Influence of drier combination on through-drying in waterborne alkyd emulsion coatings observed with magnetic resonance profiling / J. Mallégol in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 74, N° 933 (10/2002)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 74, N° 933 (10/2002) . - p. 113-124 Titre : Influence of drier combination on through-drying in waterborne alkyd emulsion coatings observed with magnetic resonance profiling Type de document : texte imprimé Auteurs : J. Mallégol, Auteur ; P. K. Weissenborn, Auteur ; A. Motiejauskaite, Auteur ; M. Wallin, Auteur ; Joseph L. Keddie, Auteur ; P. J. McDonald, Auteur ; P. M. Glover, Auteur ; E. Ciampi, Auteur ; A. M. Barry, Auteur Année de publication : 2002 Article en page(s) : p. 113-124 Note générale : Bibliogr. Langues : Américain (ame) Tags : Etude  expérimentale  Mécanisme  réaction  Dureté  Feuil  Propriété  mécanique  Résonance  magnétique  Adjuvant  Siccatif  Séchage  Formation  feuille  Alkyde  résine  Peinture  émulsion  eau  Matériau  revêtement Index. décimale : 667.9 Revêtements et enduits Résumé : Achieving fast and uniform crosslinking in alkyd coatings poses a challenge to formulators that demands a fundamental understanding of drier efficiency. In recognition of this, we have examined the physical changes that accompany autooxidative crosslinking in alkyd films (cast from waterborne emulsions) in the presence of various combinations of metal carboxylate driers. A newly developed type of magnetic resonance (MR) profiling was used in conjunction with conventional techniques : Beck-Koller drying tests, pendulum hardness, and mass uptake. MR profiling noninvasively probes the molecular mobility of the alkyd as a function of depth (with a pixel resolution of about 9 µm), over drying times ranging from minutes to weeks. It thereby indicates drier efficiency via its sensitivity to viscosity build-up during drying and to subsequent film hardening. We show unequivocally that more uniform crosslinking is achieved using a combination of a primary (Co) and a secondary (Ca) drier, in support of conventional belief. Furthermore, these results yield new insight into the chemical mechanisms induced by the driers and are thus of clear benefit to coatings researchers and formulators. Notably, the secondary driers improve the efficiency of the hydroperoxide decomposition reactions, but they are only active during an initial period, after which crosslinking nonuniformity develops. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5618 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
001244	-	Périodique	Bibliothèque principale	Documentaires	Disponible

Nano-mechanical properties and topography of thermosetting acrylic powder coatings / D. C. Andrei in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 73, N° 912 (01/2001)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 73, N° 912 (01/2001) . - p. 65-73 Titre : Nano-mechanical properties and topography of thermosetting acrylic powder coatings Type de document : texte imprimé Auteurs : D. C. Andrei, Auteur ; D. Parsonage, Auteur ; B. J. Briscoe, Auteur ; S. G. Yeates, Auteur ; J. N. Hay, Auteur ; Joseph L. Keddie, Auteur Année de publication : 2001 Article en page(s) : p. 65-73 Note générale : Bibliogr. Langues : Américain (ame) Tags : Matériau  revêtement  Peinture  poudre  Propriété  mécanique  Feuil  Structure  surface  Thermodurcissable  Acrylique  dérivé  polymère  Résistance  rayure  Vernis  Dureté  Microdureté  Module  élasticité  Topographie  Etude  expérimentale Index. décimale : 667.9 Revêtements et enduits Résumé : Both nano-scratching and nano-indentation techniques have been used to evaluated the mechanical properties of the surface of acrylic coatings, with and without added pigment. The coatings were formed from thermosetting, acrylic powders. Both types of coatings-clear and pigmented-do not exhibit any significant differences in their hardness with an increase in baking time from 7 to 15 min. According to the scratching profiles, the deformation induced at the surface is virtually elastic. Introducing the pigment causes a slight increase in the elastic modulus but not significant variation in hardness. In all coatings, the computed hardness and the elastic modulus vaues are higher near the surface (perhaps as a result of tip geometry effects), but these readily reach plateau values that are consistent with other work available in the literature. A long-range surface profiler, which provided two-dimensional and three-dimensional topographical maps of the coatings surfaces, reveals undulations in the surface with a wavelength on the order of 2-4 mm. Moreover, the topography of the pigmented coating is significantly smoother than that of the clear coating in which shallow pits (about 100 µm in diameter) are randomly distributed at the surface. The nano-mechanical properties within these pits are similar to the bulk of the coating. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5688 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
001220	-	Périodique	Bibliothèque principale	Documentaires	Disponible

