ABSTRACT
Owing to the relatively low melt viscosity of thermotropic liquid-crystalline polymers (LCPs), often a small amount of LCP decreases the blend viscosity significantly and renders the matrix thermoplastics easier to process. The viscosity behavior of LCP1 is more non-Newtonian than that of LCP2, so that different levels of viscosity ratios could be obtained by using two different LCPs. In addition, for the polypropylenes, the shear thinning effect was even more pronounced. The degree of orientation of the LCP fibers can be modified through the choice of processing conditions, especially by applying high shear or elongational forces to the molten polymer. Studies with blends of LCPs and thermoplastics have shown indications that for good fibrillation to be achieved the viscosity of the dispersed LCP phase should be lower than that of the matrix. The viscosity ratio between LCP and PP was shown to have a great influence on particle size of the dispersed LCP domains evidenced by the microscopy.
