Elastic properties and mechanical relaxation behaviors of PVDF (poly (vinylidene fluoride)) at temperatures between-20 and 100 °C and at 2 MHz ultrasonic frequency

The elastic properties of PVDF have been investigated as a function of temperature. The propagation velocity and absorption of longitudinal and transverse ultrasonic waves have been measured at a constant frequency of 2 MHz and temperatures between -20 and 100 degrees C. Hence, the temperature dependences of storage and loss elastic constants have been obtained for temperatures between -20 and 100 degrees C. It has been seen that the relaxation behavior is affected from the form of mechanical disturbance. For the longitudinal mode, only one relaxation peak at 42 degrees C, but for transverse mode three relaxation peaks at 28 degrees C, 60 degrees C, and 94 degrees C have been observed. The results have been compared with the literature values obtained previously for PVDF. (c) 2005 Wiley Periodicals, Inc.