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Assessment of various analytical techniques on naturally weathered paints as a predictor of long-term gloss retention for waterborne acrylic architectural paints / Matthew S. Gebhard in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 3, N° 1 (01/2006)
[article]
Titre : Assessment of various analytical techniques on naturally weathered paints as a predictor of long-term gloss retention for waterborne acrylic architectural paints Type de document : texte imprimé Auteurs : Matthew S. Gebhard, Auteur ; Michael B. Clark, Auteur ; Kenneth. F. Willey, Auteur ; Robert F. Antrim, Auteur ; Francis V. Acholla, Auteur ; John B. Newman, Auteur ; Kristin Weidemaier, Auteur Année de publication : 2006 Article en page(s) : p. 15-27 Note générale : bibliogr. Langues : Américain (ame) Catégories : Colloides
Durée de vie (Ingénierie)
Essais accélérés (technologie)
Formulation (Génie chimique)
Latex
Polyacryliques
Revêtements -- Analyse:Peinture -- Analyse
Revêtements décoratifs:Peinture décorative
Revêtements en bâtiment -- Détérioration:Peinture en bâtiment -- Détérioration
Revêtements en phase aqueuse:Peinture en phase aqueuse
Revêtements organiquesIndex. décimale : 667.6 Peintures Résumé : Gloss retention of waterborne acrylic architectural paints is one of many properties defining exterior durability. Assessing gloss retention is a time consuming process, and accelerated weathering protocols (Weather-Ometer®) typically have poor correlation with natural exposures for this class of paints. The recent development of new analytical techniques for assessing automotive paint durability raises the possibility of detecting subtle changes in short-term natural exposures that would be predictive of long-term gloss retention; however, extension to architectural paints has yet to be demonstrated. To test the concept, seven paints based on different aqueous emulsion polymers were exposed to natural weathering at the same time for 12 weeks at the Paint Quality Institute (PQI) test site, and were then examined using scanning probe microscopy, optical profilometry, chemiluminescence, XPS, and FTIR. These paints were also exposed for 1000 hr in a Weather-Ometer (WOM). Scanning probe microscopy, optical profilometry, chemiluminescence, FTIR, and the WOM results all showed poor correlation with 96-week natural exposure at the PQI test site. The lack of correlation for the WOM results emphasizes the crucial importance of using natural weathering to assess gloss retention. In contrast, the XPS shows some promise for qualitatively predicting subsequent gloss loss and appears worthy of further exploration. As employed here, the XPS was used to monitor the ratio of pigment (Al, Si, and Ti) to carbon coming from the TiO2 in the top few nanometers of the paint surface. A correlation (R2 = 0.731) was found between gloss retention after 96 weeks and the change (2 versus 12 weeks of exposure) in pigment to carbon ratio. This correlation is probably sufficient to rank a series of paints and allow for an assessment against well-established controls. While promising, XPS has some issues. Surface contamination, equipment expense, the considerable expertise required, and precision make utility for screening less than ideal. Note de contenu : - GLOSS RETENTION
- ALTERNATIVE APPROACH TO PREDICTING GLOSS RETENTION
- APPROPRIATE ANALYTICAL METHODS FOR ASSESSING COATING DEGRADATION : Scanning probe microscopy - Optical profilometry - Chemiluminescence - Photoacoustic spectroscopy - X-ray photoelectron spectroscopy
- ASSESSMENT PROTOCOL
- EXPERIMENTAL DETAILS : Paint formulations
- Gloss measurements - Scanning probe microscopy - Optical profilometry - Chemiluminescence - Photoacoustic spectra - X-ray photoelectron spectroscopy
- RESULTS AND DISCUSSION : Gloss - Weather-ometer - Surface topography - Chemiluminescence - PAS - XPS
- Table 1 : Paint formulatio used to prepara paints using the seven emulsion polymers
- Table 2 : Initial 60° gloss values for the paints based on the seven latex emulsion polymers
- Table 3 : PAS-FTIR parametersPermalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3709
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 3, N° 1 (01/2006) . - p. 15-27[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 003762 - Périodique Bibliothèque principale Documentaires Disponible A lasting design / Matthew S. Gebhard in POLYMERS PAINT COLOUR JOURNAL - PPCJ, Vol. 193, N° 4460 (01/2003)
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Titre : A lasting design Type de document : texte imprimé Auteurs : Matthew S. Gebhard, Auteur Année de publication : 2003 Article en page(s) : p. 24-28 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Formulation (Génie chimique)
Latex
Milieu hétérogène
Polymères
Revêtements en phase aqueuse:Peinture en phase aqueuseIndex. décimale : 667.9 Revêtements et enduits Résumé : Pressure to further reduce VOC emissions has had a negative impact on the exterior durability characteristics of emulsion polymer coatings. But heterogeneous polymer morphologies are able to address these shortcomings.
