RHEOLOGICAL PROPERTIES OF CARBON BLACK-FILLED BLENDS OF LIQUID-CRYSTALLINE COPOLYESTER WITH THERMOPLASTIC POLYSULFONE

Rheological properties of a two-phase polymeric blend containing LC-CP E of poly(ethylene terephthalate) and p-hydroxybenzoic acid and thermo plastic polysulfone with varying concentrations of polymeric component s and particulate filler have been studied. The rheological behavior o f such blends at different temperatures is governed by variation of th e degree of ordering of LC-CPE macromolecules associated with the phas e transition in the CPE at 260-degrees-C. Experimental results are dis cussed on the basis of concepts of compatibility of polymeric componen ts in the melt or, if the system is incompatible, of the degree of int erphase interaction between the components, as well as the impact of t he filler and of the shear straining conditions on structurization in the system and compatibility. The filler exerts a compatibilizing effe ct on blend components, while the shear stress encourages the phase se paration in the system. An extremal variation of viscosity of the LC-C PE/carbon black, silica and talk blends with the filler concentration on both at the flow in a uniform shear stress field and at the capilla ry flow has been found. Normalization of the filler concentration with respect to its specific surface yields a unified concentration depend ence of the relative viscosity of LC-CPE filled with solid particles o f various natures and specific surfaces.