Embedding Multiple Site-Specific Functionalities into Polymer Chains via Nitrone-Mediated Radical Coupling Reactions

Abstract

A facile method to generate polymer materials with embedded functional groups at known and precise positions along the polymer backbone is described. In the presented approach, well-defined bifunctional poly(isobornyl acrylate)s preformed via atom transfer radical polymerization (ATRP) containing a, x-bromo end groups are reactivated and subsequently coupled in a stepwise manner via the nitrone-mediated radical coupling (NMRC) technique. The generated polymers contain on average four nitrone moieties at evenly spaced locations. The number of embedded functionalities, and thus, the size of the polymer is limited by disproportionation reactions occurring during the nitroxide termination sequence. Using the nitrone as a functional carrier, secondary functionalities can be incorporated into the polymer with ease. To exemplify such an approach, an alkyne-functionalized nitrone is used to construct a multisegment structure via NMRC reactions followed by postmodification of the obtained polymers with 3-mercaptopropionic acid via UV-induced thiol-yne reactions. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 2118-2126, 2011