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The influence of different shapes and size distributions of coating pigments on packing and dewatering / Jae Y. Shin in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 17, N° 6 (11/2020)
[article]
Titre : The influence of different shapes and size distributions of coating pigments on packing and dewatering Type de document : texte imprimé Auteurs : Jae Y. Shin, Auteur ; Hak Lae Lee, Auteur Année de publication : 2020 Article en page(s) : p. 1425–1436 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Caractérisation
Déshydratation
Dispersions et suspensions
Emballages
Formes des particules
Granulométrie
Papier et carton couché
Pigments
Revêtements
RhéologieIndex. décimale : 667.9 Revêtements et enduits Résumé : Particle shape and particle-size distribution (PSD) are important factors for pigment packing and water retention in the pigment coating process, being closely associated with many runnability problems. Diverse experimental investigations on the packing and dewatering of pigment slurries have been made. However, theoretical approaches remain lacking. This paper presents a joint experimental and theoretical analysis of the influence of pigment shape and PSD on pigment packing and dewatering. The relative viscosities of very dilute pigment slurries were measured and used to determine the intrinsic viscosity, based on the Einstein equation. The deviation of pigment shape from spherical caused an increase in viscosity of the slurries. Acicular precipitated calcium carbonates gave lower shape factor values than platy clay particles, which indicated that the needle-like particles could rotate more easily around their long axes under shearing conditions. The packing of pigments, which determines porosity, permeability, light scattering, and mechanical properties, was examined. The packing volumes of nonspherical pigments were estimated based on their respective PSDs, using an algorithm developed for spherical particles, modified with a correction factor. This model is based on the close random-packing volume fraction (∅2p) of particles of uniform size being an independent variable, regardless of their shape. Therefore, it was valid as long as the particles always achieve the same close random-packing volume (∅1p) by sedimentation or tapping. Overall, the effect of the particle shape and PSD on the dewatering and filter-cake permeability (Kf) was analyzed. The dewatering rates were measured with a common pressure filtration method, and the permeability of the filter cakes was obtained by fitting the data to a filtration equation. The particle size and PSD were found to influence the permeability constant, but there was little correlation between the permeability and particle shape. Note de contenu : - MATERIALS AND METHODS : Particle size distribution of pigments and SEM images - Characterization of pigments by viscosity measurement - Sedimentation volume of dispersion - Dewatering rate
- THEORY AND CALCULATION : Model development - New approach
- RESULTS AND DISCUSSION : Particle-size distribution of pigments - Effect of electrolyte on viscosity - Aspect ratio of pigment particles - Sedimentation volume of dispersion by centrifugation - Packing volume fractions of nonspherical particles - Dewatering and permeability of filter cakeDOI : https://doi.org/10.1007/s11998-020-00371-y En ligne : https://link.springer.com/content/pdf/10.1007/s11998-020-00371-y.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34949
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 17, N° 6 (11/2020) . - p. 1425–1436[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 22458 - Périodique Bibliothèque principale Documentaires Disponible Water resistance improvement of paperboard by coating formulations based on nanoscale pigments / Wasin Thitsartarn in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 17, N° 6 (11/2020)
[article]
Titre : Water resistance improvement of paperboard by coating formulations based on nanoscale pigments Type de document : texte imprimé Auteurs : Wasin Thitsartarn, Auteur ; Tunyarut Jinkarn, Auteur Année de publication : 2020 Article en page(s) : p. 1609-1617 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Caractérisation
Cartonnages -- Propriétés mécaniques
Emballages
Enrobage (technologie)
Formulation (Génie chimique)
Hydrophobie
Kaolin
Morphologie (matériaux)
Nanoparticules
Papier et carton couché
Pigments
Résistance à l'humidité:Résistance à l'eau
Rugosité
Surfaces (Physique)
Surfaces -- AnalyseIndex. décimale : 667.9 Revêtements et enduits Résumé : This research assessed how type, particle size, and concentration of pigment in coating formulations influenced water and water vapor barriers of paperboard packaging. Calcium carbonate (CaCO3) and kaolin of micro- and nanosize of 1 and 0.05 µm, respectively, were added to 3% (w/v) gelatinized cassava starch to prepare coating formulations with different pigment concentrations of 5, 15, and 25% (w/v). These were applied on paperboard surfaces using the rod coating technique. Results showed that water resistance of paperboard, evaluated by contact angle (CA) and water absorptiveness (Cobb) were strongly influenced by pigment type (chemistry), particle size and shape, and pigment concentration (coating layer thickness). A hydrophobic surface (CA > 100) was obtained only for the nano-CaCO3 formulation with 25% (w/v) by combined effects of the nanosize scale, the spherical shape, and the hydrophobic surface of CaCO3 particulates. Kaolin nanoparticle coatings produced hydrophilic surfaces (CA ~ 90) with high water absorptiveness, while high concentrations of kaolin microparticle coating slightly improved water and water vapor barriers by compact arrangement of flattened particles. Mechanical strength properties of the paperboard were not significantly affected by coatings, but surface cracking was observed for large particle size or at high pigment concentration due to the increase in pigment/starch ratio. Note de contenu : - MATERIALS AND METHODS : Materials - Coating formulation preparation - Coating process and conditioning - Physical properties and surface characterization - Water resistance and water vapor analysis - Mechanical property measurement
- RESULTS AND DISCUSSION : Coating weight and coating layer thickness - Surface roughness and morphology - Water resistance and water vapor barrier - Mechanical property analysisDOI : https://doi.org/10.1007/s11998-020-00386-5 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-020-00386-5.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34964
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 17, N° 6 (11/2020) . - p. 1609-1617[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 22458 - Périodique Bibliothèque principale Documentaires Disponible