Dielectric relaxation studies of four aliphatic esters in benzene at 30°, 40°, 50° and 60°

Abstract

Abstract The complex permittivity at 9.92 GHz, the static permittivity and the high frequency limiting permittivity have been determined for n-butyl-acrylate, allyl-methacrylate, isobutyl-methacrylate and isobutyl-acrylate monomers in benzene at 30°, 40°, 50° and 60°C. The relaxation time values and the dipole moment values calculated from these data employing different methods, are interpreted in terms of the molecular and the intramolecular rotations. Various thermodynamic parameters calculated for the dielectric relaxation as well as the viscous flow processes also suggest the existence of both the intramolecular and the overall orientations in these monomer esters. The comparative study of enthalpies of activation for the dipolar relaxation and the viscous flow suggests the absence of any solid rotator phase in these molecules. Values of the Debye's factor and the Kalman's factor show that the Kalman's equation represents the relation between the dielectric relaxation and the viscosity, more satisfactorily than the Debye's equation.