REAL-TIME STUDY OF FAILURE EVENTS IN POLYMERS .1. ADVANCED METHODS FOR CRACK-PROPAGATION STUDIES OF BULK POLYMER SECTIONS AT THE SUBMICROMETER LEVEL

Experimental methods have been developed so that in situ transmission electron microscope (TEM) tensile studies can be performed on bulk pol ymer sections, and failure processes observed; real time can be correl ated with failure in bulk parts. Using specially designed support grid s, polymer section geometry and in situ tensile procedures, the submic rometre failure response of polycarbonate-poly(ethylene terephthalate) phase morphology to crack propagation has been studied. This paper fo cuses on the design of the tensile grids, sections and procedures, whi ch had to be devised for these studies. The techniques developed allow quantification of strain rates and crack velocities. TEM experiments performed showed that artefacts, such as vacuum or radiation damage, w ere not significant factors influencing the morphological response to crack propagation. A companion paper presents the failure processes fo und insitu and correlations with failure processes found in bulk teste d parts.