Organocatalyzed Living Radical Polymerization via in Situ Halogen Exchange of Alkyl Bromides to Alkyl Iodides
Date of Issue2017
School of Physical and Mathematical Sciences
Halogen exchange of alkyl bromide (R–Br) with sodium iodide (NaI) was used for the transformation of R–Br to alkyl iodide (R–I) in situ in organocatalyzed living radical polymerization (LRP). R–Br was employed as a starting compound (precursor), and the R–I formed in situ was employed as an initiating dormant species for the polymerization. The efficiency of the transformation significantly depends on the R group of R–Br. By the rational selection of the R group and reaction temperature along with the use of tetrabutylammonium iodide (Bu4NI) as a catalyst, low-polydispersity (Mw/Mn = 1.1–1.4) polymers were obtained with high conversions (e.g., 70–90%) in reasonably short periods of time (typically 3–10 h) in the polymerizations of methyl methacrylate, butyl acrylate, styrene, acrylonitrile, and functional methacrylates. Well-defined diblock and triblock copolymers and a chain-end functional polymer were also obtained. R–Br is generally much more stable than R–I upon storage. Various R–Br are commercially available. The use of simple, stable, and inexpensive R–Br as precursors of the dormant species is an attractive feature of this system. The high monomer versatility and the accessibility to a wide range of polymer structural designs demonstrated in this work show the capability of this system for use in a range of applications.
© 2017 American Chemical Society (ACS). This is the author created version of a work that has been peer reviewed and accepted for publication by Macromolecules, American Chemical Society (ACS). It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1021/acs.macromol.6b02813].