Tribology of Sized Glass Fibers

Abstract

Lateral force microscopy (LFM) and an electronic microbalance method are used for a friction force analysis of sized glass fibers, which are generally used to reinforce com posite materials. Friction coefficients of glass fibers A and E, coated with sizes containing a starch and an epoxy film former, respectively, are determined. Friction force values measured between a scanning Si₃ N4 microtip and the fiber's surface are smaller than those evaluated between two sliding glass fibers. Important variations of lateral force signals by the LFM reveal the chemical heterogeneity of the sized glass fiber A, while for fiber E, plowing effects and variations of the friction coefficient from one fiber to another as well as a greater friction coefficient than fiber A are detected. With the second technique, there is a large distribution of friction coefficient values due to chemical and/or physical heterogeneities of the fiber surface. Statistical methods are used to interpret the results. Interfiber friction values are correlated to the friction values obtained by lateral force microscopy. The overall results show that these two methods are very effective in determining tribological properties of sized glass fibers.