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Curing kinetics and chemorheological analysis of polyurethane formation
Author(s) -
Dimier F.,
Sbirrazzuoli N.,
Vergnes B.,
Vincent M.
Publication year - 2004
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.20046
Subject(s) - rheometry , materials science , curing (chemistry) , polyurethane , rheology , activation energy , isothermal process , kinetics , shear rate , phenomenological model , thermodynamics , chemical kinetics , composite material , polymer chemistry , chemistry , physics , quantum mechanics
The cross‐linking kinetics and the rheological behavior of a polyurethane system during curing are investigated by DSC and small amplitude oscillatory shear rheometry. In this study, isoconversional methods are applied to understand the reaction complexity. The activation energy depends on the extent of conversion. It can be shown that three parallel reactions occur during the evolution of the global reaction in non‐isothermal conditions. An original multi‐step model can involve these three parallel independent reactions. Dynamic viscosity is measured as a function of time and is found independent of shear rate. Isothermal viscosity rise is related to reaction extent by a phenomenological model. The gelation time is determined by the tanδ crossover at different frequencies. Polym. Eng. Sci. 44:518–527, 2004. © 2004 Society of Plastics Engineers.