Lyotropic Liquid Crystalline Polyamides Containing Aromatic, Heterocyclic Structures: Preparation and Properties

✍ Scribed by Pengtao Liu; Jinyan Wang; Cheng Liu; Xigao Jian

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 245 KB
• Volume: 207
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.200600202

✦ Synopsis

Abstract

Summary: A series of novel lyotropic liquid crystalline polyamides derived from 1,2‐dihydro‐2‐(4‐aminophenyl)‐4‐[4‐(4‐(aminophenoxyl)phenyl)]‐phthalazinone (DHPZ‐DA), p‐phenylene diamine (PPD) and terephthaloyl dichloride (TPC) have been successfully synthesized by the low temperature solution polycondensation method. The copolymers obtained with inherent viscosity of ≈1.21 to 3.29 dl · g^−1^, determined in NMP (1 wt.‐% LiCl) or concentrated H~2~SO~4~ at 25 °C, were confirmed to be amorphous by WAXD and differential scanning calorimetry (DSC). Their solubility was improved by the introduction of non‐coplanar, twisted phthalazinone moieties and ether linkages into the main chain with the result that they can be soluble in some polar solvents containing a small amount of LiCl. Their T~g~s were all above 310 °C and 10% weight loss temperatures in nitrogen above 500 °C. Most of these polyamides can form an anisotropic phase in concentrated H~2~SO~4~, NMP (1 wt.‐% LiCl) and DMAc (1 wt.‐% LiCl) solutions, observed on a polarizing light microscope.

Optical micrograph (×40) of polyamide P‐4060 at 10 wt.‐% in NMP/LiCl (1% w/v) solution at room temperature.

imageOptical micrograph (×40) of polyamide P‐4060 at 10 wt.‐% in NMP/LiCl (1% w/v) solution at room temperature.