Heat of reaction, cure kinetics, and viscosity of Araldite LY-556 resin

The cure kinetics expression for Araldite LY-556 epoxy resin is determined by a differential scanning calorimeter (DSC). The heat of reaction, the rate of cure, and degree of cure are determined at constant temperature of 363, 373, 383, 393, 403, and 413 K (isothermal scanning) using the data generated by DSC. The ultimate heat of reaction also is measured at a constant heating rate of 5, 10, and 15 K/min (dynamic scanning). The viscosity is measured as a function of time at constant temperatures of 323, 343, and 363 K using a dynamic mechanical analyzer (DMA). Expressions are developed using the data generated by DSC and DMA, and by the curve fitting method, which represent the rate of cure, and the viscosity versus degree of cure and temperature. The new and accurate expressions are used for better modeling of the resin behavior.