Effect of loadings of nanocellulose on the significantly improved crystallization and mechanical properties of biodegradable poly(ε-caprolactone).

Biodegradable poly(ε-caprolactone) (PCL)/nanocellulose (NC) nanocomposites were prepared using solvent-free melt processing techniques with various NC contents. Both the nonisothermal and isothermal melt crystallization processes of PCL/NC nanocomposites were significantly accelerated by adding NC. The nonisothermal melt crystallization peak temperature obviously increased from 18.8 °C for neat PCL to 30.9 °C for the PCL/NC nanocomposite with 10 wt% NC content at a cooling rate of 10 °C min-1; moreover, the half-time isothermal crystallization at 40 °C significantly decreased from 12.2 min for neat PCL to 2.0 min. Apparently, NC enhanced PCL's crystallization rate. The crystalline morphology study confirmed the increased nucleation density of PCL spherulites, indicating the role of NC as an efficient nucleating agent. Moreover, the loading of NC did not change the crystal structure of PCL, and with increase in NC content, the Young's modulus and yield strength increased; however, the elongation-at-break and the breaking strength decreased. Compared with pure PCL, the thermomechanical properties of PCL/NC nanocomposites were significantly improved. These biodegradable PCL/NC nanocomposites showed excellent crystallization capabilities and tailored mechanical properties, thus proving their potential as a substitute for traditional commercial plastics.