Characterization and properties of gradient polyacrylate latex particles by gradient emulsion polymerization / Xinya Zhang in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 9, N° 6 (11/2012)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 9, N° 6 (11/2012) . - p. 765-774 Titre : Characterization and properties of gradient polyacrylate latex particles by gradient emulsion polymerization Type de document : texte imprimé Auteurs : Xinya Zhang, Auteur ; Xia Wei, Auteur ; Wenxing Yang, Auteur ; Yongjin Li, Auteur ; Huanqin Chen, Auteur Année de publication : 2012 Article en page(s) : p. 765-774 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Acrylate de butyle Analyse thermique Caractérisation Chromatographie sur gel Copolymérisation Latex Méthacrylate de méthyle Microscopie à force atomique Microscopie électronique en transmission Particules (matières) Polyacrylates Polymérisation en émulsion Résonance magnétique nucléaire Index. décimale : 667.9 Revêtements et enduits Résumé : In this study, gradient acrylate latex particles were synthesized by gradient copolymerization. n-Butyl acrylate (BA) and methyl methacrylate (MMA) were used as co-monomers, dodecyl diphenyl ether sodium disulfonate as the emulsifier, and potassium persulfate as the initiator. The technique involved the continuous addition of one monomer mixture into a stirred tank containing another monomer mixture. Their microstructure and properties were analyzed by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), atomic force microscopy (AFM), transmission electron microscopy (TEM), and particle size analysis. 1H-NMR spectra show a gradual change in the chemical composition with the growth of molecular chains. The gradient polymer latexes, the instantaneous copolymer composition of which varies as the polymerization proceeds, are obtained. GPC analyses show that the aggregated molecular chain in the BA-centered latex particle experiences a process from dominant BA to MMA with changes in the monomer's feed composition during the polymerization. Particle size and TEM analyses show that the increasing latex size agrees well with the gradient growth pattern. DSC analyses show that the gradient latex particles exhibit only one broadened and ambiguous glass transition region. AFM analyses indicate no obvious microphase segregation occurs in the gradient latex particles, further verifying that the gradient microstructure is obtained. Note de contenu : - EXPERIMENTAL DETAILS : Materials - Gradient emulsion polymerization - Testing and characterization - RESULTS AND DISCUSSION : H-NMR analyses - GPC analyses - Particle size analyses - DSC and MFT analyses - AFM analyses DOI : 10.1007/s11998-012-9422-x En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-012-9422-x.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=16662 [article]

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A novel hydroxyl polyacrylate latex modified by OvPOSS and its application in two-component waterborne polyurethane coatings / Wu Zeng in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 17, N° 1 (01/2020)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 17, N° 1 (01/2020) . - p. 181-191 Titre : A novel hydroxyl polyacrylate latex modified by OvPOSS and its application in two-component waterborne polyurethane coatings Type de document : texte imprimé Auteurs : Wu Zeng, Auteur ; Haowei Huang, Auteur ; Liujun Song, Auteur ; Xiang Jiang, Auteur ; Xinya Zhang, Auteur Année de publication : 2020 Article en page(s) : p. 181-191 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Caractérisation Composés organiques -- Synthèse Copolymérisation Essai de dureté Essai Wolff-Wilborn Polyacrylates Polymères à terminaison hydroxyle Polyuréthanes Revêtements -- Propriétés thermiques Revêtements bi-composant Revêtements organiques Silsesquioxanes oligomères polyhèdres Index. décimale : 667.9 Revêtements et enduits Résumé : Octavinyl polyhedral oligomeric silsesquioxane (OvPOSS) was synthesized via hydrolysis and condensation of vinyltriethoxysilane. The structure of OvPOSS was determined by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), 1H nuclear magnetic resonance and 29Si nuclear magnetic resonance. A novel hydroxyl functional polyacrylate latex (HPA) with core–shell structure modified by OvPOSS (OvPOSS/HPA) was successfully prepared via emulsion copolymerization. Consequently two-component waterborne polyurethane (2K-WPU) coatings were prepared by using the as-prepared latex as hydroxyl components and hydrophilic polyisocyanates as curing agents. The structure and properties of OvPOSS/HPA were marked by FTIR, XRD, differential scanning calorimetry and thermogravimetric analysis. The results of FTIR and XRD show that OvPOSS has been successfully embedded into HPA, and OvPOSS occupies a homogeneous distribution in the HPA matrix. The effect of OvPOSS on the properties of OvPOSS/HPA as well as the application performance of 2K-WPU coatings film were also investigated. The results show that OvPOSS/HPA possesses core–shell structure with the OvPOSS core and enhanced thermal stability. The glass transition temperature (Tg) of OvPOSS/HPA with 2.0% OvPOSS content is 22.3°C, which is 8.4°C higher than that of pure HPA. The performance properties of the 2K-WPU coating films such as pencil hardness were also improved by incorporation of OvPOSS. Note de contenu : - EXPERIMENTAL : Materials - Synthesis of octavinyl-POSS (Ov POSS) - Synthesis of OvPOSS/HPA - Preparation of 2K-WPU coatings - Characterizations and instruments - RESULTS AND DISCUSSION : Structure characterization of OvPOSS - Structure characterization of OvPOSS/HPA - Particle size distribution of OvPOSS/HPA - Thermal properties of OvPOSS/HPA films DOI : 10.1007/s11998-019-00256-9 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-019-00256-9.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33737 [article]

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