Molecular dimension and behaviour of polyvinyl-pyridine in alcoholic silver nitrate solution
01 Nov 1964-Vol. 200, Iss: 1, pp 32-34
TL;DR: The structure of the pyridine-silver complex has been known for quite some time as discussed by the authors, and it behaves like a polyelectrolyte in the presence of alcohol.
Abstract: Light-scattering behaviour of polyvinyl pyridine and silver nitrate mixture in alcohol showed that the system behaves like a poly-electrolyte. This has been explained by the structure of the pyridine-silver complex that has been known for quite some time.
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TL;DR: In this paper, a poly-4-vinylpyridine was precipitated from a toluene solution of the monomer after addition of benzoyl peroxide, and the sample used in these experiments had a molecular weight of 77,000, as determined by osmotic pressure in alcohol solution, and an intrinsic viscosity of 0.36 in this solvent.
Abstract: Poly-4-vinylpyridine was precipitated from a toluene solution of the monomer after addition of benzoyl Peroxide. The sample used in these experiments had a molecular weight of 77,000, (DP 730) as determined by osmotic pressure in alcohol solution, and an intrinsic viscosity of 0.36 in this solvent. The hydrochloride is water soluble and behaves like the salt of an extremely weak base with an over-all average base dissociation constant of 0.011 × 10−9, about one thousandth that of 4-ethylpyridine. The decrease in apparent base strength is ascribed to the chain structure which produces high local concentrations of pyridine groups, independent of the total concentration. By addition of butyl bromide to the polymer in nitromethane, a long chain quaternary ammonium salt is formed which is also water soluble. Its conductance is not sensitive to concentration down to about 0.003 N, after which the conductance rises sharply with further dilution. Dissociation, calculated by the classical Arrhenius method, indicates that a minimum of about 20% of the bromide ions are free, the remainder being associated by Coulomb attraction to the chainlike positive ion. As the dielectric constant of the solvent is decreased by addition of ethanol, the relative amount of free bromide ions decreases. The viscosity of the polyelectrolyte in aqueous or alcoholic solution, when plotted in the conventional way (ηsp/c versus c), approaches infinity at zero concentration instead of approaching a limiting constant linearly. A plot of versus is, however, linear; this behavior is characteristic of strong electrolytes. The coefficient of the square root term in concentration for the polymer is larger, by orders of magnitude, than that for ordinary electrolytes. The coefficient of the linear term in the square root function is about equal to the intrinsic viscosity of the parent polymer.
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TL;DR: In this paper, a polyvinyl pyridine and silver nitrate mixture in alcoholic solution showed that the system behaves like a polyelectrolyte, which has been explained by the structure of the complex that has been known for quite some times.
Abstract: Viscosimetric behaviour of a polyvinyl pyridine and silver nitrate mixture in alcoholic solution showed that the system behaves like a polyelectrolyte. This has been explained by the structure of pyridine-silver complex that has been known for quite some times.
Eine Mischung von Polyvinylpyridin und Silbernitrat in alkoholischer Losung zeigte das viskosimetrische Verhalten eines Polyelektrolyten. Dies wurde mit der seit langerem bekannten Struktur des Pyridin-Silber-Komplexes erklart.
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TL;DR: The machanism proposed by MULLIKEN, on the basis of molecular interaction, for pyridine-iodine interaction in polar medium has been found sufficient to explain the viscosity behaviour of polyvinyl pyridin-Iodine systems.
Abstract: The machanism proposed by MULLIKEN, on the basis of molecular interaction, for pyridine-iodine interaction in polar medium has been found sufficient to explain the viscosity behaviour of polyvinyl pyridine-iodine systems. Transition from the outer to inner complex has been found to be a time dependent process. Separation of polymer out of a solution containing rather excess iodine has been suggested to be due to intermolecular cross-linking. Direct iodination of the pyridine nucleus has been found to take place after quite a long time.
Der von MULLIKEN fur die Wechselwirking von Pyridin und Jod in polarem Medium vorgeschlagene Mechanismus kann such das Viskositatsverhalten der Polyvinylpyridin-Jod-Systeme erklaren. Der Ubergang des auseren zum inneren Komplex ist abhangig von der Zeit. Das Ausfallen der Polymeren aus einer Losung, die Jod im Uberschus enthalt, wird durch eine intermolekulare Vernetzung erklart. Eine direkte Jodierung des Pyridinekerns tritt erst nach langerer Zeit ein.
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