MECHANICAL PROPERTIES AND MORPHOLOGY OF THE BLENDS OF A COPOLYESTER LCP AND POLYAMIDE 66

Dynamic mechanical properties and morphology of a thermotropic liquid crystalline polymer poly(HBA/PET 80/20) and polyamide 66 (PA66) blends were studied. Rectangular samples were obtained by injection molding at 280 (C, which is above the nematic transition temperature of the LCP. Two parameters were investigated: LCP content varying from 0 to 100 wt% and the mould cavity thickness ranging from 1 to 4 mm. At a given mould thickness, the storage modulus (E') increased with increasing LCP content, which is due to an enhancement in the concentration of LCP fibers. The tan(peak was broad for the blends and the peak value decreased with increasing LCP content, resulting from the inclusion of rod-like rigid molecules. For pure LCP, E' increased with decreasing mould thickness in the temperature range studied (0-200(C). It was ascertained by XRD and SEM methods that better LCP fibrillation in the skin region could be achieved by increasing the shear rate through the reduction of the mould cavity thickness.