Effects of preparation method on microstructure and properties of UV-curable nanocomposite coatings containing silica

摘要

UV-curable nanocomposites were prepared by the blending method or the in situ method with nanosilica obtained from a sol-gel process. The microstructure and properties of the nanocomposite coatings were investigated using Si-29-NMR cross-polarization/magic-angle spinning, transmission electron microscopy (TEM), Fourier transform IR (FTIR), differential scanning calorimetry (DSC), and UV-visible (UV-vis) spectra, respectively. The NMR and TEM showed that during the blending method, tetraethyl orthosilicate (TEOS) completely hydrolyzed to form nanosilica particles, which were evenly dispersed in the polymer matrix. However, for the in situ method, TEOS partially hydrolyzed to form some kind of microstructure and morphology of inorganic phases intertwisted with organic molecules. FTIR analysis indicated that the nanocomposites prepared from the in situ method had much higher curing rates than those from the blending method. DSC and UV-vis measurements showed that the blending method caused higher glass-transition temperatures and UV absorbance than the in situ method. (c) 2005 Wiley Periodicals, Inc.