PROPERTIES OF ELECTRORHEOLOGICAL FLUIDS CONTAINING SULFONATED POLY(STYRENE-CO-DIVINYLBENZENE) PARTICLES

Abstract

Two series of sulfonated poly(styrene-co-divinylbenzene) particles (SSD), different in average particle diameter and in sulfonic acid substitution level were synthesized. The vertical sectional views of the SSD particles showed that the sulfonic acid groups were uniformly distributed all over the SSD particles. The electrorheological behavior of the suspensions of the SSD particles in silicone oil was investigated. Induced shear stress under an electric field increased with the increase of average particle diameter and sulfonic acid substitution level. The sedimentation velocity of the dispersed particles was monotonous with the average particle diameter and the sulfonic acid substitution level. Another series of sulfonated poly(styrene-co-divinylbenzene) particles (SSDH), different in sulfonic acid substitution level, was separately prepared. The vertical sectional views of the SSDH particles showed that the particles had sulfonated surface layer and unsulfonated core. The suspensions of the SSDH particles having the sulfonated layer of not less than 1.4 microns induced similar shear stress at the same electric field strength. The sedimentation velocity of the dispersed particles was lowered with diminishing the thickness of the sulfonated layer.