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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.

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 progression of gas turbine engine design encompasses a relentless drive towards more powerful, higher thrust, lighter weight, fuel efficient engines, with accompanying reductions in noise and emissions, as well as better reliability, operating safety and longer time on wing. These trends converge to push engine thermodynamics to their limits, invariably culminating in higher operating temperatures. As a result, engine builders have adopted advanced lubricants with higher thermo-oxidative stability (HTS), in order to achieve long life engine performance. These HTS oils are proving to be significantly more aggressive towards standard fluoroelastomers. As a result, there is a gradual migration to specialty grades that offer significantly improved compatibility with HTS oils. As temperatures have escalated, higher performance perfluoroelastomers have found greater use in aircraft engines.

Prevailing trends in aircraft turbine engine applications are pushing current elastomeric seal materials to their limits. These trends include the continued drive towards more powerful, lighter weight engines, with accompanying reductions in noise, emissions and fuel consumption, as well as ongoing improvements in reliability, maintainability, and longer intervals between engine overhauls. These trends converge to push engine thermodynamics to their limits, which manifests in higher operating and soakback temperatures. As a result, engine manufacturers specify high temperature stabilized (HTS) oils in order to achieve engine performance and life targets. Aircraft engine lubricants have had to keep pace with higher operating temperatures while still meeting stringent performance requirements and regulatory and environmental compliance.

The automotive industry is continually seeking new elastomers capable of withstanding aggressive fluids at temperature extremes, while providing high quality at attractive costs. The challenge is formidable in view of reliability and warranty considerations, cost pressures and technology limitations. This paper presents the technical basis for a new class of specialty elastomers. DuPont has designed these elastomers to provide heat resistance that exceeds that of currently available elastomers of comparable price. The paper will discuss initial offerings in the ADVANTA™ product family. They offer a unique balance of heat resistance, oil resistance and sealing properties. Potential end-use applications include O-rings, oil seals, gaskets and custom molded sealing devices for engines, transmissions and axles. Features and benefits of selected compound formulations will be presented and benchmarked to other specialty elastomers currently used in the automotive sealing arena.

The low temperature properties of fluorohydrocarbon elastomers (FKM) have been well documented using traditional rubber laboratory tests such as brittle point, temperature retraction, glass transition, and stiffness by Clash-berg and Gehman methods. Although these tests are considered good indicators of low temperature behavior, these techniques have not proven to be entirely accurate in predicting the low temperature sealing capability of fluoroelastomer molded products such as O-rings. The purpose of this paper is to present an overview of the low temperature properties of standard fluoroelastomers and the newer improved low temperature types, by both traditional test methods and a recently developed static O-ring testing device. Through use of this static testing apparatus, the influence of several variables are investigated, which include polymer type, compound design, seal interference, temperature, and fuel plasticization of the FKM compounds.

In recent years, fluoroelastomers have been used in automotive fuel systems with increasing regularity. Automotive fuels have become increasingly aggressive on fuel handling polymers. Gasolines blended with alcohols, alcohol by-products, and additives place a broader challenge on fuel handling polymers. Fluoroelastomers, especially high fluorine types, are viewed by many engineers as a method of stabilizing part performance in the face of today's ever-changing fuels. This paper will compare a traditional fluoroelastomer used in automotive fuel systems to new development fluoroelastomers that are designed to help both the end user and the rubber part manufacturer. The testing done will focus on benefits available from the new FKM polymers, such as low swell in fuel/alcohol blends, improved low temperature flexibility, and improved compression set resistance.