POLYMER GAS INTERACTIONS AT HIGH-PRESSURE - THE USE OF ULTRASONIC PROBES

This paper describes the use of ultrasonic transducers to estimate the physical and mechanical changes produced in organic polymers when they are subjected to high pressure gas media. Two experimental methods, involving the use of commercial ultrasonic transducers, are outlined to exemplify the potential of the techniques. One method uses a transducer as a simple displacement probe where the linear strain in the sample is sensed by measuring an acoustic distance in a liquid chamber attached to the sample. A second method measures an acoustic length in the sample itself. Both methods require appropriate calibration. The second technique also provides data on the physical state of the sample, in particular the acoustic modulus and the formation of internal fissures or bubbles which may be generated in fluctuating gas pressure fields. © 1990.