Design and fabrication of NiTi shape memory alloy/aramid composite fabric for thermal protective clothing

Developing fabrics with enhanced thermal protection is a cutting-edge topic in area of thermal protective clothing (TPC) for workers under heat hazards. Here, temperature-responsive NiTi shape memory alloy (SMA) filaments, which transform into a sinusoid form under a stimulus of temperature exceeding their austenite start temperature of 45.1 degrees C, were prepared. Nine composite fabrics (CFs) using SMA filaments and aramid yarns, different in filament interval, air gap orientation, aramid yarn type and fabric density, were fabricated and incorporated into traditional three-layer TPC fabric system, resulting in a four-layer smart fabric system (SFS) with adaptive structure. Thermal protective performance (TPP) tests demonstrated the addition of CF could significantly slow down the rise of temperature at skin surface and prolong the time to the first-degree burn. With the decrease of filament interval or increase of fabric density, TPP of SFS was improved due to more heat accumulation within and less heat conduction through the fabric. This study would inspire engineering CFs with enhanced TPP, thus pushing forward the development of smart technology in textile engineering.