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Auteur Eric Byrd |
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Ajouter le résultat dans votre panier Affiner la rechercheAccelerated UV weathering of polymeric systems : recent innovations and new perspectives / Joannie W. Chin in COATINGS TECH, Vol. 3, N° 2 (02/2006)
Titre : Accelerated UV weathering of polymeric systems : recent innovations and new perspectives Type de document : texte imprimé Auteurs : Joannie W. Chin, Auteur ; Tinh Nguyen, Auteur ; Xiaohong Gu, Auteur ; Eric Byrd, Auteur ; Jonathan Martin, Auteur Année de publication : 2006 Article en page(s) : p. 20-26 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 667.9 Revêtements et enduits Résumé : Polymeric materials used in an outdoor environment are subjected to a wide variety of environmental factors, including solar ultraviolet (UV) radiation, temperature, and moisture, in a process known as weathering. Understanding the factors that govern the weathering performance of commercial polymeric materials has great practical importance, as does the ability to relate laboratory performance of a polymeric system to its performance in the field. At present, the full potential of these materials is inhibited by the absence of a methodology for accurately predicting their service life during exposure in their end-use environments. A reliability-based methodology utilizing total effective dosage as an exposure metric has been proposed as an alternative to the conventional methodology for carrying out laboratory and outdoor weathering studies. The use of this proposed methodology involves not only a shift in paradigm but also in the way that laboratory and outdoor weathering experiments are carried out. The concepts of reciprocity and additivity, which were first introduced by the photographic community and then studied by the medical and biological communities, are also proposed as models for synthetic polymeric systems. En ligne : https://drive.google.com/file/d/1sdM_jq9cpGhaWi6mm-LpkVhp6zk44N5p/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5491
in COATINGS TECH > Vol. 3, N° 2 (02/2006) . - p. 20-26[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 005876 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Degradation modes of crosslinked coatings exposed to photolytic environment Type de document : texte imprimé Auteurs : Tinh Nguyen, Auteur ; Xiaohong Gu, Auteur ; Mark R. VanLandingham, Auteur ; Eric Byrd, Auteur ; Rose Ann Ryntz, Auteur ; Jonathan W. Martin, Auteur Année de publication : 2013 Article en page(s) : p. 1-14 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Fourier, Spectroscopie infrarouge à transformée de
Microscopie à force atomique
Photochimie
Photodétérioration
Polymères réticulés
Revêtements -- Détérioration
Revêtements -- Effets du rayonnement ultravioletIndex. décimale : 667.9 Revêtements et enduits Résumé : The objective of this study is to assess the degradation modes of crosslinked coatings exposed to photolytic environments. Three model crosslinked coatings were exposed in various ultraviolet environments. Atomic force microscopy and Fourier transform infrared spectroscopy were used in following nanoscale physical and chemical degradation during exposures. Results indicated that photodegradation of crosslinked coatings is a spatially localized (inhomogeneous) process in which nanometer-sized pits are initially formed; these pits deepen and enlarge with exposure. A conceptual model is proposed to explain the inhomogeneous degradation mode. The model proposes that nanosize “hydrophilic” domains are dispersed randomly with the highly crosslinked units. These hydrophilic domains, which are energetically preferred, comprise polar, unreacted and partially polymerized molecules, chromophores, and other additives. Photodegradation initiates at degradation-susceptible hydrophilic domains spreading to surrounding areas contiguous with the initiation site. Note de contenu : - EXPERIMENTAL PROCEDURES : Materials and sample preparation - exposures and apparatus - Degradation measurements
- RESULTS AND DISCUSSION : Amine-cured epoxy - Acrylic urethane - Acrylic melamine
- CONCEPTUAL MODEL FOR THE INHOMOGENEOUS DEGRADATIONDOI : 10.1007/s11998-012-9455-1 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-012-9455-1.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=17467
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 10, N° 1 (01/2013) . - p. 1-14[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 14636 - Périodique Bibliothèque principale Documentaires Disponible 15124 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Microstructure and morphology of amine-cured epoxy coatings before and after outdoor exposures - an AFM study Type de document : texte imprimé Auteurs : Xiaohong Gu, Auteur ; Y. C. Jean, Auteur ; Derek L. Ho, Auteur ; Jonathan W. Martin, Auteur ; Eric Byrd, Auteur ; Li-Piin Sung, Auteur ; Aziz Rezig, Auteur ; Joan Jasmin, Auteur ; Bouchra Kidah, Auteur ; David Martin, Auteur ; Mounina Oudina, Auteur ; Tinh Nguyen, Auteur Année de publication : 2005 Article en page(s) : p. 547-556 Note générale : Bibliogr. Langues : Américain (ame) Tags : Dégradation photooxydante photochimique Propriété chimique Etude expérimentale Diffusion neutron centrale Microscopie force atomique Résistance intempérie Méthode analyse Durabilité Epoxyde résine Structure surface Temps exposition Relation mise en oeuvre propriété Amine Durcissement(matière plastique) Vieillissement produit Matériau revêtement Morphologie Microstructure Index. décimale : 667.9 Revêtements et enduits Résumé : Atomic force microscopy (AFM) has been used to study the morphology and microstructure of an amine-cured epoxy