A Model Reaction for the Chain Extension Reaction of Polyurethaneurea: Rate of the Reaction between Butylamines and Phenyl Isocyanate

The reaction between butylamines and phenyl isocyanate was studied as a model reaction for the formation of the hard segment in segmented polyurethaneurea. Since the reaction was too fast to measure by a conventional titration method, aniline was used as a competitive component in the reaction between n-butylamine (NBA) or sec-butylamine (SBA) and phenyl isocyanate (PHI) at O, 17 and 39°C. The rate constants of the reaction be-tween NBA and PHI were 30.9×10-2, 44.2×10-2 and 59.3×10-2 L•mol-1 • s-1 at 0, 17 and 39°C and those for SBA and PHI were 8.3×10-2, 18.8×10-2 and 44.5×10-2 L•mol-1•s-1 at 0, 17 and 39°C, respectively, The activation energies were 2.8 and 7.3 kcal/mol, respectively.