Blends of a polyetherimide and a liquid crystalline polymer. Fiber orientation and mechanical properties

Addition of liquid crystalline polymers (LCPs) can be an outstanding tool to improve processability of engineering thermoplastics without decreasing their mechanical properties. LCPs can reduce the extrusion temperature of the host matrix, due to their low melt viscosity, even if added in low amounts. Some of us worked in the past on the physical characterization of the blends of a thermoplastic polyetherimide (ULTEM 1000 by GE) and a liquid crystalline polymer (K 161 by Bayer Co.). The mechanical analysis evidenced that the values of the tensile modulus of ULTEM were not affected by the inclusion of low amounts of liquid crystalline filler. On the other hand, if 30% w/w of thermotropic filler is added, a considerable decrease in the viscosity as well as a large increase in the fiber's Young modulus results. In this article, we propose to relate the mechanical properties with the structure of the blends on the basis of X-ray diffraction patterns of the spun fibers.