Synthesis and characterization of segmented liquid crystal poly(azoxy polyester‐co‐polyoxypropylene)

In this study a series of a segmented copolyester, poly(4,4′‐dioxy‐2,2′‐dimethyl‐azoxybenzene dodecanedioyl) (PMABD)‐co‐polyoxypropylene 400 (POP), was prepared. The chain length of PMABD studied (n) was varied from 7.8‐18.2, and that of POP was unchanged. The intrinsic viscosity of the segmented copolyesters was 1.04‐1.30, and the number average molecular weight obtained was 2.53 × 10⁴−3.49 × 10⁴ g/mol. The mesophase texture and thermal properties of the segmented copolyesters were measured as functions of n. It was found that the insert of flexible POP between those liquid crystalline domains of PMABD did affect thermotropic properties of PMABD. As the n value was 9.0 and 7.8 (or 7.4 and 8.6% by weight POP) the texture appeared as cholesteric‐like oily streaks. The effect could not be attained by simply copolymerizing a mesogenic moiety with a pair of spacers of different lengths. The fluidity and domain structure of the flexible dodecanedioyl‐POP‐dodcanedioyl segments are taken into account for the obtained results. © 1995 John Wiley & Sons, Inc.