纤维素-二氧化硅复合颗粒的制备与表征

探索了可用作色谱填料的纤维素-SiO2复合颗粒的制备方法，将纤维素和硅胶溶于NaOH／尿素体系中，得到纤维素-SiO2溶液，用溶胶一凝胶转相法制得复合颗粒．研究了乳化剂用量、搅拌转速、纤维素分子量以及纤维素和SiO2的投料比对所制备的复合颗粒粒径和形貌的影响，以扫描电镜、粒径分析等对复合颗粒进行了表征．发现粘度小的分散相和分子量小的纤维素适合制备粒径大的复合颗粒，反之亦然．当纤维素与SiOz的投料比大于3：1时，复合颗粒呈球形，小于3：1时，多数颗粒的形状为无定形；当乳化剂Span80的用量为10％，搅拌转速为600r／min时，复合颗粒的形状较规则．在不同的条件下，所制备颗粒的体积平均粒径为9～45μm，比表面积在110～4802／g之间．调节乳化剂用量、搅拌转速、纤维素分子量以及纤维素与SiO2的投料比，能制备出粒径适当、比表面积大的复合颗粒，这些颗粒具有介孔结构，且孔径分布较均匀，机械强度高，适合用作色谱分离填料．

Preparation and characterization of cellulose-SiO2 composite beads

The aim of the present work is to develop a method to prepare cellulose-SiO2 composite beads, which can be used as chromatographic packing materials. Thus, cellulose and silica gel were dissolved in an aqueous solution of NaOH/urea, and then cellulose-SiOz composite beads were prepared by a sol-gel method. The influence of the fed amount of the emulsifier, the stirring speed, the molecular weight of cellulose and the fed ratio of cellulose and SiOz on the particle size and the morphology of cellulose-SiO2 beads were studied. electron microscopy, particle size analysis etc. It The composite beads were characterized by scanning is found that the dispersant of low viscosity and the cellulose of low molecular weight are suitable for the preparation of the composite beads of large particle size, and vice versa. When the fed ratio of cellulose and SlOe is higher than 3 ： 1, the composite beads are spherical in shape, and are irregular when the Span 80 and the stirring speed of 600 r/min are the fed ratio is less than 3 ~ 1. The emulsifier of 10% appropriate technique parameters to prepare regular composite beads. The volume-average diameters and the specific surface areas of the as-prepared composite beads are in the ranges from 9 μm to 45 μm, and from 110 me/g to 480 mZ/g, respectively. The composite beads with appropriate particle sizes and big specific surface areas can be prepared by adjusting the fed amount of the emulsifier, the agitation speed, the molecular weight of cellulose and the fed ratio of cellulose and SiOz. These beads possess mesoporous structures and high mechanical strength. Their pore diameters are relatively uniform. Accordingly they are applicable to be used as chromatographic oacking materials.