The reinforcing effect of crosslinkable waterborne polyurethane/polysiloxane composite emulsion by aqueous sol–gel method / Yan Wu 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. 243-253 Titre : The reinforcing effect of crosslinkable waterborne polyurethane/polysiloxane composite emulsion by aqueous sol–gel method Type de document : texte imprimé Auteurs : Yan Wu, Auteur ; Junbao Wu, Auteur ; Yunxia Feng, Auteur Année de publication : 2020 Article en page(s) : p. 243-253 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Angle de contact Caractérisation Composites à fibres de carbone -- Propriétés mécaniques Diffractométrie de rayons X Matériaux -- Renforcement Micrographie Polymères en émulsion Polyuréthanes Silicones Les silicones, ou polysiloxanes, sont des composés inorganiques formés d'une chaine silicium-oxygène (...-Si-O-Si-O-Si-O-...) sur laquelle des groupes se fixent, sur les atomes de silicium. Certains groupes organiques peuvent être utilisés pour relier entre elles plusieurs de ces chaines (...-Si-O-...). Le type le plus courant est le poly(diméthylsiloxane) linéaire ou PDMS. Le second groupe en importance de matériaux en silicone est celui des résines de silicone, formées par des oligosiloxanes ramifiés ou en forme de cage (wiki). Sol-gel, Procédé Thermogravimétrie Index. décimale : 667.9 Revêtements et enduits Résumé : A highly branched polysiloxane (S2) was prepared by an aqueous sol–gel process and used as an underlying crosslinker to modify silanized waterborne polyurethane (WPUS), and a novel crosslinked waterborne polyurethane (WPU)/polysiloxane composite with low VOC features was obtained. The good dispersibility of polysiloxane (S2) was proved by both TEM and DLS analyses, implying that the polysiloxane had an excellent intermiscibility with the WPU. The larger silsesquioxane network in the composite was proved by XPS, which was generated from the condensation of the Si–OH groups of polysiloxane and WPUS. On the basis of tensile results, the content of polysiloxane had a significant impact on the mechanical properties. The reinforcing and toughening synergy effect was found in the composite with a low concentration of S2. According to micrographs of the fracture surface, the dominating toughening mechanism was dependent on microcracks, while the high concentration of polysiloxane turned into silica particles in the WPU matrix, resulting in force concentration and degradation of the mechanical properties. However, the Young’s modulus increased with the increasing content of S2. Additionally, the incorporation of the crosslinked silsesquioxane structure also improved the hydrophobic properties and thermal stability of the composite. Note de contenu : - EXPERIMENTAL : Materials - Preparation of highly branched polysiloxane (S2) in aqueous medium - Preparation of waterborne polyurethane/polysiloxane composite emulsion - Characterization - RESULTS AND DISCUSSION : Characterization of highly branched polysiloxane - Dispersibility of aqueous polysiloxane - Siliceous structure - Mechanical properties - Micrographs of fracture surfaces - Dynamic mechanical properties - Microstructure during the film formation - XRD - Surface contact angle of composite - Thermogravimetric analysis DOI : 10.1007/s11998-019-00264-9 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-019-00264-9.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33742 [article]

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