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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]

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Nanostructured polyurethane ceramer coatings for aircraft / Mark D. Soucek 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. 125-134 Titre : Nanostructured polyurethane ceramer coatings for aircraft Type de document : texte imprimé Auteurs : Mark D. Soucek, Auteur ; Hai Ni, Auteur Année de publication : 2002 Article en page(s) : p. 125-134 Note générale : Bibliogr. Langues : Américain (ame) Tags : Microstructure  Ténacité  Résistance  traction  Propriété  mécanique  Feuil  Préparation  Liant  Formulation  Industrie  aéronautique  Céramique  Polymère  Matériau  composite  Peinture  revêtement Index. décimale : 667.9 Revêtements et enduits Résumé : A new low VOC (volatile organic compounds) polyurethane/oligosiloxane coating was formulated using 1,6-hexamethylene diisocyanate (HDI) isocyanurate, alkoxysilane-functionalized HDI isocyanurate, tetraethyl orthosilicate (TEOS) oligomers, and three cycloaliphatic polyesters. One series of polyesters was synthesized using 1,4-cyclohexanedimethanol (CHDM) with 1,4-cyclohexanedicarboxylic acid (1,4-CHDA) and 1,3-cyclohexanedicarboxylic acid (1,3-CHDA). A second series of polyesters was synthesized using 2-butyl-2-ethyl-1,3-propanediol (BEPD) with 1,4-CHDA or 1,4-CHDA, and 1,3-CHDA, respectively. The polyurethane provided the general mechanical properties and the polysiloxane functioned as an adhesion promoter and corrosion inhibitor. The continuous organic polyurethane phase was coupled with the inorganic polysiloxane phase via the alkoxysilane-functionalized HDI isocyanurate. The general coatings, tensile, and viscoelastic properties were evaluated for the ceramer coatings as functions of the polyester and concentration of TEOS oligomers. Damage tolerance was evaluated via fracture toughness and development of the film deformation zone prior to crack propagation. The coatings'properties were dominated by the organic phase. The film morphology was investigated using the combination of SEM (scanning electron microscope) and X-ray analysis. Phase separation was observed for ceramer coatings resulting in SiO2 particles. The size of the preceramic silicon-oxo-particles was controlled by the Tg of the organic phase and the concentration of TEOS oligomers. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5619 [article]

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Structure/property relationships in flexible alkoxysilane automotive coatings / Phillip V. Yaneff 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. 135-141 Titre : Structure/property relationships in flexible alkoxysilane automotive coatings Type de document : texte imprimé Auteurs : Phillip V. Yaneff, Auteur ; Karlis Adamsons, Auteur ; Rose Ann Ryntz, Auteur ; Dottie Britz, Auteur Année de publication : 2002 Article en page(s) : p. 135-141 Note générale : Bibliogr. Langues : Américain (ame) Tags : Silane(alcoxy)  polymère  Vieillissement  Dégradation  Essai  mécanique  Vernis  Résistance  intempérie  Contrainte  compression  Cisaillement  Indentation  rayure  Flexibilité  Feuil  Propriété  Liant  Formulation  Relation  structure  propriété  Industrie  automobile  Peinture  Matériau  revêtement Index. décimale : 667.9 Revêtements et enduits Résumé : Flexible automotive coatings are susceptible to scratch and mar damage, especially during finishing and assembly operations. One-component (1K) flexible clearcoats exhibit very good scratch and mar resistance, but unfortunately suffer from poor durability and environmental etch resistance. Two-component clearcoats offer improvements in both etch and durability, but at the expense of scratch and mar. In this paper, the concept and properties of 1K flexibilized silane clearcoats for use on automotive plastics will be introduced and their structure/ property relationships examined as they apply to scratch and mar. The role of coating crosslink density, toughness, glass transition temperature (Tg), and surface profile on the scratch damage of coated plastic substrates will be described. In addition, a new scratch methodology, termed Scratcho, is utilized to determine relative scratch performance and is compared to conventional scratch resistance testing. Results to date indicate that hardness, as affected by the glass transition temperature, and crosslink density, as it contributes to higher essential work values, both affect resultant scratch propensityofthe flexible coatings. The relative ranking of different-coating systems employing alternate crosslinkers (e.g., isocyanate and melamine) is also presented and compared to the newly developed silane crosslinked coatings. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5620 [article]

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