Fatigue and mechanical properties of NR SBR and NR NBR blend vulcanizates

One of the important considerations in the selection of a polymer blend for a practical application is how it resists crack growth and/or failure from a material flaw, under static or fatigue conditions. The blending of two or more rubbers is a useful technique to improve certain properties not inherent in a single rubber. In the present work, fatigue and mechanical failure tests have been performed to evaluate the behaviour of blend vulcanizates of natural rubber/styrene butadiene rubber (NR/SBR) and natural rubber/butadiene acrylonitrile rubber (NR/NBR). It has been found that the fatigue life and the strain energy varies linearly with blend composition in the compatible blend (NR/SBR), but they deviate from linearity in the case of the incompatible blend (NR/NBR). These results are in good agreement with the mechanical property measurements for the various compatible and incompatible blends studied.