The present work discusses the friction coefficient and wear of polyester composites sliding against dry rough steel surface. Polyethylene (PE) fibres were used to reinforce polyester in order to increase wear resistance of the tested composites. Vegetable oils such as almond, olives, cress, sesame and baraka oils were added to polyester during moulding. Based on the experiments, it was found that the results confirmed good tribological performance of the vegetable oils as filling materials in the polyester matrix, especially in terms of the low coefficient of friction. This effect is proportional to the amount of polar groups and double bonds in their fatty acids, related to increased adsorption and shear strength at the interface. Friction coefficient of polyester composites filled by the tested vegetables oils decreased with increasing oil content, where minimum friction values were displayed by composites containing 9.0 wt. % oil content. Increasing PE fibres decreased friction content. As the PE fibres content increased friction decreased due to strengthening effect of the PE fibres which were responsible for the retarding epoxy transfer into steel surface. Besides, wear of polyester composites filled by the tested oils decreased down to minimum then increased with increasing oil content. Besides, reinforcing the tested composites by PE fibres significantly decreased wear. The lowest wear was displayed by composites filled by 6.0 wt. % almond oil and reinforced by 3.0 wt. % PE.
Youssef et al. (Tue,) studied this question.