Construction of a novel Schiff structure curing agent endowing vitrimer with excellent inherent flame-retardant properties, char-forming capability, toughness, and degradation performance

The tensile and impact strengths of CNEP were 35.81% and 58.02% higher than DGEBA/DDM, respectively. • PNEP-25 wt% had a LOI of 30.5% and achieved UL-94 V-0 rating. • CNEP exhibited excellent controllable degradation, self-healing and transparency. The application scope of epoxy resin, one of the most extensively utilized engineering materials, is notably restricted by limitations such as inherent flammability, brittleness, and non-degradability. Herein, two novel epoxy curing agents (BTAP and DPO-BTAP) were synthesized and reacted with DGEBA to prepare a series of novel vitrimer materials (CNEP and PNEP-xwt%, where x = 15, 20, and 25). The tensile strength of CNEP was 64.1 MPa, and the impact strength was 25.6 kJ/m 2 , which were 35.8% and 58.0% greater than those of DGEBA/DDM, respectively, indicating a combination of rigidity and flexibility. TGA analysis revealed that PENP-25 wt% had residual char contents of 2.9 wt% and 24.6 wt% in air and N 2 , respectively. PNEP-25 wt% had a limiting oxygen index (LOI) of 30.5% and achieved a UL-94 V-0 rating. Its peak heat release rate (PHRR) and total heat release (THR) decreased to 567 kW/m 2 and 45.96 MJ/m 2 , respectively, representing decreases of 56.9% and 39.7% compared with those of DGEBA/DDM. CNEP exhibited a relaxation time of 314 s at 175 °C, demonstrating good controllable degradation, self-healing properties, and transparency. This new vitrimer may represent a new generation of high-fire safety and degradable high-performance engineering materials. Download: Download high-res image (449KB) Download: Download full-size image