Inducing large deformation in wood cell walls by enzymatic modification
Inducing large deformation in wood cell walls by enzymatic modification
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通过酶改性诱导木材细胞壁发生大变形
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
I. Burgert
中科院分区：
文献类型：
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作者：
Luna Goswami;M. Eder;N. Gierlinger;I. Burgert
最近的研究表明，在s2层中具有高纤维素微纤维角的木材，例如压缩木材，会表现出永久性的塑性变形，而不会对基体造成明显的机械损伤。这种分子粘滑机制可以用纤维素原纤维在基体中超过一定剪切应力后发生滑动来解释。这种材料性能对于各种应用都是理想的，例如，在汽车工业中需要覆盖具有高度可变形贴面的复杂几何形状。然而，通常用于这些目的的贴面具有相当脆的破坏行为，这会导致断裂，以及严重的质量和生产力损失。当通过修改木材细胞壁成分，特别是纤维素原纤维及其基质耦合来赋予潜在的变形原理时，这种贴面的更好的可变形性可能会实现。对机械分离的木纤维进行酶处理，使整个木质化的次生细胞壁塑化。利用绿色木霉（Trichoderma viride， E.C.3.2.1.4）中具有纤维素和木聚糖活性的Onozuka R-10纤维素酶。显微力学测试和红外光谱显微镜研究揭示了细胞壁的力学性能和纳米结构特征的变化。十种改性纤维中有两种具有延长的可变形性。
It has been shown recently that wood with a high cellulose microfibril angle in the S2-layer, e.g. compression wood, shows permanent plastic deformation without significant mechanical damage to the matrix. This molecular stick-slip mechanism was explained by a gliding of the cellulose fibrils, after a certain shear stress in the matrix was exceeded [1]. Such a material behaviour would be desirable for various applications, for instance, to cover complex geometries with highly deformable veneers as needed in the automotive industry. However, veneers that are typically used for these purposes have a rather brittle failure behaviour, which leads to breakage, and drastic quality and productivity losses. A better deformability of such veneers might be achieved when the underlying deformation principles are conferred by modifying the wood cell wall components, in particular the cellulose fibrils and their matrix coupling. Enzyme treatments were performed on mechanically isolated wood fibres to plastify the entire lignified secondary cell wall. Cellulase Onozuka R-10 from Trichoderma viride (E.C.3.2.1.4) with activity on cellulose and xylan was utilized. Micromechanical tests and FT-IR microscopy studies revealed the change of mechanical properties and nanostructural features of the cell wall. An extended deformability was achieved for two of ten of the modified fibres.