Synthesis and characterization of side-chain liquid crystal polyurethanes

✍ Scribed by M. Brecl; T. Malavas˘ic˘

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 488 KB
• Volume: 35
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(199710)35:14<2871::aid-pola8>3.0.co;2-t

✦ Synopsis

A series of liquid crystal a-[bis(2-hydroxyethyl)amino]-v-(4-nitroazobenzene-4-oxy)alkanes (Cn-diol) with different alkyl chain length has been synthesized. All Cn-diols exhibit a smectic phase that has been identified by means of polarizing microscopy and differential scanning calorimetry. These compounds are suitable monomers for the synthesis of side-chain liquid crystalline polyurethanes and polyesters. They were polymerized with hexamethylene diisocyanate to corresponding SCLC polyurethanes in which the spacer length was varied from 2 to 12 methylene units. Polyurethanes (CnP) with spacer lengths n ¢ 4 exhibited liquid crystalline behavior. Fourier transform infrared temperature studies of the CnP were done focusing on H-bonds between the N{H and C|O groups of the urethane backbone.