MICROBOND AND FRAGMENTATION TESTS FOR THE FIBER/MATRIX INTERFACIAL SHEAR STRENGTH

Abstract

Fiber reinforced plastics are essentially heterogeneous materials where plastic matrix is reinforced by fibers. Therefore, it is important to know the properties of fiber/matrix interaction in addition to the properties of fiber and matrix themselves. To measure the fiber/matrix adhesive strength, various kinds of tests such as fiber pull-out, fragmentation, microbond, etc. have so far been tried. However the correlation of the strength among these test methods is not necessarily clear although the argument of Herrera-Franco and Drzal [1] has a point. In the present study, we tried two kinds of tests, microbond test and fragmentation test, to get reliable interfacial shear strength. According to the present study, the interfacial shear strength by means of the microbond test was a little smaller than that of the fragmentation test, which coincided with the other researchers' result. The interfacial shear strength of a sample where siging agent was removed was smaller than that of as-received specimen. It was also demonstrated from two-fiber fragmentation tests that the interfacial property affects the failure process of unidirectional composites.