【作者】 张小勇；

【导师】 陈蔚萍； 乔聪震；

【作者基本信息】 河南大学 ， 化学工程， 2012， 硕士

【摘要】 SiO₂气凝胶是一种多功能的介孔材料，由于它具有高孔隙率，高比表面积，低密度等特性使它有广阔的应用前景。多孔结构赋予了SiO₂气凝胶绝热、吸声、催化、吸附等特性，由于它的高比表面积和高孔隙率使它在新型催化剂以及催化剂载体等方面具有广泛的应用，同时它也可以用作冰箱隔热材料，窗户的透明隔热材料，声阻抗藕合材料等，它可以作为研究分析结构动力学的最佳材料，还应用于超级电容材料、集成电路中、新型气体过滤器中等。本文研究了通过添加扩孔剂制备不同孔径的SiO₂气凝胶，实现了对制备的二氧化硅气凝胶的孔径调控和优化，并进一步研究了SiO₂气凝胶负载药物的初步性能。首先：本课题选用尿素、乌洛托品、聚乙二醇、十二烷基伯胺作为扩孔剂来制备扩孔的二氧化硅气凝胶。制备过程为，用正硅酸乙酯（TEOS）和水为原料，乙醇为溶剂，采用溶胶-凝胶法，通过常压干燥或者超临界干燥，制备出轻质多孔SiO₂气凝胶。扩孔剂是在湿凝胶形成之前被加入，被加入的扩孔剂可以均匀的分散在形成的凝胶网状结构中，通过焙烧把二氧化硅气凝胶中含有的扩孔剂除去，释放了扩孔剂占据的空间，达到了扩孔的目的。实验考察了扩孔剂的种类、水解时间、扩孔剂的用量、焙烧温度等因素对二氧化硅气凝胶孔径的影响。其中，乌洛托品的扩孔效果最好；水解时间由12h⁶0h增加时，制备的二氧化硅气凝胶的孔径先增大后不变，水解时间在24h时二氧化硅气凝胶的孔径达到最大；扩孔剂乌洛托品的用量依次增加时，硅气凝胶的孔径也是逐渐增加的（由于扩孔剂在溶液中的溶解度的影响，加入的扩孔剂的量不能无限增加）；在考察的焙烧温度范围内（100℃⁵00℃），随着焙烧温度的增加，二氧化硅气凝胶的孔径也逐渐增加，温度越高分散在气凝胶孔中的扩孔剂的分解越彻底，释放的空间也就越大，制备出来的二氧化硅气凝胶的孔径也就越大。通过实验确立最佳实验条件为：扩孔剂用乌洛托品时扩孔效果最好；水解时间为24h；扩孔剂乌洛托品的用量为0.044mol/mol TEOS；焙烧温度为500℃，最终制备的二氧化硅气凝胶的孔径达14.67nm。其次，利用上述过程制备不同孔径的二氧化硅气凝胶负载药物洛伐他订。利用超临界技术，通过吸附、结晶过程实现扩孔二氧化硅气凝胶对药物洛伐他订的负载。采用FTIR、TG、N2吸附-脱附和HPLC等分析方法对负载过洛伐他订的硅气凝胶样品进行了表征。结果表明：用硅气凝胶负载过药物的样品既有硅气凝胶的骨架结构又有药物的官能团，说明硅气凝胶负载上了部分洛伐他订药物；BET表征结果显示负载过药物的二氧化硅气凝胶的吸附量比载药之前二氧化硅气凝胶的吸附量有了明显的降低，说明有一部分药物会结晶在硅气凝胶的孔道里面，使二氧化硅气凝胶的孔容变小，吸附量降低；热重数据显示硅气凝胶对洛伐他订有一定的负载量，负载量在9.0%（wt%）左右；用HPLC测定样品的释放性显示经过硅气凝胶负载过的洛伐他订的样品有一定的缓释效果，并且硅气凝胶的负载量随着硅气凝胶孔径的增加而升高。最后，通过实验我们成功制备了不同孔径的二氧化硅气凝胶，并且掌握了通过改变制备过程中一些因素来控制所形成的二氧化硅气凝胶的孔径；在载药实验中，利用超临界流体快速膨胀法制备了硅气凝胶负载药物洛伐他订的样品，由硅气凝胶负载的洛伐他订样品的释放曲线和纯的洛伐他订样品的释放曲线对比可知，在释放的前期，经过硅气凝胶负载的药物有一定的缓释效果。更多还原

【Abstract】 Silica aerogel is one kind of Mutifunction mesoporous materials，it has a lot of characteristics andapplications because silica aerogel has porosity、 the lowest density、larger surface area. Therefore, silicaaerogel has a lot of characteristics and applications, such as thermal insulation, sound absorptive, catalysis,adsorptive property and so on. Silica aerogel has a wide range of applications in the new catalysts andcatalytic carrier Because of its high surface area and high porosity, it can be used as a transparent insulatingmaterial, refrigerator insulation, and acoustic impedance coupled materials. As a study of fractal structuraldynamics of the best materials used in integrated circuits, also super capacitor materials, new gas filter, andso has multiple uses.In this paper, the silica aerogel of different diameter be prepared by adding pore expanding,and findsome factors which control and optimization the the pore of silica aerogel.then, further studies the differentdiameter of silica aerogel as carrier and Lovastatin as target drug preliminary performance.First, hexamethylene tetramine、urea、 polyethylene and dodecane amine as pore expanding,usingtetraethoxysilane (TEOS) as the silica source，Silica aerogels were prepared via sol-gel method and ambientdrying process,the pore expanding be added in alcohol gel form before. Factors which influence the poresize of silica aerogels,uch as hydrolysis time and the different roasting temperature wereinvestigated.FTIR、SEM、TG and N2Adsorption/Desorption were used to analysize and characterize theaerogels.Results show that the sample with hexamethylene tetramine keep skeleton structure of silicaaerogels、good dispersivity、good thermal stability and larger pore size;Then, hexamethylene tetramine aspore expanding when the pore size of silica aerogels was bigger than another,he pore size of silica aerogelsno longer get bigger at24h around when hydrolysis time increase from12h to60h,and the pore size ofsamples was increase with the increase of the mount of hexamethylene tetramine and roasting temperatureimprove. The best experimental conditions:The pore size of samples were biggest use hexamethylene tetramineas expanding agent;Hydrolysis time for24h;The amount of hexamethylene tetramine0.044mol/mol TEOS;Roasting temperature for500℃.The pore size of silica aerogels was14.67nm.Secondly,silica aerogels were carried with Lovastatin by adsorption and crystallization in supercriticalCO2.Factors,difference pore size which influence the loading of silica aerogels.FTIR、TG and N2Adsorption/Desorption were used to analysize and characterize the samples.Results show that the loadedsamples both skeleton structure of silica aerogels and skeleton structure of Lovastatin、the absolute quantityof loaded samples were smaller than absolute quantity of silica demonstrate that a little of Lovastatincrystallize in silicas’ pore by BET、the loading rate of silica aerogels up to9.0%(wt%) by TG，the loadingof silica was increase with the improve the pore size of silica.Finally, the prepartion silica aerogel of different diameter,and change some factors which during thepreparation process to control the pore size of silica aerogel formation;In the drug trial,by the rapidexpansion of supercritical solution to prepartion the sample of silica load Lovastatin.Compared the releasecurve of the silica aerogel load Lovastatin and the Lovastatin,it reveal that the sample of silica aerogel loadLovastatin contributing to controlled-release.更多还原