Fluoroelastomer Compatibility with Biodiesel Fuels 2007-01-4061

Global acceptance and use of biofuels is growing rapidly in the transportation sector. Diminishing reserves of fossil fuels will continue to drive investment in sustainable biofuels. Market drivers for biofuels include a renewable supply, reduced greenhouse gas emissions and airborne pollutants, and reducing dependence on energy imports. One such fuel is biodiesel, an alternative diesel fuel produced by transesterification of vegetable oils or animal fats with alcohol, usually methanol.

The use of biodiesel fuels is rapidly growing in North America, not only for the environmental and economic reasons mentioned above, but because of its inherent lubricity. EPA emission regulations now require the use of ultra-low sulfur diesel (ULSD) fuels in all highway diesel engines. ULSD has inherently poor lubricity and biodiesel's superior lubricating properties can reduce wear in diesel engines fueled with blends of ULSD, thereby extending engine life and warranty.

The compatibility of seal and hose materials commonly used in automotive fuel systems using conventional hydrocarbon fuels has long been established. However, there is much less information available on the compatibility of fuel system elastomers with biodiesel fuels.

In this presentation the compatibility of several fluoroelastomers with biodiesel and biodiesel blend fuels will be reviewed. Conventionally formulated fluoroelastomers that have historically been used for petrodiesel and biodiesel service will be compared to optimized formulations that display improved compatibility with biodiesel fuels. The significance of rubber formulation will be discussed. Accelerated testing will characterize physical properties and property retention in biodiesel through 3024 hours at 125°C. Properties relevant to sealing applications and hose will also be discussed and best in class 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 biodiesel service.