Elastomer Swell Behavior in 1-Propanol, Diisobutylene, Cyclopentanone, and a Furan Mixture Blended in E10 and a Blendstock for Oxygenate Blending (BOB) 04-12-03-0011

The compatibility of four potential bio-derived blendstock molecules with infrastructure elastomers was determined by measuring the volume change following exposure. The blendstock molecules included 1-propanol, diisobutylene, cyclopentanone, and a furan mixture. The elastomers included two fluorocarbons, six nitrile rubbers (NBRs), and one each of fluorosilicone, neoprene, polyurethane, and silicone. The elastomers were exposed to the fuel molecules as blends ranging from 0 to 30 vol.% in both a blendstock for oxygenate blending (BOB) formulation and an E10 fuel. Silicone exhibited excessive swelling in each test fuel, while the other elastomers showed good compatibility (low swell) with diisobutylene, 1-propanol, and the furan mixture when BOB was used as the base fuel. The E10 base fuel produced high (>30%) swell in neoprene, polyurethane, and some nitrile rubbers. In most cases diisobutylene produced the least amount of volume expansion. In contrast, the addition of cyclopentanone produced unacceptably high swelling in each elastomer and is not considered suitable for use with these fuels. Analysis of the results showed that the swelling behavior is predominantly due to the polarity of the elastomer and test fuels.