W. Brostow et al., Thermal expansivity and thermal conductivity of amorphous thermoplastic polyimide acid polymer liquid crystal blends, POLYM ENG S, 40(2), 2000, pp. 490-498
Linear thermal expansivities alpha(L),and thermal conductivities of polyimi
de (TPI) and polymer liquid crystal (PLC) blends were studied. The glass tr
ansition temperatures T-g of our amorphous TPI and the PLC are, respectivel
y, 240 and 220 degrees C. The addition of the PLC induces orientation throu
gh the channeling process, as predicted by an extension of the Flory statis
tical-mechanical theory of PLCs (27). Channeling was observed at PLC concen
trations as low as 5 wt%. Thermal conductivity decreases with the addition
of the PLC to the TPI. The anisotropic expansivity of the blends shows a st
rong dependence on PLC concentration and orientation direction. The pure PL
C shows a maximum on the along-the-flow expansivity vs, temperature curves
and also negative alpha(L) values. TPI addition moves the expansivities to
positive values, but the maximum persists, even for 5% PLC only.