Synthesis And Properties Study Of Organic/Inorganic Composite Microspheres

In recent years, the preparation of organic-inorganic composite microspheres have been widely concerned because such composite microspheres combined the merits of organic materials and inorganic materials and its structure can be obtained by altering the two-phase composition, size and structure. Organic-inorganic composite microspheres as lubricant have some excellent properties, such as great heat-resistant and good strength. In this paper, the composite microspheres with different structures and properties were prepared by two different methods. The structures and properties of those composite microspheres had been studied. The main research contents as follows:(1) Preparation and characterization of intercalated composite microspheres.The intercalated composite microspheres were prepared by suspension polymerization with styrene(St), divinylbenzene(DVB) and organic montmorillonite(OMMT). OMMT were prepared by ion-exchange method between sodium montmorillonite(MMT) and cetyltrimethyl ammonium bromide (CTAB) in an aqueous solution. OMMT and organic monomer were mixed by using ultrasonic. And then the organic monomer inserted into the montmorillonite interlayer. When the free radical initiator caused polymerization, the polymer chains were growed up among the layers of OMMT. After 8h of polymerization, the intercalated polystyrene/organicmontmorillonite(PS/OMMT) composite microspheres were obtained.The microstructure and shape of composites were characterized by FT-IR,XRD,TEM and SEM. The result revealed that the polymer chains inserted into the montmorillonite interlayer and formed intercalated composite microspheres. The thermal stability of composites was studied by thermogravimetric analysis (TG). The TG result showed that the weight loss temperature of pure polystyrene was 399℃. While the weight loss temperature of composite microspheres with 5% MMT and 10% DVB was 437℃, which enhanced 38℃than pure polystyrene microspheres. The lubricity of intercalated composite microspheres in drilling fluid was tested by ZN-3A and. The result showed that the composite microspheres could reduce the friction coefficient, decrease the filter loss and improve the lubricity of drilling fluid.(2) Preparation and characterization of core-shell composite microspheres.The polystyrene microspheres with positively charged were prepared via dispersion polymerization of St with 2-(methacryloyl) ethyl trimethyl ammonium chlorilde (MTC). Using PS microspheres as template, TEOS as precursor, TEOS hydrolysised under alkaline conditions. The hydrolysate of TEOS with negative charged were captured by the PS template microspheres with positively charged. So the core-shell composite microspheres were obtained by this method. Then the core-shell composite microspheres were treated with high temperature and the hollow SiO₂ microspheres were obtained.The microstructure and shape of core-shell composites microspheres were characterized by FT-IR, XRD, TEM and SEM. The lubricity of hollow SiO₂ was tested by MR-S10B four-ball friction test machine. The result revealed that the hollow SiO₂ microspheres exhibited great lubricity at low load.