Patent ID: 6255424
Filing Date: 2001-07-03
Classification: C08F,C08G

Abstract:
A convergent method for synthesizing dendritic polymeric materials, the method comprising:providing a living polymerization reaction mixture including polymeric precursor segments each having a living end capable of reacting in a polymerization reaction;coupling said precursor segments together in a convergent manner involving reaction of a multi-functional coupling agent to form a hyperbranched structure including branch points at reaction residues of said coupling agent, said coupling agent having at least a first group and a second group that are each capable of independently reacting with said living end and each capable of reacting at a different rate with said living end of said polymeric precursor segments to produce first generation branch structures, said coupling in a convergent manner further involving coupling at least first generation branch structures to form second generation branch structures, wherein first generation branch structures react more slowly to produce said second generation branch structures than said rates at which said coupling agent reacts with said polymeric precursor segments to produce said first generation branch structures;wherein, during said coupling step, reaction of said coupling agent being controlled by the addition of said multi-functional coupling agent to said living polymerization reaction mixture at a rate that is slow enough to leave enough living ends with which the coupling agent can react so as to form said hyperbranched structure and of sufficient quantity overtime to form said hyperbranched structure, wherein said hyperbranched structure is a multi-generational dendritic structure having an average of at least about 2 generations of branching and a polydispersity index of smaller than about 3, and including said precursor segments in exterior branches of said dendritic structure.