ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
A series of polyethers was synthesized from 4-[2-(4-hydroxyphenyl)ethyl]-3-methylphenol and α, ω-dibromoalkenes, MBPE-n. The polymers with odd-numbered methylene spacers show a monotropic mesophase behavior during cooling from the isotropic melt before crystallization. The crystal structures of MBPE (n = odd) polyethers have been investigated through wide angle X-ray diffraction fiber patterns. Two crystallographic periods along the c-axis are found, one of which corresponds to the length of methylene spacers, and the other is close to an integral number times the length of the repeating unit. Polarized light microscopy observations of the uniaxially oriented samples obtained through mechanical shear show a banded texture, which is a typical morphology found in liquid crystal polymers. Transmission electron microscopy experiments provide morphological evidence to identify that this mesophase is a nematic liquid crystal state based on the disclination defect patterns defined by Frank. A relationship between splay elastic constant k11 and bend elastic constant k33 is discussed through lamellar decoration of disclination defects.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1993.021941117
