Supplemental Activator and Reducing Agent Atom Transfer Radical Polymerization of 2‐Hydroxyethyl Acrylate from High Molar Mass Poly(ethylene oxide) Macroinitiator in Dilute Solution

Publisher： John Wiley & Sons Inc

E-ISSN： 1521-3935|216|13|1405-1414

ISSN： 1022-1352

Source： MACROMOLECULAR CHEMISTRY AND PHYSICS, Vol.216, Iss.13, 2015-07, pp. : 1405-1414

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Abstract

Triple hydrophilic asymmetric poly(2‐hydroxyethyl acrylate)‐b‐poly(ethylene oxide)‐b‐poly(2‐hydroxyethyl acrylate) (PHEA‐b‐PEO‐b‐PHEA) triblock copolymers are obtained by copper(0) catalyzed reversible deactivation radical polymerization (RDRP). Copper wire catalyzed polymerization of HEA from large PEO (Mn = 35 000 g mol−1) macroinitiator in dimethylsulfoxide or in water fails to reach high monomer conversion in a controlled manner contrary to what is previously published with a shorter PEO macroinitiator. Catalysis by nascent Cu(0) particles generated by disproportionating CuBr in water allows rapid polymerization and high monomer conversion with a rather good control of both dispersity and HEA block length. Model disproportionation experiment shows that HEA influences the disproportionation/comproportionation equilibrium. Larger quantities of HEA lead to higher apparent rate constants and less disproportionation of CuBr which is in agreement with the supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) mechanism and not with the single electron transfer–living radical polymerization (SET‐LRP) mechanism.