Electrorheological activity of polyphenylenediamine suspensions in silicone oil

Electrorheological and dielectric properties of suspensions of polyphenylen ediamine isomers in silicone oil have been investigated. The effectiveness of the base forms of polymers was higher than that of their protonated coun terparts. The dielectric spectra showed a low rate of polarization which su pport the idea of mechanism of interfacial particle polarization. The difer ences in the low-shear-rate relative apparent viscosity of the systems were explained as a result of different particle dipole coefficients. (C) 2000 Elsevier Science B.V. All rights reserved.