相分离法制备多孔聚甲基丙烯酸甲酯（PMMA）微胶囊

摘要

N-isopropylacrylamide polymer (PNIPAm) as thermosensitive pore-foaming agent was introduced into the system for the synthesis of porous core-shell microcapsules by internal phase separation. The system is composed of n-octadecane (n-Oct), methylmethacrylate (MMA) and sodium salt of styrene-maleic anhydride copolymer (SMA) aqueous solution forming a micro emulsion. The effect of PNIPAm on the formation mechanism, surface morpholo-gies, and thermal stabilities of the MicroPCMs was studied by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TG), respectively. The results indicate that adding PNIPAm into the system, the resulting microcap-sules have some irregular holes on the capsule shell. The size of the microcapsules is in the range of 2.0-4.0μm. The number of holes increases with the addition of PNIPAm, when the addition amount of 0.3-1.2 g. At the same time, the number of the holes decreases with the increase of the molecular weight of PNIPAm and the content of MMA, so only the PNIPAm with small molecular weight conducive to the synthesis of porous microcapsules.%以具有温敏性的线性聚N-异丙基丙烯酰胺（PNIPAm）为致孔剂，在十八烷（n-Oct）/甲基丙烯酸甲酯（MMA）/苯乙烯马来酸酐共聚物钠盐（SMA）水溶液微乳液体系中用相分离法制得包覆有n-Oct的多孔聚甲基丙烯酸甲酯（PMMA）微胶囊，采用扫描电子显微镜（SEM）、差示扫描量热仪（DSC）、热重分析仪（TG）等手段分别考察了这种多孔PMMA微胶囊.实验结果表明：所得多孔微胶囊粒径在2.0~4.0μm，呈多孔微球状，当PNIPAm的添加质量为0.3~1.2 g时，多孔PMMA微胶囊表面孔隙数量稍有增加，而当增加MMA的用量或者增加PNIPAm相对分子质量时，多孔PMMA微胶囊表面孔隙数量下降.