Radiative heating performance of sodium alginate–based sustainable composite films incorporating ceramic fillers

Radiative heating structures engineered through the management of natural radiation find applications across technical fields owing to their superior comfort, healing and energy-saving benefits. This study presents development of composite films exhibiting passive heating function by incorporating zinc oxide, tourmaline, and pumice particles into sodium alginate matrix. Besides standard chemical and morphological analyses, performances of the films in managing mid-infrared and solar radiation were evaluated via FT-IR and UV-VIS-NIR Spectroscopy devices equipped with integrating spheres. Besides heating, heat retention performances were determined under simulated conditions by a hotplate system including FIR lamp. Results indicate that films containing pumice and tourmaline particles created similar passive heating performances up to 10.09 °C and 8.55 °C relative to their particle-free counterparts and a black fabric in turn. The mentioned performances can be attributed to their superior MIR reflectance effectively redirecting MIR radiation back to the body, coupled with minimal MIR emissivity, mitigating heat loss. The results demonstrate the significant potential of the produced biodegradable passive heating composite films.