Ambient pressure drying preparation of kaolin-reinforced cellulose sponges with low thermal conductivity

Cellulose sponges are widely used in the fields of thermal insulation, adsorption and catalysis owing to their low density, high porosity and low thermal conductivity. However, they suffer from complex preparation process and poor mechanical property. In response to this, an ambient pressure drying route was investigated to prepare the mineral-reinforced cellulose sponges using bagasse and minerals as main raw materials. Thanks to the cross-linking reactions among cellulose, mineral, glutaraldehyde and chitosan, a more stable three-dimensional network structure was formed, enhancing the mechanical property of sponge. The kaolin-reinforced cellulose sponges exhibited a bulk density of 70.10 mg/cm³, a porosity of 99.20 %, a compressive strength of 231.20 kPa at 50 % strain, and a thermal conductivity of 43.50 mW/(m·K). The present cellulose sponge prepared by ambient pressure drying, with its easy operation and low cost, low thermal conductivity and acceptable mechanical strength, can be potentially be used as thermal insulation materials in buildings.