The rheological properties of dielectric polymers

The rheological properties of a number of dielectrics have been studied by the application of shear stress to a cylindrical tube of the material. Creep under constant stress has been measured over periods ranging from a few milliseconds to 18 months after applying the stress and the dynamic modulus and internal friction coefficient have been measured over a frequency range of 10 -4 to 10 3 c/s. The results obtained indicate that the rheological properties can be expressed in terms of a distribution of mechanical relaxation times. This distribution is hyperbolic for a range of times from 10 -3 to 10 7 sec and enables creep and dynamic measurements to be correlated.