Preparation of phosphorus-containing polymers—XV. Preparation of phosphorus-containing polyamide-imides from N,N′-bis(4-carboxyphthalimido)-3,3′-diphenylalkylphosphine oxide and aromatic diacetamides

Phosphorus-containing polyamide-imides were prepared from N,N′-bis(4-carboxyphthalimido)-3,3′-diphenylalkylphosphine oxide and aromatic diacetamido derivatives by acidolysis; the reaction conditions are discussed. The resulting polymers were fairly soluble in DMA, DMF and conc. H₂SO₄; the reduced viscosities of polymers in DMA or cone. H₂SO₄ (0.2 g/dl) at 30° were 0.19–0.32. The phosphorus-containing polymers have good thermal stability, and are self-extinguished immediately after the flame is removed. Most of the i.r. absorption bands of polymers vanished on heating at above 600°.