before and after outdoor exposure. Measurements were made from samples prepared in an essentially CO2-free, H2O-free glove box and from samples prepared in ambient conditions. For those prepared in a CO2-free glove box, AFM imaging was conducted on (1) an unexposed air/coating surface, (2) an unexposed coating bulk, (3) an unexposed coating/substrate interface, and (4) a field exposed air/coating surface. For samples prepared in ambient conditions, only the unexposed air/coating surface was investigated. The same regions of the exposed samples were scanned periodically by the AFM to monitor changes in the surface morphology of the coating as UV exposure progressed. Small angle neutron scattering and Fourier transfonn infrared spectroscopy (FTIR) studies were performed to verify the microstructure and to follow chemical changes during outdoor exposure, respectively. The results have shown that amine blushing, which occurs only under ambient conditions, had a significant effect on the surface morphology and microstructure of the epoxy. The surface morphology of the samples prepared under CO2-free, dry conditions was generally smooth and homogeneous. However, the interface and the bulk samples clearly revealed a two-phase structure consisting of bright nodular domains and dark interstitial regions, indicating an inhomogeneous microstructure. Such heterogeneous structure of the bulk was in good agreement with results obtained by small angle neutron scattering of unexposed samples and by AFM phase imaging of the degraded sample surface. The relationship between submicrometer physical changes and molecular chemical degradation is discussed. DOI : 10.1007/s11998-005-0014-x En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-005-0014-x.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3802
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 2, N° 7 (07/2005) . - p. 547-556[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 002327 - Périodique Bibliothèque principale Documentaires Disponible
Titre : On the use of the atomic force microscope to monitor physical degradation of polymeric coating surfaces Type de document : texte imprimé Auteurs : Mark R. VanLandingham, Auteur ; Jonathan W. Martin, Auteur ; Eric Byrd, Auteur ; Tinh Nguyen, Auteur Année de publication : 2001 Article en page(s) : p. 43-50 Note générale : Bibliogr. Langues : Américain (ame) Tags : Etude expérimentale Essai vieillissement accéléré Mélamine résine Acrylique dérivé polymère Microscopie force atomique Dégradation Feuil Polymère Peinture Matériau revêtement Index. décimale : 667.9 Revêtements et enduits Résumé : The atomic force microscope (AFM) was used to monitor changes in surface features of an acrylic melamine coating that was exposed to a variety of conditions. Exposure to ultraviolet (UV) radiation and high relative humidity caused general roughening of the surface and the formation of pits. Further, the damage of the coating surface was much more substantial for exposure to high relative humidity compared to exposure to dry environments. This difference in degradation rates correlated with measurements of chemical degradation determined using infrared spectra that were acquired along with the AFM images. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5770
in JOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 73, N° 923 (12/2001) . - p. 43-50[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001231 - Périodique Bibliothèque principale Documentaires Disponible
Titre : Relating laboratory and outdoor exposure of coatings : II. Effects of relative humidity on photodegradation and the apparent quantum yield of acrylic - melamine coatings Type de document : texte imprimé Auteurs : Tinh Nguyen, Auteur ; Jonathan Martin, Auteur ; Eric Byrd, Auteur ; Ned Embree, Auteur Année de publication : 2002 Article en page(s) : p. 65-80 Note générale : Bibliogr. Langues : Américain (ame) Tags : Etude expérimentale Rayonnement UV Corrélation Mélamine résine Acrylique dérivé polymère Rendement quantique Feuil Dégradation photochimique Humidité relative Exposition intempérie Essai vieillissement naturel accéléré Peinture Matériau revêtement Index. décimale : 667.9 Revêtements et enduits Résumé : The effect of relative humidity (RH) from <<1% to 90% on the photodegradation and quantum efficiency for a partially-methylated melamine acrylic coating exposed to UV/50°C condition has been investigated. The UV source is supplied by two 1000 W Xenon arc solar simulators and the relative humidities are provided by specially designed humidity generators, which control relative humidity in the 0 to 90% range to within <3% of the measured values. Radiation absorbed in the coating and degradation of the films are measured by UV-visible and Fourier transform infrared spectroscopies, respectively. The degradation at a particular RH/UV condition consists of four different modes: reactions taken place during post curing, hydrolysis due to water in the film at a particular RH, photodegradation, and moisture-enhanced photodegradation. Total degradation, hydrolysis, and moisture-enhanced photodegradation increase with increasing RH. At low relative humidities, photodegradation is an important degradation mode but hydrolysis dominates the degradation at high RH levels. Moisture in the film is found to increase the quantum efficiency of acrylic melamine coating photodegradation. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5633
in JOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 74, N° 932 (09/2002) . - p. 65-80[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001243 - Périodique Bibliothèque principale Documentaires Disponible
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