Modeling and simulation of urethane acrylates synthesis. I. Kinetics of uncatalyzed reaction of toluene diisocyanate with a monoalcohol

Abstract

Toluene diisocyanate reacts with poly(propylene glycol) during the synthesis of some urethane acrylate oligomers. The present work deals with kinetic studies and molecular characterization of the uncatalyzed bulk reaction of these two difunctional monomers. Back titration and H1-NMR are used to follow the reaction of the different isocyanate groups with an alcohol group belonging to poly(propylene glycol) and to allow a good description of the urethane groups evolution. The global reaction rate as well as that of each individual isocyanate group are well described by a second-order equation. Kinetic constants were calculated by using the software SIMULBATCH®. The reaction of two difunctional monomers leads to the formation of oligomers of different polymerization degrees, opposite to the reaction of TDI with a monoalcohol. Thus, another approach was developed to characterize the oligomers by size exclusion chromatography and to calculate the molecular weight distribution by using a combination of kinetic and probabilistic arguments. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3149–3160, 2001