木材弱界面对其变形和韧性的影响研究进展OA

Wood fulfils critical structural functions and exhibits a unique combinations of stiffness,strength and toughness.These properties are attributed to its intricate architecture,which is organized hierarchically across multiple length scales.The size,shape,and arrangement of the building blocks that constitute these materials,such as cell walls and cellulose microfibrils,are crucial in defining their properties and exceptional performance.However,growing evidence suggests that their deformation behavior and toughness are also significantly influenced by the interfaces connecting these building blocks,including the middle lamella,hemicellulose,and intermolecular hydrogen bond.Although those interfaces occupy only a small fraction of the overall volume and have relatively low strength compared to the building blocks,they play a critical role in maintaining cohesion between the building blocks and ensuring the structural integrity of the material.Furthermore,the interfaces facilitate the shear slip of the building blocks,enhancing the plastic deformation of wood,which in turn promotes crack blunting and deflection,contributing to its toughness.Both thermal and chemical modification caused the change of weak interface structure,resulting in increased brittleness of modification wood.In this review,the composition,structure and mechanics of a set of representative biological interfaces in wood were discussed and the effects of weak interface on deformation and toughness of wood were evaluated from weak interface structure-performance characterization.The effects of heat treatment and chemical treatment on wood toughness and weak interfaces were also discussed.Finally,the weak interface of wood was emphasized.In the future,the following studies can be carried out:the research on multiscale weak interfaces would be utilized as the structure-mechanical properties relationship between the wood structure and mechanical properties.The bonding strength of weak interfaces and shear slip of building blocks induced by weak interfaces should be characterized.In terms of the mechanism of wood deformation and toughness,the study of adaptive structural reorientation of cells and microfibrils would be focused on,and the effects of weak interfaces on wood toughness at the macromolecule scale would be revealed.In terms of toughness of modified wood,the research would be concentrate on the fracture behavior and deformation of modified wood,such as heat-modified,furfurylated,and acetyl-modified woods,and the influences of thermal degradation of wood polymers and reaction between resin and cell wall materials on the structure-mechanical properties relationship of the multiscale weak interfaces.The mechanism of reduced toughness in thermally treated and chemically modified would be elucidated.