Thermotropic behavior of lithocholic acid derivative linked hydroxyethyl cellulose

✍ Scribed by V. A. E. Shaikh; N. N. Maldar; S. V. Lonikar; C. R. Rajan; S. Ponrathnam

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 252 KB
• Volume: 100
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.22285

✦ Synopsis

Abstract

Various mesogenic lithocholic acid (LA) derivatives [3‐acetyl LA (LAAC); 3‐propionyl LA (LAP), 3‐cinnamoyl LA (LACin); 3‐benzoyl LA (LAB), 3‐(4‐nitrobenzoyl) LA (LANB); and methyl‐3‐(3‐carboxypropionyl) LA, i.e., LA methyl ester monosuccinate (LAMeMS)] were reacted with hydroxyethyl cellulose (HEC) to obtain a series of LA derivatives of HEC. These polymers were characterized by the mesogen content, IR, differential scanning calorimetry, and hot‐stage coupled polarizing optical microscopy. The degree of substitution (DS) ranged from 0.27 to 1.11. Polymers HEC‐LAB (DS = 1.11), HEC‐LANB (DS = 0.80), HEC‐LACin (DS = 0.76), and HEC‐LAP (DS = 0.27) exhibited a mesophase on heating whereas HEC‐LAB also showed a mesophase on cooling. The other polymers HEC‐LAAC (DS = 0.89) and HEC‐LAMeMS (DS = 0.36) did not reveal mesophase formation with either heating or cooling. It is observed that the formation of a mesophase is affected by the type of mesogen that is used rather than the mesogen content of the polymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1995–2001, 2006