Experimental evidence for a mechanical function of the cellulose microfibril angle in wood cell walls
Experimental evidence for a mechanical function of the cellulose microfibril angle in wood cell walls
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DOI：
10.1080/01418619908210415
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发表时间：
1999-09-01
期刊：
影响因子：
--
通讯作者：
Fratzl, P
中科院分区：
文献类型：
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作者：
Reiterer, A;Lichtenegger, H;Fratzl, P
木材是一种天然纤维复合材料，具有特定强度和特定弹性系数的层次化蜂窝结构，可以与其他常见建筑材料相媲美。每个木材细胞通常是由沿着宏观纤维方向螺旋排列的纤维素纤维构成的。虽然假设微纤丝角(MFA)与力学性能之间的关系是很自然的，但到目前为止，只对单纤维建立了良好的相关性，其中发现具有较大MFA的纤维具有较大的延伸性。在本文中，我们首次证明了这种关系甚至存在于木材的薄片(200微米)中，这为MFA优化木材的延伸性提供了有力的证据。在同一云杉试件的拉伸试验和小角X射线散射结构研究相结合的基础上，我们发现，随着MFA的增加，最大应变显著增加，弹性模量也发生了变化。
Wood is a natural fibre composite with a hierarchical cellular structure of a specific strength and a specific modulus of elasticity that can be compared with those of other common construction materials. Each wood cell is typically built of cellulose fibrils spiralling around the macroscopic fibre direction. While it is natural to assume a relation between the microfibril angle (MFA) and the mechanical properties, a good correlation has up to now only been established for single fibres, where a larger extensibility was found for fibres with larger MFA. In the present paper, we show for the first time that this relation even exists for thin (200 mu m) sections of wood: which provides strong evidence for the fact that the MFA optimizes the extensibility of wood. In a combination of tensile tests with structural investigations by small angle X-ray scattering on the same sample of Picea abies, we found a remarkable increase in maximum strain with increasing MFA, and also a change in the elastic moduli.