Structure – thermomechanical property correlations of highly branched siloxane – urethane networks / Someshwarnath Pandey in Industrial & engineering chemistry research, Vol. 51 N° 9 (Mars 2012)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 51 N° 9 (Mars 2012) . - pp. 3531-3540 Titre : Structure – thermomechanical property correlations of highly branched siloxane – urethane networks Type de document : texte imprimé Auteurs : Someshwarnath Pandey, Auteur ; Sangram K. Rath, Auteur ; Asit. B. Samui, Auteur Année de publication : 2012 Article en page(s) : pp. 3531-3540 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Correlation analysis Thermomechanical properties Résumé : A series of B3 core-terminated highly branched siloxane―urethane polymers was synthesized through the A2 + B3 route. Isophorone diisocyanate (IPDI)-terminated polydimethylsiloxane (PDMS) was used as the A2 unit and triethanol amine as the B3 core. Size exclusion chromatography (SEC) studies revealed decreasing number-average molecular weights for the branched polymers and increasing tendency toward lower molecular weight species formation with increased proportion of B3 core in the branched polymers. The degree of branching and fraction of dendritic units, evaluated from 1H NMR, increased monotonically with increasing B3 core in the branched polymers. Cross-linked networks of the highly branched polymers were prepared by reaction of the terminal hydroxyl groups with tetraethoxysilane (TEOS) at room temperature. The sol fractions obtained for the networks from solvent extraction studies were consistent with the non-network-forming low molecular weight fractions obtained from the deconvoluted SEC traces. The solubility parameter, Flory―Huggins interaction parameter, and cross-link density of the networks were evaluated from swelling studies. FTIR spectroscopy was used to evaluate the degree of hydrogen bonding of the branched networks. The thermomechanical properties of the networks were evaluated by stress-strain measurements and dynamic mechanical analysis, and the results were correlated with the structural parameters, such as degree of branching, extent of hydrogen bonding, and cross-link density. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25595777 [article] Structure – thermomechanical property correlations of highly branched siloxane – urethane networks [texte imprimé] / Someshwarnath Pandey, Auteur ; Sangram K. Rath, Auteur ; Asit. B. Samui, Auteur . - 2012 . - pp. 3531-3540. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 9 (Mars 2012) . - pp. 3531-3540 Mots-clés : Correlation analysis Thermomechanical properties Résumé : A series of B3 core-terminated highly branched siloxane―urethane polymers was synthesized through the A2 + B3 route. Isophorone diisocyanate (IPDI)-terminated polydimethylsiloxane (PDMS) was used as the A2 unit and triethanol amine as the B3 core. Size exclusion chromatography (SEC) studies revealed decreasing number-average molecular weights for the branched polymers and increasing tendency toward lower molecular weight species formation with increased proportion of B3 core in the branched polymers. The degree of branching and fraction of dendritic units, evaluated from 1H NMR, increased monotonically with increasing B3 core in the branched polymers. Cross-linked networks of the highly branched polymers were prepared by reaction of the terminal hydroxyl groups with tetraethoxysilane (TEOS) at room temperature. The sol fractions obtained for the networks from solvent extraction studies were consistent with the non-network-forming low molecular weight fractions obtained from the deconvoluted SEC traces. The solubility parameter, Flory―Huggins interaction parameter, and cross-link density of the networks were evaluated from swelling studies. FTIR spectroscopy was used to evaluate the degree of hydrogen bonding of the branched networks. The thermomechanical properties of the networks were evaluated by stress-strain measurements and dynamic mechanical analysis, and the results were correlated with the structural parameters, such as degree of branching, extent of hydrogen bonding, and cross-link density. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25595777

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