Effect of pyridazine structure on thin-film polymerization and phase behavior of thermotropic liquid crystalline copolyesters

M. M. Teoh, S. L. Liu, Tai-Shung Chung*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)2230-2242
Number of pages13
JournalJournal of Polymer Science, Part B: Polymer Physics
Volume43
Issue number16
DOIs
StatePublished - Aug 15 2005

Keywords

  • Copolyester
  • Phase behavior
  • Pyridazine heteroatom
  • Thermotropic liquid crystalline polymer

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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