INTERMOLECULAR REACTION-KINETICS FOR THE PGE NMA BDMA ANHYDRIDE-CURED EPOXY

Intermolecular reactions for a thermoplastic, epoxy resin cured with an anhydride hardener and catalyzed by a tertiary amine were studied extensively at the molecular level. The reaction mechanism described by Antoon and Koenig was condensed to two reactions: (i) a propagation reaction involving the epoxy monomer and a hydrogen-bonded carboxyl/tertiary amine and (ii) an equilibrium reaction between the hydrogen-bonded carboxyl/tertiary amine and a carboxyl/tertiary ammonium. For isothermal, batch reactions the model predicts an exponential decay for the two monomers with respect to increasing reaction time and a population density distribution of polymeric molecules described by a Poisson molar distribution. Both functions were experimentally observed. Data interpretation yielded numerical values for the propagation rate constant and for the equilibrium constant as Arrhenius functions in temperature. The concentration of initiator in the resin was also determined. Experimental measurements used the analytical capabilities of gel permeation chromatography.