Synthesis And Characterization Of Hyperbranched Polyamides

In this paper, two new AB2 monomers, ?-(3,5-diaminobenz -amido)-propionic acid and 6-(3,5-diaminobenzamido) -n-caproic acid were prepared and characterized. Hyperbranched aromatic polyamides were prepared by direct polycondensations of the two monomers in the presence of triphenyl phosphite and pyridine as condensation agents in NMP. End-capping reactions of the terminal amino groups were accomplished with seven kinds of acid chlorides. The structures of the resulting polymers were confirmed by IR, NMR. Their inherent viscosity, solubility and glass transi -tion temperatures were measured. Their inherent viscosity was low and solu -bility was high, consistent with a highly branched structure. Their glass transition temperatures were affected by the polarity and flexibility of end-groups. The glass transition is shifted toward higher temperatures with increasing polarity of end-groups, but shifted toward lower temperatures with increasing flexibility of end-groups.