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http://dx.doi.org/10.14478/ace.2013.1101

Synthesis and Properties of Liquid Crystalline Polyesters with X-shaped Mesogenic Group in Main Chain  

Park, Jong-Ryul (Division of Advanced Materials Science and Engineering, Kongju National University)
Cho, Kuk-Young (Division of Advanced Materials Science and Engineering, Kongju National University)
Bang, Moon-Soo (Division of Advanced Materials Science and Engineering, Kongju National University)
Publication Information
Applied Chemistry for Engineering / v.25, no.1, 2014 , pp. 47-52 More about this Journal
Abstract
A series of liquid crystalline polyesters containing X-shaped mesogenic groups in main chain were synthesized through the solution polymerization of 2,5-di(4-substituted benzoate)hydroquinones and 4,4'-dicarboxy-1,8-diphenoxyoctane. The structures and properties of synthesized polymers were investigated by $^1H$-NMR, FT-IR, differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), polarized optical microscopy (POM) and wide angel X-ray diffraction (WXRD). Inherent viscosities (${\eta}_{inh}$) of polymers were measured between 0.35 and 0.66 dL/g in 1,1,2,2-tetrachloroethane, and they were easily soluble in most of organic solvents used for this experiment. All polymers revealed relatively low melting transition temperature ($T_m$) and crystallinity, and also showed thermotropic nematic liquid crystallinity when they were heated to their melting temperatures. These properties of polymers were presumably due to the presence of the bulky substituting groups on the hydroquinone unit in mesogenic group.
Keywords
liquid crystalline polymer; polyester; X-shaped mesogenic group; methylene spacer;
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