Synthesis and characterization of polyimides containing heterocyclic units

Five new polyimides containing phenoxaphosphine as well as dibenzothiophene, phenoxathiin, and thianthrene units have been synthesized from 10‐phenylphenoxaphosphine‐2,3,7,8‐tetracarboxylic dianhydride‐10‐oxide and heterocyclic diamines by the cyclopolycondensation method. These polyimides had inherent viscosities in the 0.75–1.10 dL/g range in conc. H2SO4 at 30°C. All the polymers were characterized by elemental analysis, density, solubility, crystallinity, IR spectra, and thermal methods. Copyright © 1988 John Wiley & Sons, Inc.