The investigation of flame-retardant fiber mats for high performance composites: flame retardancy and structure performance

The flame-retardant performance of carbon fiber reinforced composites serves as a critical metric for structural stability. Nonetheless, the prevalent methodologies for improving the flame retardancy of composites struggle to reconcile the dual objectives of flame retardancy and mechanical robustness, due in part to the constraints imposed by the conventional additive-based approach on the material interface. This study introduced a novel method involving a glass fiber mat, which was augmented with a polyurethane-based treatment integrated with flame-retardant substances, in particular ammonium polyphosphate and nickel hydroxide. This fiber mat was strategically applied to the composite surface, conferring both flame retardancy and enhanced structural resilience. The structure performance and flame retardancy of composites were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and the cone calorimeter test. Experimental comparisons with nontreated controls indicated that the innovative composites exhibited a reduction in total heat release and total smoke production by 13.7% and 18.8%, respectively. Concurrently, a notable enhancement in mechanical properties was observed, with increases of 20.9% and 23.1% for tensile and flexural strength. This well-balanced performance is attributable to the structure design, with toughened glass fiber mats to protect the composite surfaces from structural failure, and flame-retardant agent composition for combustion resistance and smoke suppression. Consequently, the proposed integrative flame-retardant structural design, enriched with specific flame-retardant treatments, offers a promising avenue for fabricating high-performance composite materials with potential utility in the aviation and aerospace sectors.