A novel composite of alginate aerogel with PET nonwoven with enhanced thermal resistance

There is a need to develop new composite fabrics with improved thermal properties. Aerogels are highly porous materials with low thermal conductivities and can be used to develop new composites with standard nonwoven fabrics. In this study, a new composite of alginate aerogel with polyester (PET) nonwoven was synthesized by a sol-gel method. A needle punched PET nonwoven was soaked with an alginate solution and then immersed in an aqueous CaCl2 solution which resulted in the formation of a gel inside the PET nonwoven. The gel was dried with supercritical CO2 after solvent exchange with ethanol leading to alginate aerogel-PET nonwoven composite. The aerogels were porous and were in the form of blocks in between the PET fibers as evident from SEM images. The thermal properties of the composite were measured using a heat flow meter. The thermal diffusivity of the composite was significantly lower than the thermal diffusivity of the pure PET nonwoven. The composite also had a higher thermal resistance and also a higher tensile strength than the pure PET nonwoven. Experiments using a thermal imaging camera indicated that the heat flux in the composite is much lower than in pure PET nonwoven due to the presence of alginate aerogel. The results show that the new composite material is promising for use in thermal clothing applications.