正十六烷聚脲微胶囊化相变材料

用界面聚合法，合成了直径大约2.5 μm可用于热能储存含相变材料的聚脲包覆微胶囊.在含乳化剂的水溶液中，将溶有芯材正十六烷的有机相乳化成微米级油性液滴，随后加入的水溶性单体二胺与甲苯2,4-二异氰酸酯在胶束界面相互反应形成囊壁.分别用乙烯二胺，1,6-己二胺和它们的混合物作为水溶性单体进行了研究.并用红外光谱和热分析分别考察了不同胺类对微胶囊化学结构和热性质的影响.红外谱图显示合成了聚脲微胶囊，热重曲线表明含正十六烷的聚脲微胶囊能够耐受大约300 ℃高温，差示扫描量热测试表明所有样品均具有合适的相转变热，冷热循环实验揭示微胶囊能够维持储热容量不衰减.研究表明微胶囊化的正十六烷作为相变储热材料具有良好的应用前景.

Microencapsulation of n-Hexadecane as a Phase Change Material in Polyurea

For thermal energy storage application,polyurea microcapsules about 2.5 μ m in diameter containing phase change material were prepared using interfacial polycondensation method.In the system droplets in microns are first formed by emulsifying an organic phase consisting of a core material (n- hexadecane) and an oil- soluble reactive monomer,toluene- 2,4- diisocyanate (TDI),in an aqueous phase.By adding water- soluble reactive monomer,diamine,monomers TDI and diamine react with each other at the interface of micelles to become a shell.Ethylenediamine (EDA),1,6- hexane diamine (HAD) and their mixture were employed as water- soluble reactive monomers.The effects of diamine type on chemical structure and thermal properties of the microcapsules were investigated by FT- IR and thermal analysis respectively.The infrared spectra indicate that polyurea microcapsules have been successfully synthesized;all the TG thermographs show microcapsules containing n- hexadecane can sustain high temperature about 300 ℃ without broken and the DSC measurements display that all samples possess a moderate heat of phase transition; thermal cyclic tests show that the encapsulated paraffin kept its energy storage capacity even after 50 cycles of operation.The results obtained from experiments show that the encapsulated n- hexadecane possesses a good potential as a thermal energy storage material.