Fabrication of Crack-Free Flattened Bamboo and Its Macro-/MicroMorphological and Mechanical Properties

This work aimed to help the bamboo industry develop methodology for producing imperfection-free bamboo boards that can serve either decorative or structural benefit to consumers seeking to engage with the bioeconomy.Specifically,softened and slotted bamboo tubes were handled by a roller device with nails to render crack-free flattened bamboo board.Softening temperature and time were optimized herein according to findings regarding chemical composition and board mechanical properties.The optimal softening parameters for saturated steam heat treatment is proved to be 160°C for 8 min.The flattened bamboo board possesses an increased bending strength of 101.5 MPa and a decreased bending modulus of 7.7 GPa,being compared with only-softened bamboo.The corresponding changing mechanism is determined in-depth by the micro-morphological and mechanical results based on in-situ SEM and AFM technologies.Under the action of nails and rolling processes,the bamboo texture becomes compact with crushed and fragmented conduit walls.The resulting cell cavity then becomes stretched and compressed,taking on a morphology which allows for the mechanical penalties associated with flattening to be avoided.According to the micro-mechanical results obtained by AFM,compared with unflatten bamboo,the Young’s modulus of the cell membrane in transverse direction(YT)decreases to 1.00 GPa while the corresponding Young’s modulus in radial direction(YR)increases to 7.29 GPa.

基于桐油热处理的竹材理化性质研究

寻求绿色、可持续发展的改性方法来生产耐用竹材制品,是目前竹产业面临的挑战。本文将桐油热处理技术应用于竹材改性,探讨了桐油热处理过程中桐油在竹材中的渗透行为和分布,研究了桐油与热处理的协同作用对竹材化学性质、物理性质、力学性质的影响以及相互作用机制。结果表明,桐油热处理不仅可以增强竹材的疏水性能和尺寸稳定性,改善竹材的防霉性能,而且竹材可以保持其良好的力学性能。与未处理竹材相比,200℃桐油热处理后竹材的饱水膨胀率从3.17%下降至2.42%,200℃桐油热处理后竹材径切面的接触角在300 s时仍可保持在100°以上。桐油热处理后竹材性能的改善归因于竹材化学成分的变化、纤维结晶度的增加、竹材外表面和细胞腔内表面油膜的形成。因此,桐油热处技术在竹材工业改性中具有良好的发展前景。