In the present work, the main objective is to investigate the effect of reinforcing epoxy floor coatings by copper wires of different diameters on friction coefficient displayed by their sliding against rubber sole. Experiments were carried out to measure friction coefficient to guarantee appropriate level of motion resistance to avoid excessive movement and slip accidents. Epoxy was reinforced by copper wires of different diameters.
Based on the experiments carried out in the present work, it was found that at dry, water and detergent sliding of the tested epoxy against rubber sheet, friction coefficient increased by increasing the number and diameter of wires reinforcing epoxy. When the wires were closer to the surface, they were strongly influenced by the electric field and consequently the intensity of the electric charge increased leading to an increase in friction coefficient. At water wetted sliding, the observed friction values were relatively high due to the formation of the double layer of electric static charge on the two sliding surfaces causing an increase in the adhesion between the mating surfaces, where the water film facilitated the distribution of electric static charge on the sliding surface. Besides, detergent wetted sliding displayed values of friction much lower than that observed at water wetted sliding.
Triboelectrification is the generation of double layer of electric static charge on the two sliding surfaces. When two dissimilar materials are pressed or rubbed together, the surface of one usually becomes positive charged, while the other becomes negative charged. The intensity of the generated charge depends on the pressure and velocity of rubbing. Once charged, the two surfaces attract each other. In the present work, epoxy reinforced by copper wires and sheet of rubber are sliding against each other. The distribution of charges on the sliding surfaces generates electric field. Epoxy as insulator contains a distribution of charges which are conserved. The double layer of the electric static charge generated on the sliding surfaces would generate an E-field inside the matrix of epoxy. Presence of copper wire inside epoxy matrix would generate extra electric static charge on the sliding surfaces leading to further increase in the adhesion force acting on the two sliding surfaces leading to significant increase in friction coefficient.