ANOMALOUS ORIENTATION BEHAVIOR IN A SERIES OF COPOLY(ESTER IMIDE)S OBSERVED BY WIDE-ANGLE X-RAY-DIFFRACTION

A series of copoly(ester imide)s (CPEIs) was synthesized by the esteri fication of N,N'-dodecane-1,12-diylbis(trimellitimide) to two differen t acetylated diols, 4,4'-dihydroxybiphenyl and hydroquinone, in varyin g proportions. On the basis of their compositions, six samples are des ignated as CPEI(A-F), in which CPEI(A) is a homopolymer having 100% of incorporated 4,4'-dihydroxybiphenyl and CPEI(F), a homopolymer having 100% of incorporated hydroquinone. The composition ratios of the copo lymers are 80/20 (B), 60/40 (C), 40/60 (D), and 20/80 (E). Except for CPEI(F), the five CPEI(A-E)s show enantiotropic liquid crystalline beh avior during cooling from the isotropic melt. In all of the samples, h ighly ordered smectic crystal phases are assumed in the solid state. I n the course of structural identification, it has been found that CPEI (A-E)s often exhibit anomalous wide-angle X-ray diffraction (WAXD) fib er patterns: the smectic layer normal is perpendicular to the fiber di rection while the (hkO) reflections exhibit maxima along the meridian. Furthermore, the degree of orientation for the (hkO) reflections is a pparently much lower than that of the layer structure. Crystallographi c analysis is given to provide a quantitative explanation of experimen tally obtained WAXD fiber patterns.