| Abstract: | A series of polybenzoxazinones containing phenoxathiin and phenoxaphosphine units were prepared from tricyclic diacid chlorides and 4,4′-diaminobiphenyl-3,3′-dicarboxylic acid and 4,4′-diamino-3,3′-diphenylmethane dicarboxylic acid. The low temperature solution polymerization technique afforded polyamic acid which subsequently underwent cyclization along the polymer chain in a solvent mixture of refluxing N,N′-dimethylacetamide, acetic anhydride, and pyridine to give polybenzoxazinones in moderate yields. The polymers thus obtained had inherent viscosities in the range of 0.15–0.23 dL/g, were sparingly soluble in N-methyl-2-pyrrolidone, and were found to be thermally more stable than the corresponding open-chain polymer with diphenylether linkage. |
