中文摘要：

采用原位聚合法制备以液体石蜡为囊芯、密胺树脂为囊壁的相变微胶囊,考察了乳化工艺、预聚时间、囊壁含量和聚合反应时间对微胶囊质量的影响,优化了制备工艺.利用电子天平、扫描电镜、激光粒度仪、傅里叶红外光谱仪（FT-IR）、热分析仪（DSC和TG/DTA）分别研究了优化工艺下微胶囊的囊芯含量、形貌特征、粒径分布、结构和热性能,并考察了其循环稳定性、抗压性能、抗渗透性.结果表明,微胶囊包覆完整无粘连,表面光洁致密,囊芯含量76%（ψ）,囊壁厚度至少可达50~100nm,粒径分布集中在1~5μm,平均为3.32μm.DSC显示有2个吸热峰,起始相变温度分别为4.4和28.6℃,总相变潜热14.9J/g.胶囊耐热温度可达215℃,能承受1.0MPa外压,经300次冷/热循环仍保持良好稳定性,且有很高的抗渗透性.

英文摘要：

As a novel type of low-temperature phase change materials, the microcapsules with the core of liquid paraffin and shell of melamine-formaldehyde resin （MF resin） were synthesized by using in-situ polymerization process. The effects of emulsion formulations, pre-polymerization conditions, shell material content and reaction time were investigated to obtain the optimized microcapsules. The as-prepared products under the optimal conditions showed high quality, their surface was smooth and dense, and free of any adhesion. The experimental characterization showed that in the microcapsules over 75%（ω） paraffin liquid was well encapsulated by MF resin, of which the thickness was in the range of no less than 50~100 nm. The microcapsule size was within the range of 1~5 μm and most intense distribution at 3.32 μm. DSC measurements gave two endothermic peaks with the initial phase change temperatures of 4.4 and 28.6℃ respectively, and the total enthalpy was 14.9 J/g which is comparable to the latent heat of commercial liquid paraffin. The microcapsules keep stable up to a high temperature 215℃ or a pressure of 1.0 MPa, as well as excellent thermal resistance against long-term thermal aging and thermal cycle near 300 times.