الفهرس 
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Abstract
The present work investigates experimentally the effect of reinforcing epoxy matrix by polyamide and polyester fibers of different diameters on the friction and wear at dry sliding against steel surface.
The experiments showed that, friction coefficient displayed by the tested composites drastically decreased as the polyamide content increased, while it significantly increased up to maximum then drastically decreased with increasing polyamide fiber diameter. Wear increased up to maximum then slightly decreased with increasing fiber diameter. At constant content of polyamide fibers to epoxy matrix, fibers of relatively low diameter showed the lowest wear. Wear mechanism of the tested composites is based on the triboelectrification of the sliding surfaces, where the contact area is charged by double layer of electrostatic charge (ESC) of different charge. Consequently, layers of epoxy can transfer and adhere to the steel counterface, where the contact will be epoxy/epoxy rather than epoxy/steel. Those contact materials are responsible for the friction increase. The transfer and transfer back of polymeric materials that accumulated to form film adhered to the steel surface are representing the prevailed wear mechanism.
The present work also investigates experimentally the effect of reinforcing epoxy matrix by continuous polyester fibers of different diameters on the friction and wear at dry sliding against steel surface.
It was observed that epoxy composites reinforced by polyester fibers showed drastic decrease in friction coefficient, where the highest value was observed for epoxy free of fibers. Besides, friction coefficient significantly increased with increasing fiber diameter. Wear of the tested composites decreased with increasing polyester content, while wear remarkably increased with increasing fiber diameter.