Enhanced thermal resistance of carbon/phenolic composites by addition of novel nano-g-C3N4

Effects of a novel carbon/phenolic (CF/PR) ablator filled with acidified graphitic carbon nitride (ag-C 3 N 4 ) on ablative resistance were evaluated. Ablative properties of CF/PR composites were significantly enhanced by 69.23% with incorporating 0.2 wt% ag-C 3 N 4 , ascribing to the formation of the dense carbon layer over the fibers, increased graphitization degree and more pyrolysis gases . Molecular dynamics simulations of ag-C 3 N 4 inside the matrix confirm the origins of improved ablation resistance arising from the fact that ag-C 3 N 4 alters the breaking patterns and spatial distribution of the polymer fragments, and reduces the graphitic growth temperature by 400 K. And the decomposition of ag-C 3 N 4 and phenolic at the fiber-matrix interface collides the fibers' surfaces to undermine the structural integrity, which induces the phase transformation from short-range to long-range order of the matrix carbon because of the templating effect (transverse) and the interlayer π-π stacking (longitudinal) of the fibers at extremely high temperature.