沙柳的孔隙结构、微纤丝角和纤维素结晶度研究

Pore structure,microfibril angle and cellulose crystallinity of Salix psammophila

【目的】研究不同年轮沙柳(Salix psammophila)材的孔隙结构、微纤丝角和纤维素结晶度,为更合理、有效地利用沙柳资源提供依据。【方法】以取自内蒙古鄂尔多斯沙地的3年生沙柳为研究对象,利用氮气吸附法(NAD)研究不同年轮处沙柳木材的孔隙结构,并用X射线衍射(XRD)测定不同年轮处沙柳木材的微纤丝角和纤维素结晶度。【结果】从髓心到树皮的3个年轮处沙柳木材的比表面积逐渐增大,分别为0.54,0.68和1.81m2/g;孔体积逐渐增大,分别为0.002,0.468和1.560cm3/g,大多数孔隙的直径为2~10nm;而微纤丝角逐渐减小,分别为14.35°,12.17°和10.71°;纤维素结晶度从第1年轮到第3年轮略有增加,分别为48.15%,49.23%和49.58%。【结论】靠近树皮的沙柳材具有较大的比表面积、孔体积、纤维素结晶度和较小的微纤丝角,是制取纤维素材料和生物质能源的较好原材料。

【Objective】The pore structure,microfibril angle（MFA）and cellulose crystallinity of Salix psammophila were studies to provide basis for more reasonable and effective use.【Method】In this study,S.psammophila in Kubuqi Desert,Inner Mongolia was collected,and nitrogen adsorption desorption（NAD）and X-ray diffraction（XRD）were used to estimate pore structure,microfibril angle and cellulose crystallinity at different annual rings.【Result】The specific surface areas and pore volumes of three annual rings of S.psammophilaincreased from pith to bark.The specific surface areas were 0.54,0.68 and 1.81 m^2/g,and the pore volumes were 0.002,0.468 and 1.560 cm^3/g,respectively.Most pore diameters ranged from 2 to 10 nm.MFA of three annual rings of S.psammophiladecreased with the values of 14.35°,12.17°and 10.71°.The cellulose crystallinity of S.psammophilaincreased slightly from the first ring to the third ring,with the values of 48.15%,49.23% and 49.58%,respectively.【Conclusion】Salix wood near the bark had higher specific surface area,pore volume and cellulose crystallinity as well as lower MFA,indicating that it is better raw material in producing cellulose materials and bioenergy.