INTERRELATIONSHIPS BETWEEN RHEOLOGICAL, MORPHOLOGICAL, AND MECHANICAL-PROPERTIES OF POLYSTYRENE LIQUID CRYSTALLINE POLYMER BLENDS/

The effects of the viscosity ratio of dispersed phase to matrix on the rheological, morphological, and mechanical properties of blends of po lystyrene and two rheologically different liquid crystalline polymers (LCPs) were investigated. Two different rheological behaviors are obta ined by blending polystyrene (PS) and two different LCPs: one is the c ase that the viscosity of dispersed phase is lower than that of matrix phase as observed in PS/Rodrun blends, and another one is the case th at the viscosity of dispersed phase is higher than that of matrix phas e as observed in PS/Vectra blends. Scanning electron micrographs of Fr acture surfaces of injection-molded samples show that the finely distr ibuted LCP fibril structure is observed for PS/Rodrun blends where the viscosity of the dispersed LCP phase is lower than that of the polyst yrene matrix phase, whereas dispersed LCP phase in PS/Vectra blends sh ow the spherical form of LCP domains. Mechanical properties of injecti on molded specimens show that the modulus of PS/Rodrun blends shows a strong positive deviation from the simple additive rule, whereas the m odulus of PS/Vectra blends follows the simple additive rule of mixture . These mechanical properties are well consistent with the morphologic al characteristics of the PS/LCP blends.