Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
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Effects of Alkoxy Side Chain on the Properties of Wholly Aromatic Liquid Crystalline Polyesters with Biphenylene Units

알콕시 곁사슬기가 비페닐렌구조를 갖는 전방향족 액정폴리에스터의 물성에 미치는 영향

  • Lee, Eung-Jae (Dept. of Bioenvironmental & Chemical Engineering, Chosun College University of Science & Technology) ;
  • Bang, Moon-Soo (Division of Advanced Materials Science and Engineering, Kongju National University)
  • 이응재 (조선이공대학 생명환경화공과) ;
  • 방문수 (공주대학교 신소재공학부)
  • Received : 2010.08.05
  • Accepted : 2010.10.15
  • Published : 2010.10.31
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Abstract

Wholly aromatic polyesters having flexible alkoxy side chain were synthesized by direct polycondensation. The synthetic polymers have been characterized by $^1H$-NMR, FT-IR. DSC, TGA, optical polarizing microscope and X-ray diffractometer. The inherent viscosities (${\eta}_{inh}$) measured in 1,1,2,2-tetrachloroethane (TCE) were 0.46~2.41 dL/g. The polymers having side chain showed double melting transition, ie, solid-sanidic liquid crystalline (LC) phase transition ($T_{m1}$) and sanidic LC phase-nematic LC phase transition ($T_{m2}$). As incresing length of alkoxy side chain, phase transition temperatures decreased and solubilities in organic solvents incresed. The peaks of $2{\theta}\;{\simeq}5$ and $2{\theta}\;{\simeq}20$ in X-ray diffractograms are due to crystallization of polymer main chain and of long side chain, respectively.

유연한 알콕시 곁사슬을 갖는 전방향족 폴리에스터가 direct polycondensation에 의하여 합성되었으며, 합성된 중합체들은 $^1H$-NMR, FT-IR, DSC, TGA, 편광현미경 및 X-ray 분석기에 의하여 조사되었다. 1,1,2,2-테트라클로로에탄(TCE)을 용매로 사용하여 측정된 중합체의 고유점성도(${\eta}_{inh}$)는 0.46~2.41 dL/g의 값을 나타내었다. 곁사슬을 갖는 중합체들은 두 개의 용융전이 즉, 고체상-sanidic 액정상으로의 전이 ($T_{m1}$)와 sanidic 액정상-nematic 액정상으로의 전이 ($T_{m2}$)를 나타내었으며, 알콕시 곁사슬의 길이가 증가함에 따라 상전이온도들은 감소하고, 유기용매에 의한 용해도는 증가하는 경향을 나타내었다. X-ray 분석에서, $2{\theta}\;{\simeq}5$와 $2{\theta}\;{\simeq}20$ 피이크는 각각 중합체 주사슬과 긴 곁사슬의 결정화에 의한 것으로 나타났다.

