Thermal decomposition behavior of self-catalyzed and fire-retardant phosphorus-nitrogen Vitrimer material

Epoxy resin (EP) encountered dual challenges of flammability and non-recyclability, prompting the proposal of covalent adaptable networks to enhance its sustainability. However, achieving strong flame-retardant performance remained a significant hurdle. In this study, diglycidyl ether of bisphenol A (DGEBA), DOPO derivatives (DDP), glutamic acid (GA), and itaconic acid (IA) were employed as raw materials to synthesize a phosphorus-nitrogen synergistic flame-retardant covalent adaptable network epoxy resin. This synthesis, which involved the introduction of secondary amines and self-catalysis, resulted in a novel material with excellent thermal stability at 349 ℃, and superior flame-retardant properties, including a limiting oxygen index of 32 % and a V-0 flammability rating. Comprehensive analysis of the material's thermal decomposition and gas-phase products was conducted using techniques such as residual carbon morphology and structure, TGA-FTIR, and TGA-GC/MS, providing deeper insights into the thermal decomposition mechanism of the material.