Epoxy Resin — Melting & Curing

As temperature is ramped, the multi-frequency loss factor ε" shows a series of dipole relaxation peaks as the epoxy resin passes through its glass transition temperature. The loss factor then rises rapidly as the epoxy melts, reflecting the dramatically increasing ionic mobility in the resin. The ion viscosity curve is derived from the ionic mobility component of the loss factor and is a frequency independent parameter related to the viscosity of the polymer before gelation and to rigidity after gelation. The ion viscosity initially decreases reflecting the effect of increasing temperature on the dynamic viscosity, of the resin. The initiation of reaction, however, competes with the temperature effect by restricting mobility and results in a clearly defined viscosity rises, reflecting the increasing viscosity and cure state of the material. To illustrate the degree of cure, the dielectric cure index may be utilized. (measurement with DEA 288)