Influencing Factors of the Bending Properties of Resin-Treated Flattened Bamboo and Its Decorative Characteristics

Cracking frequently occurs during the pressing process of flattened bamboo, significantly reducing yield rates. To address the lack of effective strategies for the mechanical reutilisation of cracked flattened bamboo, an epoxy resin-based treatment approach was proposed to improve both mechanical and decorative performance, inspired by resin-based decorative composites. Crack filling and full-cell impregnation methods were then systematically evaluated. This work is the first to systematically compare crack filling and full-cell impregnation strategies across different bamboo radial positions, with a simultaneous evaluation of mechanical performance and decorative properties. The results show that bamboo radial position has a pronounced influence on bending performance. The outer layer exhibits markedly higher bending strength and Young’s modulus than the inner layer, with mean differences of approximately 134 MPa and 13.3 GPa, respectively. Crack filling results in a measurable improvement in the bending performance of cracked flattened bamboo, whereas full-cell impregnation leads to a reduction in the bending properties of the outer layer. These results suggest that crack filling represents a more mechanically efficient and cost-effective treatment strategy. Resin treatment increases surface colour variation but minimally impacts yellowing resistance performance. These findings demonstrate that resin-treated flattened bamboo with cracks supports the resource utilisation of waste bamboo and shows potential for decorative and interior material applications.