石墨烯/正十八烷微胶囊的制备与及其热性能研究

Preparation and Thermal Performance of Microcapsules with Graphene/n-Octadecane as Core Material

以石墨烯/正十八烷为芯材,三聚氰胺-尿素-甲醛树脂（MUF）为壁材,苯乙烯马来酸酐共聚物（SMA）为乳化剂,采用乳液聚合法制备相变微胶囊.系统研究了石墨烯对于正十八烷微胶囊性能的影响.采用场发射扫描电子显微镜（FE-SEM）、傅里叶变换红外光谱分析仪（FTIR）、拉曼光谱仪、X射线衍射仪（XRD）、Hot Disk热常数分析仪、示差扫描量热仪（DSC）和热重分析仪（TGA）对相变微胶囊的外貌形态、晶型结构和热性能进行表征和分析.结果表明,微胶囊呈圆球形且光滑,粒径约为1～30μm.当石墨烯添加量为0.1 g时,微胶囊的形貌无明显变化.当加入过量石墨烯时,微胶囊出现了明显的团聚现象.XRD测试表明,包覆于微胶囊中的石墨烯没有使微胶囊的结晶峰位置发生明显的偏移,这对于微胶囊的实际应用是有利的.微胶囊的相变热焓和包覆率随着石墨烯的加入而不断减小,但芯材的过冷现象得到了明显的改善.石墨烯对于微胶囊传热性能的提升有着显著的效果.当石墨烯的添加量为0.2 g时,微胶囊的导热系数为0.092 W·m^-1·K^-1,与纯微胶囊相比提高了约51%,这说明石墨烯改善了传统相变微胶囊的传热性能,提升了相变微胶囊的应用性能.

Novel microcapsules containing graphene / n-octadecane as core material and melamine-ureaformaldehyde polymer as shell material were prepared by emulsion polymerization with styrene maleic anhydride copolymer（ SMA） used as emulsifier. The effects of graphene on the properties of n-octadecane microcapsules were studied. Surface morphology,crystallography and thermal properties of microcapsules were characterized and analyzed by using field emission scanning electron microscopy（ FE-SEM）,Fourier transform infrared spectroscopy（ FTIR）,Raman spectroscopy,X-Ray diffraction（ XRD）,thermal constant Hot Disk analyzer,differential scanning calorimetry（ DSC）,and thermal gravimetric analysis（ TGA）. The results indicate that the microcapsules are spherical and have relatively smooth surface. The particle size of microcapsules is about 1- 30 μm. In addition,the morphology of microcapsules has no obvious change the with0. 1 g graphene addition. Too much graphene intensifies the reunion of microcapsules. XRD shows that graphene in microcapsules does not change the crystallization peak position of microcapsules,which is good for the practical application of the microcapsules. Heat enthalpy and encapsulation of microcapsules decrease with the increase of graphene addition,but the supercooling phenomenon of core material has been observably improved. Heat transfer performance of microcapsules is markedly improved due to graphene. Thermal conductivity coefficient of microcapsules is 0. 092 W·m^-1·K^-1 with 0. 2 g graphene addition,which is enhanced by about 51%,compared with the pure microcapsule. It illustrates that graphene may improve the heat transfer performance of traditional phase change microcapsules and promoted the application performance of phase change microcapsules.