ELECTRON MICROSCOPY AND SMALL ANGLE X-RAY STUDIES OF AMORPHOUS POLYMERS.

General considerations of heterogeneity and nodular structure of amorphous polymers and their studies by using small angle x-ray scattering (SAXS) techniques are followed by presentation of results of an investigation in which polycarbonate polymer was tested. The investigation was carried out using a Bonse-Hart small angle scattering system. The measured intensities were corrected for absorption and residual background; and sufficiently long counting times were used so that the scattering at any angle attributable to the polycarbonate was accurate to better than 10 pct. THe data, suitably scaled, are in substantial agreement with those of W. Lin and E. J. Kramer. Results obtained are analyzed by using mathematical techniques. It is suggested that the SAXS from glassy polycarbonate, and other glassy polymers as well, be taken as representative of a generally random structure, with a small concentration (in the range of 0. 04 volume pct. or less) of heterogeneities such as crystallites, second-phase particles or surface defects. It is further suggested that the nodular structures seen in glassy polymers be associated with surface effects rather than structural features of the bulk material.