Polyetheramine‐type flexible chain benzooxazine for simultaneously enhancing flame retardancy and mechanical performance of polyoxymethylene

Abstract

To solve the problems of flammability of polyoxymethylene (POM) and insufficient combustion ability to form carbon, the intumescent flame retardant (IFR) was physically coated by polyetheramine flexible chain benzoxazine (D230‐BOZ, D400‐BOZ), and the flame retardant (D@IFR) was constructed, then POM flame retardant composites were prepared by melt blending. The results showed that although the addition of IFR reduced the initial decomposition temperature of the system, it significantly increased the residual carbon formation. After D‐BOZ coating, the thermal stability of the system was restored to a certain extent. Among them, the T ‐5% and T ‐10% of the POM/4D230@IFR system increased to 258.6°C and 259.7°C, respectively, and the residual carbon content reached 22.24%, which was the highest among all systems. The T ‐5% and T ‐10% of the POM/4D400@IFR system were 251.7°C and 252.9°C, respectively, and the residual carbon content was 19.03%, while the residual carbon content was 18.3% when the coating amount was 2D400@IFR. The analysis of cone calorimetry and carbon morphology showed that the expanded carbon layer formed by the D230@IFR system was larger in height, denser and more stable in structure, while the height of the carbon layer in the D400@IFR system was about 73 mm, and there were still certain holes on the surface. The results showed that the polyetheramine flexible chain benzoxazine coating strategy could regulate the thermal decomposition behavior of IFR, improve the carbon‐forming capacity and carbon layer density of POM at high temperature, and the D230@IFR system showed better synergistic enhancement effect in condensed phase flame retardancy.