Over the years the optimisation of waterborne emulsion polymers has resulted in waterborne coatings with excellent exterior durability and significantly reduced solvent emissions versus solventborne coatings.
In recent years, pressure to further reduce emissions has necessitated the use of softer polymer compositions that can negatively impact gloss and tint retention, and dirt pick up resistance. The use of heterogeneous polymer morphologies are addressing these short comings. However care must still be taken not to affect paint durability.
The development of low solvent emission thickeners and mildewcides has allowed further reduction in paint emissions.Note de contenu : - In the beginning
- Low VOC formulation issues
- Homogeneous polymer controls
- Heterogeneous polymers
- TABLE : 1. Experimental paint formulation
- FIGURES : 1. % 60 degree gloss for homogeneous latex polymers at various - 2. Delta b' for homogeneous latex polymers at various Tg'S - 3. Delta L' for homogeneous latex polymers at various Tg'S - 4. % 60 degree gloss for heterogeneous latex polymers - 5. Delta b' for heterogeneous latex polymers - 6. Delta L' for heterogeneous latex polymersPermalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=27964
in POLYMERS PAINT COLOUR JOURNAL - PPCJ > Vol. 193, N° 4460 (01/2003) . - p. 24-28[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 000317 - Périodique Bibliothèque principale Documentaires Disponible Reduction of air bubbles in spray-applied coatings / Matthew S. Gebhard in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 66, N° 830 (03/1994)
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Titre : Reduction of air bubbles in spray-applied coatings Type de document : texte imprimé Auteurs : Matthew S. Gebhard, Auteur ; L. E. Scriven, Auteur Année de publication : 1994 Article en page(s) : p. 27-39 Note générale : Bibliogr. Langues : Américain (ame) Tags : Peinturage Pulvérisation 'Bulle air' 'Peinture eau' Défaut 'Etude expérimentale' 'Photographie rapide' 'Technique vidéo' Index. décimale : 667.9 Revêtements et enduits Résumé : Microfoam (i.e., tiny (10 μm) air bubbles) in spray-applied coatings is a frequently encountered problem which may be aggravated in water-based coatings. This paper describes recent work to understand the dynamics of the microfoam formation and dissipation process. The data indicate that the majority of microfoam does not form by the splashing of atomized drops on the building liquid film. In fact, the atomized drops arrive at the substrate with numerous air bubbles, and poor atomization is observed to be a key to the problem. It is found that air bubbles dissipate through a dissolution mechanism and not the generally accepted rise and rupture mechanism. The dissolution is driven by surface tension and is mediated by diffusion through the liquid. The experimental data are found to agree with the Epstein and Plesset model, with lower diffusion coefficients, lower air solubility, and lower surface tension reducing the dissolution rate. This study has led to a novel solution to the problem and involves using carbon dioxide (CO2) as the driving gas instead of air. It is found that this leads to a significant reduction in entrapped air in conventional, high volume low pressure (HVLP), and air-assisted airless spray techniques. This approach is found to work because of the much higher solubility of CO2 in water versus air in water. Note de contenu : - EXPERIMENTAL : High-speed video microscopy - High-speed photography - Dissolution measurements - Determination of diffusion coefficients - Spray applications using CO2 and air
- RESULTS AND ANALYSIS : High-speed video microscopy - High-speed photography - Microfoam dissipation in spray-applied coatings - Dissolution measurements - Determination of diffusion coefficients - Spray applications using CO2 and airPermalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18606
in JOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 66, N° 830 (03/1994) . - p. 27-39[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 003464 - Périodique Bibliothèque principale Documentaires Disponible 003477 - Périodique Bibliothèque principale Documentaires Exclu du prêt