Dilute THF-solutions of different fractions of polymers of methyl, ethyl, n-propyl, n-, i-and t-butyl, n-hexyl, 2-ethylhexyl, and lauryl acrylate, prepared by solution polymerization in benzene, were studied by light scattering and viscosity methods. Poly(acry1ic acid) was examined in dioxane. For the different polyacrylic esters the [q]-M,-relations were established and the dependence of the radius of gyration (r:) on the molecular weight was determined.
ZUSAMMENFASSUNG:Methyl-, Ethyl-, n-Propyl-, n-, i-und t-Butyl-, n-Hexyl-, 2-Ethylhexyl-und Laurylacrylat wurden in Benzol polymerisiert. Verdiinnte Wsungen in THF einzelner Fraktionen dieser Polymeren wurden durch Lichtstreuungs-und Viskositatsmessungen untersucht. Polyacrylsaure wurde in Dioxan gemessen.Fur die verschiedenen Polyacrylester und Polyacrylsaure wird die Molekulargewichtsabhangigkeit des Staudinger-Index [q] und des Tragheitsradius (r: ) angegeben.
According to existing well-known theories unperturbed dimensions can be calculated from light scattering and viscosity measurements. The statistical segment A, proposed by Kuhn is a good measure for the flexibility of an unperturbed polymer coil. With the data reported in part I of the dependence of the radius of gyration and the Staudinger index, respectively, on the molecular weight, A, was calculated for nine polyacrylic esters and poly(acry1ic acid). Poly(acry1ic acid) with A, = 13,6 A has the highest flexibility. The stiffness of the polymer chain is increased with growing Cnumber of the alcohol. Branching in the alcohol further increases the stiffness of the polymer chain.
ZUSAMMENFASSUNGAus Lichtstreuungs-und Viskositatsmessungen werden nach bekannten Theorien aus der Abhangigkeit des Staudinger-Index und des Tragheitsradius vom Molekulargewicht ungestorte Dimensionen berechnet. Das statistische Fadenelement nach Kuhn A,,, ist ein gutes MaB zur Beschreibung der Flexibilitat einer ungestdrten Polymerkette. Es wurde fur neun Polyacrylate und Polyacrylsaure berechnet. Polyacrylsaure mit A, = 13,6 A besitzt die hochste Flexibilitat. Mit steigender C-Anzahl im Alkoholrest nimmt die Flexibilitat der Polymerkette ab. Verzweigungen im Alkoholrest bewirken eine weitere Versteifung der Polymerkette.
The high diastereoselectivity of the Grignard addition to various α‐triazolyl ketones or α‐alkoxy‐α‐triazolyl ketones such as (I), (IV) or (VII) can be rationalized via postulated intermediate chelate complexes.
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