The effect of a third component on the morphology and mechanical properties of liquid-crystalline polymer and polypropylene in situ composites

Maleic-anhydride-grafted PP (MAGPP) and polycarbonate (PC) were used as the third component and their effect on the morphology and the mechanical prop erties of in situ composites of Rodrun liquid-crystalline polymer (LCP) and polypropylene (PP) has been investigated. The addition of LCP in a PP matr ix resulted in an increase in tensile modulus but a decrease in tensile str ength. The addition of MAGPP as third component in the LCP/PP binary system has considerable effect on both the tensile strength and tensile strain. F urthermore, the introduction of PC in the LCP/PP binary system resulted in a significant increase in tensile modulus, tensile strength and tensile str ain. The 30 wt% of PC in the LCP/PP/PC ternary system was an optimum value for the best mechanical properties. A lamella-like morphology was found at the tensile fracture surface of the LCP/PP/PC ternary system whereas it was ribbon-like structure in the LCP/PP binary system. (C) 1999 Elsevier Scien ce Ltd. All rights reserved.