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Molecular Design, Synthesis and Properties of Novel Polyurethanes Containing Tetracyanocyclopropyl Groups as Piezoelectric Chromophores
Author(s) -
Lee JuYeon,
Bang HanBae
Publication year - 2004
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200300067
Subject(s) - polymer , chromophore , thermal stability , glass transition , diol , materials science , yield (engineering) , polymer chemistry , piezoelectricity , hydrogen bond , composite material , chemistry , molecule , organic chemistry
Summary: 1‐(2′,2′,3′,3′‐Tetracyanocyclopropyl)‐3,4‐di‐2′‐hydroxyethoxybenzene (4) was prepared by the reaction of bromomalononitrile with 3,4‐di‐(2′‐hydroxyethoxy)benzylidenemalononitrile (3). The dipole moment of diol 4, calculated by the ASED‐MO method, was 4.01 D. Diol 4 was condensed with 2,4‐toluenediisocyanate and 3,3′‐dimethoxy‐4,4′‐biphenylenediisocyanate to yield polyurethanes 5 and 6 containing tetracyanocyclopropane functionalities in the side‐group. The resulting polymers 5 and 6 were soluble in common organic solvents and the inherent viscosities were in the range of 0.25–0.30 dL · g −1 . Solution‐cast films showed a thermal stability up to 280 °C with glass‐transition temperatures of 163–167 °C. The approximate lengths of aligned piezoelectric chromophores estimated from AFM images of poled polymer films were about 4 nm. Piezoelectric coefficients ( d 31 ) of the poled polymer films 5 and 6 were around 2.2–2.4 pC · N −1 . These polymers showed good temporal and long‐term thermal stability due to the hydrogen bonding of the urethane linkage.Structure of one of the obtained polymers.