THE ROLE OF PARTIAL MISCIBILITY ON THE PROPERTIES OF BLENDS OF A POLYETHERIMIDE AND 2 LIQUID-CRYSTALLINE POLYMERS

This paper is concerned with the existence of partial miscibility of a polyetherimide (PEI) with both amorphous and semicrystalline liquid crystalline polymers (LCPs) and its effect on the morphology of the blends of these polymers. Partial miscibility was determined by measuring the shift in the glass transition temperatures as determined by dynamic mechanical thermal analysis and differential scanning calorimetry. With increasing concentration of the LCP in the PEI/LCP blends, the glass transition temperature of the PEI phase shifted to a lower temperature. Annealing and mixing history were also observed to affect the degree of shift in the glass transition temperature. Morphologies of the partially miscible systems were found to be quite different from those of an immiscible system. It is likely that due to partial miscibility in these blends, a PEI-LCP solid solution coexists with the neat LCP phase.