耐火、耐水的增强型聚合物/黏土气凝胶保温材料制备与结构性能研究

Due to the practical problems of currently used insulation material, this project focuses on the achievement of fire-resistant, water-tolerant and mechanically-strong polymer/clay aerogel insulation material with low thermal conductivity. Polymer/clay aerogel matrix would be fabricated with freeze-drying method firstly, and then coated with irradiation-crosslinkable flame retardant. The gamma ray would be expected to cure the coatings and simultaneously cause crosslinking of the polymer matrix, thus endowing the material with improved flame retardant properties, mechanical properties and water-tolerant properties. The author would explore the fabrication, structure and properties (including mechanical properties, thermal stabilities, flame-retardant properties, thermal conductivity, and water-tolerant properties), and then the relationships among these would be revealed. The flame-retardant mechanisms of coated aerogel materials with different components, absorbed dose and structure would also be investigated. Therefore, this project has both scientific meanings and application prospects and hence to provide a scientific basis for development of fire-resistant, water-tolerant and mechanically-strong polymer/clay aerogel insulation material with low thermal conductivity. This project also provides a scientific basis for the development of mechanically-strong polymer-based material with coatings.

针对现有保温防护材料存在易燃、隔热效率低、不耐水或力学性能差的问题，本项目以聚合物、黏土为原料，通过液氮冷冻-冻干的方法制备出聚合物/黏土气凝胶基体，在其上涂覆可辐照固化阻燃剂，采用高能射线辐照固化阻燃剂的同时辐照交联增强聚合物/黏土气凝胶，研究气凝胶及阻燃剂的含量、组成、结构、制备及辐照工艺与产物结构、性能（力学性能、热稳定性、耐火性能、耐水性能及隔热性能）的关系，研究并揭示气凝胶材料的阻燃机理，为研制出同时实现耐火、耐水和增强目的的低导热系数聚合物/黏土气凝胶保温材料提供科学依据。本项目也为聚合物基材料同时涂覆、交联增强技术提供科学依据。因此，本项目既具有科学意义，又具有应用前景。

本课题分几个阶段制备出阻燃、增强、耐水的聚合物/黏土气凝胶材料，并进一步拓展了气凝胶材料的应用。（1）采用伽马辐照交联的方法，以聚乙烯醇和黏土为原料，水为溶剂，采用冻干的方法制备出增强型聚乙烯醇/黏土气凝胶材料：所得材料绿色环保，经辐照交联的样品其压缩模量明显提高，与聚氨酯硬泡性能相当。从力学性能来观察，30kGy是制备强的聚乙烯醇复合物的最优剂量。随着吸收剂量的提高，气凝胶的微观结构变得更加致密，热稳定性随剂量的增加略有下降。锥形量热测试显示，增强型聚乙烯醇/黏土气凝胶难以燃烧。（2）在辐照交联的基础上，本课题还研究了不同分子量的聚乙烯醇对气凝胶的影响：基于高分子量聚乙烯醇的气凝胶的拥有更高的压缩模量，因此随着分子量提高所需辐照剂量下降。气凝胶的热稳定性能和燃烧性能均没有随聚合物分子量或较低剂量的辐照发生改变，但与聚合物和黏土的比例相关。（3）通过添加阻燃剂的方式制备出高阻燃聚乙烯醇和粘土气凝胶：所得材料的压缩模量、阻燃性能均随着阻燃剂和高聚物含量增加明显提高。气凝胶材料的热导率很低且不受阻燃剂含量影响，表明其是良好的保温材料。（4）：通过涂覆方法制备了耐火、耐水的阻燃增强型气凝胶：涂覆后的气凝胶材料耐水性显著提升，且材料耐水性随涂层厚度增大而提升，辐照固化的材料耐水性比热固化材料略有提高；涂覆后材料的阻燃性能、力学性能有明显提高，涂覆后可有效降低气凝胶材料吸湿饱和后的导热系数。（5）聚合物/粘土气凝胶的拓展应用：以高阻燃性的藻酸盐/粘土气凝胶为涂层制备了高效阻燃聚氨酯泡沫；以高阻燃性的藻酸盐/粘土气凝胶为基体，制备了具有高效中子屏蔽性能的气凝胶材料；采用苯胺和生物降解的果胶制备了力学性能优异的新型生物基导电气凝胶。本基金的支持使得项目按计划顺利完成，进一步的拓展研究发现聚合物/黏土气凝胶材料在多方面有吸引力的应用前景，值得进一步深入研究。