STUDIES ON THE MORPHOLOGY OF RIB STRUCTURE AT THE CRACKED SURFACE OF CROSSLINKED POLYMETHYL METHARYLACTE BY OPTICAL MICROSCOPE
光学显微镜研究交联有机玻璃断面上的肋状形态

The rib fractography of cross-linked PMMA has been explored by optical microscopy. It was observed that there was a direct connection between the fractographs, the fracture path and the crack tip crazes or microcracks in rib region. The rib consisted of one sandmark and one rough shattered belts. The former corresponded to peeling at the wedge craze/solid polymer interface, the later to shearing of microcrack shower which was formed ahead of sharpened crack tip. These two processes may be explained by "slip-stick" model. It was observed on unstable rib that the crack pro-pagation mechanisms in both mist and rib regions may transfer into each other.