Fluoroelastomer Compatibility with Bioalcohol Fuels

Global acceptance and use of biofuels is growing rapidly in the transportation sector. Diminishing reserves of limited and costly fossil fuel resources and a growing realization that world peak oil production will most likely occur within the next decade is driving significant investment in sustainable biofuels. Legislative, regulatory and market forces are driving developments which seek to reduce vehicle emissions, improve fuel efficiency, lower environmental greenhouse gases and strengthen the economy. The use of alternate, sustainable, renewable fuels, preferably of domestic origin, is fostering considerable investment in new technologies. One promising technology is the addition of aliphatic alcohols to gasoline and diesel fuels. The compatibility of seal and hose materials commonly used in automotive fuel systems with conventional hydrocarbon fuels is well known. Over the past forty-five years fluorohydrocarbon elastomers have been successfully used in passenger car and truck and off-highway gasoline and petrodiesel fuel delivery and metering systems. More recently, biofuels such as ethanol have become technically and economically attractive blending constituents for gasoline and diesel fuels. These biomass fuels present their own set of material compatibility challenges to automotive fuel storage, delivery, and metering system component hardware. In this presentation the compatibility of selected fluoroelastomers with ethanol and butanol, and their respective alcohol-based blend fuels, will be reviewed. Fluoroelastomers that have historically been used for petroleum based fuels will be compared to several new types that display improved compatibility and sealing functionality with alcohol-based fuels. Accelerated long term testing results will be presented that characterize physical properties and property retention in bioalcohols through 1008 hours at 40°C. Properties relevant to sealing applications and hose will also be discussed and best in class elastomers will be highlighted, so that, in gaining a better understanding of the respective capabilities of high performance fluorohydrocarbon elastomers, the engineer may design more robust sealing systems for bioalcohol service.Cross Reference: