DYNAMIC RHEOLOGICAL PROPERTIES OF POLYETHERIMIDE/POLYETHERETHERKETONE/LIQUID CRYSTALLINE POLYMER TERNARY BLENDS

The dynamic theological properties of poly(etherimide)/poly(etheretherketone)/liquid crystalline polymer (LCP) ternary blends were measured in order to correlate these properties with the morphology obtained after extrusion. The viscosity radio, eta(d)/eta(m), where eta(d) = disperse phase viscosity and eta(m) = matrix viscosity, had to be redefined. Below 50 wt% LCP, eta(d) = eta(LCP), eta(m) = eta(PEEK+PEI) and eta(d)/eta(m) < 1. Above 50 wt% LCP, eta(d) = eta(PEEK+PEI), eta(m) = eta(LCP) and eta(d)/eta(m) > 1. Fibrillar morphologies were obtained in both cases, except below a concentration of 20 wt% LCP. At low concentrations of LCP the ternary blends had lower viscosities than the component polymers, showing a flow promotion effect of the LCP on the PEI- and PEEK-rich phases.