On the Compatibility Between Biomass Fuel and Elastomer

The compatibilities, especially in swelling behaviors, between three kinds of automotive rubber seal rings and crude rice husk biomass fuel, distilled biomass fuel, and emulsified biomass fuel were studied in the present paper. The results showed that the elastomers presented variable swelling degrees as they were immersed in the fuels at 40°C for 7 days. Their mass and volume variations of nitrile-butadiene elastomer (NBR) and fluoro-elastomer (FKM) were bigger than those of silicone elastomer (SR) as they were immersed in the crude biomass fuel. Their NBR were 200.0% and 316.5%, respectively. FKM were 85.7% and 101.7%, respectively. In contrast to the distilled biomass fuel, the changes of mass and volume of FKM were 229.0% and 368.9%, respectively. For the emulsified biomass fuel, the changes of mass and volume of SR were 49.8% and 13.6%, respectively. The phenomena were ascribed to similar structures and groups between the varied biomass fuel and the different rubbers based on scanning electron microscopy, thermogravimetry, and Fourier transform-infrared results. The swelling mechanism of elastomers could be explained based on the “ideal” solution laws for the molecules of equal size and acid-base reactions.