Effect of different polyethers on surface and thermal properties of polyurethane-siloxane copolymers modified with side-chain siloxaneReportar como inadecuado




Effect of different polyethers on surface and thermal properties of polyurethane-siloxane copolymers modified with side-chain siloxane - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Journal of Thermal Analysis and Calorimetry

, Volume 114, Issue 1, pp 397–408

First Online: 16 January 2013Received: 06 August 2012Accepted: 14 December 2012

Abstract

Polyurethane-dimethylsiloxane PU-PDMS copolymers with 4,4′-methylenebiscyclohexyl isocyanate, different polyethers i.e., polyoxytetramethylenediol, polyethylene glycol, polypropylene glycol, and α,ω-dihydroxy terminated polydimethylsiloxane extended with 1,4-butanediol in two-step solution polymerization were obtained. The PU-PDMS were modified using 1.25 mol% of polydimethylsiloxane which was incorporated into main polyurethane backbone as a side chain. The structure of the synthesized PU-PDMS was confirmed by FTIR as well as H and C-NMR spectroscopy. The effect of different soft segments on free surface energy FSE components and thermal stability of polyurethane-siloxane copolymers was investigated. The activation energy of the thermal degradation of PU-PDMS using isoconversional methods Ozawa–Flynn–Wall and Friedman was calculated. It was concluded that molecular mass, thermal stability, and FSE of PU-PDMS copolymers depend on polyol used. The apparent activation energy at first step of degradation in nitrogen generally increases with the extent of conversion which may result from complex mechanism related to formation of decomposition products. Hydrophobic character of side-chain siloxane on surface properties of the PU-PDMS coatings was confirmed. The obtained coatings are generally soft with the relative hardness in the range of 0.120–0.027.

KeywordsPolyurethane Siloxane Side chain Surface free energy Thermal stability Kinetics  Download fulltext PDF



Autor: Łukasz Byczyński

Fuente: https://link.springer.com/







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