SiO2-PEG凝胶体系的热物理化学特征

用程序升温热重法分析了SiO2及SiO2-PEG干凝胶的热物理化学行为，结果表明：采用不同的环境气氛对SiO2-PEG干凝胶进行热处理，聚乙二醇（PEG）表现出不同的热稳定性，并由此影响干凝胶的织构性质；通过对氮气气氛中得到的DTG曲线进行处理，得到不同温度段的表现活化能，说明SiO2干凝胶脱羟反应表现出动力学控制，而SiO2-PEG干凝胶随着温度的升高则表现出动力学控制逐步向表面羟基的扩散控制转变．

Thermal Physical Chemical Characteristics of SiO2-PEG Xerogels

The thermal behavior of SiO2-PEG/SiO2 xerogels was analyzed by using a temperature-programmed thermogravimertric method. The results showed the PEG in the xerogel had different thermal stability when the SiO2-PEG xerogel being heated under different atmosphere, and therefore influenced the textural properties. The apparent activation energy in different temperature stages was obtained from the DTG curves in N2. It indicated that the dehydroxyl reaction of SiO2 xerogel was kinetic-controlled, but, undergone the transition from kinetic-controll to diffusion-controll of the surface hydroxyl gradually with increasing temperature.