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Liquid sorption in a segmented polyurethane elastomer
Author(s) -
Schneider N. S.,
Illinger J. L.,
Cleaves M. A.
Publication year - 1986
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760262204
Subject(s) - materials science , sorption , heptane , polyurethane , swelling , solvent , polymer chemistry , desorption , polymer , phase (matter) , elastomer , chemical engineering , thermodynamics , composite material , chemistry , organic chemistry , adsorption , physics , engineering
The sorption and diffusion of a series of liquids in a segmented polyurethane have been studied to determine how the behavior is affected by the choice of solvent and the heterophase nature of the polymer. The polyurethane was composed of methylene‐di‐para‐phenylene isocyanate (MDI) butanediol, and poly(tetramethylene oxide) (1000) with a mole ratio 3:2:1. Immersion experiments in n‐heptane liquid, a poor solvent, and incremental sorption experiments in n‐heptane vapor showed normal Fickian havior. In the set of liquids of increasing polarity, which included 1‐chloroheptane, three dichloroalkanes and orthodichlorobenzene, the swelling increased to very high levels. Effective values of the molecular weight between crosslinks computed from the Flory Rhener equation, assuming complete phase segregation, varied widely with the different liquids. Agreement could be improved by allowing 30 percent mixing of hard segments with the soft segment phase. The sorption and desorption curves for the highly swelling liquids showed various anomalies some of which might be the result of solvent induced relaxation of hard segment domains.