Rheology and dispersion behavior of high‐impact polystyrene/ethylene–vinyl acetate copolymer/TiO2 nanocomposites

Abstract

AbstractTiO2 nanoparticles were introduced into high‐impact polystyrene (HIPS) in the form of a master batch in which TiO2 was predispersed in composites of HIPS and ethylene–vinyl acetate copolymer (EVA) by melt compounding. The resulting materials were analyzed with a Rosand Precision rheometer, transmission electron microscopy, atomic force microscopy, and ultraviolet–visible light spectrophotometry. The results showed that the introduction of TiO2 nanoparticles into HIPS influenced the apparent viscosity of the composites to a rather small extent. The addition of EVA could regulate the rheological behavior of the HIPS/TiO2 master batch greatly. EVA helped the dispersions of the agglomerates of TiO2 nanoparticles in the flow; this was featured by the distinct yielding in the flow after the introduction of EVA, as well as the large change in the non‐Newtonian indices. The dispersions of the HIPS/TiO2 master batch in the HIPS matrix were improved greatly by the addition of EVA. TiO2 nanoparticles were dispersed randomly in HIPS/EVA/TiO2 nanocomposites. The dispersion improvement of the HIPS/EVA/TiO2 master batch was also proved by atomic force microscopy and ultraviolet–visible spectroscopy investigations. The mechanical properties of HIPS/EVA/TiO2 nanocomposites with low TiO2 contents were slightly higher than those of pure HIPS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4434–4438, 2006