SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2023, Vol. 58 ›› Issue (6): 266-281.DOI: 10.1016/j.cjche.2022.10.018

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Insight into pyrolysis of hydrophobic silica aerogels: Kinetics, reaction mechanism and effect on the aerogels

Xinyu Liu1, Hongliang Sheng2, Song He1, Chunhua Du1, Yuansheng Ma1, Chichi Ruan1, Chunxiang He1, Huaming Dai1, Yajun Huang3, Yuelei Pan3   

  1. 1. School of Safety Science and Emergency Management, Wuhan University of Technology, Wuhan 430070, China;
    2. Wuhan Building Material Industry Design & Research Institute Co., Ltd, Wuhan 430200, China;
    3. State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230027, China
  • Received:2022-06-14 Revised:2022-10-21 Online:2023-08-31 Published:2023-06-28
  • Contact: Hongliang Sheng,E-mail:sheng.hl@sinoma-wbmdi.cn;Song He,E-mail:hsong@whut.edu.cn
  • Supported by:
    This research was financially supported by the National Natural Science Foundation of China (52074201 & 51706165) and China Postdoctoral Science Foundation (2021M703082).

Insight into pyrolysis of hydrophobic silica aerogels: Kinetics, reaction mechanism and effect on the aerogels

Xinyu Liu1, Hongliang Sheng2, Song He1, Chunhua Du1, Yuansheng Ma1, Chichi Ruan1, Chunxiang He1, Huaming Dai1, Yajun Huang3, Yuelei Pan3   

  1. 1. School of Safety Science and Emergency Management, Wuhan University of Technology, Wuhan 430070, China;
    2. Wuhan Building Material Industry Design & Research Institute Co., Ltd, Wuhan 430200, China;
    3. State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230027, China
  • 通讯作者: Hongliang Sheng,E-mail:sheng.hl@sinoma-wbmdi.cn;Song He,E-mail:hsong@whut.edu.cn
  • 基金资助:
    This research was financially supported by the National Natural Science Foundation of China (52074201 & 51706165) and China Postdoctoral Science Foundation (2021M703082).

Abstract: Silica aerogels have promising applications in thermal insulation, but their flammability and reaction mechanisms have rarely been investigated. The pyrolysis kinetics and thermodynamics of hydrophobic silica aerogels under N2 environment were studied. The kinetic and thermodynamic parameters were obtained by three model-free methods. Based on the calculated kinetic parameters, the pyrolysis mechanism of silica aerogels was discussed by the master plots method. The results indicate that the reactions of the whole pyrolysis phase can be characterized by a random nuclear model. In addition, FTIR test results show that the volatile products of silica aerogel pyrolysis are mainly hydrocarbons generated by the decomposition of hydrophobic groups (methyl groups) on the surface. Finally, the effects of pyrolysis on the properties of silica aerogels Finally, the effects of pyrolysis on the properties of silica aerogels were investigated based on the analysis results of SEM, specific surface area, pore size distribution, X-ray diffraction, XPS and infrared spectroscopy.

Key words: Pyrolysis, Thermodynamics, Reaction kinetics

摘要: Silica aerogels have promising applications in thermal insulation, but their flammability and reaction mechanisms have rarely been investigated. The pyrolysis kinetics and thermodynamics of hydrophobic silica aerogels under N2 environment were studied. The kinetic and thermodynamic parameters were obtained by three model-free methods. Based on the calculated kinetic parameters, the pyrolysis mechanism of silica aerogels was discussed by the master plots method. The results indicate that the reactions of the whole pyrolysis phase can be characterized by a random nuclear model. In addition, FTIR test results show that the volatile products of silica aerogel pyrolysis are mainly hydrocarbons generated by the decomposition of hydrophobic groups (methyl groups) on the surface. Finally, the effects of pyrolysis on the properties of silica aerogels Finally, the effects of pyrolysis on the properties of silica aerogels were investigated based on the analysis results of SEM, specific surface area, pore size distribution, X-ray diffraction, XPS and infrared spectroscopy.

关键词: Pyrolysis, Thermodynamics, Reaction kinetics