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为解决十八烷酸在固–液相变过程中的体积变化问题,针对十八烷酸的结构特点,以十八烷酸、水玻璃和聚乙二醇(polyethylene glycol,PEG)为原料制备了PEG–SiO2复合壳和SiO2单层壳2种十八烷酸微胶囊,采用参比温度、差热分析、热重分析、X射线衍射、Fourier变换红外光谱,扫描电子显微镜和X射线能谱分析仪分别对2种微胶囊的热性能、形貌和结构进行了比较。结果表明:热循环50次后,PEG–SiO2复合壳结构的相变热稳定性比SiO2单层壳结构微胶囊的更好;PEG–SiO2复合壳和SiO2单层壳十八烷酸微胶囊的相变焓分别为78.40J/g和88.61J/g,PEG–SiO2复合壳微胶囊中PEG与十八烷酸接枝导致十八烷酸的相变焓降低,并出现结晶缺陷;PEG–SiO2复合壳为PEG与SiO2相互交错结构。
In order to solve the problem of the volume change of octadecanoic acid during the solid-liquid phase change, octadecanoic acid was prepared from octadecanoic acid, water glass and polyethylene glycol (PEG) Two kinds of octadecanoic acid microcapsules, PEG-SiO2 composite shell and SiO2 single-shell, were investigated by reference temperature, differential thermal analysis, thermogravimetry, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray energy dispersive spectroscopy The analyzer separately compared the thermal properties, morphology and structure of the two microcapsules. The results show that the thermal stability of phase transition of PEG-SiO2 composite shell is better than that of single-shell SiO2 microcapsules after thermal cycling for 50 times. The PEG-SiO2 composite shell and SiO2 monolayer shell octadecanoic acid microcapsules The enthalpy of phase transition was 78.40 J / g and 88.61 J / g, respectively. The grafting enthalpy of octadecanoic acid decreased with PEG and octadecanoic acid grafted onto PEG-SiO2 composite shell microcapsules. The composite shell is a cross-linked structure of PEG and SiO2.