ISSN:
0021-8995
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
,
Physik
Notizen:
Polyurethane prepolymers were prepared in ethylacetate from TDI and poly(oxypropilene)glicols) (PE-PU) or poly(tetramethyleneglycoladipate)diols (PES-PU) of different molecular weights (M). Homogeneous membranes were prepared by spreading the pre-polymer solution added with a three, four or pentafunctional crosslinking agent, in the presence of stannous octoate as a catalyst. On increasing M, the PUs Tg decreases regularly in the range +30 to -47°C. PU's are amorphous with the exception of PES-PU obtained from highest M polyester diols. Permeability P, diffusivity D, solubility coefficient S of N2, O2, CO2, CH4, CO were measured at T=35°C (〉Tg).P, D, S do not depend on the crosslinker functionality, but mainly on M. P and D in PE-PU are linear function of T-Tg while in PES-PU the function is not linear. Gas solubility fulfills in general the regular solution theory. P, D, S of water vapor is also given. Permeability decreases in the order H2O〉CO2 〉 O2 〉 CH4 〉 CO 〉 N2. Some practical application based on particular selectivities is suggested.
Zusätzliches Material:
10 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/app.1991.070430406
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