Study of the structure of atactic poly-4-vinylpyridine using paramagnetic shearing reagents

• Published in: Polymer science USSR 1979, Vol.21 (6), p.1553-1564
• Main Authors: Vorontsov, Ye.D., Rusak, A.F., Gusev, V.V., Filippova, Ye.Ye, Nikolayev, N.N., Yevdakov, V.P.
• Format: Article
• Language: English
• ISSN: 0032-3950; 1878-268X
• DOI: 10.1016/0032-3950(79)90064-9

A study was made of the addition of paramagnetic shearing reagents of Eu(DPM) 3 and Pr(DPM) 3 on 1H and 13C NMR spectra of atactic poly-4-vinylpyridine in a deuterochloroform solution in the temperature range of 28–100°. Form an analysis of 1H (360 Mc/s) and 13C (22·63 Mc/s) spectra microtactivity of radical poly-4-vinylpyridine was determined and described by Bernoulli's statistics with P m = 0·52. It was shown that 1H shear of the polymer induced using Eu(DPM) 3 is pseudo-contact. Geometrical factors (proportional to the value of pseudo-contact shear) were calculated for fragments of regular conformations of macromolecular iso- and syndiochains. A comparative analysis was made (using the principle of maximum probability) of experimental and calculated shear values induced using Eu(DPM) 3 to determine the conformation composition of the polymer, which is in agreement with the proposed model of microtactivity of poly-4-vinylpyridine. From the temperature dependence of 1H of the shear of the polymer it was concluded that the conformation of poly-4-vinylpyridine changes in the direction of higher content of the syndio- trans-form.