Smoke suppression; Thermal latency; Carbon fiber reinforced epoxy composite; Flame retardancy; Thermal latency; Smoke suppression; One-component epoxy resin
• ISSN: 0141-3910
• DOI: 10.1016/j.polymdegradstab.2023.110261

•Two phosphorus-derived imidazoliums were synthesized by aqueous self-assembly.•CEPM-1 and CEPM-2 endowed single-component EPs with superior latency and fast curing speed.•The fabricated EPs and CFRE composites achieved improved flame retardancy and smoke suppression. Carbon fiber reinforced polymer (CFRP) composite is a kind of lightweight material with excellent comprehensive properties, but low production efficiency and inherent flammability have become two crucial limitations for its further application. Herein, two phosphorus-derived imidazoliums (CEPM-1 and CEPM-2) were synthesized by aqueous self-assembly, and applied to flame-retardant, one-component epoxy resins (EPs). Moreover, the well-designed EPs (EP/CEPM-1–25 and EP/CEPM-2–20) were used as resin matrixes for CFRP. Both EPs featured superior latency and modest-temperature fast curing, especially EP/CEPM-1-25, which had a long shelf life of 30 days and can gel within 20 min at 150 °C. The limiting oxygen index (LOI) and UL-94 classification of EP/CEPM-1-25 were 33.0% and V-0, indicative of superior flame retardancy. The total smoke production and maximum smoke density of EP/CEPM-1-25 displayed 37.7 and 72.1% reductions relative to those of the control EP sample cured by imidazole, demonstrating improved smoke suppression. EP/CEPM-2-20 also displayed satisfactory fire safety, but slightly inferior to EP/CEPM-1-25. As expected, the CFRP composites based on EP/CEPM-1-25 and EP/CEPM-2-20 showed high LOIs (42.5 and 39.0%) and UL-94 V-0 classification due to the inhibition of P-containing groups in CEPM-1 and CEPM-2 on the wick effect. Therefore, this work proposes a facile and ‘green’ methodology to create high-performance, intrinsically fire-safe single-component EPs and CFRP composites. [Display omitted]