The Volume Increase of Fuel Handling Rubbers in Gasoline/Alcohol Blends

The volume increase of fluorohydrocarbon, fluorosilicone, nitrile, epichlorohydrin homopolymer and copolymer rubbers has been determined by total immersion in high aromatic gasoline blended with methanol and ethanol at 21°C and 54°C. The methanol blends caused more swelling than the ethanol blends at equivalent alcohol concentrations over the range of 10 to 100 volume percent alcohol. In both fuel systems the highly fluorinated fluorohydrocarbon rubbers showed the best resistance to swelling.