Abstract: Narrow dispersed CaCO3/poly(styrene-co-n-butylacrylate)(CaCO3/P(St-co-nBA)) composite particles with average diameter of 1.76 μm were obtained via a dispersion copolymerization of St and nBA in the presence of stearic acid modified nano-CaCO3 particles. The products were characterized by transmission electron microscopy(TEM), optical microscope（OM), fourier transfer infrared spectroscopy(FT-IR), thermogravimetric analysis(TGA), and X-ray diffraction(XRD). The TEM images indicated the composite particles had nano-CaCO3 core and P(St-co-nBA) shell structure. The TGA analysis results of composite particles before and after being extracted with dimethylbenzene showed the thermal decomposition temperature of the cladding polymer was higher than that of pure copolymer P(St-co-nBA), and some copolymer couldn′t be extracted. The FT-IR spectra also confirmed the existence of copolymer on the composite particles after extracting. It suggested that the copolymer had chemical bonding with nano-CaCO3. The mass proportion of P(St-co-nBA) which couldn't be extracted with accounted for 6.6% based on the mass of nano-CaCO3.

Key words: nano-CaCO3, dispersion polymerization, encapsulation, composite