SYNTHESIS OF POLY(BENZYLIDENE PHTHALIDE)S - A NEW CLASS OF POLYMERS

Pyromellitic dianhydride (PMDA) was condensed with different aromatic diacetic acids via a Perkin reaction to produce new polymers containing the benzylidenephthalide group in the backbone. Yields ranged from 50 to 90% with inherent viscosities ranging from 0.07 to 0.37 dL/g. Polymerizations at 275-degrees-C for 4 h using p-phenylenediacetic acid and PMDA gave the polymer with highest inherent viscosity. However, polymerization under identical conditions of p,p'-diphenyldiacetic acid and p,p'-diphenyl ether diacetic acid, each with PMDA, yielded poor results. For these two monomers the best polymerization conditions were 250-degrees-C for 8 h. In general, the most thermally stable polymer was derived from the diphenyl ether diacetic acid monomer (308-degrees-C). This polymer was obtained in highest yields and gave the greatest amount of pyrolytic residue in argon (67%).