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Synthesis and characterization of novel optically active poly(imide–urethane)s derived from N , N ′‐(pyromellitoyl)‐bis‐( L ‐leucine) diisocyanate and aromatic diols
Author(s) -
Mallakpour Shadpour,
Shahmohammadi Mohammad Hassan
Publication year - 2004
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.1416
Subject(s) - specific rotation , polymer chemistry , imide , inherent viscosity , ethyl chloroformate , triethylamine , condensation polymer , monomer , chemistry , phenolphthalein , polymerization , hydroquinone , organic chemistry , polymer , intrinsic viscosity
N , N ′‐(Pyromellitoyl)‐bis‐( L ‐leucine) diacid was reacted with ethyl chloroformate in the presence of triethylamine followed by reaction with activated sodium azide and gave N , N ′‐(pyromellitoyl)‐bis‐( L ‐leucine) diacylazide in high yield. This diacylazide was heated in dry benzene and gave the unstable N , N ′‐(pyromellitoyl)‐bis‐( L ‐leucine) diisocyanate ( 5 ) in quantitative yield. Thus, diisocyanate 5 was generated in situ and polycondensation reaction of this monomer with several aromatic diols, such as 4,4′‐dihydroxybiphenyl, 1,4‐hydroquinone, bisphenol A, phenolphthalein and 1,4‐dihydroxyanthraquinone, was performed in dry toluene under refluxing in the presence of 1,4‐diazabicyclo[2.2.2]octane (triethylenediamine) as a catalyst. The polymerization reactions proceeded within 48 h, producing a series of optically active poly(imide–urethane)s with good yield and moderate inherent viscosity in the range 0.18–0.28 dl g −1 . All of the above polymers were fully characterized by infrared spectra, elemental analyses and specific rotation. Some structural characterization and physical properties of these optically active poly(imide–urethane)s are reported Copyright © 2003 Society of Chemical Industry