Preparation and characterization of poly(trifluoropropylmethyl)siloxane-block-polyurethane-urea elastomers

A series of poly(trifluoropropylmethyl)-siloxane-block-polyurethane-urea (FSPUU) films is prepared through moisture curing based on a three-step process. First, prepolymers are produced from poly(tetramethylene oxide) and toluenediisocyanate. Second, the prepolymers are chain-extended by α,ω-bis(3-aminopropyldiethoxylsilane) poly(trifluoropropylmethyl)siloxane (APFS). Third, another chain extension is performed using 3,3′-dichliride-4,4′-diaminodiphenylmethane (DDDPM). The FSPUU films are characterized by Fourier transform IR spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, scanning electron microscopy, and mechanical testing. The effects of the APFS amount on the microstructure of the materials are also investigated. The results show that the material with approximately 15 wt% APFS exhibits high phase mixing. The materials display strong phase separations and weak tensile strengths when the APFS amounts range from 21.6 to 26.8 wt%. In particular, due to the incorporation of DDDPM in FSPUU, this segment increases the bonding of the different phases when the APFS amount is in the range of 35.6–44.5 wt%. The APFS segment is involved in compatibilizing the different phases in the materials. The tensile strength of the FSPUU films containing DDDPM can reach or surpass that of polyurethane. The copolymers may also have a functional application in coatings and adhesives.