'One-step' synthesis of hyperbranched macromolecules

Highly branched polymers, with branches at almost every repeat unit, has been a neglected subject until recently. Initial interest dates back to the early 1950's with the publication of a theoretical paper by Flory on polymers made from A_XB monomers. We wish to report the 'one-step' synthesis of a hyperbranched polyether using 3,5-dihydroxybenzyl bromide, 1, as the A_XB monomer unit. We have demonstrated that the synthesis of hyperbranched polyether macromolecules from the A₂B monomer, 3,5-dihydroxybenzyl bromide is both viable and practical. The polymers obtained are of acceptable molecular weights, and yields varied from fair to good. The use of a variety of other A₂B monomers in 'one-step' polycondenstion reactions to give hyperbranched macromolecules is currently under active investigation. At present, the synthesis of these hyperbranched macromolecules is being refined to give better control over variables such as molecular weight, polydispersity and degree of branching. Modification of the 'surface' functional groups with various reactive small molecules and polymers is also under investigation.