Degradation of nitrile rubber fuel hose by biodiesel use

Nowadays biodiesel is becoming an increasingly important and popular fuel, obtained from renewable sources, and contributes to pollutant emissions reduction and decreasing fossil fuels dependence. However, its easier oxidation and faster degradation in comparison to diesel led to compatibility problems between biodiesel and various metallic and polymeric materials contacted. Therefore, the objective of this work is to investigate the effect of different mixtures diesel–biodiesel (fuel type B5, B10, B20) used in Baja California, Mexico on the resistance of nitrile rubber fuel hoses at temperatures of 25 °C and 70 °C applying gravimetric tests, tensile strength measurements and scanning electron microscopy analysis. The factors affecting the material mass change were identified using an experimental design analysis. It was found that the fuel temperature did not conduct to significant mass loss of nitrile rubber fuel hose, while biodiesel concentration affected the properties of the elastomer, causing the phenomenon of swelling. The exposure of hoses to fuel with increasing concentrations of biodiesel led to tensile strength decrease.