Synthesis and characterization of microencapsulated paraffin with TiO2 shell as thermal energy storage materials
Synthesis and characterization of microencapsulated paraffin with TiO2 shell as thermal energy storage materials
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DOI：
10.1007/s10854-018-9666-z
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发表时间：
2018-07
期刊：
影响因子：
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通讯作者：
Xiaochun Ma;Yanjun Liu;Han Liu;Bing Xu;Jing Zhou;F. Xiao
中科院分区：
文献类型：
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作者：
Xiaochun Ma;Yanjun Liu;Han Liu;Bing Xu;Jing Zhou;F. Xiao
本研究以甲酰胺为水相，通过钛酸四丁酯在非水水包油乳液中原位水解缩聚，成功合成了以石蜡为核、无机TiO2壳的微胶囊相变材料。采用傅里叶变换红外光谱(FT-IR)、X射线衍射仪(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对石蜡@TiO2微胶囊的化学成分、晶体结构、形貌和微观结构进行表征。通过差示扫描量热仪（DSC）和热重分析仪（TGA）测量了微胶囊的热性能和热稳定性。 FT-IR和XRD结果证明石蜡核与TiO2壳材料之间没有发生化学反应。 SEM 图像表明石蜡@TiO2 微胶囊呈规则球形，平均直径为 2-5 µm，外壳光滑。 SEM 和 TEM 研究还证实石蜡被 TiO2 完全封装。 DSC分析表明微胶囊具有与纯石蜡相似的相变行为。典型样品冻结温度为52.24℃，潜热为110.42Jg−1；熔化温度为60.41℃，潜热为107.54Jg−1，封装率达到54.58%。 TGA结果表明，通过封装，TiO2壳的保护提高了石蜡的热稳定性。
In this study, the microencapsulated phase change material with paraffin as core and inorganic TiO2shell was successfully synthesized by in situ hydrolysis and polycondensation of tetrabutyl titanate in a nonaqueous oil-in-water emulsion using formamide as aqueous phase. The chemical compositions, crystalline structure, morphology and microstructure of paraffin@TiO2microcapsules were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The thermal properties and thermal stability of the microcapsules were measured by differential scanning calorimeter (DSC) and thermo-gravimetric analyzer (TGA). FT-IR and XRD results proved that there was no chemical reaction between paraffin core and TiO2shell material. SEM images indicated that the paraffin@TiO2microcapsules showed a regular spherical shape with the average diameters of 2–5 µm with a smooth shell. SEM and TEM studies also confirmed the paraffin was fully encapsulated with TiO2. DSC analysis indicated that the microcapsules had similar phase change behaviors as those of pure paraffin. Typical sample froze at 52.24 °C with a latent heat of 110.42 J g−1and melt at 60.41 °C with a latent heat of 107.54 J g−1, of which the encapsulation ratio achieved to 54.58%. TGA results indicated the thermal stability of paraffin was improved by the protection of TiO2shell through the encapsulation.