MECHANICAL-PROPERTIES OF BLENDS OF LIQUID-CRYSTALLINE COPOLYESTERS WITH POLYPROPHYLENE

As new composites produced in the form of blends of thermotropic liquid crystals (LCP) with less expensive engineering thermoplastics became very popular recently, increased interest about the production and investigations of these materials is noted during the last few years [1-5]. First, the addition of the LCP permits us to essentially decrease the viscosity of certain engineering thermoplastics and therefore to facilitate the processing considerably. Second, during injection molding the drops of the LCP, as a dispersed phase, are lengthening out themselves into aniso-diametrical, thread-like forms, finally reinforcing the isotropic thermoplastic matrix. It allows us to obtain reinforced composites with improved physicomechanical properties directly during processing. To optimize the selection and the composition of the components as well as the processing conditions, investigations of the melt theological properties and the mechanical and physical properties of the products are necessary. The main purpose of our work was to determine the mechanical properties of the blend of the LCP with polypropylene and the anisotropy of mechanical properties produced as a result of processing by injection molding.