STUDIES ON MESOMORPHIC BEHAVIORS OF SEGMENTED AZOXY POLYESTER CONTAINING POLYOXYETHYLENE

A series of a segmented copolymer, poly(4,4'-dioxy-2,2'-dimethyl-azoxy benzene dodecanedioyl) -co-polyoxyethylene 400 (PMABD-co-POE) was prep ared; the average chain lengths n, of the PMABD studied are 8.1 to 20. 6. The thermotropic properties and the mesophase texture of the segmen ted copolymers were elucidated as functions of n using a differential scanning calorimeter and a polarized optical microscope with a hot sta ge. The results show that the incorporation of POE with PMABD decrease s the intermolecular interaction force and changes the chain flexibili ty. The nematic droplets obtained near the isotropic temperature all e xhibited a twisted bipolar configuration. Also, in the undercooling pr ocess, the nematic textures obtained before crystallizing varied with n. The copolymers containing n greater than or equal to 17, like PMABD , develop a Schlieren texture, whereas those containing n < 17 develop a distorted-stripe conformation. A possible mechanism for interpretat ion of the obtained results has been proposed. (C) 1995 John Wiley and Sons, Inc.