The diacetone acrylamide crosslinking reaction and its influence on the film formation of an acrylic latex / Nicola Kessel in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 5, N° 3 (09/2008)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 5, N° 3 (09/2008) . - p. 285-297 Titre : The diacetone acrylamide crosslinking reaction and its influence on the film formation of an acrylic latex Type de document : texte imprimé Auteurs : Nicola Kessel, Auteur ; Derek R. Illsley, Auteur ; Joseph L. Keddie, Auteur Année de publication : 2008 Article en page(s) : p. 285-297 Note générale : Bibliogr. Langues : Américain (ame) Tags : Crosslinking  'Diacetone  acrylamide'  'Film  formation'  'Keto-hydrazide'  Surfactant Index. décimale : 667.9 Revêtements et enduits Résumé : Waterborne colloidal polymers (i.e. latex) represent a promising alternative to organic solvent-based systems in coatings applications. The development of mechanical strength and hardness is often enhanced by chemical crosslinking that creates a three-dimensional network. If extensive crosslinking occurs within the particles prior to their coalescence, however, interdiffusion will be prevented. A weaker product will result. We have explored the inter-relationship between coalescence, crosslinking, and surfactant exudation in an acrylic latex containing diacetone acrylamide exploiting the “keto-hydrazide” crosslinking reaction. The complementary use of spectroscopic techniques on a model system determined that the crosslinking reaction yields an imine, not an enamine as has been proposed in some literature. Gel fraction measurements were used to probe the rate and amount of crosslinking and identified a slower rate in larger particles, suggesting that the transport of crosslinking agent is rate-limiting. The keto-hydrazide reaction was found to be acid catalyzed and favored at lower water concentration. Measurement of the latex pH relative to the polymer mass fraction during film formation clarified the expected point of onset for crosslinking in relation to particle packing. Atomic force microscopy was used to follow surface leveling relative to the competing influence of crosslinking. The rate and total amount of surfactant exudation were found to be influenced by crosslinking, particle deformability (as determined by the temperature relative to the polymer glass transition temperature), and the evaporation rate (as controlled by the relative humidity). There is evidence that surfactant exudation can be triggered by the particle deformation that occurs at film formation temperatures well above the glass transition temperature. DOI : 10.1007/s11998-008-9096-6 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-008-9096-6.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2973 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
010633	-	Périodique	Bibliothèque principale	Documentaires	Disponible

Understanding water-borne coatings : New techniques to answer old questions / Joseph L. Keddie in SURFACE COATINGS INTERNATIONAL. PART A : COATINGS JOURNAL, Vol 87, A02 (03/2004)  

[article]  inSURFACE COATINGS INTERNATIONAL. PART A : COATINGS JOURNAL > Vol 87, A02 (03/2004) . - p. 70-73 Titre : Understanding water-borne coatings : New techniques to answer old questions Type de document : texte imprimé Auteurs : Joseph L. Keddie, Auteur ; J.-P. Gorce, Auteur ; J. Mallégol, Auteur ; P. J. McDonald, Auteur Année de publication : 2004 Article en page(s) : p. 70-73 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Couches minces Imagerie par résonance magnétique Latex Réticulation (polymérisation) Revêtements en phase aqueuse -- Séchage:Peinture en phase aqueuse -- Séchage Index. décimale : 667.9 Revêtements et enduits Résumé : Ever since latexes were first developed in the 1940s, questions have been asked about the process by which polymer particles are transformed into a continuous film or coating. The process of latex film formation, as it is called, has always been mysterious. With the refinement of new non-invasive analytical techniques to probe the process, it is now becoming much better understood. We will consider a few of the 'old questions' that have now been with the help of these 'new techniques'. Note de contenu : - THIS IS AN EXTENDED REPORTON THE LECTURE PRESENTED TO THE LONDON SECTION - QUESTION ABOUT DRYING ANSWERED WITH MAGNETIC RESONANCE PROFILING : Observations of lateral drying - MR imaging of drying on the vertical direction - QUESTIONS ABOUT PARTICLE COALESCENCE ANSWERED WITH ATOMIC FORCE MICROSCOPY En ligne : https://drive.google.com/file/d/1aehfIEWNS0WrEg94jMVuZYsiHUVkD0Xq/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=16304 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
000395	-	Périodique	Bibliothèque principale	Documentaires	Disponible

---

1 (1 - 4 / 4)