混合溶剂法制备SiO_2/十八烷酸相变微胶囊的方法与表征  

Fabrication and Characterization of SiO_2/ Stearic Acid Microencapsulated Phase Change Materials Prepared in Different Solvents

作　　者：蹇守卫[1] 马保国[1] 李相国[1] 金磊[1] 穆松[1] 张琴[1] 

机构地区：[1]武汉理工大学硅酸盐材料工程教育部重点试验室,湖北武汉430070

出　　处：《高校化学工程学报》2010年第2期280-285,共6页Journal of Chemical Engineering of Chinese Universities

基　　金：国家十一五科技支撑计划项目(2006BAF02A29)

摘　　要：为解决SiO2/十八烷酸相变微胶囊制备过程中十八烷酸的分散问题,提高十八烷酸相变材料的有效含量,提出并比较了在水和乙醇/水混合溶液两种环境中以水玻璃和十八烷酸为基本原料制备SiO2/十八烷酸相变微胶囊的方法。具体为:以水为溶剂时,利用十八烷酸与水玻璃间发生的酸碱正反应解决其分散问题,而利用其逆反应完成相变材料的包裹,以乙醇/水为混合溶剂时,则利用其酯化、水解双向反应分别完成十八烷酸的分散、包裹过程。在此基础上,采用SEM、DSC、XRD、FT-IR等测试技术分别评价了微胶囊的表面形貌、热性能、囊壁结构和囊芯结构。结果表明:采用2种方法所制备的微胶囊均为粒度均匀、表面光滑的颗粒,其区别在于在水中所制备的微胶囊大小为0.4～0.6μm、相变焓为78.2J·g-1,而在乙醇/水混合溶剂中所制备的微胶囊粒径减小为0.3～0.4μm,相变焓增加为84.9J·g-1。与水溶剂相比,在乙醇/水混合溶剂中制备的相变微胶囊细度提高了0.1～0.2μm,相变材料有效含量提高8.6%,此方法可为类似有机酸类相变微胶囊的制备提供借鉴。In order to disperse the stearic acid effectively during the preparation of the SiO2/stearic acid microencapsulate and enhance the content of phase–change material （PCM）, the stearic acid, in the microencapsulate, the means of using water and alcohol/water mixed solution as solvent for the microencapsulate preparation, respectively, were proposed and their results were compared. During the preparation, when the water was used as solvent, the sodium stearate is dispersed by the acid-base neutralization reaction between sodium silicate and stearic acid in water solution, and is encapsuled by the reverse reaction; while when the alcohol/water mixed solution was used, the dispersion and encapsulation of the stearic acid is accomplished via esterification and hydrolysis in alcohol/water solvent. The surface morphology, thermal characteristics and the structure of the wall and the core of the prepared microencapsulates were evaluated by SEM, DSC, XRD and FT-IR. The results show that both the microencapsulates prepared by using the above two kinds of solvent, respectively, have a uniform and smooth surface, while the particle size is 0.40～0.60 μm and the enthalpy due to phase change is 78.2 J·g-1 for the microencapsulate prepared with water as solvent and those for the microencapsulate prepared with alcohol/water as solvent are 0.30～0.40 μm and 84.9 J·g-1, respectively. Compared with the microencapsulate prepared with water as solvent, the stearic content in the microencapsulate prepared with alcohol/water as solvent increases 8.6%. This study shows that, for the fabrication of phase change microencapsulte with similar organic acids, the way of trying using different solvents to improve the product quality is adoptable.

关 键 词：相变储能 微胶囊 制备 表征 

分 类 号：TQ225.1[化学工程—有机化工] TB383[一般工业技术—材料科学与工程]