Amphiphilic Block Copolymer from Hydroxyl-Terminated Polymers Functionalized with TEMPO. A New Synthetic Method Using Oxoammonium Salt

• Published in: Macromolecular chemistry and physics Vol. 212; no. 15; pp. 1654 - 1662
• Main Authors: Bonilla-Cruz, José, Lara-Ceniceros, Tania E., Ramírez-Wong, D. G., Saldívar-Guerra, Enrique, Pérez-Rodríguez, F., Márquez-Lamas, Uriel
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 02.08.2011; WILEY‐VCH Verlag; Wiley
• Subjects: Applied sciences; Block copolymers; Exact sciences and technology; functionalization of polymers; nitroxides; Nuclear magnetic resonance; Operating systems; Organic polymers; oxoammonium salts; Pathways; Peroxides; Physicochemistry of polymers; poly(propylene glycol); Polymerization; Polymers; polysiloxanes; Preparation, kinetics, thermodynamics, mechanism and catalysts; Radicals; Synthesis; End group; Telechelic polymer; Priming activity; nitroxides; Ethylene oxide polymer; functionalization of polymers; Reaction mechanism; Molecular aggregation; Amphiphilic polymer; Vesicle; Nitroxyl; Ethylene oxide copolymer; Experimental study; Piperidone derivatives; Chemical coupling; Radical catalyst; Triblock copolymer; Chemical modification; Initiator polymer; Free radical polymerization; poly(propylene glycol); Preparation; polysiloxanes; Styrene; Living copolymer; Aqueous solution; oxoammonium salts; Styrene copolymer
• DOI: 10.1002/macp.201100070
• ISSN: 1022-1352; 1521-3935

A simple approach for the end‐functionalization of hydroxyl‐terminated polymers with nitroxide moieties using oxoammonium salts (OS) is presented. The functionalization is carried out using only one synthetic pathway in which high levels of functionalization (90%) are found. A mechanism for the functionalization with TEMPO moieties using OS is proposed in which the formation of peroxide groups is suggested. The structures of the functionalized polymers are characterized in detail by 1H NMR, 13C NMR, DQF‐COSY, and HETCOR. Bifunctional macroalkoxyamines are used to demonstrate how to extend the polymer chain for the synthesis of amphiphilic triblock copolymers by polymerizing St in a second block mediated by a nitroxide radical which provides the block length control. A new and simple approach to functionalize hydroxyl‐terminated polymers with nitroxide moieties using oxoammonium salts (Br‐TEMPO) is discussed. The formation of peroxidic bonds is confirmed by 1H‐NMR, finding high levels of functionalization (≈90%). The functionalized polymers are used as macroalkoxyamines to produce amphiphilic block copolymers. 1H NMR, GPC, TEM, and SEM analyses support the findings.