Effects of Fiberized Carbons on Ablative Performances of Poly[(2,2,2-Trichloroethoxy)/(Aryloxy)] Phosphazene Flexible Heat Shielding Materials

Carbon fiber-reinforced polymer composites are commonly used in ablative materials, but achieving a balance between thermal insulation, mechanical strength, and anti-ablation performance is challenging. This study presents a series of polyphosphazenes with trichloroethoxy substituents, which enhance the mechanical and thermal properties of the synthesized polyphosphazenes. The effects of different types and amounts of fiberized carbon fillers, including carbon fibers, carbon fiber powder, and carbon nanofibers, on the poly[(2,2,2-trichloroethoxy)/(aryloxy)] phosphazene composites were investigated. The composite reinforced with 10 phr (parts per hundred rubber) of fiberized carbon fillers showed a 49.1% reduction in linear ablation rate and 31.4% in charring ablation rate, compared with the baseline. The mechanical properties of the composite and charred layer improved by 57.5% and 215%, respectively. This is due to the fact that the carbon filler facilitates the formation of dense charred layers with low porosity and high graphitization, which prevent heat and flame penetration. The fiberized carbon-reinforced polyphosphazene composites exhibit excellent ablation resistance and mechanical performance, making them ideal for high-performance thermal insulation in extreme conditions.