Velocity and absorption of ultrasound in binary solutions of polyvinylpyrrolidone and water

Abstract

Ultrasonic velocity and absorption and shear viscosity measurements were made as a function of concentration and temperature for binary aqueous solutions of the polymer polyvinylpyrrolidone. The polymer has a molecular weight of 360 000 and was mixed with water in several concentrations ranging from 0% to 9% by weight. The frequency used was 21 MHz and the temperature range was 20 °C to 45 °C. The velocity shows a nonlinear increase with temperature and a nearly linear increase with concentration. The α/f 2 and viscosity values increase monotonically with concentration, and these values decrease with temperature. The temperature behavior, in a general sense, for the velocity and α/f 2 of the solution is similar to that of pure water. As the concentration increases from 0% to 9%, the viscosity increases by more than two orders of magnitude, while the α/f 2 value increases by less than one order of magnitude. No strong evidence of a critical concentration was observed.