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http://dx.doi.org/10.14478/ace.2015.1052

Effect of Linkage Groups on the Properties of Semi-flexible Liquid Crystalline Polymers  

Park, Jong-Ryul (Division of Advanced Materials Science and Engineering, Kongju National University)
Yoon, Doo-Soo (Dept. of Bioenvironmental & Chemical Engineering, Chosun College of Science & Technology)
Bang, Moon-Soo (Division of Advanced Materials Science and Engineering, Kongju National University)
Publication Information
Applied Chemistry for Engineering / v.26, no.4, 2015 , pp. 445-451 More about this Journal
Abstract
Semi-flexible liquid crystalline polymers containing a mesogenic group and an octamethylene flexible spacer in the main chain were synthesized by solution polycondensation. The mesogenic group in the polymer consists of four aromatic rings connected by ester and ketone, ether, sulfide, methylene, sulfone, or isopropylidene linkage groups. This paper discusses effects of the central linker of the mesogenic group on polymer properties. The structures and properties of synthesized polymers were investigated by $^1H$-NMR, FT-IR, differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA), X-ray diffractometer (XRD), and polarizing optical microscope (POM). Polymers having bent linkage groups exhibited low thermal transition temperatures, narrow mesophase temperature ranges, low liquid crystallinity, and good solubilities in organic solvents, while those having bulky linkage groups were amorphous and exhibited high glass transition temperatures.
Keywords
aromatic; flexible spacer; linkage group; liquid crystalline polymer; mesogenic unit;
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