Dielectric Relaxation Study on EpoxyMatrix/Polyurethane Polymer Blend

A series of polymer blends are prepared by sequential mixing of epoxy resin EP with polyurethane PU. The effect of different amount of polyurethane 10%, 20%and 30% wt fraction on conduction and dielectric relaxation has been reported. It was found that all blends showed three activation energies (Eac) at all frequencies, and the glass transition temperature (Tg) was increased with PU wt fraction. The exponent s values were estimated to be less than unity for all blends. Cole-Cole diagram was used to evaluate the polarizability (α), molecular relaxation time (τ) and optical dielectric constant (εOP). The thermodynamic parameters also determined, the result showed that the Gibbs free energy of activation (∆G) and enthalpy (∆H) are high for all blends.