Morphology and Properties of SAN-Clay Nanocomposites Prepared Principally by Water-Assisted Extrusion

An efficient extrusion process involving the injection of water while processing was used to prepare poly (styrene-co-acrylonitrile) (SAN)/clay nanocomposites with a high degree of nanoclay delamination. The usefulness of water-assisted extrusion is highlighted here, in comparison with classical extrusion and roll mill processes. Cloisite (R) 30B (C30B), a montmorillonite clay organomodified with alkylammonium cations bearing 2-hydroxyethyl chains, and pristine montmorillonite were melt blended with SAN (25 wt% AN) in a semi-industrial scale extruder specially designed to allow water injection. XRD analysis, visual and TEM observations were used to evaluate the quality of clay dispersion. The relationship between the nanocomposite morphology and its mechanical and thermal properties was then investigated. The superiority of the SAN/C30B nanocomposite extruded with water has been evidenced by cone calorimetry tests and thermogravimetric measurements (TGA). These analyses showed a substantial improvement of the fire behavior and the thermal properties, while a 20% increase of the Young modulus was recorded. POLYM. ENG. SCI., 50:10-21, 2010. (C) 2009 Society of Plastics Engineers