Conclusions
The invariance of the characteristics of electronic distribution and the presence of limiting values of Δλ(N) with increasing chain length permits us to conclude that the macromolecule of the aromatic polyamide behaves like an oligomeric molecule of five to ten monomer units. Evidently this circumstance also, and not only the disruption of coplanarity of the individual units of the macromolecule, explains a number of experimental data leading to the conclusion of the presence of “blocks of conjugation” in polymers with a system of conjugated bonds [22].
With such substantial energetic profitability of the amide forms as is obtained from quantum mechanical calculations, we might expect substantial concentration predominance of these forms in real systems, and, consequently, natural experimental difficulties in the detection of imidol forms. Moreover, the results obtained permit an explanation of the presence of paramagnetic centers in polyamidoacids and polyaminoamidoacids without enlisting the concept of the existence of isoamide and isoimide forms in them [23].
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Vladimir Scientific Research Institute of Synthetic Resins. Translated from Zhumal Strukturnoi Khimii, Vol. 12, No. 5, pp. 822–830, September–October, 1971.
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Kosobutskii, V.A., Kagan, G.I., Belyakov, V.K. et al. Amide-imidol tautomerism in aromatic polyamides. J Struct Chem 12, 753–760 (1972). https://doi.org/10.1007/BF00743341
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DOI: https://doi.org/10.1007/BF00743341