REORIENTATIONAL DYNAMICS AND INTERMOLECULAR COOPERATIVITY OF REACTIVEPOLYMERS .1. MODEL EPOXY-AMINE SYSTEMS

An investigation was conducted to determine how the advancement of che mical reactions and the prepolymer molecular weight affect the reorien tational dynamics and intermolecular cooperativity in model epoxy-amin e systems. Experimental results were obtained by dielectric spectrosco py over a wide range of frequency and temperature. A strong effect of the progress of reaction on reorientational dynamics was noted and an explanation was put forward within the framework of the coupling theor y, marking the first time this concept was applied to reactive systems . It was proposed that the molecular-level characteristics that govern the intermolecular cooperativity of reactive systems can be classifie d into two categories: (1) molecular architecture, determined by molec ular symmetry, rigidity, and steric hindrance, and (2) dielectric arch itecture, determined by the type and concentration of all dielectrical ly active species. Both molecular and dielectric architecture Vary in the course of chemical reaction, and the overall direction in which th e cooperativity shifts is governed by the interplay between these two phenomena.