ON THE STRUCTURE OF GLASSY POLYMERS - 6. ELECTRON MICROSCOPY OF POLYCARBONATE, POLY(EHTYLENE TEREPHTHALATE), POLY(VINYL CHLORIDE), AND POLYSTYRENE.

In the reported experiments, high-resolution electron microscopy studies have been carried out on four glassy polymers examined in previous small-angle x-ray scattering (SAXS) investigations. The polymers include polycarbonate, poly(ethylene terephthalate), poly(vinyl chloride), and polystyrene. For all four polymers, both bright-field and dark-field observations indicate the general absence of microstructural features of a size down to the resolution limit of the electron microscope. Only ″pepper and salt″ features on a scale ca. 5A are seen as characteristic of the structures. These features reflect simple interferences as the resolution limit is approached, and are seen for single crystals and oxide glasses as well as for the polymers. The present results, taken together with structural information from light scattering, SAXS and small-angle neutron scattering, indicate that glassy polymers should be regarded as having random structures. The combined results are inconsistent with heterogeneous microstructures having regions of locally high order present in large volume fractions.