ONE-STEP PREPARATION OF ELECTRORHEOLOGICAL SUSPENSION CONTAINING POLY(LITHIUM ACRYLATE) VIA INVERSE EMULSION POLYMERIZATION AND STUDY OF ITS ELECTRORHEOLOGICAL EFFECT

Electrorheological (ER) fluid or suspension containing lithium salt of poly(acrylic acid) were synthesized directly by inverse emulsion poly merization. Effects of the amounts of crosslinking agent and the stabi lizer and neutralization degree used in the polymerization, as well as water content of the polymer particles on the ER activity were invest igated. The ER suspension exhibited maximum yield stress at optimum am ounts of stabilizer and crosslinking agent used in the inverse emulsio n polymerization, as well as at optimum water content of the polymer p articles. Glycerol was tried to be used as an activator instead of wat er and was shown to have a favorable effect on the thermal stability o f the ER suspension. Core-shell-type polymer particles were synthesize d through inverse emulsion polymerization with supplemental addition o f a second monomer. The ER suspension containing particles with poly(l ithium acrylate) as core and polyacrylamide as shell showed better ER behavior than those without the polyacrylamide shell. (C) 1998 John Wi ley & Sons, Inc.