A series of poly(ester imide)s (PEIMs) has been synthesized from N-[4-(chloroformyl)phenyl] -4-(chloroformyl)phthalimide and different diols with methylene units of 4 to 12 (n). PEIMs with both even and odd methylene units exhibit a monotropic mesophase behavior during cooling due to the supercooling necessary for crystallization. Identification of this mesophase as a monotropic liquid crystal with smectic A order has been carried out via differential scanning calorimetry, wide angle X-ray diffraction (WAXD), small angle X-ray scattering, polarized light microscopy, and transmission electron microscopy. It is found that the methylene units in these chain molecules are also largely responsible for the formation of this liquid crystal phase. After investigating different types of main chain mesogen-nonmesogen liquid crystal polymers, a general concept considering the contributions to enthalpy aind entropy changes during the liquid crystal transitions may be associated with the relative rigidity, linearity, and regularity of the mesogenic groups compared to the methylene units. Detailed WAXD study of fiber and powder patterns indicates that the degree of orientation and the order correlation lengths along and perpendicular to the direction of chain molecules (chain lateral packing and layer structure) not only increase with the number of methylene units but also show an even-odd alternation. A possible chain packing model is suggested. The morphology and defects of this smectic A liquid crystal phtwe are also discussed.

Mesophase behavior of two poly(ester imides) synthesized from N-[4-(chloroformyl)phenyl]-4-(chloroformyl)phthalimide and 1,4-butanediol or 1,9-nonanediol has been extensively studied. One of the polymers has four methylene units (even) and the other nine methylene units (odd) in its respective flexible spacers. Both polymers show monotropic liquid crystal behavior which has been identified by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and polarized light microscopy (PLM) experiments. The liquid crystal phase seems to be more ordered than the nematic phase. Further crystallization from this liquid crystal phase can be achieved during cooling and/or isothermal experiments below the isotropic melt to liquid crystal transition temperature. This indicates that the molecules in the liquid crystal phase possess high mobility. Isothermal experiments on these polymers at temperatures above the monotropic liquid crystal transition lead to direct crystallization from the isotropic melt with large axilitic or spherulitic texture.

SynopsisA number of methyl-substituted bis[(phenyleneoxy) sulfone] dianilines were synthesized and reacted with pyromellitic dianhydride (PMDA), benzophenone tetracarboxylic acid dianhydride (BTDA), terephthaloyl chloride (TPC), isophthaloyl chloride (IPC), and trimellitic anhydride acid chloride (TMAC) to prepare a series of polyimides, polyamides, and poly(amide-imides), respectively. Low temperature solution and interfacial polymerization techniques were utilized to prepare the above polymers. Most of the polymers prepared formed tough, transparent flexible films. The prepared polymers were characterized by solution viscosity, thermal gravimetric analysis (dynamic and isothermal), and differential scanning calorimetry. The effect of the number and the ring substitution of methyl groups on polymer properties is discussed.

A spectrum of newly synthesized polyamides have been characterized with the intent of elucidating crystalline and possible liquid crystalline behavior. The different polymers contained various rotatable linkages in the main chain as well as substituent methyl groups in some cases. These were deemed as important variables for controlling the propensity to form ordered morphologies in these polymers. Methods of characterization included: X‐ray diffraction analysis, differential scanning calorimetry, and optical birefringence.

SYNOPSISA series of novel poly (ester-imide) s were prepared by the reaction of meta-and parasubstituted trimellitimide dicarboxylic diacid chlorides with various diols containing four, five, six, seven, eight, nine, 10, and 12 methylene groups by a solution polymerization technique utilizing refluxing 1,2,4-trichlorobenzene as a solvent. The poly (ester-imide) s were characterized by dilute solution viscosity, infrared spectroscopy, differential scanning calorimetry, and polarized light microscopy. The inherent viscosities of the meta-substituted poly( ester-imide) s ranged from 0.06 to 0.25 dL/g while those of the para-substituted poly(ester-imide) s ranged from 0.10 to 0.65 dL/g and were obviously of higher molecular weight. The meta series were amorphous and showed no mesophase formation. All parasubstituted poly (ester-imide ) s exhibited monotropic mesophase identified as smectic A order.