Diffusion and reaction of epoxy and amine in polysulfone-transport modeling and experimental validation

In this work, a mathematical model for the multi-component diffusion of rea cting thermosets into amorphous thermoplastics is presented for the epoxy-a mine-polysulfone (PSU) system. The governing Fickian diffusion-reaction equ ations for the epoxy and amine are strongly coupled through the amine conce ntration dependence of the epoxy diffusivity and the autocatalytic reaction terms for the epoxy and amine. Expressions for epoxy and amine diffusivity were used to formulate the coupled governing equations for the epoxy and a mine, and solved numerically using finite difference methods. The model pre dictions are coupled with experimental Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Scanning Electron Microscop y-Energy Dispersive Spectroscopy (SEM-EDS) data. It is shown that despite c ertain simplifying assumptions, relatively good agreement is found for the concentration distributions with time and distance, and the interphase size as a function of processing temperature. (C) 2000 Elsevier Science Ltd. Al l rights reserved.