Yield stress measurements and microstructure of colloidal kaolin powders clusterized and dispersed in different liquids

Beruto, D.; Lagazzo, Alberto; Botter, R.; Grillo, Roberto

doi:10.1016/j.partic.2009.06.011

Cited by 8 publications

(14 citation statements)

References 15 publications

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“…Apart from kaolin powders A-D, which have already been used as dispersed nano-particles in liquid rubber, paraffin oil and water (Beruto et al, 2009), kaolin powder E is a new commercial kaolin, with the same percentage of particles in the size range of 1-2 m as kaolin powder A, but has different specific surface area. Table 1 lists the specific surface area (m 2 /g), the percentage of particles between 1 and 2 m and the isoeletric point from data given by different producers.…”

Section: Methodsmentioning

confidence: 99%

“…It would thus be desirable to study the micro-scale mechanism of the mixing of fillers in the rubber. Unfortunately this is a difficult task, though some clues might have been obtained through rheological studies of liquid systems consisting of the same kind of solid fillers dispersed in liquid media, as shown in a recent paper (Beruto, Lagazzo, Botter, & Grillo, 2009), on the same kaolin powders as investigated here, while dispersed in water, in paraffin oil and in liquid rubber to form colloidal dispersions that obey the pseudo-plastic model (Barnes, 2000). These authors measured the dependence of the yield stress • in quasi-static conditions on the volume fraction Â of the dispersed particles, and on the ground of another paper (Beruto, Botter, & Converti, 2008), they confirmed that this parameter is linked to the tendency of the kaolin powders to form a chain-like aggregates.…”

Section: Introductionmentioning

confidence: 99%

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A rheological method for selecting nano-kaolin powder as filler in SBR rubber

Lagazzo

Lenzi²,

Botter

et al. 2010

Particuology

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A rheological method for selecting nano-kaolin powder as filler in SBR rubber

Lagazzo

Lenzi²,

Botter

et al. 2010

Particuology

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“…[15][16][17][18][19] and references therein. The role of the microstructure that can lead to effects like aging (or re-juvenation [20]), as well as concepts like shear-thinning or -thickening and their relation to the present study are not detailed further.…”

Section: Practical Examplesmentioning

confidence: 99%

The critical-state yield stress (termination locus) of adhesive powders from a single numerical experiment

Luding¹,

Alonso‐Marroquín

2011

Granular Matter

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Dry granular materials in a split-bottom ring shear cell geometry show wide shear bands under slow, quasistatic, large deformation. This system is studied in the presence of contact adhesion, using the discrete element method (DEM). Several continuum fields like the density, the deformation gradient and the stress tensor are computed locally and are analyzed with the goal to formulate objective constitutive relations for the flow behavior of cohesive powders. From a single simulation only, by applying time-and (local) space-averaging, and focusing on the regions of the system that experienced considerable deformations, the critical-state yield stress (termination locus) can be obtained. It is close to linear, for non-cohesive granular materials, and nonlinear with peculiar pressure dependence, for adhesive powdersdue to the nonlinear dependence of the contact adhesion on the confining forces. The contact model is simplified and possibly will need refinements and additional effects in order to resemble realistic powders. However, the promising method of how to obtain a critical-state yield stress from a single numerical test of one material is generally applicable and waits for calibration and validation.

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“…When the 20% of solid volume fraction of the lime powders, are dispersed in liquid paraffin, a colloidal system characterised by a percolate network, is formed [28,29]. The percolate network is a dynamic structure due to bonds between microstructure units [19,29,30].…”

Section: Resultsmentioning

confidence: 99%

“…The percolate network is a dynamic structure due to bonds between microstructure units [19,29,30]. Since the paraffin molecules do not contain aromatic and naphthenic groups, only two forces are present: the attractive van der Waals forces and the steric repulsive forces at the solidliquid interfaces formed between CaO surfaces and paraffin molecules.…”

Section: Resultsmentioning

confidence: 99%

Immersion Calorimetric Method to Study Lime Surfaces Impurities and Particles Aggregate Morphologies

Beruto

Botter

Lagazzo

2015

Advances in Ceramic Science and Engineering

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A new application of the immersion calorimetric method has been developed to study the specific wetting heat of colloidal lime particles dispersed in liquid paraffin. This method, combined with SEM, EDAX and Hg porosimeter measurements, allows to evaluate the effects of the limestone impurities on the shape of the limes particles aggregates. These morphologies are dependent upon the limestone thermal decomposition conditions and upon the impurities of the limestone rocks. The impurities that influence the shape of individual and agglomerated limes particle, according to this study, are SiO2 and Al2O3, in percentages at least of 0.24 wt% and 0.12 wt% respectively. At the temperature of 1300°C these oxides, combined with CaO, they can form a viscous liquid-like phase that changes dramatically the shape of the lime particles. Rhombohedra or irregular grains of about 0.4-3 μm, change their shape into flat and large crystallites of 10×10×1 μm. For the platelet microstructure, the specific exothermic heat ξ [J/m 2 ] is equal to -8 ±2 J/m 2 , while, for the aggregates of rhombohedric grains, is in the average -0.9 ±0.1 J/m 2 .From a technological point of view this study can be used to optimise the thermal decomposition conditions of limestone rocks with a proper content of silica and alumina oxides.

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Yield stress measurements and microstructure of colloidal kaolin powders clusterized and dispersed in different liquids

Cited by 8 publications

References 15 publications

A rheological method for selecting nano-kaolin powder as filler in SBR rubber

A rheological method for selecting nano-kaolin powder as filler in SBR rubber

The critical-state yield stress (termination locus) of adhesive powders from a single numerical experiment

Immersion Calorimetric Method to Study Lime Surfaces Impurities and Particles Aggregate Morphologies

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