Cure progress in epoxy systems: dependence on temperature and time

We have developed an analytical formula for the cure progress of epoxy systems as a function of both time t and temperature T. Complex viscosity h* or the storage modulus G' are used as the measures of the cure progress. The equation is based on the shape of the isothermal viscosity vs. time curves typically found for thermoset systems; temperature dependence of the isothermal parameters is established, resulting in a single equation. The equation has been tested for two vastly different thermoset epoxy systems and found to provide reliable predictive capabilities. The equation seems applicable for predicting curing progress of most thermoset systems, without a limitation to epoxies. Moreover, the equation can be used for discriminating accurate experimental results from less accurate ones.