光学显微镜研究交联有机玻璃断面上的肋状形态

用光学显微镜观察了交联有机玻璃断面上的肋状形态。发现断面形态、裂纹路径以及肋状区裂端簇射状银纹群之间有直接联系。每一肋条由一细砂带和一粗破带构成。前者对应于裂端楔形银纹/固体聚合物之间界面的剥离;后者对应于剥离后锐化裂端银纹群之间的剪切;这两个交替过程可以用“滑-粘”模型来解释。在不稳定肋状区发现到裂纹在霉纹区和肋状区的扩展机理是可以相互转化的。

STUDIES ON THE MORPHOLOGY OF RIB STRUCTURE AT THE CRACKED SURFACE OF CROSSLINKED POLYMETHYL METHARYLACTE BY OPTICAL MICROSCOPE

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.