. 66,2658 (1988). Phase-sensitive tensammetry is shown to be a convenient and useful way to analyse polyacrylamides and associated derivatives (pams) in dilute aqueous solutions. Standard curves were obtained with ranges varying from 9 to 25 ppm and limits of detection varying from 0.7 to 2 ppm. Ways to change the range and sensitivity are discussed and demonstrated. Typical interferences and their effects are tabulated, and the analysis of pams in coal washings is discussed. The analysis of certain mixtures of polyacrylarnides is shown to be possible. Chem. 66, 2658Chem. 66, (1988. On a dkmontrt que la tensamttrie sensible la phase est une mtthode approprike et utile dlanalyser des solutions aqueuses dilutes de polyacrylamides et des dtrivts qui leur sont associks (pams). On a obtenu des courbes standards pour des concentrations allant de 9 a 25 ppm et des L.D.D allant de 0,7 2 ppm. On discute des mkthodes qui permettraient de modifier la limite de dktection ainsi que la sensibilitk et on en fait la dtmonstration. On prtsente un tableau rksumant les interfkrences typiques ainsi que leurs effets et on discute de l'analyse des pams dans les lavages de charbon. On dkmontre que l'analyse de certains mklanges de polyacrylamides est possible.[Traduit par la revue]
. Can. J. Chem. 65, 557 (1987). The use of polarographic maximum suppression methods for determining polyacrylamides and polyacrylic acid-based polymers was investigated. Using the oxygen, co2+, and H~~+ maxima these polymers were determined at the low ppm level. The effectiveness of polymers as maximum suppressors was dependent on the charge of the polymer and that of the electrode at the potential at which the polarographic wave occurred. The maximum suppression of various binary mixtures of polyacrylamides indicated that in some mixtures suppression was additive while in other mixtures, particularly those containing both anionic and cationic polymers, the suppression was greatly reduced. Aqueous extracts of chosen coals contained various interfering substances which could be removed most efficiently using Sephadex G-75, although this resin was only compatible with anionic and neutral polymers. BYRON R. WENTZELL, TRUIS SMITH-PALMER et JOHN C. DONINI. Can. J. Chem. 65,557 (1987). On a CtudiC la possibilitt d'utiliser les mCthodes de suppression polarographiques maximales pour dCterminer les polyacrylamides ainsi que les polymkres dCrivCs de l'acide polyacrylique. En utilisant les maxima de l'oxygkne, du co2+ et du Hg2+, on a dCtermint ces polymkres 2 des niveaux de ppm. L'efficacitC des polyrnkres comme suppresseurs maximaux dCpend de la charge du polymkre ainsi que de celle de 1'Clectrode au potentiel de laquelle la vague polarographique se produit. La suppression maximale de divers mtlanges binaires de polyacrylamides indique que, dans quelques mClanges, la suppression est additive; toutefois, dans d'autres mClanges et particulikrement dans ceux contenant h la fois des polymeres anioniques et des polymbres cationiques, la suppression est fortement rkduite. Les extraits aqueux de charbons choisis contiennent diverses substances qui internrent et qui peuvent &tre CliminCes efficacement en utilisant du Sephadex G-75; toutefois, cette k i n e n'est compatible qu'avec les polymkres anioniques ou neutres.[Traduit par la revue]
ABSTRACT:The flocculation of a thickener feed using three cationic polyacrylamide copolymers of high molar mass and different charge densities was studied at three pHs in washery water. The binding capacities were very dependent on pH but only slightly dependent on the polymeric charge density. The reverse was true for the settling rates. At pH 7, all three polymers were equally effective at clarifying the suspensions, but there were marked differences at pH 4 and 9. For the polymers of highest charge density, reducing the pH increased their effectiveness; for the polymer of lower charge density, changing the pH had little effect on the residual turbidity.
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