AbstractThe adhesive properties of a self-prepared bio-based epoxy resin with native cellulose nanocrystals (CNCs) are evaluated in this article. The porosity of actual CNCs is high. The most promising finding is the acquisition of high tensile modulus. The addition of CNC composites significantly increased the tensile modulus at lower wt.%, and the maximum crystallinity of CNCs was obtained. Bearing in mind the advantages of CNCs, scanning electron microscopy (SEM) showed a uniform distribution of concentrated CNCs. Clusters were formed at higher CNCs ratios, and the composite matrix content with high CNCs produced good expansion, low crystallinity, and increased elongation. Our analysis showed that the original CNCs were more evenly distributed in the self-prepared bio-based epoxy resin, which enhanced transformation, supported by improved dispersion of native CNCs. The presence of native CNCs greatly improved and enhanced the bonding performance of the bio-based epoxy resin in the interface area. Enhancing the mechanical properties of native CNCs has broad application prospects in environmental areas. This suggests that the widespread use of native CNCs in environmental engineering applications is feasible, especially in terms of adhesives properties.