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Preparation and characterization of aqueous polyurethane dispersions with well-defined soft segments



Novel aqueous polyurethane (PU) hybrid dispersions were successfully prepared with 5–15 mol % functionalized hexamethylene diisocynate trimer modified by N-(n-butyl)-3-aminopropyltriethoxysilane and dihydroxylpropyl-terminated siloxane oligomers (TS). The results of the differential scanning calorimetry and X-ray diffraction tests show that the degree of segment order was reduced by the introduction of TS. The hybrid polymer films with TS introduced into the PU backbone displayed excellent water and xylene resistance. Atomic force microscopy showed that the films had a smooth surface. It was noticeable that the tensile strength (σb) and Young's modulus of the films increased simultaneously when TS was incorporated into PU; σb of the PU15 film with 15 mol % TS was much higher than that of the neat PU0 film, and the breaking elongation of the film with 10 mol % TS was clearly higher than that of the other films. The results indicate that an appropriate content of TS significantly improved the properties of the aqueous PU hybrids. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011