Sorption of water vapor by hydrophilic polyurethane-ureas

✍ Scribed by S. Petřík; F. Hadobaš; L. Šimek; M. Bohdanecký

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 535 KB
• Volume: 47
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1993.070470411

✦ Synopsis

Segmented polyurethane-ureas were prepared from low-molecular weight homopolymers or triblock (PEP ) copolymers of ethylene and propylene oxides and 4,4'-diphenylmethane diisocyanate with hydrazine as chain extender. Equilibrium sorption of water vapor at 23°C was measured at eight to nine values of relative vapor pressure, 0.08 I p / p o I 0.97. The effect of the structure (composition and length) of soft segments was studied. Sorption capacities were found to be lower than the reference values computed under the assumption that the contributions to sorption by the chain constituents are additive. This finding was assigned to the shielding effect of hard segment domains on the interaction of water molecules with hydrophilic (ethoxamer) groups of soft segments.