Acoustic properties of nitrile butadiene rubber for underwater applications

Abstract

Acoustic properties of nitrile butadiene rubber (NBR) specimens with carbon black as filler were investigated with different sulfur contents in the frequency range of 300-1000 kHz. Their mechanical properties, such as density, hardness, tensile strength, were conventionally measured and correlated with their acoustic properties. Sound speeds in the specimens were increased with an increase in the sulfur content. The variation of sound speed was about 2-5% in the specimens, whereas the variation of density was less than 0.4%. Enhanced acoustic transmission was also observed with increasing sulfur content. It may be due to the hardness change from the increase of crosslinking density in the specimens. These results show that the mechanical properties of NBR can be nondestructively and accurately determined with the acoustic property measurements. By use of the desired mechanical and acoustic properties, the utilization of the NBR for underwater applications becomes less difficult. (C) 2002 Wiley Periodicals, Inc.