HIGHLY BRANCHED AROMATIC POLYMERS PREPARED BY SINGLE-STEP SYNTHESES

Highly branched polyphenylenes, polyphenylene ethers, aromatic polyesters and polyamides synthesized from AB2 type monomers are reviewed. Polyphenylenes were obtained by aryl-aryl coupling reactions of 3,5-dihalo-phenyl organometallic reagents. C-13 NMR indicates about 70% branching efficiency. A T(g) at 236-degrees-C was observed, but the polymer did not form films. Polyethers were prepared by oxidative coupling of 2,4,6-tribromophenol and 2,4-dibromophenol. The former monomer gave high molecular weight polymers but the latter monomer did not polymerize well. Condensation of 3,5-diaminobenzoic acid (I) and 3-aminoisophthalic acid derivatives in an amide solvent gave lyotropic hyperbranched aromatic polyamides. The GPC indicated a large degree of polymer aggregation in the amide solvent in the absence of a complexing salt.