The use of cellulose fiber from office waste paper to improve the thermal insulation-related property of konjac glucomannan/starch aerogel

The development of eco-friendly thermal insulation material composed of recyclable wastes contributes to enhancing environmental sustainability with less pollution. In this study, polysaccharide-based aerogels with improved thermal insulation property were obtained by using konjac glucomannan, starch, and office waste paper cellulose fiber (WPCF) via sol-gel and freeze-drying method. The obtained aerogels had a bulk density of 30.1–44.9 mg/cm3, a porosity of 95.1–97.0%. Results revealed that increased WPCF addition did not impact the thermal stability, but improved the sol stability, reduced the pore size, strengthened the mechanical property, and lowered the hygroscopicity of the aerogels, benefiting practical application. Although WPCF solids showed a high thermal conductivity, increased WPCF addition at 0.1–0.5 wt% reduced the aerogel thermal conductivity, which was explained by the longer heat path and less heat convention. Further higher WPCF addition at 0.5–1.5 wt% increased the aerogel thermal conductivity as the heat conduction of solid matrix was increased and the heat convection was strengthened. Therefore, the lowest thermal conductivity (0.0335 Wm−1 K−1) of the aerogel was reached at the optimized WPCF addition of 0.5 wt%. This work showed the high potential of the WPCF to be used to strengthen the thermal insulation property of polysaccharide-based aerogels.