Effect of Introducing Edge Cuts into Strained Natural Rubber Samples

Typical tests to determine sensitivity of a compound to flaws involve placing edgecuts into an unstrained specimen and stretching it to failure.  However, in certain situations, flaws are created only after the sample is strained.  The debonding which occurs from a ground rubber particle and the matrix it is imbedded within is such an example.  In this work, the effect of placing edgecuts into a gum and carbon black filled Natural Rubber compound at various strains, and therefore, different stages of crystallization, are evaluated.  Interesting results show the materials are able to withstand large cuts introduced at high strain without breaking the sample.  Strength is significantly enhanced if the cut is introduced after the onset of strain-induced crystallization.