Fast-growing bamboo composites with the delignification and densification fabricating processes have been widely applied for sustainable structural materials, but the environmentally stability still hinders its further development. Here, we demonstrate a robust and environmental stable modified densified bamboo composites consisting of hierarchical AlO nanoparticles and organic coupling agent γ-Aminopropyl triethoxysilane (KH550) layer. KH550 densified bamboo exhibits superb tensile strength and flexural strength of 462 MPa and 364 MPa, which are, respectively, 237% and 198% higher than those of natural bamboo. Flexible molecular chains of KH550 decorate cellulose with silane groups and amino groups, the thermal decomposition temperature significantly delays ∼80 ℃ and hydrophilic densified bamboo turns hydrophobic with the contact angle of ∼112°. The obtained AlO densified bamboo however shows rough and porous defects, and only exhibits slight increase in tensile properties, but decreases on flexural and thermal properties. Real-time acoustic emission also reveals that the introduction of coupling agent enhances the load delivery between fibers and parenchyma cells, leading to high energy consumption and fracture resistance. This work shows the complex effects of organic and inorganic modification designs for bamboo materials, which might arouse potential application prospects for environmentally stable, sustainable robust structural biomass composites.

中文翻译：

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机械坚固且环境稳定的 Al2O3/KH550 致密竹结构材料

采用脱木质素和致密化制造工艺的速生竹复合材料已广泛应用于可持续结构材料，但环境稳定性仍然阻碍其进一步发展。在这里，我们展示了一种坚固且环境稳定的改性致密竹复合材料，由分层 Al2O3 纳米颗粒和有机偶联剂 γ-氨丙基三乙氧基硅烷 (KH550) 层组成。KH550致密竹具有优异的拉伸强度和弯曲强度，分别为462兆帕和364兆帕，分别比天然竹高237%和198%。KH550的柔性分子链用硅烷基团和氨基修饰纤维素，热分解温度显着延迟~80℃，亲水性致密竹材转疏水性，接触角~112°。然而，所获得的Al2O3致密竹材表现出粗糙和多孔缺陷，并且仅表现出拉伸性能的轻微提高，但弯曲性能和热性能下降。实时声发射还表明，耦合剂的引入增强了纤维和薄壁细胞之间的载荷传递，导致高能耗和抗断裂性。这项工作展示了有机和无机改性设计对竹材料的复杂影响，这可能会激发环境稳定、可持续的坚固结构生物质复合材料的潜在应用前景。