小角X射线散射方法测定二氧化硅干凝胶的平均孔径

提出了当多孔体系的小角X射线散射不遵守Porod定理的情况下，应用Debye法(相关函数法) 和Guinier法(逐级切线法和多级斜线法)计算它们的平均孔径的方法.对不同制备条件下部分 二氧化硅干凝胶的测试，取得了比较一致的结果，并与氮气吸附法测定结果进行了对比. 关键词： 小角X射线散射 二氧化硅干凝胶 平均孔径

DETERMINATION OF AVERAGE PORE DIAMETER OF SiO2 XEROGELS BY SMALL ANGLE X-RA Y SCATTERING

Small angle X-ray scattering (SAXS) with synchrotron radiation as X-ray source h as been used to study the structure of SiO_{2 xerogels prepared by sol-gel pr ocess. All SAXS profiles in this paper deviate from Porod's law and show negativ e or positive deviation. In order to obtain the information of pore in SiO2 xerogels, we have proposed the corresponding methods to correct the negat ive and positive deviations from Porod's law. Then, the average pore diameter of SiO2 xerogels is determined with Debye's method and Guinier's method , separately, and the results are found to be close to each other. The average d iameters fall in the rangl 3-25nm for samples prepared under various conditions. The results of SAXS are also close to that determined by N2 adsorption met hod at 77K with ASAP2000.}