基于SR-WAXS技术的竹材纤维素晶胞模型研究

竹材中纤维素聚集态结构的不同，将直接影响到竹纤维复合材料性能，对于竹材纤维素晶胞单元的认识主要基于Meyer-Misch模型，由于天然纤维素的同质异构体，在每种植物中存在比例不同，所以竹材中纤维素应有其特有的晶胞模型。以毛竹(Phyllostachys edulis (carriere) J. Houz)为研究对象，通过同步辐射广角X射线散射技术对毛竹纤维素晶胞模型进行研究，利用单斜晶系晶面间距公式与毛竹纤维素衍射峰，精确计算晶胞模型。结果显示，若以b轴为纤维轴的单斜晶系纤维素单元，则晶胞参数为：a=8.35 ，b=10.38 ，c=8.02 ，β=84.99°，该晶胞包含四个葡萄糖基，由两条反向平行分子链构成。研究结果可为开发制作高性能竹纤维复合材料等高附加值应用提供理论依据。

Study on the Crystal Structure of Cellulose in Bamboo with Synchrotron Radiation Wide Angle X-Ray Scattering

The crystal structure of cellulose will directly affect the properties of bamboo fiber -reinforced composite, but the unit cell of native cellulose in bamboo has never been investigated. The most accepted model for the structure of native cellulose is Meyer-Misch model which provides a reference to understand the unit cell of native cellulose in bamboo. The native cellulose consists of two different crystal structures (Ⅰ_α and Ⅰ_β) which exist in different plants with different proportions. Because of this situation, the crystal structure of bamboo cellulose should have a unique model. The moso bamboo (Phyllostachys edulis (Carr. ) H. de Lehaie)was selected. The crystal structure of cellulose of bamboo was investigated with two dimensional synchrotron radiation wide angle X-ray scattering (SR-WAXS). The values of the interplanar spacings of each peak were obtained from SR-WAXS patterns, and then crystal structure parameters were calculated according to monoclinic crystal system. The results show that the fibre axis of a bamboo cellulose unit cell with a monoclinic unit cell of a=8.35 , b (fiber axis)=10.38 , c=8.02 , β=84.99°. This model has a two antiparallel arrangement for the chains in unit cell, with four glucose residues. Thus, the model may be used to provide a theoretical basis for high value-added bamboo fiber -reinforced composite.