| Abstract: | The interfacial reaction between a liquid polyfunctional aromatic isocyanate and a diol was studied using infrared spectroscopy to follow the reduction in concentration of the isocyanate group. It was shown that the product polyurethane formed a gel layer around dispersed isocyanate droplets which were swollen by the diol but not by the isocyanate. A model for the process is suggested based on the reaction occuring at the interface of a diminishing droplet surface. It is suggested that the reaction is controlled by the reaction kinetic parameters and the mass transfer by diffusion of the diol through the product layer. Quantitative evaluation is based on steady and nonsteady state diffusion theories. |
