High-efficiency phosphorus/nitrogen-containing flame retardant on epoxy resin. (May 2021)

• Record Type: Journal Article
• Authors: Wang, Donghui; Liu, Quanyi; Peng, Xiaoliang; Liu, Chuanbang; Li, Zekun; Li, Zhifa; Wang, Rui; Zheng, Penglun; Zhang, Hui
• Is Part Of: Polymer degradation and stability. Volume 187(2021)
• Publication Date: 2021-05
• Subjects: Epoxy resin -- Flame retardancy -- Lower phosphorus content -- Gas phase -- Condensed phase; Polymers -- Deterioration -- Periodicals; Stabilizing agents -- Periodicals; Polymères -- Dégradation -- Périodiques; Stabilisants -- Périodiques; 668.9
• DOI: 10.1016/j.polymdegradstab.2021.109544
• Languages: English
• ISSNs: 0141-3910

Abstract

Highlights: A novel phosphorus/nitrogen-containing hybrid containing phosphophenanthrene and nitrile groups It significantly improved both thermal stability and flame retardancy of epoxy resins at low phosphorus content. The flame-retardant mechanism acted in both gas phase and condensed phase. Limiting oxygen index of epoxy resin increased to 41.2%. Abstract: A phosphorus/nitrogen-containing compound (named DOPO-BAPh) was synthesized via the graft reaction between 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and bisphenol A bis(phthalonitrile) containing benzoxazine. The flame retardancy of DOPO-BAPh was investigated on epoxy resin (EP). The results showed that DOPO-BAPh catalyzed the curing reaction of due to the phenolic hydroxyl groups in the structure. The nitrile group in DOPO-BAPh was self-cured in EP to form cross-linked networks containing aromatic heterocycles, further enhancing the stability of the char layer formed after combustion. The introduction of DOPO-BAPh strengthened flame retardancy of the EP. With only 0.26 wt.% phosphorus of loading level, the modified EP reached an LOI value of 35.8% and obtained V-0 rating in UL-94 testing. And DOPO-BAPh exhibited char-forming ability during the decomposition. Besides, the DOPO-BAPh showed flame-retardant activity in both the gas and condensed phases.