Preparation And Characterization Of Polycarbonate Silica Core Shell Mesoporous Hybrid Microsphere

Recently, organic-inorganic hybrid microspheres because of theirapplications in adsorption, separation and catalysis fields have drawn greaterattention. Emulsification polycarbonate solution method was used to preparehybrid microspheres with polycarbonate core and silica shell in this paper. Theeffect of acidic and basic conditions to the experiment had been investigated.The microspheres were prepared in ammonia and ethanol mix solutionwith P123(EO20-PO70-EO20) as the emulsifier and TEOS as the silicon source.The particle size and distribution, morphology, components, amount of allcomponents were tested by Nanoparticle Tracking Analysis (NTA), ScanningElectron Microscopy (SEM), Fourier Transform Infrared (FTIR),ThermoGravimetry (TG) and Differential Scanning Calorimetry (DSC). Theresults had revealed that the size of the microspheres had monodisperseddistribution, and the diameter was about200nm-300nm. The main component was silica with a bit of polycarbonate fragment and no emulsifier.Much of following experiment was designed to investigate the reasons further.The results had revealed saponification reaction happened betweenpolycarbonate and ammonia and probably produced some small moleculesthat can be dissolved in ammonia and ethanol solution and led to the systembecoming unstable. The emulsifier had some effect to control the particle size.TEOS had taken place sol-gel reaction in ammonia and ethanol mixed solutionand formed silica microspheres.The hybrid microspheres were prepared by sol-gel method usingpolycarbonate emulsion as the template in acid condition. And the effect oftwo kinds of emulsifiers P123and CTAB to the experiment had beeninvestigated. The size distribution of emulsion droplets, the component ofemulsion and microspheres, specific surface and the structure of themicrospheres after calcined were tested by Nanoparticle Tracking Analysis(NTA), Fourier Transform Infrared (FTIR), ThermoGravimetry (TG),Nitrogen Adsorption and Desorption and Transmission Electron Microscopy(TEM). The result had shown that CTAB was more effective to pack PCsolution and form PC emulsion compared to P123. The microsphere hadnoticeable core-shell structure with much disordered mesoporous in the shelland the diameter of mesoporous was2.5nm, specific area had reached up toabout1050m2/g. The reason was that CTAB had formed much of worm-likemicelles in this condition and assembled to the surface of the PC emulsion droplets.