Paper friction at the various measuring conditions - Effect of relative humidity

Abstract

Friction of commercial papers under dry, moderate and humid atmospheres was examined, comparing with those of cellulose film and aluminum foil. The friction coefficient between different papers generally gave their intermediate value. The coefficient between equal cellulosic materials including paper increased with humidity, while that of aluminum against aluminum was constant irrespective of surrounding humidity. However the surface wetting with a slight amount of water on aluminum caused rapid increase in the coefficient. The capillary force may cause this phenomenon, and the sharp increase of friction between cellulose films in humid atmosphere was similar to that observed with aluminum foils which were wetted with a slight amount of water. These suggest that the capillary force by a slight amount of water may raise frictional force of cellulosic materials including paper at high humidity.