Damage mechanisms in natural (NR) and synthetic rubber (SBR): nucleation, growth and instability of the cavitation*

Elastomeric matrix composites (EMCs) subjected to static and fluctuating loads basically fail due to the nucleation and growth of defects. Also, high hydrostatic pressure can influence the mechanical behaviour of EMCs. The change in behaviour of EMCs due to the nucleation of cavitations under hydrostatic pressure is studied here to understand the mechanics underlying the damage mechanism. Two types of materials for pancake specimens are used in this study; natural rubber (NR) vulcanized and reinforced by carbon black and synthetic rubber (styrene-butadiene-rubber, SBR). In situ observations of uniaxial tension and torsion tests are also presented by using X-ray computed tomography (CT) (medical scanner) and the results are compared with those from scanning electron microscopy (SEM).