Fiber-reinforced phenolic resin aerogel (FRPRA) composite materials are seductive candidates for high-temperature thermal protection owing to their low density, excellent thermostability, and thermal insulation. However, the intrinsic stiffness restricts their further application for high efficiency. We report a homogeneous and chemical bonding strategy for fabricating lightweight and flexible FRPRA with good ablative thermal insulation performance. The compressible (cyclic strain of 60%) and bendable (cyclic strain of 30%) abilities as well as the structural stability during ablation all benefit from the compatibility between the phenolic resin aerogel matrix and the phenolic fiber reinforcement. Additionally, low bulk density and thermal conductivity of 0.20 g cm-3 and 0.043 W m-1 K-1, respectively, endow the composite with efficient thermal insulation capability. With an 8 mm-thick coupon, the temperature of 200 °C can be decreased to 70.6 °C and the temperature around 1200 °C can be camouflaged to 78 °C through combining with the Al panel. The material also enables a conformal stealth of 600 °C based on its bendability. Hence, the composite has potential in applications of both static and dynamic thermal insulation.
Keywords: ablation; fiber-reinforcement; flexibility; phenolic resin aerogels; thermal insulation.