Bamboo-based cellulose nanofibers as reinforcement for polyurethane imitation wood

In recent years, the shortage of resources and the homogeneity of species severely limit the further application of wood. Polyurethane imitation wood (PUIW) can effectively solve these problems and replace wood in a wide range of high-end furniture and interior decoration applications. However, most of the PUIWs have the defects of low strength, heat resistance, water resistance, and antistatic. Herein, we prepared cellulose nanofibers (CNFs) by treating bamboo powder with pre-hydrolysis in conjunction with a deep eutectic solvent (DES) system, and used them as fillers to reinforce PUIW. To evaluate the effect of CNFs on the physical-chemical properties of PUIW, tests such as FTIR, SEM, AFM, TG, DTG, and universal testing mechanics were conducted. It was demonstrated that the abundant active sites on the surface of CNFs form hydrogen bonds with PUIW to enhance the activity of its chain segments and improve its flexibility. The entanglement between CNFs molecules and the PUIW matrix limited the movement of molecular chains, thereby improving the thermal stability. Furthermore, by regulating the concentration of CNFs in CNFs-PUIW, the enhancement of its compressive, tensile, and flexural properties can be achieved. Therefore, these studies showed that the CNFs can improve the physical-chemical properties of PUIW materials, which indicates great potential in the field of PU-based artificial wood.