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Lyotropic Liquid Crystalline Polyamides Containing Aromatic, Heterocyclic Structures: Preparation and Properties
Author(s) -
Liu Pengtao,
Wang Jinyan,
Liu Cheng,
Jian Xigao
Publication year - 2006
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200600202
Subject(s) - differential scanning calorimetry , polyamide , polymer chemistry , lyotropic , materials science , solubility , condensation polymer , diamine , optical microscope , micrograph , polymer , chemistry , crystallography , scanning electron microscope , organic chemistry , liquid crystalline , composite material , physics , thermodynamics
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.