Molecular Design, Synthesis and Properties of Novel Polyurethanes Containing Tetracyanocyclopropyl Groups as Piezoelectric Chromophores

✍ Scribed by Ju-Yeon Lee; Han-Bae Bang

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 147 KB
• Volume: 205
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.200300067

✦ Synopsis

Abstract

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.

imageStructure of one of the obtained polymers.