Flame retardation of vinyl ester resins and their glass fiber reinforced composites via liquid DOPO-containing 1-vinylimidazole salts. (1st April 2022)

• Record Type: Journal Article
• Authors: Zhang, Feng-Qi; Zhao, Yuan-Zheng; Xu, Ying-Jun; Liu, Yun; Zhu, Ping
• Is Part Of: Composites. Number 234(2022)
• Publication Date: 2022-04-01
• Subjects: Flame retardancy -- Vinyl ester resin -- Glass fiber reinforced composite -- DOPO; Composite materials -- Periodicals; Materials science -- Periodicals; Composite materials; Periodicals; Electronic journals; 620.118
• DOI: 10.1016/j.compositesb.2022.109697
• Languages: English
• ISSNs: 1359-8368

Abstract

Abstract: Aiming for obtaining flame-retardant vinyl ester resins (VER) and the composite, a kind of liquid 9, 10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO)-containing 1-vinylimidazole salt (called VIDOP) was conveniently synthesized through the neutralization of the DOPO-derived acid and 1-vinylimidazole to be applied as flame-retardant crosslinking agents of VER. Curing behaviors, flame retardancy, thermal decomposition behaviors, thermal-mechanical properties, and mechanical performance of VER materials were investigated. With 25 wt% addition of VIDOP, the modified resin (VIDOP25/VER) and their glass fiber reinforced composites (VIDOP25/VER/GF) achieved UL 94 V-0 rating with a limiting oxygen index value of 32.1% and 38.3%, respectively. Both heat release and smoke release of VIDOP25/VER and VIDOP25/VER/GF decreased compared to those of the reference sample in the cone calorimetry test. VIDOP showed flame-retardant activities in both gaseous and condensed phases for the resin, while they didn't work well in the condensed phase for the composite. VIDOP/VER presented a little lower a glass transition temperature than VER with a relatively low crosslinking density, in which 1-vinylimidazoles covalently linked with the VER chain and the DOPO-derived group attached to the resin via ionic bonds. VIDOP/VER and the composite had better mechanical properties than the unmodified sample and outperform other systems in well-balanced performance. Graphical abstract: Image 1