Ultrasonic velocity and absorption measurements for polyethylene glycol and water solutions

Ultrasonic velocity at 3 MHz using the pulse echo overlap method over the temperature range of 10-90 °C and absorption coefficient over the frequency range of 0.2-2 MHz using the plano-concave resonator method at 30 °C were measured in an aqueous solution of polyethylene glycol over the concentration range of 5% to 25% by weight. The velocity exhibited a maximum value at approximately 30 °C, 40 °C, 50 °C, 60 °C and 70 °C in 25%, 20%, 15%, 10%, and 5% solutions, respectively. The velocity increased with concentration at a given temperature. The ultrasonic relaxation in polyethylene glycol aqueous solutions, which may be the result of structural fluctuations of polymer molecules such as the internal motion of the polymer chains, was observed, and the change of α/f2 was greater at lower frequencies, especially below 0.5 MHz. The shear viscosity decreased with temperature and increased with concentration.