Synthesis and mesogenic properties of polyurethanes containing a naphthalene ring

✍ Scribed by Moriyuki Sato; Tetsuya Ito; Takanori Kobayashi; Ken-ichi Mukaida

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 352 KB
• Volume: 28
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(92)90274-6

✦ Synopsis

New polyurethanes with high inherent viscosities of 1.74-2.10 dl/g in l,l,l,3,3,3-hexafluoro-2propanol were prepared by melt polycondensation of a 2,6-dioxydihexanol derivative of naphthalene, prepared from naphthalene-2,6-diol and 6-chloro-l-hexanol, with even alkylene diphenyl dicarbamates (n = 6, 8, 10 and 12). The structures of the polymers were confirmed by FTIR, 13C-NMR spectra and elemental analyses. Thermotropic liquid-crystalline (LC) properties of the polyurethanes were evaluated by differential scanning calormetry, by optical texture observation with a polarizing microscope and with a X-ray diffractometer. It was discovered that the polyurethanes having only the naphthalene ring could form nematic LC textures in spite of low aspect ratio of the mesogenic unit.