ELECTRORHEOLOGICAL PROPERTIES OF HYDROLYZED POLY(GLYCIDYL METHACRYLATE) SUSPENSIONS

Electrorheological behavior of silicone oil suspensions of macroporous poly[(glycidyl methacrylate)-co-(ethylene dimethacrylate)]) (0.60 : 0 .40 w) hydrolyzed to various degrees was investigated. Polarizability of particles expressed by the particle dipole coefficient and, consequ ently, pseudoplasticity of the system at low shear rates after applica tion of an external electric held steeply increased with the hydrolysi s degree of the copolymer. As the size and shape of particles remain u nchanged during hydrolysis, a series of model suspensions with the sam e hydrodynamic properties (Newtonian or slightly pseudoplastic when no electric field was applied) but with different intensity of the elect rorheological effect could be prepared. Under these conditions, the us e of Mason number failed to correlate the apparent viscosity of suspen sions of particles with different polarizability in the electric field . On the other hand, when polarizability of particles of a suspension system changes due to a higher temperature, a single curve in the plot of apparent viscosity vs. the Mason number could be obtained.