Miniemulsion polymerized titania/polystyrene core-shell nanocomposite particles based on nanotitania powder: Morphology, composition and suspension rheology

Core-shell nanocomposite particles with a diameter of 200 nm and containing 22 wt.% polystyrene (PS) and 78 wt.% titania were fabricated via miniemulsion polymerization of styrene in the presence of modified nanotitania powder. The PS shell of nanocomposite particles had a crosslinked structure. The effects of reaction temperature, emulsifier concentration, and costabilizer on morphology, size and size distribution were investigated. By adjusting these parameters, it was able to control the size and morphology of the nanocomposite particles. The nanocomposite particles had a fine dispersibility and compatibility with PS solution. Steady rheology of the core-shell nanocomposite particles suspended PS solution revealed a slight viscosity reduction deviating from Stokes-Einstein prediction at 0.6 wt.% particle loading and a slight viscosity increase to the level of pure PS solution at 2.0 wt.% particle loading, which was significantly different from the nanotitania suspensions. (C) 2012 Elsevier B.V. All rights reserved.