Synthesis and electrorheological characteristics of SAN-clay composite suspensions

Particles of non-extractable styrene-acrylonitrile (SAN) copolymer-Na+-mont morillonite clay composite were synthesized by emulsion polymerization and then used to create an electrorheological (ER) fluid by dispersing the synt hesized SAN-clay composite particles in silicone oil. The structures of the composites determined by FT-IR spectroscopy and X-ray diffraction confirme d the insertion of SAN between the interlayers of clay, whose separation co nsequently becomes larger than in polymer-free clay. The thermal stability of the organic polymers was found to be sustained. ER properties under the influence of externally applied electric fields were also investigated. ER fluids composed of SAN-clay composite show typical ER behavior and possess "pseudo-Newtonian" behavior at high shear rates. (C) 1999 Published by Else vier Science Ltd. All rights reserved.