Ablative and mechanical evaluation of CNT/phenolic composites by thermal and microstructural analyses

Highly ablation resistant carbon nanotube (CNT)/phenolic composites were fabricated by the addition of low concentrations of CNTs. Tensile and compressive mechanical properties as well as ablation resistance were significantly improved by the addition of only 0.1 and 0.3 wt% of uniformly dispersed CNTs. An oxygen–kerosene-flame torch and a scanning electron microscope (SEM) were used to evaluate the ablative properties and microstructures. Thermal gravimetric analysis (TGA) revealed that the ablation rate was lower for the 0.3 wt% CNT/phenolic composites than for neat phenolic or the composite with 0.1 wt% CNTs. Ablation mechanisms for all three materials were investigated using TGA in conjunction with microstructural studies using a SEM. The microstructural studies revealed that CNTs acted as an ablation resistant phase at high temperatures, and that the uniformity of the CNT dispersion played an important role in this ablation resistance.