Synthesis and properties of new organosoluble and alternating aromatic poly(ester-amide-imide)s with pendant phosphorus groups

New phosphorus-containing aromatic diesteramines, 1,4-bis(4-aminobenzoyloxy)-2-(6-oxido-6H-dibenz〈c,e〉〈1,2〉oxaphosphorin-6-yl)naphthalene (p- 3 ) and 1,4-bis(3-aminobenzoyloxy)-2-(6-oxido-6H-dibenz〈c,e〉〈1,2〉oxaphosphorin-6-yl)naphthalene (m- 3 ), were synthesized by the reaction of 2-(6-oxido-6H-dibenz〈c,e〉〈1,2〉oxaphosphorin-6-yl)-1,4-naphthalenediol with 4-nitrobenzoyl chloride and 3-nitrobenzoyl chloride, respectively, followed by catalytic reduction. Two series of phosphorus-containing aromatic poly(ester-amide-imide)s with inherent viscosities of 0.94–2.00 and 0.41–0.56 dL/g were prepared via low-temperature solution polycondensation from p- 3 and m- 3 , respectively, with three imide ring-preformed diacid chlorides. All the poly(ester-amide-imide)s were amorphous and readily soluble in many organic solvents such as N,N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone (NMP). Transparent, tough, and flexible films of these polymers were cast from DMAc or NMP solutions. Their casting films possessed a tensile strength range of 118–181 MPa, an elongation to break of 5–11%, and an initial modulus range of 2.41–4.46 GPa. They had useful levels of thermal stability associated with relatively high glass-transition temperatures (264–286 °C) and 10% weight-loss temperatures in excess of 450 °C in nitrogen or air. The limiting oxygen indices of these polymers were 41–46. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1786–1799, 2001