THE EFFECT OF BIODIESEL ON THE ELECTRICAL PROPERTIES OF AUTOMOTIVE ELASTOMERIC COMPOUNDS

The lack of electrical conductivity on materials, which are used in automotive fuel systems, can lead to electrostatic charges buildup in the components of such systems. This accumulation of energy can reach levels that exceed their capacity to withstand voltage surges, which considerably increases the risk of electrical discharges or sparks. Another important factor to consider is the conductivity of the commercially available fuels, such as biodiesel, which contributes to dissipate these charges to a proper grounding point in automobiles. From 2013, the diesel regulation in Brazil have changed and the levels of sulfur in the composition of diesel were reduced considerably, changing its natural characteristic of promoting electrostatic discharges, becoming more insulating. Taking into account the critical factors mentioned above, the SAE J1645 standard specifies the levels of conductivity and maximum electrostatic energy accumulation (ESD) that automotive materials must meet to avoid unintentional discharges on these systems and guarantee the integrity of the involved components and the safety of occupants. Thus, this work aims to analyze the effect of (bio)diesel on the electrical properties of a new elastomeric composition (PVC/NBR+) for fuel filler hoses. The findings present evidence that this new formulation has high performance in the dissipation of electrostatic charges and can meet the conductivity levels requested by SAE J1645, even in aging test with aggressive biodiosel.