Cellulose nanocrystals/water‐based polyurethane nanocomposite films with excellent wear resistance and softness

Abstract Waterborne polyurethane (WBPU) has the advantages of environmental, excellent film‐forming property and high bonding strength. However, the mechanical strength of waterborne polyurethane in coating products is not enough, and its wear resistance and softness are poor. In this paper, the Cellulose Nanocrystals (CNC) AQ3 obtained by acid hydrolysis of microcrystalline cellulose was successfully dispersed in the waterborne polyurethane matrix to prepare nanocomposite films with different contents. The mechanical properties, thermal properties, wear resistance and softness of the nanocomposite films were studied by Thermogravimetric (TG), tensile test, dry friction test and KES test. The morphology of CNC dispersed in waterborne polyurethane matrix was studied by Scanning electron microscope (SEM). The results show that the lower content of CNC was uniformly dispersed in the waterborne polyurethane matrix and the interaction between the two forms hydrogen bonds. Compared with waterborne polyurethane, the initial degradation temperature of the nanocomposite films made by adding only 1 wt% CNC increased by 50°C, the tensile strength increased by 179.3%, the wear resistance increased by 19%, and the minimum bending stiffness B reached 0.161 (gf·cm 2 ). The results of this study can be used for textile coating applications, such as polyurethane synthetic leather.