Ablation and thermo-mechanical investigation of short carbon fiber impregnated elastomeric ablatives for ultrahigh temperature applications

Elastomeric ablative composites for ultrahigh temperature applications were processed and characterized to elucidate the potential of short carbon fibers (SCF) to tailor the thermo-mechanical and ablation characteristics of acrylonitrile butadiene rubber (NBR) composites. SCF was dispersed within NBR using dispersion kneader and two roller mixing mill. Ablation and thermal properties versus back-face temperature elevation during oxy-acetylene flame test, linear/radial ablation rates, percent char yields, insulation index, and thermal conductivity of the fabricated ablatives were measured. Experimental results revealed that the thermo-mechanical and ablation characteristics were significantly improved with increasing SCF concentration in the presence of coupling agent. Improvement in tensile strength, hardness and reduction in elongation at break were obtained with increasing SCF to matrix ratio. The microscopic analysis of the tensile fracture and ablation specimen showed the porosity generation during ablation and uniform dispersion of the impregnated SCF in NBR.