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).
Changes in fuel composition and the introduction of alternative fuels often create problems of degradation in materials. The objective of this research is to study the interaction of the sealing materials FKM, EPDM, CR, CSM, N8R, IIR, VMQ, FVMQ and PA and biofuels such as non-aged and 2 year aged biodiesel (FAME), E1 0 (fuel with 10% ethanol, E85 (fuel with 85% ethanol} and non-aged and 1 year aged 810 (heating oil with 10% biodiesel) in comparison with premium grade fuel without ethanol. Exposure tests were performed with test specimens at 20 °C, 40 oc and 70 oc for 84 days to document the changes in mass, volume and tensile properties. The sealing materials FKM, FVMQ and PA were evaluated as resistant in E10, and FVMQ, VMQ and PA as resistant in E85 at 20 oc and 40 oc. S welling resulted from the high absorption by the elastemers CR, CSM, EPDM, IIR and N8R in comparison to their dissolution in non-aged biodiesei at 40 °C. FKM was still resistant in aged biodiesei at 40 oc but only to a limited degree at 70 °C. The sealing materials CR, CSM, EPDM, IIR and N8R were damaged to a high extent in non-aged and aged 810. Of all the sealing materials, FKM and FVMQ showed high compatibility with these biofuels up to 70 °C.
The objective of this research was to determine the resistance of frequently used sealing materials such as fluorocarbon rubber (FKM), fluorosilicone rubber (FVMQ), silicone rubber (VMQ), ethylene-propylene-diene rubber (EPDM), chloroprene rub-ber (CR), chlorosulfonated polyethylene (CSM), butyl rubber (IIR), acrylonitrile buta-diene rubber (NBR), polyester urethane rubber (PUR) and polyamide (PA) in non-aged/aged biodiesel and heating oil with 10 % biodiesel at 20 °C, 40 °C and 70 °C. Mass, tensile properties and Shore hardness A/D (for polyamide) of the test speci-mens were determined before and after the exposure for 84/42 days in the aged and non-aged fuels of different age.
Biodiesel fuels are easily oxidized and contain acids and water. The sealing materi-als: acrylonitrile butadiene rubber, butyl rubber, chloroprene rubber, chlorosulfonated polyethylene and ethylene-propylene-diene rubber and were generally not resistant to biodiesel and heating oil with 10 % biodiesel. Fluorocarbon rubber, fluorosilicone rubber and polyamide were the most resistant materials in all tested fuels up to 70 °C. The degree of damage to the sealing materials increased with higher test temperatures and the age of the fuels.
The objective of this research was to determine the resistance of frequently used sealing materials such as EPDM, FKM, FVMQ, CR, CSM, IIR, NBR, PA, PUR and VMQ in aged biodiesel and heating oil B10 with 10 % biodiesel.
The mass, tensile strength, breaking elongation and Shore hardnesses of the test specimens were determined before and after exposure in non-aged, one-year, two-year, three-year and four-year aged biodiesel and B10 at 20 °C, 40 °C and 70 °C.
A threshold for the reduction in tensile properties and Shore hardness is not set in the international standards. Therefore, a threshold of 15 % was set for the evaluation of the compatibility. The decrease in tensile properties and Shore hardness increased with the age and the temperature of the biodiesel and the heating oil.
The age of the biodiesel was not relevant for the sealing materials CR, CSM, EPDM, IIR and NBR, which were generally not resistant to biodiesel and B10. FKM and PA showed high compatibility in non-aged and aged biodiesel. FVMQ and PA could be evaluated as resistant in non-aged and aged B10 at 20°C and 40°C, whereas FKM was resistant up to 70°C despite of the age of B10.