Functionalized cellulose-based adhesive with epoxy groups having high humidity resistance performance.

Sustainable and environment friendly natural-based adhesive has been considered as an optimum alternative of industrial adhesive which is non-renewable and harmful to health. Cellulose is the most abundant natural polymer in nature and has potential applications in the field of adhesives. However, the inherent hydrophilic nature of cellulose-based adhesive significantly challenges its use in high humidity environments. In this paper, a highly hydrophobic and anti-swelling cellulose-based adhesive was prepared by epoxy modification of microcrystalline cellulose (MCC). The simultaneous enhancement of adhesive and cohesive properties is achieved through the reaction of epoxy groups with the hydroxyl groups from the wood and adhesive during the hot-pressing process. Prepared adhesive has excellent properties in extremely humid environments. The dry bonding strength of the prepared adhesive reached 6.02 ± 0.26 MPa, while the wet bonding strength was 4.78 ± 0.21 MPa after immersed in water at 63 °C for 3 h. Furthermore, the bonding strength remained largely stable in 90 % atmospheric humidity. The adhesive has a certain universality, which can bond to substrates such as aluminium, iron, and glass. This study presents an innovative approach to the manufacturing of cellulose-based adhesive with enhanced bonding performance and exceptional water resistance.