Convergent self-branching polymerization

摘要

A method of forming a branched polymer includes forming a plurality of growing linear polymer chains by polymerizing a monomer which is protected against branching and which forms a reactive end group which is in a first condition which is one of electrophilic or nucleophilic, exposing the growing linear polymer chains to a chain transfer agent to cause the reactive end group of at least a first growing linear polymer chain to reverse its electrophilic or nucleophilic character, whereby a non-reversed reactive end group on a second growing linear polymer chain reacts with the reversed reactive end group on the first growing linear polymer chain to create a branched polymer and reverses the electrophilic or nucleophilic character of the reversed reactive end group back to its first condition, whereby it may continue adding monomer in a linear fashion; and quenching the polymerization by adding a compound having multiple reactive sites capable of reacting with the reactive end groups of the polymer chains when they are in the first condition. The method allows the preparation of ultra-high molecular weight dendritic polymers in which the branching junctures are assembled in situ (i.e., are self-branching) in a convergent manner during polymerization of the monomers.