Silane-modified phenolic resin for enhancing mechanical and thermal properties of quartz knitted fabric

Fabrics are widely utilized in various fields, including aerospace due to their outstanding properties such as lightweight and flexibility. However, under high-temperature conditions, fabrics face challenges including property degradation and reduced structural stability, while the practical application for large deformation is seriously underestimated. To develop a deformable ablative thermal insulation material, silane-modified phenolic resin (PR) reinforced quartz knitted fabric (PR-Si/QKF) was fabricated, and its mechanical and thermal properties were systematically investigated. The results indicated that the maximum decomposition temperature of PR-Si resin increased from 504 °C to 583 °C, while the residual carbon content increased from 47 % to 58 %. The PR-Si/QKF exhibited a fracture load of approximately 400 N and an elongation at break of about 240%. Compared with untreated QKF, the tensile strength was significantly enhanced by up to 304%, accompanied by a marked reduction in plastic deformation. Moreover, PR-Si/QKF demonstrated excellent fatigue resistance after 10 cycles to 20% tensile strain, and large out-of-plane bulging deformation capability. In addition, it showed superior thermal insulation, oxidation and ablative resistance properties under high-temperature and oxygen-rich environments. The PR-Si/QKF provides a promising approach for deformable ablative thermal insulation applications and is suitable for flexible thermal protection systems.