TY - JOUR
T1 - Electron microscopy and SAXS studies of amorphous polymers
AU - Uhlmann, D. R.
N1 - Funding Information:
Among the SANS studies, that of Benoit12 can be taken as representative. The radii of gyration of eight molecular weight polystyrene polymers were found to be the same, within experimental error, as those of the polymers in a theta solvent (where the random coil is widely acknowledged as providing a useful representation of the chain conformation). The combined weight of all these studies, together with those cited in ref. ( 5 ) , leads to the conclusion that the structure of amorphous thermoplastics should be represented by random array models such as the random coil, rather than by models such as the nodule hypothesis, whose essence involves regions of locally high order. When examined in detail, all the evidence advanced in support of such local-order models seems subject to question. Even the observation of TI, transitions seems to involve the interaction of the liquid with the braid on which it is supported, and cannot be taken as unequivocal support for regions of local order. It is suggested, therefore, that the controversy be laid to rest, and that attention be directed to more fruitful areas such as the structural changes involved in crystallization and the structural differences between surfaces and bulk material. Financial support for the present work was provided by the U.S. Air Force Office of Scientific Research. This support is gratefully acknowleged, as is the previous support of the National Science Foundation. The direct contributions of Drs. Renninger, Wicks, Straff and Vander Sande, as well as Mr. Matyi and Miss Meyer, made this presentation possible. G. S. Y. Yeh, Crit. Rev. Macromol. Chem., 1972, 1, 173. P. H. Geil, Morphology of Amorphous Polymers, Final Report USAROD, Contract DAHCOC J. L. Racich and J. A. Koutsky, Bull. Amer. Phys. Soc., 1975, 20, 456, J. K. Gillham and R. F. Boyer, J. Macromol. Sci. Phys., 1977, B13, 497. P. J. Flory, J . Macromol. Sci. Phys., 1976, B12, 1 . D. G. H. Ballard, G. D. Wignall and J. Schelten, Europ. Polymer J . 1973, 9 965. G. D. Wignall and G. W. Longman, J. Mater. Sci., 1973, 8, 1439. A. L. Renninger, G. G. Wicks and D. R. Uhlmann, J . Polymer Sci. Phys., 1975, 13, 1247. M. Meyer, J. Vander Sande and D. R. Uhlmann, J. Polymer Sci. Phys. 1978,16,2005. 7OC-0032. lo D. L. Weinberg, Phys. Letters 1963, 7, 324. l1 G. Patterson, J . Macromol. Sci. Phys., 1976, B12, 61. l2 H. Benoit, J. Macromol. Sci. Phys., 1976, B12, 27.
PY - 1979
Y1 - 1979
N2 - Small angle X-ray scattering (SAXS) and high resolution electron microscopy have been used to characterize the structure of glassy polymers. The SAXS from polycarbonate, poly(methyl methacrylate), poly(ethylene terephthalate), poly(vinyl chloride) and polystyrene is inconsistent, both in the form and magnitude of the scattered intensity, with the presence of nodules as representative of the bulk structure. The electron microscope results provide no evidence for heterogeneities on a scale and volume fraction of the reported nodules. Only the pepper and salt features characteristic of microscope operation near the resolution limit are seen. It is suggested that the structures of these amorphous thermoplastics be regarded as random arrays.
AB - Small angle X-ray scattering (SAXS) and high resolution electron microscopy have been used to characterize the structure of glassy polymers. The SAXS from polycarbonate, poly(methyl methacrylate), poly(ethylene terephthalate), poly(vinyl chloride) and polystyrene is inconsistent, both in the form and magnitude of the scattered intensity, with the presence of nodules as representative of the bulk structure. The electron microscope results provide no evidence for heterogeneities on a scale and volume fraction of the reported nodules. Only the pepper and salt features characteristic of microscope operation near the resolution limit are seen. It is suggested that the structures of these amorphous thermoplastics be regarded as random arrays.
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U2 - 10.1039/DC9796800087
DO - 10.1039/DC9796800087
M3 - Article
AN - SCOPUS:32544446672
SN - 0301-7249
VL - 68
SP - 87
EP - 95
JO - Faraday Discussions of the Chemical Society
JF - Faraday Discussions of the Chemical Society
ER -