Ordered structures in a series of liquid crystalline poly(ester imide)s

Journal Article · Mon Jul 05 00:00:00 EDT 1993 · Macromolecules; (United States)

DOI:https://doi.org/10.1021/ma00066a030· OSTI ID:6468992

Pardey, R; Shen, D; Gabori, P A; Harris, F W; Cheng, S Z.D. ^[1]; Adduci, J; Facinelli, J V ^[2]; Lenz, R W ^[3]

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1. Univ. of Akron, OH (United States). Institute and Dept. of Polymer Science
2. Rochester Institute of Technology, NY (United States). Dept. of Chemistry
3. Univ. of Massachusetts, Amherst, (United States). Dept. of Polymer Science and Engineering

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 and 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 WAXDR 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 phase are also discussed.

• OSTI ID: 6468992
• Journal Information: Macromolecules; (United States), Journal Name: Macromolecules; (United States) Vol. 26:14; ISSN MAMOBX; ISSN 0024-9297
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
CALORIMETRY
COHERENT SCATTERING
CRYSTALS
DIFFRACTION
ENTHALPY
ENTROPY
ESTERS
FLUIDS
IMIDES
LIQUID CRYSTALS
LIQUIDS
MATHEMATICAL MODELS
MICROSCOPY
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC POLYMERS
PHASE STUDIES
PHYSICAL PROPERTIES
POLYESTERS
POLYMERS
SCATTERING
SMALL ANGLE SCATTERING
SYNTHESIS
THERMODYNAMIC PROPERTIES
X-RAY DIFFRACTION