Epoxy Composites Reinforced by Different Size Silica Nanoparticles

Three series of epoxy/SiO(2) composites, containing 0.3-7 wt % nanosized SiO(2) with different specific surface area, were prepared by solution blending. The resulting composites exhibit the higher glass transition temperature (T(g)) than that of pure epoxy. The T(g) of composite showed a maximum increment of 35.3 degrees C by the addition of 7 wt % A300. The trade name of A300 is Aerosil 300. It is one of the fumed silica nanoparticles products of Degussa. The decomposition temperatures (T(d)) of composites were always higher than that of pure epoxy and showed a maximum increment of 20.8 degrees C by the addition of 5 wt % A300. The light transmittance of composites was as a function of the SiO(2) content and size. The water permeability of composites decreased with increasing SiO(2) content and the 7 wt % A300 composite exhibits a maximum decrement percentage of 35.6%. The T(g), T(d), storage modulus, and water-vapor barrier property are as a function of the SiO(2) content and size. These properties increased as the content Of SiO(2) increased. The finer SiO(2) are more effective in increasing the T(g), T(d), and water-vapor barrier property. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 2648-2653, 2010