物理化学学报 >> 1999, Vol. 15 >> Issue (06): 517-521.doi: 10.3866/PKU.WHXB19990607

研究论文 上一篇    下一篇

SiO2-PEG凝胶体系的热物理化学特征

孙继红, 巩雁军, 范文浩, 吴东, 孙予罕   

  1. 中国科学院山西煤炭化学研究所 煤转化国家重点实验室，太原 030001
  • 收稿日期:1998-08-31 修回日期:1998-12-18 发布日期:1999-06-15
  • 通讯作者: 孙予罕

Themal Physical Chemical Characteristics of SiO2-PEG Xerogels

Sun Ji-Hong, Gong Yan-Jun, Fan Wen-Hao, Wu Dong, Sun Yu-Han   

  1. State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001
  • Received:1998-08-31 Revised:1998-12-18 Published:1999-06-15
  • Contact: Sun Yu-Han

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摘要：

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．

关键词: TG-DTA, SiO2-PEG, PEG, SiO2干凝胶

Abstract:

 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.

Key words: TG-DTA, SiO2-PEG, PEG(Polyethylene glycol), SiO2 xerogel