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Highly thermostable and low birefringent norbornene-styrene copolymers with advanced optical properties: A potential plastic substrate for flexible displays

Authors

  • Hoang The Ban,

    Corresponding author
    1. National Institute of Advanced Industrial Science and Technology (AIST), Central 5-8, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
    2. R & D Center, Zeon Corporation, 1-2-1 Yako, Kawasaki-ku, Kawasaki-shi, Kanagawa 210-9507, Japan
    • National Institute of Advanced Industrial Science and Technology (AIST), Central 5-8, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
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  • Hideaki Hagihara,

    1. National Institute of Advanced Industrial Science and Technology (AIST), Central 5-8, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
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  • Yasuo Tsunogae,

    1. R & D Center, Zeon Corporation, 1-2-1 Yako, Kawasaki-ku, Kawasaki-shi, Kanagawa 210-9507, Japan
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  • Zhengguo Cai,

    1. Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
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  • Takeshi Shiono

    1. Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
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Abstract

This article reports the synthesis and characterization of an extremely high thermostable cyclic olefin copolymer with advanced optical properties resulting from the vinyl addition copolymerization of norbornene with styrene catalyzed by a substituted fluorenylamidodimethyltitanium catalyst [Me2Si(3,6-tBu2Flu)(tBuN)]TiMe2 activated with a [Ph3C] [B(C6F5)4]/Al(iBu)3 cocatalyst using o-dichlorobenzene as solvent. The prepared copolymer possesses a glass transition temperature as high as polyimide (Tg > 300 °C) and a high transmittance which is comparable with that of the conventional optical resins ([T] > 90%). The incorporation of polystyrene, which exhibits a negative birefringence into the vinyl-added polynorbornene that possesses an intrinsic positive birefringence, effectively reduced the birefringent magnitude of the norbornene-styrene copolymer due to a mutual compensation between these opposite-sign birefringences. The absence of any functional and aromatic heterocyclic groups and the presence of highly hydrophobic saturated bicyclic rings in the copolymer main chains effectively prevented the diffusion of water/oxygen and thus enhanced the dimensional and optical stabilities of the material. Preliminary results on the characterization of the thermal stability, mechanical, and optical properties of the vinyl-added norbornene-styrene copolymers indicate that they satisfy all the rigorous requirements for a polymer to be applied as a flexible substrate for the manufacturing of the flexible displays. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

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