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- E85 (2) (entfernen)
Biofuels including ethanol and biodiesel (fatty acid methyl ester) represent an impor-tant renewable fuel alternative to petroleum-derived transport fuels. Increasing bio-fuel use would bring some benefits, such as a reduction in oil demands and green-house gas emissions, and an improvement in air quality.
Materials compatibility is a major concern whenever the fuel composition is changed in a fuel system.
The aim of this work is to study the interaction between sealing materials such as FKM (fluorocarbon rubber), EPDM (ethylene-propylene-diene rubber), CR (chloro-prene rubber), CSM (chlorosulfonated polyethylene), NBR (acrylonitrile-butadiene rubber), IIR (butyl rubber), VMQ (methyl-vinyl-silicone rubber) and FVMQ (methyl-fluoro-silicone rubber) and biofuels such as biodiesel, E85 (fuel with 85% ethanol) and B10 (heating oil with 10% biodiesel) at 70°C for 84 days. Experiments were con-ducted with tests specimens of theses elastomers to document the changes in the mass and tensile properties of these sealing materials according to ISO 1817.
The exposure tests of the elastomers in E85 at 70°C showed that the weight gain caused by swelling of the test specimens was in the range of 3% to 12%. However, the weight gain of the fluorinated elastomers was at the lower end of this range. Tensile strength and breaking elongation decreased by 22% to 61% or 13% to 77%. The lowest decrease in the tensile properties was determined for FKM, EPDM und IIR. These sealing materials were evaluated as resistant to E85 up to a temperature of 70°C.
Biodiesel absorbed water more quickly and aged faster than conventional diesel fuel. The weight loss of the elastomers varied between 9% (FKM) and 126% (CSM) in biodiesel. FKM was evaluated as resistant with a 16% reduction in tensile strength, a 2% reduction in breaking elongation and low weight loss. NBR, EPDM, CSM and VMQ were evaluated as not resistant. CSM even lost 84% of its original tensile strength and 78% of its breaking elongation.
The highest weight gain as a result of swelling was measured for CSM with 86%, for EPDM with 84% and for VMQ with 54% in B10, while the fluorine-containing elasto-mers FKM (1%) and FVMQ (3%) absorbed much less B10 and swelled less. FKM lost 23% in tensile strength and 17% in breaking elongation; FMVQ lost 29% in ten-sile strength and 36% in breaking elongation. FMVQ was, therefore, only limited in its resistance to B10.
The elastomers NBR, EPDM, CSM and VMQ were not resistant to B10 at all as the decrease in the tensile properties was significantly over 50%. NBR lost about 93% and CSM about 100% of its breaking elongation.
The conclusion of the investigations at 70°C is that FKM is the most resistant sealing material in biodiesel, E85 (fuel with 85% ethanol) and B10 (heating oil with 10% biodiesel).
Biofuels represent an important renewable fuel alternative to petroleum-derived transport fuels. Materials compatibility is a major concern whenever the fuel composition is changed. The aim of this work is to study the interaction of the elastomers: FKM, EPDM, CR, CSM, NBR, IIR, VMQ and FVMQ and biofuels such as biodiesel (FAME), E85 (fuel with 85% ethanol) and B10 (heating oil with 10% biodiesel). Exposure tests were performed with test specimens at 40°C (104°F) and 70°C (158°F) for 84 days to document the changes in mass, volume and tensile properties according to ISO 1817. The exposure tests in E85 showed that the weight gain caused by swelling was in the range up to 12%. The lowest decrease in the tensile properties was determined for FKM, VMQ and IIR. The weight gain of the elastomers in biodiesel varied between 10% (FKM) and 126% (CSM) and the loss of tensile strength between 16% (FKM) and 100% (CSM) at 70°C (158°F). FKM and FVMQ absorbed much less B10 and swelled less. NBR, EPDM, CR, CSM, IIR and VMQ were not resistant to B10 at all as the decrease in the tensile properties was significantly over 50%. Among all of the elastomers FKM showed high compatibility with these biofuels up to 70°C (158°F).