A novel DOPO-based flame retardant containing benzimidazolone structure with high charring ability towards low flammability and smoke epoxy resins

• Published in: Polymer degradation and stability Vol. 183; p. 109426
• Main Authors: Wang, Hao, Li, Shan, Zhu, Zongmin, Yin, Xianze, Wang, Luoxin, Weng, Yunxuan, Wang, Xuyi
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.01.2021; Elsevier BV
• Subjects: Capture effect; Combustion; Composite materials; degradation; Enthalpy; epoxides; Epoxy resin; Epoxy resins; fire behavior; Fire resistance; Flame retardancy; Flame retardants; Flame-retardant mechanism; Flammability; Fourier transforms; Free radicals; heat; Heat release rate; Heat transfer; Infrared spectroscopy; Morphology; NMR; Nuclear magnetic resonance; oxygen; Phosphorus; phosphorus content; Photoelectrons; polymers; Smoke; Smoke suppression; Thermal stability; X ray photoelectron spectroscopy; Epoxy resin; Flame retardancy; Flame-retardant mechanism; Smoke suppression
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2020.109426

•A phosphaphenanthrene/benzimidazolone-containing flame retardant (POBDBI) was synthesized successfully.•POBDBI imparted excellent flame retardancy and smoke suppression to EP.•POBDBI exerted flame-retardant effect both in condensed phase and gaseous phase. A novel flame retardant POBDBI was generated by the reaction of p-dibenzaldehyde, 5-amino-2-benzimidazolinone and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), and employed to epoxy resin. The structure of POBDBI was measured by FT-IR and NMR tests. Then flame-retardant EP was fabricated by using POBDBI as a flame-retardant. The thermal stability, flame-retardant performance and fire behavior were investigated by a serious of comprehensive instruments. Combustion tests show the flame-retardant performance of composite materials has been significantly improved. For example, the EP/POBDBI-1.0 with the phosphorus content of 1.0% accorded a V-0 rating and its limiting oxygen index (LOI) value increased to 36.5%. Besides, total smoke production (TSP), peak heat release rate (PHRR) and total heat release (THR) of EP/POBDBI-1.0 dropped significantly, and the corresponding values were decreased by 48.4%, 48.9% and 8.7%, respectively. At the same time, the composition, morphology of chars and gaseous products of POBDBI were studied by X-ray photoelectron spectroscopy (XPS), FT-IR, scanning electron microscope (SEM) and Py-GC/MS. These results presented that POBDBI could not only exerted free radical capture effect, but also enhanced the density of char residue.