PRE-TILT ANGLES AS S FUNCTION OF POLYIMIDE COMPOSITION FOR COPOLYIMIDES

Six series of copolyimides have been synthesized. The pre-tilt angle h as been measured as a function of the composition of these copolyimide s. A linear relationship was found between the pre-tilt angle and the composition when both the simple polyimides are amorphous. When one or more of the simple polyimides is semi-crystalline there is normally a strong deviation from linearity. The copolyimides will then usually g ive pre-tilt angles lower than expected from an average of these for t he two simple polyimides.