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Kinetic study of the reaction between hydroxyl‐terminated polybutadiene and isophorone diisocyanate in bulk by quantitative FTIR spectroscopy
Author(s) -
Kincal Dilek,
Özkar Saim
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(19971205)66:10<1979::aid-app14>3.0.co;2-q
Subject(s) - isophorone diisocyanate , polybutadiene , hydroxyl terminated polybutadiene , fourier transform infrared spectroscopy , polyurethane , reaction mechanism , polymer chemistry , activation energy , order of reaction , chemistry , isophorone , materials science , kinetics , reaction rate constant , chemical engineering , organic chemistry , copolymer , catalysis , physics , diamine , quantum mechanics , engineering , polymer
A kinetic study of the reaction between a hydroxyl‐terminated polybutadiene (HTPB) and isophorone diisocyanate (IPDI) was carried out in the bulk state by using quantitative Fourier transform infrared (FTIR) spectroscopy. The reaction is shown to obey a second‐order rate law, being first order in both the HTPB and IPDI concentrations. The activation parameters obtained from the evaluation of kinetic data are Δ H ‡ = 41.1 ± 0.4 kJ mol, Δ S ‡ = −198 ± 2 J K −1 mol −1 and E a = 43.8 ± 0.4 kJ mol −1 , which are quite different from the solution values. However, they are in agreement with the results obtained on propellants by torsional braid measurements. The large negative value of the activation entropy is indicative of an associative mechanism, which is in accord with the second‐order rate law for the polyurethane formation. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1979–1983, 1997