3D Large Space Warp-Knitted Composite Fabric with Heating and Insulation for Extremely Cold Environments

The extremely cold environment restricts certain activities, making the preparation of a material with both heating and insulation functions a significant challenge. This study presents the large space warp-knitted composite fabric (LSWCF) as an electric heating inflatable material with a three-dimensional structure. It is designed and developed from three modes to mitigate heat loss. The top layer of LSWCF is combined with the electric heating film as the heating layer, showing high electric heating efficiency (577.33 °C/(W·cm-2)), high electrothermal conversion efficiency (95%), and excellent conductivity (12.5 S/cm). The bottom layer of LSWCF is coated with TiO2/WPU coatings as a thermal radiation layer. The inflated LSWCF retains a substantial volume of still air within its middle layer and exhibits low thermal conductivity (0.037 W·m-1·K-1), with resulting minimization of heat loss due to convection and conduction. LSWCF's radiant coating, on the other hand, reduces heat loss through directed radiation. Contributed to the structural design, the LSWCF demonstrates an enhanced ability to generate heat at low temperatures (up to 35 °C at -20 °C, 980 W·m-2) compared to the existing literature. This study offers a novel strategy for the development of materials for use in extremely cold environments.