SynopsisExperimental results on pressure losses of flows of dilute polymer solutions through porous media are summarized. The polymer products employed in this study consisted of partially hydrolyzed polyacrylamides (HPAM) with different degrees of hydrolysis. The effect of the hydrolysis on the pressure drop is investigated in a porous media test section designed to minimize polymer degradation. The investigations were carried out for various solvent conditions, and it is shown that the maximum increase in pressure drop is mainly dependent on the molecular weight of the polymers. The onset of the polymer action is measured for various fluid and solvent properties. Particular attention is given to measurements near &conditions. The results stress the importance of the solvent properties on the actions of the polymers and on the resultant pressure drop for porous media flows. The addition of salt ions to solutions of partially hydrolyzed polyacrylamides yields onset behavior previously observed for nonionic polymers. The differences measured between various solvent properties can be explained by the actual hydrodynamic molecule dimensions for a given molecular weight and polymer concentration. To quantify the influences of the solvent properties on the polymers, measurements were carried out in aqueous solutions for various pH values and therefore at various degrees of dissociation. The importance of separating polymer effects caused by their linear dimension in the solution from those that are introduced by an increase in solvent viscosity is shown. Measurements were performed to quantify the effects of solvent viscosity on the polymer action and to separate these effects from those due to changes in molecule dimensions. The implications of the present results are stressed in connection with applications of polymer solutions in tertiary oil recovery, and the positive features of the molecule actions on flow in such applications are described.
ZUSAMMENFASSUNG:Aus a-, / Iund y-Aminosauren und Acryloylchlorid wurde eine Reihe von Monomeren mit sauren Gruppen erhalten. Ihre Einfuhrung in einen stark basischen, makroporosen Anionenaustauscher (Lewatit@) und anschliefiende Polymerisation fuhrte zu Schlangenkafig-Polyelektrolyten, die durch die restliche Anionenaustauschkapazitat, die neuentstandene Kationenaustauschkapazitat und die Menge an immobilisierten Grundbausteinen charakterisiert wurden.
SUMMARY:A series of monomers with acidic groups were synthesized by the reaction of a-, p-and y-amino acids and acryloyl chloride. The corresponding snake-cage polyelectrolytes were obtained by charging a strongly basic, macroporous anion exchanger (Lewatit @) with these monomers and subsequent polymerization. The snake-cage systems were characterized by the residual anion exchange capacity, the newly-formed cation exchange capacity, and the amount of immobilized monomeric units.
ZUSAMMENFASSUNG :Es wird eine Methode zur quantitativen Bestimmung von Vinylacetat in Copolymeren beschrieben. Sie beruht auf der Eliminierung von Essigsaure in einer Schmelze von p-Toluolsulfonsiiure (pTss) bei 160 "C. Die abgespaltene Essigsiiure wird neben der pTss potentiometrisch titriert. Die Methode ist anwendbar fiir Gehalte
Die kürzlich für die quantitative Bestimmung von Vinylacetat in Copolymeren beschriebene Methode wird auf andere Vinylester übertragen. Es wurden Vinylacetat‐Vinylpropionat‐Copolymere in Dispersion und fester Form mit Vinylacetatgehalten zwischen 0 und 100% untersucht. Die Summe der in geschmolzener p‐Toluolsulfonsäure abgespaltenen aliphatischen Säuren wird potentiometrisch bestimmt. Die Identifizierung der Säuren und die Bestimmung der Mengenverhältnisse erfolgt durch Gaschromatographie.
rerseits erweist sich die Reassoziationskinetik nach Dissoziation und Desaktivierung bei pH<3 als langsam im Vergleich zur Renaturierungskinetik.
Glycerinaldehyd-3-phosphat-Dehydrogenase liegt unterden Standardbedingungen des enzymatischen Tests partiell dissoziiert vor ; die Dissoziation fuhrt konzentrationsabhlngig sowohl zum Dimeren als auch zum Monomeren, so da5 anzunehmen ist, da5 hier die Untereinheit zumindest partiell aktiv ist.
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