Film formation of vinyl acrylic latexes ; effects of surfactant type, water and latex particle size / Gerald A. Vandezande in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 68, N° 860 (09/1996)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 68, N° 860 (09/1996) . - p. 63-73 Titre : Film formation of vinyl acrylic latexes ; effects of surfactant type, water and latex particle size Type de document : texte imprimé Auteurs : Gerald A. Vandezande, Auteur ; Alfred Rudin, Auteur Année de publication : 1996 Article en page(s) : p. 63-73 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Coalescence (Sciences physiques) Formation de film Plastifiants Polyacétate de vinyle Polyacrylate de butyle Revêtements Revêtements -- Additifs Revêtements en phase aqueuse:Peinture en phase aqueuse Surfactants Taille des particules Température de transition Transition vitreuse Index. décimale : 667.9 Revêtements et enduits Résumé : The process of film formation from an 85/15 vinyl acetate/butyl acrylate latex was studied with respect to the effects of particle size and surfactant type on minimum film formation temperature (MFFT), glass transition temperature (Tg), drying rates, and optical clarity of the coalesced films. Water plasticizes this polymer and thus only wet viscoelastic parameters and Tg values are realistic in film formation theories. The polymer is plasticized by ethoxylated alkylphenol nonionic surfactants. The surfactants with shorter ethylene oxide chains are better plasticizers and poorer steric stabilizers than their longer analogs. The type and concentration of stabilizing entities on the latex particle surfaces have very significant effects on the drying and coalescence properties of these latexes. Coalescence is somewhat faster with smaller latex particle sizes but larger particle size products dry at a faster rate than smaller ones in the absence of surfactant effects. Note de contenu : - EXPERIMENTAL : Latex production apparatus - Production of monodisperse latexes - Seeded monodisperse latexes - Addition of surfactants to latexes - Conversion - Particle size and distribution measurements - Differential scanning calorimetry - Dynamic mechanical measurements - Minimum film forming temperature - Drying rates of latexes using a UV/vis spectrometer - Drying of latexes using gravimetric analysis - RESULTS AND DISCUSSION : Stabilizer and surfactant effects on the Tg and minimum film forming temperatures of latexes - Drying rates of latexes - Water as a plasticizer - Combining water and surfactant effects Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18443 [article]

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Novel composite latex particles for use in coatings / Gerald A. Vandezande in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 66, N° 828 (01/1994)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 66, N° 828 (01/1994) . - p. 99-108 Titre : Novel composite latex particles for use in coatings Type de document : texte imprimé Auteurs : Gerald A. Vandezande, Auteur ; Alfred Rudin, Auteur Année de publication : 1994 Article en page(s) : p. 99-108 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Core-Shell Liants Polyacétate de vinyle Polyacrylate de butyle Polymérisation en émulsion Revêtements en phase aqueuse:Peinture en phase aqueuse Index. décimale : 667.9 Revêtements et enduits Résumé : A novel emulsion polymerization technique is described to produce core-shell latex particles comprising poly(vinyl acetate) cores inside vinyl-acrylic shells. In a variation, acrylic shells can be produced surrounding poly(vinyl acetate) or vinyl acrylic cores. The latexes can be produced at commercial solids levels, with controlled, monodisperse particle sizes. The coatings formed from such core-shell particles exhibit the properties expected of the shell polymers. Core monomers are less expensive than the shell monomers, resulting in significant savings in raw material costs. The technique described is an inverted core-shell process in which the second-stage polymer is engulfed by a previously formed first-stage material. In coatings formulations the less expensive second stage monomers are more hydrophilic than those used to make the first stage polymer. Nevertheless, an inverted core-shell morphology can be made thermodynamically stable by appropriate choices of copolymerizable surfactants in the first-stage copolymer and nonionic initiator for the second-stage polymer. The resulting anchoring groups stabilize the desired particle structure. Note de contenu : - INTRODUCTION : Heterogeneous latex production theory - Thermodynamics and kinetics of heterogeneous particle formation - Practical applications of theory - Present study - EXPERIMENTAL : Latex preparation - Initial latexes - Vinyl acetate/butyl acrylate latex - MMA/butyl acrylate latex - Core-shell latexes - Cores with vinyl acetate/butylacrylates shells - Cores with MMA/butyl acrylate shells - Latex characterization Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18753 [article]

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