Ultrasonic Absorption of Polystyrenes in Toluene in MHz Region

Abstract

The molecular weight dependence of ultrasonic absorption for solutions of polystyrene in toluene was measured by the pulse method in the frequency range 5-130MHz and in temperature range 0-50°C. The molecular Weights of polystyrene samples used were 2100, 4000 and 2000000.It has been found that the ultrasonic absorption of polystyrene can be represented by a single relaxation equation over entire ranges of molecular weight and temperature. In the low molecular weight region, the temperature dependences of the relaxation frequency and relaxation strength are quite different from those in the high molecular weight region. This relaxation mechanism at the low molecular weight region is considered to be due to the motion of the end segments of polymer chains.