预聚条件对相变材料微胶囊形态的影响

以三聚氰胺-甲醛树脂(M-F)为壁材,正十二醇为芯材,采用原位聚合法制备微胶囊相变材料。利用傅里叶变换红外光谱(FT-IR)、扫描电子显微镜(SEM)和示差扫描量热法(DSC)分别对所得微胶囊的表面形态、结构及热性能进行表征。并针对微胶囊常有的结块、粘连和表面粗糙等问题,研究了预聚合反应条件对其黏度及其胶囊表面形态之间相关性。结果表明,预聚合体黏度过大时,易造成微胶囊之间的黏结和预聚体壁材的聚集。在预聚条件为反应温度72.5℃,反应时间75 min和pH值为8.5情况下,所得微胶囊表面光滑致密、分散性好且形态完整。

Effects of pre-polymerization conditions on morphology of microencapsulated phase change materials

The microcapsules containing dodecanol with melamine-formaldehyde(M-F) as shell material were fabricated by in-situ polymerization.The surface morphology,chemical structure and thermal properties of microcapsules were characterized by using Fourier-transform infrared spectroscope(FT-IR),scanning electron microscope(SEM) and differential scanning calorimetry(DSC),respectively.Focusing on the existing problems of microcapsules such as coagulating,sticking and coarse surface,the effects of synthesis conditions for the prepolymer on the viscosity of prepolymer and the surface morphology of microcapsules were studied.The results show that when the viscosity of prepolymer is excessively high,it may easily cause the sticking of microcapsules and deposition of M-F prepolymer.Under the optimal reaction conditions of reaction temperature 72.5 ℃,reaction time 75 min and pH 8.5,the microcapsules prepared are featured by smooth outer surface,good disparity and complete morphology.