Witold Brostow (1), Nandika A. D'Souza (1), Bhaskar Gopalanarayanan (1) and Elizabeth Jacobs (2) 

(1) Department of Materials Science, University of North Texas, Denton, TX 76203-5310, USA
(2) Texas Instruments, Inc., MS. 477, 13532 North Central Expressway, Dallas, Texas 752443

ABSTRACT

Linear thermal expansivities aL and thermal conductivities of polyimide (TPI) and polymer liquid crystals (PLC) blends were studied. The glass transition temperatures Tg of our amorphous TPI and the PLC are, respectively, 240 and 220C. The addition of the PLC induces orientation through the channeling process, as predicted by an extension of the Flory statistical-mechanics theory of PLCs. Channeling was observed at PLC concentrations as low as 5wt%. Thermal conductivity decreases with the addition of the PLC to the TPI. The anisotropic expansivity of the blends shows a strong dependence on PLC concentration and orientation direction. The pure PLC shows a maximum on the along-the-flow expansivity vs. temperature curves and also negative aL values. TPI addition moves the expansivities to positive values, but the maximum persists, even for 5% PLC only.