硅甲基对纳米多孔疏水性二氧化硅气凝胶热危害形成的影响机理

Nanoporous hydrophobic SiO2 aerogels (HSAs) have thermal hazard risk due to the existence of organic characteristic functional groups, silylmethyl. Taking characteristic functional groups (i.e. silylmethyl) as the breakthrough point, this proposal will study the formation mechanisms and characteristics of the thermal hazard of different silylmethyl nanoporous HSAs through test analyses and small/medium-scale combustion experiments combined with theoretical analyses and computational simulations. In the response law of thermal action, the microstructure evolution and thermal properties changes of different silylmethyl HSAs will be analyzed and the corresponding relationship between them will be constructed. The pyrolysis characteristics of different silylmethyl HSAs will be systematically studied via a series of test technologies. The reaction mechanisms during the pyrolysis will be predicted by pyrolysis kinetics, which will be further validated by the simulated pyrolysis processes based on genetic algorithms. Combined the pyrolysis characteristics and pyrolysis kinetics, the effects of various silylmethyl groups on the pyrolysis mechanisms of HSAs will be revealed eventually. Furthermore, the combustion characteristics and flame spread behavior of various silylmethyl HSAs will be explored. Combined with the above investigations, the temperature depended microstructure parameters will be introduced to establish the coupled multi-parameter combustion models for the different silylmethyl HSAs. The research results will deepen the understanding of thermal hazards of nanoporous HSAs and simultaneously provide the theoretical guidance for the prevention of their thermal hazards.

纳米多孔疏水性SiO2气凝胶因其有机特征官能团——硅甲基的存在而具有热危害风险。本项目以特征官能团硅甲基为切入点，通过测试分析、小/中尺度燃烧试验并结合理论分析与计算模拟，对不同硅甲基疏水性SiO2气凝胶的热危害形成机理与特性开展研究。在热作用的响应规律上，着重分析不同硅甲基SiO2气凝胶的微观结构演变和热物性变化，并构建两者之间的对应关系；借助多种测试手段研究不同硅甲基SiO2气凝胶的热解特性，利用热解动力学预测其反应机理（正向），并基于遗传算法进行模拟验证（逆向）；结合热解特性和热解动力学，阐明不同硅甲基对疏水性SiO2气凝胶热解机理的影响；研究不同硅甲基SiO2气凝胶的燃烧特性和火蔓延行为，结合以上研究并引入随温度变化的微观结构参数，构建不同硅甲基SiO2气凝胶耦合多参数的燃烧特征模型。研究成果将加深对纳米多孔疏水性SiO2气凝胶热危害的认识，同时可为其热危害防控提供理论指导。

纳米多孔疏水性SiO2气凝胶的潜在热危害严重制约了其在保温隔热领域的应用拓展。本项目以疏水SiO2气凝胶的表面基团——硅甲基为突破口，制备和表征了多种硅甲基改性的疏水性SiO2气凝胶，探究了热作用下其微观-宏观性质的演变规律。分析了硅甲基疏水性SiO2气凝胶的典型热解过程和热解产物，并基于无机理函数积分法（Kissinger-Akahira-Sunose (KAS)法和Flynn-Wall-Ozawa (FWO)法）和Coats-Redfern模型计算了表观活化能，确定了反应机理函数，揭示了硅甲基疏水性SiO2气凝胶的热解机理。采用锥形量热仪详细研究了不同硅甲基疏水SiO2气凝胶的燃烧过程和燃烧特性，对比分析了不同硅甲基疏水SiO2气凝胶的热危害风险，结合热解机理阐明了硅甲基疏水SiO2气凝胶的燃烧机理。本项目系统地探究了硅甲基对纳米多孔疏水性SiO2气凝胶热危害形成的影响机理，研究成果将加深对疏水性SiO2气凝胶热危害的认识，同时可为其热危害防控以及隔热应用拓展提供理论指导。.在本项目资助下，项目负责人以第一作者或通讯作者发表论文16篇，其中SCI论文14篇，EI论文2篇；申请发明专利9项，其中授权发明专利3项；出版学术专著《二氧化硅气凝胶材料制备及其热安全特性研究》；获第十二届中国消防协会科学技术创新奖一等奖；培养硕士研究生12人，其中毕业5人，在读7人。