Please use this identifier to cite or link to this item: https://doi.org/10.1002/polb.20509
Title: Effect of pyridazine structure on thin-film polymerization and phase behavior of thermotropic liquid crystalline copolyesters
Authors: Teoh, M.M. 
Liu, S.L.
Chung, T.S. 
Keywords: Copolyester
Phase behavior
Pyridazine heteroatom
Thermotropic liquid crystalline polymer
Issue Date: 15-Aug-2005
Citation: Teoh, M.M., Liu, S.L., Chung, T.S. (2005-08-15). Effect of pyridazine structure on thin-film polymerization and phase behavior of thermotropic liquid crystalline copolyesters. Journal of Polymer Science, Part B: Polymer Physics 43 (16) : 2230-2242. ScholarBank@NUS Repository. https://doi.org/10.1002/polb.20509
Abstract: An intensive study has been conducted to compare the effects of malei hydrazine (MH) and hydroquinone (HQ) on the liquid crystallinity and phase transition behavior in the ABA/HQ/TFTA and ABA/MH/TFTA copolyesters (p-acetoxybenzoic acid (ABA) and tetrafluoroterephthalic acid (TFTA)). These two copolyesters were prepared by thin-film polymerization and characterized by differential scanning calorimetry (DSC), polarizing light microscope (PLM), wide-angle X-ray diffraction (WAXD), as well as Cerius2 computational simulation. Characterization and comparison of the liquid crystalline (LC) evolution and morphology changes of HQ moiety with corresponding MH moiety suggest that ABA/MH/TFTA system is energetically favorable to mesophase formation than ABA/HQ/TFTA system. When the films are quenched, a surface microcrack decoration is observed in both systems. Both systems, which have the persistence ratio larger than 6.42, satisfy the minimum requirement for the LC formation by molecular science software. The ABA/MH/TFTA film exhibits only one single peak transition. However, two distinct transitions have been observed in the ABA/HQ/TFTA system. The average Avrami exponent, n, is ∼1.2, and PLM and WAXD results suggest mesophase transition in ABA/MH/TFTA film. As reflected by the results obtained from PLM, WAXD, and DSC studies, the phase transition is confirmed as crystal → nematic → isotropic in ABA/HQ/TFTA copolyester. © 2005 Wiley Periodicals, Inc.
Source Title: Journal of Polymer Science, Part B: Polymer Physics
URI: http://scholarbank.nus.edu.sg/handle/10635/88796
ISSN: 08876266
DOI: 10.1002/polb.20509
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