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. 13C NMR indicates about 70% branching efficiency. A Tgat 236°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.