Water-cured poly(urethane-urea)s containing soft segments originating from siloxane/carbonate macrodiols

摘要

Poly(urethane-urea)s (PUUs) containing oligosiloxane and oligocarbonate segments were obtained by moisture-curing of NCO-terminated prepolymers synthesized from isophorone-diisocyanate (IPDI) and either oligocarbonate co-macrodiols containing oligosiloxane segments, which were made specifically for this purpose, or from a mixture of oligosiloxane diol and oligocarbonate diol. Starting macrodiols were characterized by FT-IR, 1H NMR, ~(13)C NMR and MALDI-TOR For NCO-terminated prepolymers viscosity was tested. Molecular weight and NCO content was determined with size exclusion chromatography and titration, respectively. The progress of moisture curing was followed by FT-IR showing decrease in NCO band (ca. 2260 cm~(-1)) and was considered to be completed until that band disappeared. For resulting PUU elastomers obtained in the form of homogeneous films mechanical and thermal properties were tested. It was found that oligosiloxane-based PUUs containing sufficient amount of oligocarbonate segments, that can interact with the hard urethane and urea segments to increase the interf acial regions adhesion to a moderate level, exhibited exceptionally high mechanical strength. It can be anticipated that in this case oligocarbonate diols acted as good compatibilizers since only one glass transition temperature (T_g) was observed for these PUUs. Simple preliminary biocompatibility test (UV spectrum recorded for water extracts) indicated that all samples exhibited low absorbance from 0.019 at X = 260.2 nm to 0.180 at X = 228.2 nm.