Premium
Kinetics of copolyurethane network formation
Author(s) -
Sekkar V.,
Krishnamurthy V. N.,
Jain S. R.
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(19971128)66:9<1795::aid-app19>3.0.co;2-u
Subject(s) - polybutadiene , kinetics , viscosity , reaction rate constant , polyol , polymer chemistry , thermodynamics , stearic acid , materials science , chemistry , polyurethane , organic chemistry , polymer , copolymer , physics , quantum mechanics
Cure kinetics for the formation of copolyurethane networks of various compositions based on hydroxy‐terminated polybutadiene (HTPB), poly(12‐hydroxy stearic acid‐ co ‐TMP) ester polyol(PEP), and different isocyanates has been studied through viscosity build up during the cure reaction. The viscosity( N )—time ( t ) plots conform to the equation N = a e b t , where a and b are empirical constants, dependent on the composition and the nature of the polyols and the isocyanates. The rate constants (k) for viscosity build up, evaluated from the slopes of dN/dt versus N plots at different temperatures, were found to vary significantly from 0.0073 to 0.25 min −1 ; and the activation energies for gelation were found to be in the range 20 to 40 kJ mol −1 . The results have been interpreted in terms of the dependence of the rate constants on structural characteristics of the prepolymers. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1795–1801, 1997