Mechanical techniques for studying viscoelastic relaxation processes in polymer solutions

Abstract

The recent advent of small digital computers suitable for on-line data acquisition and processing systems (DAPS) has made possible very accurate measurements of the magnitudes and relative phasing of sinusoidally time varying signals by employing cross-correlation techniques to reduce the influence of noise, drift, and harmonic distortion. When used with transducers appropriate for measurement of dilute solution viscoelastic properties, such a DAPS provides far more accurate data than have previously been obtainable from electrical impedance measurement techniques. The DAPS and two transducers described are used to obtain infinite dilution viscoelastic properties as well as effective high frequency properties in which effects related to the incomplete flexibility of long chain molecules are observed. The principal features of the data obtained to date are described.