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Correlation of linear viscoelastic behavior and molecular weight evolution in the bulk urethane polymerization
Author(s) -
Cassagnau P.,
Mélis F.,
Michel A.
Publication year - 1997
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/(sici)1097-4628(19970919)65:12<2395::aid-app12>3.0.co;2-0
Subject(s) - viscoelasticity , rheology , polymerization , materials science , polyurethane , polymer chemistry , gel point , polymer , degree of polymerization , thermodynamics , polymer science , composite material , physics
Bulk polymerization of urethane made from diphenylmethane 4, 4′ diisocyanate (MDI) and polyether macro diol was performed from size exclusion chromatography and viscoelastic studies. Coupling the viscoelastic characterization and the kinetic law showed that the viscoelastic behavior of the urethane system is only dependent of the degree of polymerization. The rheological study proved that low physical interactions can be found between the polyurethane chains. Furthermore, the critical molecular weight corresponding to a rheological maximum effect of these interactions was observed close to the value Mc = 2Me, characterizing the onset of the topological entanglement coupling. A qualitative explanation of this singular behavior was attempted from a hydrogen bonding point of view. On the other hand, the linear viscoelastic properties of polyurethane samples of different molecular weights were studied. The main viscoelastic parameters, ηo, $J^0_{\hbox{e}}$ and $G^0_{\hbox{N}}$ were determined. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2395–2406, 1997