Transparent cyclic olefin copolymer/silica nanocomposites

Abstract In this work, melt blending of fumed nanosilica with cyclic olefin copolymer ( COC ) was carried out to prepare high strength transparent composites. The effects of various loadings (1, 2, 3 and 5 wt%) of nanosilica on the physical, mechanical, dynamic mechanical, thermal, tribological and optical properties of the COC composites were investigated in detail. The tensile test results showed that the nanocomposite with 3 wt% nanosilica content provides the highest tensile strength (55.6 MPa ) compared with the nanocomposite with 5 wt% nanosilica content (54.6 MPa ), which is believed to be significantly dependent on better dispersion. Moreover, the glass transition temperature (from tan δ) increased from 184 °C for pure COC to 194.3 °C for the COC composite with 3 wt% nanosilica. The scratch test and nano‐indentation results showed that addition of nanosilica increased the stiffness and hardness of the composite, providing higher scratch resistance and lower frictional coefficient. UV −visible spectroscopy measurements showed that the nanocomposites have excellent optical transparency which is similar to that of the pure COC film. © 2013 Society of Chemical Industry