The influence of the age of biodiesel and BIO on the resistance of sealing materials at different temperatures

摘要

Materials compatibility is a major concern whenever the fuel composition is changed in a fuel system. The objective of this research was to determine the resistance of frequently used sealing materials such as FKM, FVMQ, VMQ, EPDM CR, CSM, IIR, PA, NBR and PUR in aged fuels and heating oil with admixtures of biodiesel and B10 (heating oil with 10% biodiesel). The mass, tensile strength and breaking elongation of the test specimens were determined before and after exposure for 84 days in non-aged, one-year, two-year, three-year and four-year aged biodiesel and B10. The Shore hardnesses A and D (for PA) were determined before and after exposure of the test specimens in the biofuels for 42 days. 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. 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. FKM and PA showed high compatibility in non-aged and aged biodiesel. The decrease in tensile properties and Shore hardness increased with the age and the temperature of the biodiesel. CR, CSM, EPDM, IIR, NBR and VMQ were not resistant to B10 at all. 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 the age of the B10. The damaging impact of B10 increased with the age and the temperature.