Polymer Hollow Microspheres Preparation And Performance Studies

The surface modification of calcium carbonate, the synthesis of calcium carbonate/ poly(methyl methacrylate) composite microspheres and poly (methyl methacrylate) hollow microspheres were studied in this paper.Firstly, the process of deaggregation of CaCO3 particles were studied by pretreating CaCO3 particles via ultrasound. Different methods and several modifiers including oleic acid(OA), fatty acid and titanate were chosen to modify CaCO3 particles. The modified CaCO3 particles were characterized by laser diffraction size analyzer and UV spectrophotometer. The results showed that the CaC03 particles modified by OA (OA-CaCO3) through ultrasound method were the best one. The OA-CaCO3 was characterized by FTIR, infiltration angle test and TG. The results showed that OA was well grafted to the surface of CaCO3 particles and the OA-CaCO3 owned good hydrophobicity.Secondly, the CaCO3/PMMA composite microspheres were prepared by emulsion polymerization by pratreating CaCO3 particles via ultrasound to choose the smaller particles. The obtained microspheres were characterized by laser diffraction size analyzer, TEM, SEM, FTIR, infiltration angle test and TG. The results showed that the CaCO3 particles were well coated by PMMA, and the content of PMMA in the microspheres was about 80 wt%.Lastly, the CaCO3/PMMA composite microspheres were swelled by several solvents in different times via different methods. The swelled microspheres were observed by optical microscope. The results showed that using acetone as the solvent and ultrasound for 5 h were the most appropriate approach for CaCO3/PMMA composites. The swelled microspheres were treated with hydrochloric acid to remove the CaCO3 particles. The microspheres were characterized by laser diffraction size analyzer, TEM, SEM, FTIR and TG. The results showed that PMMA hollow microspheres have been produced, and their average particle size was about 1.31μm.