十八烷/聚(St-MMA)相变微胶囊制备及表征

采用乳液聚合的方法,分别选取聚苯乙烯(PS)、聚甲基丙烯酸甲酯(PMMA)或苯乙烯和甲基丙烯酸甲酯的共聚物为壁材,正十八烷为芯材,十二烷基苯磺酸钠(SDBS)为乳化剂,制作相变储能微胶囊。用粒径分析仪、透射电子显微镜(TEM)、热重分析仪(TG)和示差扫描量热测试仪(DSC)对微胶囊的形貌、相变热性能和热稳定性分别进行表征。结果表明:壁材选取两者共聚物,当两种单体的比例为St∶MMA=1∶5,SDBS用量为1.5g(总质量的3%)时,微胶囊粒径大小均匀,粒子分散性好,壁材的包裹性好。微胶囊的放热峰为起始温度为27.3℃,终止温度为31.9℃,相变温度为28.9℃,相变焓为48.4J/g。TG表明长期使用温度不能超过131℃。IR分析微胶囊中含有芯材和壁材。这种十八烷/聚(St-MMA)相变微胶囊可以用于诸能材料。

Preparation and Characterization of n-Octadecane/P(St-MMA) Phase-change Microcapsules

A phase-change stored energy microcapsules were prepared by polymerization,in which polystyrene (PS),poly methyl methacrylate (PMMA) or copolymers of styrene and methyl methacrylate were used as shell materials,n-octadecane was used as a core material,and sodium dodecyl benzene sulfonate (SDBS) as a emulsifier.The morphology,phase-change thermal properties and thermal stability of microcapsules,respectively,were characterized by particle size analyzer,transmission electron microscope (TEM),thermogravimetric analyzer (TG) and differential scanning calorimetry (DSC).The results show that the particle size of microcapsules is uniform,the particle dispersion is good,and the shell is well wrapped when the copolymer of styrene (St) and methyl methacrylate (MMA),both mass ratio is 1∶5),is used as shell material,and sodium dodecyl benzene sulfonate content is 1.5g (3％ of the total mass).The heat release peaks of microcapsules are at 27.3℃ of starting temperature,at 31.9℃ of end temperature,and the phase transformation temperature is 28.9℃,the phase-change enthalpy of microcapsules is 48.4J/g.Long-term use temperature should not exceed 131℃ by TG analysis.The microcapsules contain core and shell materials by IR analysis.This octadecane/poly (St-MMA) phase change microcapsules can be used for the material