Modeling and Simulation of Urethane Acrylates Synthesis. II. Kinetics of Uncatalyzed Reaction of Toluene Diisocyanate with a Polyether Diol

摘要

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 H~1-NMR and 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. Kinetics constants were calculated by using the software SIMUL-BATCH. 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 kinetics and probabilistic arguments.