Influence of ZrB2 Nanoparticles on the Mechanical and Thermal Behaviors of Carbon Nanotube Reinforced Resol Composite

• Ability to combine ZrB2 nanoparticles and multiwalled carbon nanotubes within resol resin
• Use of ZrB2 particles at nanoscale dimensions
• Dramatic improvement in the linear ablation rate of phenolic resin by 76% by adding these nanostructures
• Dramatic improvement in the mass loss rates of phenolic resin by adding these nanostructures

The present study focuses on the thermal response of carbon fiber-reinforced phenolic composites, where the matrix has been modified with different reinforcements. Two types of materials, multiwalled carbon nanotubes and zirconium diboride (ZrB2), were used in a new design of mixture to produce the heat-resistant ablative composite system. The CNT/ZrB2/carbon/phenolic nanocomposite (Z/NT-CR) system corresponding to CNT/carbon/phenolic nanocomposite (NT-CR) showed a reasonable decrease in mass loss and the ablation rate as compared to carbon/phenolic composite (CR). However, substantial drop in two factors was found for Z/NT-CR as compared to carbon/phenolic and NT-CR. Ablation mechanisms for all three composites were investigated by thermal gravimetric analysis in conjunction with microstructural studies using a field emission scanning electron microscope. The microstructural studies revealed that CNTs acted as an ablation resistant phase for protection against 2000 °C, and the conversion from ZrB2 to ZrO2 played an important role as an insulator in the performance of char layer in the ablation resistance.