FIXATION OF DISSOLVED AND COLLOIDAL SUBSTANCES ON FIBERS AND SILICON OXIDE SURFACES USING WATER SOLUBLE CROSSLINKED CATIONIC POLYMERS

• The efficiency of water soluble crosslinked cationic polymers (CCP) in the fixation of dissolved and colloidal substances (DCS) onto fibers was investigated. Two different types of CCP were synthesized by dispersion polymerization of acrylamide (AAm) and diallyldimethylammonium chloride (DADMAC), with N,N'-methylene-bis-acrylamide (MBA) as a crosslinker. Relative turbidity, zeta potential and average diameter of the colloidal particles were determined to monitor their performance in DCS fixation. The results indicated that both polymers were able to fix a maximum amount of DCS particles onto fibers around a zero zeta potential, most probably clue to a patch-type flocculation mechanism. The conclusion reached was that flocculation was significant while the particles still had a negative zeta potential. The aggregation mechanism of a fiber-free DCS suspension occurred as Charge neutralisation, changed, by the addition of 10 mM NaCl to a patch-type mechanism. The CCPI consumption necessary to attain a maximum DCS removal was lower than the CCP2 consumption, as ascribed to the higher charge density and higher molecular mass of this polymer. The experiments performed on a quartz crystal microbalance equipment with dissipation (QCM-D) showed that the adsorbed charge and layer thickness of the polymers significantly affected fixation of the DCS particles onto the pre-adsorbed polymer layers on the SiO2 surface.

Nyckelord

crosslinked cationic polymer (CCP)

dissolved and colloidal substances

(DCS)

fixation

turbidity

QCM-D

Sauerbrey equation

hyperbranched polymers

flocculation

adsorption

suspensions

retention

particles

polyelectrolytes

polymerization

polyacrylamide

performance

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ref (ämneskategori)

art (ämneskategori)