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Journal of Applied Polymer Science, Vol.58, No.12, 2141-2154, 1995
Kinetics of Reaction of N-Butanol and Triaminononane Trisisocyanate Measured via C-13 Solution NMR
The model reaction kinetics of a novel trifunctional isocyanate 4-aminomethyl-1,8-diaminooctane [informally referred to as triaminononane trisisocyanate (TTI)] with n-butanol is described. Butanol is used in place of the normal polyols used in actual coatings formulations in order to simplify the system for kinetic analysis. Using C-13-NMR, the differences in reactivity of each isocyanate group was studied in real-time measurements. There is little difference in the second-order rate constants between the three TTI isocyanate groups in the uncatalyzed systems at 25, 35, or 45 degrees C. The dibutyl tin dilaureate (DBTDL) catalyzed system exhibits similar second-order rate constants for the medium- and long-branch systems, and a smaller rate constant for the short-branch system. The activation energies increase with increasing chain length in the uncatalyzed system, while for the catalyzed system the long and medium branches have identical activation energies, and the short-branch system has the lowest activation energy. The addition of chloroform or increasing the butanol : TTI ratio results in an increase of the measured rate constant.
Keywords:DIISOCYANATE