Dispersion characteristics of ceramic powders in the application of cationic and anionic polyelectrolytes

Premachandran, R.S.; Malghan, S.G.

doi:10.1016/0032-5910(93)02793-a

Cited by 31 publications

(11 citation statements)

References 12 publications

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“…An increase in d~ of the powder indicated the presence of aggregates (usually a bimodal particle size distribution was also observed under these conditions) and hence unsatisfactory dispersion. All measurements were carried out at a concentration of 5% solids by weight (1 g solid powder in 20 ml solution); the suspension prepared by ultrasonic dispersion and the size distributions measured by HORIBA LA-900, a laser scattering particle size analyzer (Premachandran and Malghan 1994).…”

Section: Methodsmentioning

confidence: 99%

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

Pradip¹,

Premachandran

Malghan

1994

Bull. Mater. Sci.

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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.

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Section: Methodsmentioning

confidence: 99%

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

Pradip¹,

Premachandran

Malghan

1994

Bull. Mater. Sci.

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“…It was chosen to use this alumina and a high solid content, aiming to reproduce real conditions in some industrial applications. [1,2,4,5,[15][16][17][18] For the acrylic polymer with higher molecular weight (158,000 g=mol), it is observed an increase in the viscosity starting from pH 5. Probably, a smaller number of particles is recovered by the polymer and so the steric stabilization is not efficient.…”

Section: Resultsmentioning

confidence: 89%

“…[16][17][18] In this work, it was investigated the effect of the addition of a synthetic polymer (sodium polyacrylate) on the stability of aqueous alumina suspensions with high solid content. Although many works have been made with polyacrilates as stabilizing agents of alumina suspensions, [1,2,4,5,[15][16][17][18] few consider the joint use of several techniques. Viscometric results are correlated with zeta potential and particles size, determined by Fiber Optic Quasi-Elastic Light Scattering (FOQELS) technique.…”

Section: Influence Of Ph and Time On The Stability Of Aqueous Aluminamentioning

confidence: 99%

Influence of pH and Time on the Stability of Aqueous Alumina Suspensions Containing Sodium Polyacrylates: A Revisited Process

Yokosawa

Pandolfelli

Frollini

2002

Journal of Dispersion Science and Technology

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The action of polyacrilates as stabilizing agents in alumina aqueous suspensions has been investigated using viscometry, zeta potential, and photon correlation spectroscopy (PCS) measurements. The present work emphasizes that the study of stability of dispersions using polyelectrolytes must necessarily include several techniques in order to evaluate different physicochemical properties of colloidal suspensions, and thus attain a wide comprehension of the system under analysis. In our point of view, this is necessary because, for instance, while viscosity measurements suggest that there is no advantage in the use of the polyelectrolyte at some pH values, particle size measurement as a function of time shows that the presence of PANa at that pH values allows a longer handling time in suspension processing. Low molecular sodium polyacrylate presented a good performance as a deflocculating agent, because it leads to dispersions of low viscosity, stable at a wide range of pH, and also low variation in particle size as a function of time.

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“…Dispersion studies in aqueous media are less common, with polyelectrolytes being the most widely reported dispersants. [16][17][18][19][20][21][22][23][24][25][26] In such systems, particle stabilisation is very sensitive to changes in the dispersion pH and salt concentration 27 which affect the degree of ionisation and the charge repulsion, responsible for the electrostatic stabilization mechanism operating in these dispersions.…”

Section: Introductionmentioning

confidence: 99%

Controlled structure copolymers for the dispersion of high-performance ceramics in aqueous media

et al. 2001

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Statistical copolymers of a methoxy oligo(ethylene glycol) methacrylate (OEGMA) and either 2-(dimethylamino)ethyl methacrylate (DMA) or methacrylic acid (MAA) have been examined as dispersants for barium titanate powder in water and water-isopropyl alcohol mixtures. The dispersing efficiency of the polymers was assessed using gravitational sedimentation and by measuring the particle size distributions of the dispersed powders by disk centrifuge photosedimentometry (DCP). OEGMA copolymers with MAA were very efficient, causing the mean particle size of the dispersed powder to decrease by an order of magnitude in the presence of dispersant. In contrast, OEGMA-DMA copolymers were completely ineffective. The best MAA copolymers gave higher dispersion efficiency over a wider pH range (pH 1 to 10) compared to a typical commercial dispersant Darvan-C, which was efficient only above pH 7.X-Ray photoelectron spectroscopy, zeta potential measurements, infra red spectroscopy and DCP studies all show that the acid-containing copolymers bind strongly to the barium titanate surface via the carboxylic acid groups resulting in good quality dispersions. There were no changes in the dispersion quality due to desorption of the dispersant even after extensive washing and drying of the copolymer-coated particles. The dried particles showed complete redispersion in water even after washing and drying, again indicating strong binding of the copolymer to the oxide surface.

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Dispersion characteristics of ceramic powders in the application of cationic and anionic polyelectrolytes

Cited by 31 publications

References 12 publications

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

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

Influence of pH and Time on the Stability of Aqueous Alumina Suspensions Containing Sodium Polyacrylates: A Revisited Process

Controlled structure copolymers for the dispersion of high-performance ceramics in aqueous media

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