Electrokinetic behaviour and dispersion characteristics of ceramic powders with cationic and anionic polyelectrolytes

Abstract

Three different ceramic powders, viz. alumina, zirconia and silicon nitride were dispersed using two polyelectrolytes, one cationic (Betz 1190) and the other anionic (Darvan-C). All powders examined during the study could be well dispersed only under conditions of polymer dosage and pH such that the working pH is at least 2 pH units away from the primp of the powder-dispersant combination. The shift in the isoeleetrie point (IEP) of the powders were determined through electro-acoustic measurements on 1% volume suspensions. Specific free energy of interaction were also computed using a model based on the electrical double layer theory of surfactant absorption.

Electrokinetics, Adsorption and Floatation Studies of Sphalerite Using Di (2-Ethyl Hexyl) Phosphoric Acid

“…In other words, the strong specific adsorption of D 2 EHPA molecules and ions could account for the increase in negative value of zeta potential. These observations are in agreement with the results of the effect of adsorption of anionic molecules on the zeta potential reported by many workers [20,21].…”

Surface Chemical Studies on the Competitive Adsorption of Poly(acrylic acid) and Poly(vinyl alcohol) onto Alumina

“…An attractive feature of these polymeric reagents is that they confer stability both by electrostatic and steric forces of interaction. A considerable amount of work has been reported in the literature on the application of poly(acrylic acid) (PAA) as a dispersant for ceramic oxides and nitrides and its adsorption characteristics on these substrates (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11). Similarly, several reports on the adsorption of PVA, a typical binder, onto various oxides are available (12)(13)(14)(15)(16).…”

Surface chemical properties and selective flocculation studies on alumina and silica suspensions in the presence of xanthan gum

“…The addition of XG, not only results in a decrease of the positive zeta potential values of alumina, but also charge reversal takes place, with the magnitude of the negative zeta potential values increasing with the increase in the polymer concentration, as a function of pH. The shifts in the IEP of alumina towards more acidic region and the increase in the electronegative charge of alumina with the addition of anionic polymers have been observed by many workers (Das and Somasundaran, 2001;Santhiya et al, 1999;Pradip et al, 1994).…”