Hierarchical characteristics in radial direction of Bambusa textilis McClure and their influence on tensile properties

Abstract

Bamboo exhibits a unique hierarchical structure, allowing it to adjust its resistance to external load in natural conditions. However, there is a lack of basic data on the structure and performance of Bambusa textilis McClure (BTM). This work elucidates the structure and properties of BTM from macroscopic to ultra-microscopic and explored the factors potentially influencing the tensile properties of BTM. The results show that BTM exhibits significant gradient changes in its fiber volume ratio (V_f), chemical components, fiber morphology, microfibril angle, crystallite sizes, crystallinity, creep resistance, and tensile properties, while the mechanical properties of its fiber cell wall are relatively constant along the radial direction of the BTM culm. The tensile failure of BTM layers commonly forms a “broom shape”, which is affected by the distribution and morphology of the fiber bundles, parenchyma, and vessels. The promising tensile strength and modulus in the outer culm were 489.05 MPa and 37.12 GPa, respectively. Statistical analysis showed that the change in macroscopic structure exerts significant effect on tensile properties of BTM relative to the micro-and ultra-microscopic features. BTM contains 95 % monoclinic crystals with lattice constants approximating those of other higher plants. The rule of mixture was invalid in this material.