Session: General Topics: New Synthesis & Characterization of Polymers:

Atom transfer radical polymerization (ATRP) in conjunction with nitroxide radical coupling (NRC) is difficult to achieve due to nitroxide radical’s propensity to terminate radical polymerization. However, this difficulty could be overcome by introducing a functional reagent combining a nitroxide radical and an ATRP active halogen, i.e., a halogen group which can initiate one polymer chain by ATRP. For the reaction to proceed favorably, slow additions of the functional reagent to the reaction system were necessary. As a result, a polymerization with conjugated radical trapping and re-initiation took place resembling a relay race and thus was named relay polymerization. The molecular weight of these polymers increased with time, meanwhile, the molecular weight distribution stayed relatively narrow, Mw/Mn ≈ 1.20. The relay polymerization introduced dynamic chain linkages displaced among the long-chain polymer which can be used to create alternating block-copolymers by nitroxide mediated polymerization (NMP). This relay polymerization process opens a vast array of macromolecular structures that suit desired architectures and functionalities

Yu Wang

Appearances