Cure Index Analysis of Five-Minute Epoxy
Lambient Technologies tested a generic “Five-Minute Epoxy” to observe the effect of different thermal conditions on the progress of cure. For isothermal tests, ion viscosity measurements easily reveal cure state because temperature is not a variable; however, five-minute epoxy can generate a significant exotherm, making the typical reaction non-isothermal.
In this case, because ion viscosity depends on both cure state and temperature, reaction rate and degree of cure are not clear when analyzing ion viscosity alone. With Cure Index analysis, which accounts for the effect of temperature, dielectric measurements clearly show how cure time decreases and how degree of cure increases with greater peak exotherms, as expected for thermally driven reactions.