Soluble Poly (Methyl Methacrylate) Composites Containing Covalently Associated Zirconium Dioxide Nanocrystals

Well soluble composite samples of poly(methyl methacrylate) containing hybrid nanoparticles with covalently associated ZrO2 nanocrystals of an average size of (20±5) nm have been studied by light scattering, viscometry and absorption spectroscopy methods in diluted solutions. Composites were synthesized by two ways: in situ bulk polymerization of methyl methacrylate in a presence of ZrO2, and by polymerization of methyl methacrylate in toluene solution with the dispersed ZrO2 nanocrystals. Surface of ZrO2 was preliminary chemically modified by γ-(trimethoxysilyl)propyl methacrylate in both cases. Weight fraction of ZrO2 in composite samples was varied in the range 1-3 %. Solution properties of composite polymers revealed that a way of monomer polymerization (in bulk or in solution) affect the type of the produced polymer-inorganic hybrids. Sphere like “core-shell” nanoparticles with a single ZrO2 nanocrystal as a core are mainly formed when polymerization in solution is carried out. Under the conditions of in situ bulk polymerization the organic-inorganic particles of significantly larger size with the irregular number of associated ZrO2 nanocrystals are produced. The size of hybrid nanoparticles in composite samples was determined. Transmission electron microscopy was applied to visualize the difference of ZrO2 distribution in thin films of the both type composite samples.