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Polyurethane membranes from polyether and polyester diols for gas fractionation
Author(s) -
Pegoraro M.,
Zanderighi L.,
Penati A.,
Severini F.,
Bianchi F.,
Cao Nanyun,
Sisto R.,
Valentini C.
Publication year - 1991
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1991.070430406
Subject(s) - solubility , polyester , polyurethane , polymer chemistry , materials science , amorphous solid , membrane , polymer , condensation polymer , chemical engineering , chemistry , organic chemistry , composite material , biochemistry , engineering
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 N 2 , O 2 , CO 2 , CH 4 , CO were measured at T=35°C (>T g ).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‐T g 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 H 2 O>CO 2 > O 2 > CH 4 > CO > N 2 . Some practical application based on particular selectivities is suggested.