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An NBR/polyvinyl chloride (PVC) blend changed by aging (20 weeks in different fuels at room temperature) was evaluated for weight, hardness, mechanical properties, and microstructure. The exposure tests were made with premium gasoline, regular gasoline, regular gasoline doped with a rubber solvent, and an oxygenated renewable biofuel (ethanol fuel). After the aging tests, all NBR/PVC blend samples increased in both hardness and elastic modulus, whereas both elongation at break and tension at break decreased, but in different proportions. As the NBR/PVC blends aged, they became less elastomeric and more rigid. The regular gasoline doped with a rubber solvent was the most aggressive of the fuels tested because it promoted the extraction of a large quantity of the blend constituents, thus making the blend harder. In general, NBR/PVC samples immersed in the fuels showed similar mechanical behaviors, except in the case of immersion in ethanol. The values of parameters τ3 and I3 were obtained by positron annihilation lifetime spectroscopy. The changes in the mechanical properties and the reduction of the values of parameters τ3 and I3 were related to extraction of the plasticizer, which was confirmed by thermogravimetric analysis.

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