Ultrasonic properties of PVC (S‐27/R63) in the glassy region

Abstract

The ultrasonic properties of PVC (S‐27/R63) in the glassy region have been investigated as a function of temperature. The propagation velocities and absorption of the longitudinal and transverse ultrasonic waves have been measured at constant frequency of 2 MHz and at temperatures varying between −5°C and 75°C, using the ultrasonic immersion technique. The variation of the elastic moduli with temperature has been derived from these measurements. The results thus obtained have been compared to those previously published in the literature for different PVC and other polymer samples. ©1995 John Wiley & Sons, Inc.

Cure monitoring of epoxy matrices for composites by ultrasonic wave propagation

“…Although the ultrasonic wave propagation is a well‐known technique for nondestructive analysis, its application as a thermal analysis technique for measurements of dynamic mechanical properties of polymers is limited to laboratory studies. In particular, most ultrasonic characterizations of polymers are performed on thermoplastics20–23 and only a few articles are available on the characterization of the reactive properties of thermosetting resins 24–32. On the other hand, the application of the ultrasonic wave propagation to cure monitoring has been devoted essentially to an analysis of the evolution of ultrasonic properties during cure.…”

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

“…It is known that the ultrasonic wave velocity in the solid polymer decreases linearly in the temperature range, which has no phase and relaxation transition 30, 33, 34, 40. Generally, the discontinuity on the rate of change of wave velocity indicates the transition at the temperature near discontinuity temperature 15, 19, 31, 33. It is difficult to specify at which transition process this discontinuity belongs, by velocity measurements only.…”

“…Figure 5 shows that storage stiffness constants and Young's modulus, which have been calculated from eq 3a by using velocity and absorption data, depend on temperature. The Young's modulus is given by Here σ is Poisson's ratio for an isotropic material and given by As seen in the previous studies for other solid polymers, the storage stiffness constants and Young's modulus decrease with temperature 19, 31. But, the decreasing for PVDF is linear.…”

“…Mechanical relaxation experiments for PVDF have been made in static techniques or at low frequencies (0.1–1 kHz) 2, 8–10. However, elastic properties of the other thermoplastic polymers (e.g., PE, PMMA, PS, PVC, and PTFE) have been investigated in a wide range of temperature and frequency 19, 25–36. PVDF has a low acoustic velocity and high mechanical loss 37.…”