EFFECT OF REINFORCING POLYPROPYLENE BY STEEL WIRES ON FRICTION COEFFICIENT AND WEAR

Abstract

The effect of reinforcing polypropylene (PP) by unidirectional continuous steel wires on friction coefficient and wear was discussed in this work. Scratch test was carried to evaluate the tribological performance of the proposed composites. The tested composites were sheets PP of 5.0 mm thickness. The steel reinforcing wires were 0.3, 0.5, 0.6, 0.7 and 0.8 mm diameters. The numbers of wires reinforcing the test specimens were 0, 3, 6, 9, 12 and 15. The wires were distributed parallel to the direction of motion. It was observed that friction coefficient displayed by the scratch of PP reinforced by steel wires decreased with increasing number and diameter of steel wires. The presence of steel wires decreased the hardness of the PP so that the material removal by the indenter was easier, where PP was affected by the rate of cooling during molding. Besides, reinforcing PP by steel wires increased the rate of cooling causing softening of the PP matrix and decreased the hardness. It can be concluded that presence of steel wires experienced wear decreasing. In addition to that, the influence of the cooling rate on the hardness and the mechanical properties of the polymers affected the wear. Normal load showed pronounced effect on wear of PP.