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Chain‐Growth Click Polymerization of AB 2 Monomers for the Formation of Hyperbranched Polymers with Low Polydispersities in a One‐Pot Process
Author(s) -
Shi Yi,
Graff Robert W.,
Cao Xiaosong,
Wang Xiaofeng,
Gao Haifeng
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201502578
Subject(s) - monomer , polymerization , dispersity , polymer chemistry , polymer , click chemistry , branching (polymer chemistry) , azide , chemistry , cycloaddition , chain transfer , reversible addition−fragmentation chain transfer polymerization , alkyne , materials science , radical polymerization , catalysis , organic chemistry
Hyperbranched polymers are important soft nanomaterials but robust synthetic methods with which the polymer structures can be easily controlled have rarely been reported. For the first time, we present a one‐pot one‐batch synthesis of polytriazole‐based hyperbranched polymers with both low polydispersity and a high degree of branching (DB) using a copper‐catalyzed azide–alkyne cycloaddition (CuAAC) polymerization. The use of a trifunctional AB 2 monomer that contains one alkyne and two azide groups ensures that all Cu catalysts are bound to polytriazole polymers at low monomer conversion. Subsequent CuAAC polymerization displayed the features of a “living” chain‐growth mechanism with a linear increase in molecular weight with conversion and clean chain extension for repeated monomer additions. Furthermore, the triazole group in a linear (L) monomer unit complexed Cu I , which catalyzed a faster reaction of the second azide group to quickly convert the L unit into a dendritic unit, producing hyperbranched polymers with DB=0.83.