Ali A. S. and Khashaba M. I.
Friction coefficient displayed by contact and separation as well as sliding when bare foot and foot wearing rubber contacting epoxy reinforced by carbon fibres (CF) and coated by polyurethane and sand particles is investigated. Generation of electrostatic charge (ESC) and its effect on friction coefficient will be discussed. It was found that ESC generated from contact and separation of PU coated by sand particles (SiO2) and reinforced by CF recorded much higher values than PU and epoxy surfaces. Slight decrease in ESC was observed as the distance of CF from friction surface increased. ESC generated from sliding of PU coated by sand against bare foot displayed relatively higher values than that measured for epoxy and PU surfaces. Presence of sand increases friction coefficient due to the abrasive action of particles in bare foot surfaces which increases ESC. The penetration of sand particles into bare foot increases the contact area and hence increases ESC. Friction coefficient values recorded relatively higher values than that shown for epoxy and PU coating. ESC generated from contact and separation of rubber footwear and PU coated by sand displayed lower values than that observed for bare foot. In condition of sliding of PU coated by sand and reinforced by CF against rubber, it was found that ESC displayed values higher than that observed for contact and separation. The influence of sand was more pronounced during sliding than contact and separation. Friction coefficient decreased with increasing the distance of CF location from the surface. The friction values guaranteed the good adhesion required for floor materials.