Measurement of volume changes of elastomers at high strain rates

A homemade device to measure volume changes of elastomers on extension within milliseconds is described. Measurements were carried out with strain rates varying up to 1000 % per second. The following results were achieved: The increase of volume of natural rubber filled with inactive fillers is independent of the strain rate. The high volume change does not relax at constant strain. Elastomers containing active fillers result in the same behavior. The onset of void formation at the filler surface is caused by the stress acting on the surface