Ethanol has shown tremendous potential in the journey of substitution of fossil
fuels in the recent past. Primarily, the ethanol blends up to 10% in gasoline
used in many countries as the existing vehicles are compatible with lower
ethanol content. However, it is essential to address the compatibility of the
vehicle’s fuel system when using higher ethanol-containing blends. The current
study focused on the compatibility of different ethanol-gasoline blends with two
widely used elastomer materials in the vehicle’s fuel system, namely, nitrile
butadiene rubber/polyvinyl chloride blend (NBR/PVC) and epichlorohydrin (ECO).
These materials are used for manufacturing parts like seals, gaskets,
hoses/tubes, and cover of the fuel systems. The test fuels used in this study
include commercial gasoline (E0), gasoline containing 10% ethanol (E10), 12%
ethanol (E12), 15% ethanol (E15), and 20% ethanol (E20). The compositional
analysis of NBR/PVC blend and ECO samples was undertaken using Carbon, Hydrogen,
Nitrogen, Sulfur (CHNS) analyzer, Fourier-transform infrared (FTIR)
spectroscopy, and Thermogravimetric Analysis (TGA). The test material specimens
were immersed in test fuels at an elevated temperature of 55 ± 2°C for 1008 hr,
or six weeks. Critical properties of material specimens under fresh, post
immersion (wet), and dry conditions were analyzed. These properties include
visual inspection, volume change, weight change, hardness change, tensile
strength, and percentage (%) elongation change. Variations in properties of test
specimens were used to illustrate the compatibility with test fuels. The results
indicate that the volume change and weight change correspond well with hardness,
tensile strength, and % elongation trends. The behavior of E10 and E12 fuels
with test materials were found to be similar within a 5.0% tolerance. As we move
to E15 and E20, the performance of elastomers changed moderately in certain
properties, tensile strength, and % elongation change in particular.
