Study on CaCO3/PMMA nanocomposite microspheres by soapless emulsion polymerization

A soapless emulsion polymerization method was applied to synthesize CaCO3/PMMA spherical composite with different loading of CaCO3. CaCO3 nanoparticles were pretreated with oleic acid after the carbonation process of Ca(OH)2 slurry by CO2, in order to improve the compatibility between the CaCO3 particles and MMA monomer in emulsion system. The results of photon correlation spectroscopy (PCS) showed the particles size of composites were bigger than the pure PMMA. And the size increased with the increase of the content of CaCO3 nanoparticles. TEM images showed that the morphology of the composite microspheres was uniform and CaCO3 nanoparticles can be well encapsulated in the polymeric microsphere, and were located at the edge of the spheres. The results of DTG and TG indicated that the CaCO3 nanoparticles could improve the thermal stability of PMMA. Moreover, capsulation of CaCO3 by PMMA can increase the acid-resistant of CaCO3 nanofillers.