HIGHLY BRANCHED RADIAL BLOCK-COPOLYMERS VIA DENDRITIC INITIATION OF ALIPHATIC POLYESTERS

Living ring opening polymerization of epsilon-caprolactone initiated f rom the numerous chain-end hydroxymethyl groups of the analogous dendr imeric and hyperbranched polyesters derived from 2,2-bis(hydroxymethyl ) propionic acid is described. By controlling the size of the dendriti c macromolecule and the molar ratio of epsilon-caprolactone, a variety of highly branched radial block copolymers are obtained. Comparison o f the results obtained for the dendrimeric and hyperbranched initiator s demonstrates that the reactivity of the chain-end hydroxymethyl grou ps in the dendrimer are significantly greater than in the isomeric hyp erbranched case. (C) 1998 John Wiley & Sons, Inc.