Nitroxide radical coupling reaction as a tool for post-polymerization modification

The coupling reaction between nitroxides and carbon-centered radicals, also known as nitroxide radical coupling (NRC), is presented as an attractive, convenient and versatile post-polymerization modification method for both polyolefins and biodegradable aliphatic polyesters. This reaction provides excellent control of macroradical side reactions versus grafting of functional molecules thus limiting radical-induced crosslinking/branching and degradation and retaining structural properties of parent materials. A mechanistic understanding of the use of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and its derivatives is provided. Moreover, examples about the preparation of functional polymers using special designed nitroxides bearing functional moieties (i.e., chromophores, stabilizers, etc.) are given.