A series of polymer/SiO2 organic-inorganic composite microspheres were successfully prepared through miniemulsion polymerization. A TEM study indicated that the composite microspheres had raspberry-like morphology and silica particles were successfully deposited onto the surfaces of organic polymer microspheres. The average particle size and the silica content of composite microspheres could range from 180 nm to 240 nm and 15 ～ 35 wt%, respectively. The influence of reaction conditions such as the amount of emulsifier, the sonification frequency and sonification time, the amount of silica sol, butyl acrylate (BA) on the particle size, silica content and morphology of composite microspheres have been studied. 相似文献
Summary: A novel polystyrene‐encapsulated laponite composite system has been developed via a miniemulsion polymerization approach. The encapsulation mechanism and process parameters have been examined in detail using light‐scattering, sedimentation analysis, wide‐angle X‐ray diffraction (WXRD), and transmission electron microscopy (TEM). The laponite was encapsulated through a miniemulsion polymerization process in which laponite was predispersed in the monomer phase. The stability of both the miniemulsion and the latex depends on initiation loci, premixing procedures, intensity and time of ultrasonification and the surfactants and co‐stabilizer used. Hydrophobicity of the laponite clay played a vital role in both the encapsulation of the clay and the stability of the latex. A quaternary ammonium salt, cetyltrimethylammonium bromide (CTAB), was mixed with the clay in the monomer phase prior to emulsification. As a result, the clay particles were hydrophobically modified and were intercalated. The hydrophobicity not only favored the clay dispersion in the oil droplets but also aided the entry of the monomer into the clay's intergalleries during polymerization. Meanwhile, CTAB helped stabilize the system when it was used in conjunction with the nonionic surfactant polyoxyethylene (40) isooctylphenyl ether (TX‐405). In this way, the laponite is effectively encapsulated within a polystyrene shell in a stable latex form. More importantly, the polymerization initiated in the intergalleries of the clay effectively expands the clay's platelet array to form an exfoliated structure.
