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Free volume distribution during consolidation and coalescence of latex films / A. J. Hill in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 73, N° 913 (02/2001)
[article]
Titre : Free volume distribution during consolidation and coalescence of latex films Type de document : texte imprimé Auteurs : A. J. Hill, Auteur ; J. D. Cloyd, Auteur ; D. L. Murray, Auteur ; R. R. Stockl, Auteur ; P. P. Shang, Auteur ; R. L. McGill, Auteur ; M. R. Tant, Auteur Année de publication : 2001 Article en page(s) : p. 115-124 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Coalescence (Sciences physiques)
Latex
Polyméthacrylates
Revêtements en phase aqueuse:Peinture en phase aqueuseTags : 'Peinture émulsion' Latex 'Formation de film' Consolidation Coalescence 'Polyméthacrylate butyle' d'isobutyle' 'Volume libre' Annihilation positon 'Microscopie à force atomique' Index. décimale : 667.9 Revêtements et enduits Résumé : The focus of the work is the effect of molecular architecture on free volume distribution during consolidation and coalescence of aqueous latex emulsions. Two series of model emulsion polymers, iso-butyl methacrylate (i-BMA) and normal-butyl methacrylate (n-BMA) dispersions with varying level of trimethylolpropanetriacrylate (TMPTA) crosslinker, are studied. Coatings are characterized by positron annihilation lifetime spectroscopy (PALS), and atomic force microscopy (AFM). Formation of coherent brittle films without significant interdiffusion is achieved by consolidation below the glass transition temperature (Tg). Consolidation, or ordering/compaction of films following water evaporation at temperatures below the MFFT, results in a decrease in the relative free volume element size, Tau 3, as measured by PALS. An increase in the characteristic relaxation time for the consolidation process is evident as TMPTA levels and corresponding gel fraction increase. Consolidation below Tg is accompanied by physical aging. Coalescence and interdiffusion are achieved by annealing films at or above Tg. Annealed coatings show a decrease in Tg and an increase in PALS free volume attributed to erasure of physical aging in combination with the action of the surfactant (sodium dodecyl sulfate) as a plasticizer. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5693
in JOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 73, N° 913 (02/2001) . - p. 115-124[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001221 - Périodique Bibliothèque principale Documentaires Disponible The utilization of specific interactions to enhance the mechanical properties of polysiloxane coatings / Partha Majumdar in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 7, N° 2 (03/2010)
[article]
Titre : The utilization of specific interactions to enhance the mechanical properties of polysiloxane coatings Type de document : texte imprimé Auteurs : Partha Majumdar, Auteur ; Bret A. Mayo, Auteur ; Jongsoo Kim, Auteur ; Christy Gallagher-Lein, Auteur ; Elizabeth Lee, Auteur ; Nathan Gubbins, Auteur ; Bret J. Chisholm, Auteur Année de publication : 2010 Article en page(s) : p. 239-252 Note générale : Bibliogr. Langues : Américain (ame) Tags : 'Revêtements polysiloxanes' 'Sels ammonium quaternaire''Nanoparticules silice' 'Propriétés mécaniques' 'Spectroscopie annihilation positron' Index. décimale : 667.9 Revêtements et enduits Résumé : Moisture-curable polysiloxanes were modified with ionic groups to enable specific interactions between the polysiloxane matrix and silica nanoparticle reinforcement. A trimethoxysilane-functional quaternary ammonium salt (QAS) was used to modify the polysiloxane matrix. A comparison of the mechanical properties of coatings containing QAS modification to analogous coatings without QAS modification showed that QAS modification resulted in a dramatic improvement in mechanical properties of silica nanoparticle-reinforced coatings. QAS modification provided major enhancements in both tensile modulus and toughness. The coatings were characterized using positron annihilation spectroscopy, photo-acoustic FT-IR, differential scanning calorimetry, transmission electron microscope, and atomic force microscopy. The characterization results suggested that the QAS moieties present in the polysiloxane matrix undergo specific interactions with the surface of silica nanoparticles enabling an enhancement in interfacial adhesion between the polymer matrix and the nanoparticles. Most likely, the specific interaction that provided the enhanced mechanical properties was an ion–dipole interaction involving silanol groups present on the surface of the silica nanoparticles. The enhanced modulus and toughness of these polysiloxane materials may enable their application as a fouling-release coating for ship hulls, since current polysiloxane-based fouling release coatings suffer from poor mechanical properties and durability. DOI : 10.1007/s11998-009-9177-1 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-009-9177-1.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9070
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 7, N° 2 (03/2010) . - p. 239-252[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 012083 - Périodique Bibliothèque principale Documentaires Disponible