Miscibility of a nematic liquid crystalline polymer pair

This work investigates the miscibility of two commercially important thermo tropic Main chain liquid crystalline polymers (LCPs), Vectra A950 and Vectr a B950, using dynamic mechanical analysis (DMA), differential scanning calo rimetry (DSC) and positron annihilation lifetime spectroscopy (PALS). Altho ugh previously reported to be either miscible or show a compositional-depen dent miscibility, they are shown here to be immiscible based on DMA, DSC an d PALS results. The latter technique is somewhat more novel in its use to a ssess miscibility, by probing the free volume of the blends and comparing t his to rule-of-mixtures values of the two components. (C) 2001 Elsevier Sci ence Ltd. All rights reserved.