Effect of addition of cellulose nanocrystals to wood coatings on color changes and surface roughness due to accelerated weathering / Vahe Vardanyan in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 12, N° 2 (03/2015)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 12, N° 2 (03/2015) . - p. 247-258 Titre : Effect of addition of cellulose nanocrystals to wood coatings on color changes and surface roughness due to accelerated weathering Type de document : texte imprimé Auteurs : Vahe Vardanyan, Auteur ; Tigran Galstian, Auteur ; Bernard Riedl, Auteur Année de publication : 2015 Article en page(s) : p. 247-258 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Bois Cellulose La cellulose est un glucide constitué d'une chaîne linéaire de molécules de D-Glucose (entre 200 et 14 000) et principal constituant des végétaux et en particulier de la paroi de leurs cellules. Copolymère uréthane acrylate Couleurs -- Stabilité Cristaux Essais accélérés (technologie) Formulation (Génie chimique) Nanoparticules Revêtements -- Propriétés mécaniques Revêtements en phase aqueuse -- Séchage sous rayonnement ultraviolet Revêtements:Peinture Rugosité Vernis en phase aqueuse Index. décimale : 667.9 Revêtements et enduits Résumé : An aqueous ultraviolet-cured polyurethane acrylate transparent resin formulation was submitted for accelerated weathering for 1200 h, on wood substrate, with and without added cellulose nanocrystals (CNC) in coatings. In previous work, addition of CNC improved several mechanical properties of the coating without changing other desirable properties such as optical transparency, color, and gloss. Measurements of nanoroughness were performed with atomic force microscopy on coated weathered surfaces. Surface roughness increased 8–10 times following weathering. Color and lightness measurements were done periodically, each 100 h, during the weathering. Testing was also done for a multilayer coating, varnish on an opaque coating on wood. Addition of unmodified, i.e., hydrophilic, CNC to transparent coatings did not downgrade the color stability of coatings but actually increased their color stability, while the effect on hydrophobically modified CNC was somewhat less. Thus, addition of CNC to coatings not only increases mechanical properties but also increases color stability of coated wood. Note de contenu : - INTRODUCTION AND LITERATURE REVIEW : Effect of UV/humidity on color wood surfaces - Effect of UV/humidity on color of coated wood - Effect of addition of nanoparticles in coatings - EXPERIMENTAL : Varnish formulation - Wood samples preparation - Accelerated weathering - RESULTS AND DISCUSSION : Wheathering of varnishes with added CNC : color and appearance - Wheathering of paints with added CNC : color and appearance - Changes in roughness following wheathering : AFM profiles DOI : 10.1007/s11998-014-9634-3 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-014-9634-3.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=23644 [article]

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Mechanical properties of UV-waterborne varnishes reinforced by cellulose nanocrystals / Vahe Vardanyan in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 11, N° 6 (11/2014)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 11, N° 6 (11/2014) . - p. 841-852 Titre : Mechanical properties of UV-waterborne varnishes reinforced by cellulose nanocrystals Type de document : texte imprimé Auteurs : Vahe Vardanyan, Auteur ; Bouddah Poaty, Auteur ; Gregory Chauve, Auteur ; Véronic Landry, Auteur ; Tigran Galstian, Auteur ; Bernard Riedl, Auteur Année de publication : 2014 Article en page(s) : p. 841-852 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cellulose La cellulose est un glucide constitué d'une chaîne linéaire de molécules de D-Glucose (entre 200 et 14 000) et principal constituant des végétaux et en particulier de la paroi de leurs cellules. Dispersions et suspensions Matériaux nanocristallins Polyuréthanes Traîtements de surface Vernis -- Propriétés mécaniques Vernis en phase aqueuse Index. décimale : 667.9 Revêtements et enduits Résumé : There are many instances in the literature of nanocellulose-thermoplastic composites, but there are few studies on coatings reinforced by cellulose nanocrystals (CNCs). The overall objective of this research was to develop organic nanoparticles-reinforced UV-water-based coatings for wood applications and to study the effect, mainly on wear properties, of the final composite coatings. CNC was mixed in the varnishes to improve the mechanical properties of the coatings. One of the key aspects in the technology of nanocomposites remains the dispersion of the nanoparticles within the matrix as well as its affinity with the matrix. To quantify the dispersion, efficient methods of characterization are needed in order to reveal the nanosized particles. In this article, a novel characterization method based on atomic force microscopy was employed to characterize such nanocomposite coatings, by measuring surface nanoroughness, which is clearly correlated with quality of dispersion and mechanical properties. CNC was modified by either alkyl quaternary ammonium bromides or acryloyl chloride. The mechanical properties (abrasion and scratch resistances, hardness and adhesion) were analyzed and compared to the reference varnish without nanoparticles. The modified CNC addition in UV-water-based coatings results in an approximately 30–40% increase in wear resistance (abrasion and scratch), without any loss of appearance. Note de contenu : - INTRODUCTION : Waterborne coating - CNC - CNC dispersion characterization - MATERIALS AND EXPERIMENTAL PROCEDURE : The composition of the formulation - CNC - Surface modification of cellulose nanocrystals - Preparation of formulations and samples - Experimental methods - RESULTS AND DISCUSSION : Coating with unmodified CNC - Effect of surface modification of CNC - Mechanical properties of coatings DOI : 10.1007/s11998-014-9598-3 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-014-9598-3.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=22308 [article]

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