Liquid Crystalline Polymers XIII Main Chain Thermotropic Copoly (Arylidene-Ether)s Containing 4-Teriary Butyl-Cyclohexanone Moiety Linked with Polymethylene Spacers

Nayef S. Al-Muaikel, Kamal I. Aly

Chemistry Department, College of Pharmacy, Al-Jouf University, Sakaka, Saudi Arabian.
Polymer Research Laboratory, Chemistry Department, Faculty of Science, Assiut University, Assiut, Egypt.

DOI: 10.4236/ojopm.2013.31004                

Abstract

A new homologous series of thermotropic liquid crystalline copoly(arylidene-ether)s based on 4-teriary butyl cyclohexanone moiety were synthesized by solution polycondensation of 4,4’-diformyl-α,ω-diphenoxyalkanes, I_a-d or 4,4’- diformyl-2,2’-dimethoxy-α,ω-diphenoxyalkanes II_a-d with the 4-teriary butyl-cyclohexanone III and cyclopentanone. A model compound IV was synthesized from the monomer III with benzaldehyde and characterized by elemental and spectral analyses. The inherent viscosities of the resulting polymers were in the range 0.22 - 0.92 dI/g. All the copoly(arylidene-ether)s were insoluble in common organic solvents but dissolved completely in concentrated H₂SO₄ and formic acid. The mesomorphic properties of these polymers were studied as a function of the diphenoxyalkane space length. Their thermotropic liquid crystalline properties were examined by DSC and optical polarizing microscopy and demonstrated that the resulting polymers form nematic mesophases over wide temperature ranges. The thermogravimetric analyses of those polymers were evaluated by TGA and DSC measurements and correlated to their structural units. X-Ray analysis showed that copolymers having some degree of crystallinity in the region 2q = 5^° -60^°. In addition, the morphological properties of selected examples were tested by Scanning electron microscopy.

Keywords

Liquid Crystal; Thermotropic; Synthesis; Characterization; Poly(Arylidene-Ether)s

Conflicts of Interest

The authors declare no conflicts of interest.

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