Keywords

References

  1. H.Han and P.K.Bhowmik, "Wholly aromatic liquid-crystalline polyesters", Prog. Polym. Sci., 22, 1431-1502, 1997. https://doi.org/10.1016/S0079-6700(96)00028-7
  2. Y-W.Kwon, D.H.Choi, and J-I.Jin, "Liquid Crystalline Aromatic Polyesters" polymer(Korea), 29, 523-535, 2005.
  3. D.Y.Kim, "Main Chain Liquid Crystalline Polymers" Polymer Science and Technology, 2, 415-423, 1991.
  4. W.Grasser, H.-W.Schmidt, and R.Giesa, "Thermotropic liquid crystalline copolyesters with non-coplanar biphenylene units tailored-for blend fiber processing with PET", Polymer, 42, 8529-8540, 2001. https://doi.org/10.1016/S0032-3861(01)00356-1
  5. M.M.Marugan, E.Perez, R.Benavente, A.Bello, and J.M.Perena, "Solubility parameters of thermotropic polybibenzoates with various spacers", Eur. Polym. J., 28, 1159-1163, 1992. https://doi.org/10.1016/0014-3057(92)90201-C
  6. J.Watanabe, M.Hayashi, A.Morita, and M.Tokito, "Thermotropic liquid crystals of main-chain polyesters having a mesogenic 4,4'-biphenyldicarboxylate unit", Macromolecules, 28, 8073-8079, 1995. https://doi.org/10.1021/ma00128a015
  7. M.Ballauff, "Rigid rod polymers having flexible side chains,1", Makroml. Chem., Rapid Commun., 7, 407-414, 1986. https://doi.org/10.1002/marc.1986.030070615
  8. C.Han, O-C.Jeon, Y-J.Kim, D-S.Yun, K-Y.Sung, and J-K.Choi, "Syntheses and Properties of New Wholly Aromatic Polyesters Having Alkoxy Group in the Side Chains", J. Korean Ind. Eng. Chem., 11, 366-370, 2000.
  9. L.L.Lin and J.L.Hong, "Semi-rigid thermotropic polyester containing a rigid, bent spirobicromane moieties-primary characterization and the thermal behavior", Polymer, 41, 4501-4512, 2000. https://doi.org/10.1016/S0032-3861(99)00668-0
  10. M.Bagheri, Kh.Didehban, Z.Rezvani, and A.Entezami, "Thermotropic polyesters: Part 1. Synthesis, characterization and thermal transition of poly [4,4'-bis (${\omega}$-alkoxy) biphenyl isophthalate]", Eur. Polym. J. 40, 865-871, 2004. https://doi.org/10.1016/j.eurpolymj.2003.11.026
  11. M.Bagheri, Kh.Didehban, and A.Entezami, "Thermotropic Polyesters (Part 3): Synthesis, Characterization and Thermal Transition of Random Copolyesters Containing Terephthalate and Isophthalate Units", Iran. Polym. J., 13, 327-334, 2004.
  12. U.Caruso, P.Jannelli, S.Pragliola, A.Roviello, and A,Sirigu, "Mesomorphism in Segmented-Chain Polymers Containing Flexible Substituents in the Rigid Moiety", Macromolecules, 28, 6089-6094, 1995. https://doi.org/10.1021/ma00122a014
  13. P.Iannelli, U.Caruso, S.Pragliola, A.Roviello, and A.Sirigu, "Rigid-rod liquid crystalline polyesters based on n-alkoxyterephthalic acid and 4,4-dihydroxybiphenyl" J. Polym. Sci., Polym. Chem., 36, 263-267, 1998. https://doi.org/10.1002/(SICI)1099-0518(19980130)36:2<263::AID-POLA8>3.0.CO;2-S
  14. M.S.Bang, "Synthesis and Properties of Aromatic Poly(ether-ether-ester)s having Flexible Side Chain" J. the Korea Academia-Industrial Cooperation Society, 10, 3060-3065, 2009. https://doi.org/10.5762/KAIS.2009.10.11.3060
  15. M.S.Bang, "Synthesis and Properties of Liquid Crystalline Copolymers with Ether-ether-ester Linkage in Main Chain" J. the Korea Academia-Industrial Cooperation Society, 11, 1367-1372, 2010. https://doi.org/10.5762/KAIS.2010.11.4.1367
  16. K.S.Lee, B.W.Lee, J.C.Jung, and S.M.Lee, "Synthesis and Properties of Processible Wholly Aromatic Polyesters : New Types of Liquid Crystalline Polymers" Polymer(Korea), 13, 47-55, 1989.
  17. F.Higashi, T.Mashimo, and I.Takahashi, "Preparation of aromatic polyesters by direct polycondensation with thionyl chloride in pyridine" J. Polym. Sci., Polym. Chem, 24, 97-102, 1986. https://doi.org/10.1002/pola.1986.080240108
  18. H.R,Kricheldorf, and D.F.Wulff, "Layer structure 12. Chiral sanidic polyesters derived from 2,5-bis(hexadecyloxy) terephthalic acid, 2,5-bis((S)-2-methylbutoxy)terephthalic acid, and 4,4'-dihydroxybiphenyls" Polymer, 39, 2683-2692, 1998. https://doi.org/10.1016/S0032-3861(97)00580-6