Development of Cellulose-Based Wood Adhesives with Good Bonding Performance and Application Potential

Biobased adhesives prepared from renewable resources are now the focus of attention in the wood industry. Cellulose as the most abundant renewable biomass material in nature constitutes an excellent biomaterial for developing an adhesive. In this work, cellulose-based wood adhesive (APSC@HU) was successfully prepared from oxidized cellulose reacted with a polyurea (hexamethylenediamine-urea, HU). This APSC@HU adhesive exhibits excellent bonding properties, water resistance, low cost, and environmental friendliness. The cellulose oxidation process was optimized by adjusting the oxidant addition ratio, oxidation time, and reaction temperature. Optimal APSC@HU was prepared by adding 15% (w/w to cellulose) (NH4)2S2O8 and oxidizing at 70 °C for 2 h, followed by reaction with HU compounds. Its dry shear strength, 24 h cold water strength, and 3 h hot water strength were 2.06, 1.15, and 0.98 MPa, respectively. A Schiff base and addition reaction between the aldehyde groups in oxidized cellulose and the amino groups in the HU polyurea leads to a dense cross-linked network and provides good bonding effect, which is confirmed by FT-IR, XPS, and XRD analyses. Moreover, this APSC@HU adhesive can be considered as a potential adhesive for industrial wood-based panels when considering its environmental protection characteristics and cost factors.