用光引发剂2-羟基-4'-(2-羟乙氧基)-2-甲基苯丙酮(IHT-PI 659)对纳米SiO2表面进行接枝使之兼具两亲性及光引发特性;以该功能性纳米SiO2为稳定剂构筑O/W(水包油)型Pickering乳液;用紫外光引发处于内油相的甲基丙烯酸甲酯单体聚合,制备出具有中空结构的SiO2/PMMA复合微球,采用傅里叶变换红外光谱(FTIR)、热失重分析仪(TGA)、透射电镜(TEM)及扫描电子显微镜(SEM)对复合微球进行了表征,并提出了紫外光引发Pickering乳液聚合制备中空复合微球的机理.
Hollow composite microspheres can be prepared rapidly by Pickering emulsion polymerization initiated by ultraviolet light.Firstly,nano-SiO2 were endowed with amphipathy and photosensitivity by grafting with 2-hydroxy-4'-(2-hydroxyethoxy)-2-methyl-propiophenone(IHT-PI 659).Secondly,stable Pickering emulsion was fabricated by using this functional nano-SiO2 particles as stabilizer.Finally,the SiO2/polymethylmethacrylate composite microspheres with hollow structure were successfully synthesized by Pickering emulsion polymerization initiated by ultraviolet light at room temperature.The products were characterized by Fourier transformation infrared spectrum(FTIR),thermogravimetric analysis(TGA),transmission electron microscopy(TEM) and scanning electron microscope(SEM).A possible mechanism for the formation of the hollow composites by photo-initiation Pickering emulsion polymerization was also proposed.