防治煤炭自燃的智能凝胶的设计与特性研究

The spontaneous combustion of coal is one of major natural disasters in coal mines of China, and excellent extinguishing materials is the key to prevent coal spontaneous combustion. For the deficiencies of existing extinguishing materials, a novel extinguishing material"intelligent hydrogel" is suggested to prevent spontaneous combustion of coal, which has some advantages, such as authigenic gas foaming, thermal intelligence, expansion under high temperature .By studying the effect of polymer monomer, aggregate, crosslinking agent, foaming agent on microstructure and thermal intelligence of hydrogel, the relationship between composition, structure and characteristic of intelligent hydrogel is analyzed, and the best formulation of intelligent hydrogel is determined. Using modern measuring and testing approaches,such as Scanning Electron Microscope，NMR spectroscopy,etc.,the swelling/de-swelling behavior, rheological law, microstructure and chemical structure of intelligent hydrogel are studied, and the rheology dynamics and thermal intelligent mechanism of intelligent hydrogel are revealed. By constructing a cooling experimental device and a extinguishing experimental device, dynamic evolution and expasion dynamics of intelligent hydrogel under high temperature are analyzed, and then cooling, heat radiation protection and sealing properties of intelligent hydrogel are studied. Finally, the extinguishing mechanism of intelligent hydrogel is revealed. The study would provide a new theoretical method and technical means for the prevention of spontaneous combustion of coal.

煤炭自燃严重制约了我国煤矿的安全开采，制备优异的防灭火材料是防治煤炭自燃的关键。本项目针对现有防灭火材料的不足，创新性的提出"防治煤炭自燃的智能凝胶"，该材料具有自生气发泡，温度智能性、高温膨胀性等特点。通过研究聚合单体、骨料、交联剂、发泡剂、引发剂等对凝胶的微观结构和温度智能性的影响,分析智能凝胶的组分、结构与性能的关系，确定凝胶共聚体系中各组分的最佳配比。利用扫描电镜、核磁共振光谱仪等现代测试手段研究智能凝胶在不同温度下的溶胀/去溶胀行为、流变规律、微观物理结构和化学结构，揭示智能凝胶的流变动力学和温度智能机理；通过构建耐高温/降温实验装置、灭火实验装置，研究智能凝胶在高温条件下的动态演变规律和高温膨胀动力学，分析智能凝胶的降温、防热辐射、密封等特性，阐明智能凝胶的防灭火机理，为防治煤炭自燃提供新的理论方法和技术手段。

煤炭自燃严重制约了我国煤矿的安全开采，制备优异的防灭火材料是防治煤炭自燃的关键。针对现有防灭火材料的不足，本研究提出了“防治煤炭自燃的智能凝胶”，该材料具有自生气发泡性、温度敏感性、高温膨胀性、绿色环保等特点。本项目以N-异丙基丙烯酰胺（NIPAM）为温敏单体，以2-丙烯酞胺基-2-甲基丙磺酸（AMPS）、丙烯酸钠（SA）以及地瓜淀粉为吸水单体合成了温敏性水凝胶，分析了该凝胶的吸水性、微观结构和化学特性。由于NIPAM成本较高，本项目通过添加发泡剂在凝胶中引入多孔结构，提高了凝胶的温度敏感性，降低了材料成本。首先将玉米秸秆与AMPS接枝形成磺酸基纤维素，然后与丙烯酸（AA）接枝共聚合成水凝胶。通过红外光谱分析、X射线衍射、扫描电镜、热重分析、动态流变仪对秸秆复合凝胶的结构和性能进行了表征。研究了引发剂、交联剂、单体中和度、温度等对凝胶吸水率的影响，分析了玉米秸秆基水凝胶的保水性、耐盐性以及可重复利用性。结果表明经过双氧水处理后，秸秆纤维素的结晶度明显降低，水凝胶为非晶体结构。秸秆基水凝胶中布满褶皱和微孔，这些结构有利于水分的吸收。该凝胶的再吸水性能强，具有较好的重复使用价值。通过在凝胶共聚体系中添加发泡剂，制备了自生气发泡凝胶。分析了发泡剂用量对凝胶的吸水性能、溶胀动力学以及微观结构的影响；结果表明发泡剂的加入使凝胶出现了明显的孔洞结构，发泡剂越多泡孔结构越明显；凝胶的吸水倍率、温敏性和溶胀动力学指数随发泡剂用量的增加而增大。最后，在自生气发泡凝胶中添加可膨胀石墨，制备了智能凝胶。通过搭建小型灭火装置，研究了智能凝胶的自生气发泡性、高温膨胀性、粘附性、渗透性以及灭火特性（灭火过程中CO、温度、热辐射的变化），并与温敏凝胶、普通凝胶进行对比。灭火实验表明，相比其它灭火材料，智能凝胶能有效覆盖高温火源，快速降温，有效隔热，显著抑制CO的产生，在防治煤炭自燃方面具有明显优势。