Effect of Curing Agent Type on Curing Reaction Kinetics of Epoxy Resin

Abstract

Curing agent types have a great influence on the reaction kinetics and post-curing properties of epoxy resins. The dynamic process of epoxy resin curing reaction will affect the structure, morphology and mechanical properties of cured products. In this paper, low molecular weight polyamides, aromatic amines and anhydrides were selected as three kinds of curing agents and their isothermal viscosity-time properties were studied to investigate the operational time and curing speed of the resin system. The non-isothermal Differential Scanning Calorimetry (DSC) method was conducted to study the curing reaction kinetics of three kinds of curing agent/epoxy resin systems so as to deduce the curing reaction kinetics model and calculate the corresponding kinetic parameters. Results showed that a low molecular weight polyamide curing agent blend resin system can occur at a lower temperature of curing reaction and the cure rate is fast. The curing process of the aromatic amine curing agent blend resin system is divided into two steps, while the anhydride curing agent blend system should be able to cure at high temperatures and have a long operating time. The theoretical curing temperatures of the three curing agents of low molecular polyamide, aromatic amine, primary curing and secondary curing and acid anhydride are respectively 74.13°C, 86.31°C, 165.24°C and 152.90°C, which are also the recommended curing temperatures of the corresponding curing agents.