Copper-mediated living radical polymerization

Abstract Copper mediated living radical polymerization has been investigated by on-... 

Keywords copper mediated living radical polymerization, H NMR spectroscopy, poly(ethylene glycol), methacrylates, macromonomer, macroinitiator, solvent effect. 

Figure /. Copper mediated living radical polymerization of MMA using MeOPEGx as initiator (X (DP) = 12, 45, 113) in toluene.

In conclusion, it has been demonstrated that PEG-based macroinitiators are relatively slow initiators in copper mediated living radical polymerization this will result in AB block copolymers with heterogeneous composition but all macroinitiators are eventually transformed into block copolymers. Temperature or solvent has little effect on this, however, the macroinitiator chain length influences the initiator efficiency with shorter chain molecules being faster initiators than longer chain macromolecules. 

Mantovani, G., Lecolley, F., Tao, L., et al. (2005) Design and synthesis of N-maleimido-functionalized hydrophilic polymers via copper-mediated living radical polymerization A suitable alternative to PEGylation chemistry, J. Am. Chem. Soc., 127, 2%6-73. 

Darcos V, Monge S, Haddleton DM. In situ Eourier transform near infrared spectroscopy monitoring of copper mediated living radical polymerization. J Polym Sci Part A Polym Chem 2004 42 4933-4940. 

Investigations of the polymerization kinetics of 2-dimethyl-aminoethyl methacrylate (DEAEMA) copper mediated living radical polymerization were reported by Even et al. [172] using in situ H NMR spectroscopy. Polymerizations reactions were carried out at 60° and 90 °C using a poly(ethylene butylenes)-based di-initiator as a macroinitiator in NMR... 

Even M, Haddleton DM, Kukulj D. Synthesis and characterization of amphiphUic triblock polymers by copper mediated living radical polymerization. Eur Polym J 2003 39 633-639. 

Monge S, Haddleton DM (2004) Synthesis of precursors of poly(acryl amides) by copper mediated living radical polymerization in DMSO. Eur Polym J 40(1) 37 5... 

Table 1 Specific polymerization conditions for the synthesis of glycopolymers via copper-mediated living radical polymerization... 

Polyethylene glycol in the synthesis of materials. PEG has been used as a solvent in polymerization reactions. It was found to facilitate easy removal of the metal catalyst in transition metal mediated living radical polymerization (Figure 8.10). Products from this type of polymerization are usually heavily contaminated with intensely coloured copper impurities. In the case of methyl methacrylate polymerization the reaction rate was higher than in conventional organic solvents, but for styrene the reaction was slower than in xylene. 

A wider range of acrylate/styrene block copolymers have been prepared by copper catalysts, partially because the homopolymerizations of both monomers can be controlled with common initiating systems. Both AB- (B-15 to B-17)202,230,254,366,367 and BA-type (B-18 to B-21)28,112,169,230,366,368,369 block copolymers were obtained from macroinitiators prepared by the copper-based systems. The block copolymerizations can also be conducted under air230 and under emulsion conditions with water.254 Combination of the Re-and Ru-mediated living radical polymerizations in... 

The metal-catalyzed copolymerization from carbon-halogen bonds in the main chain can be employed widely for graft polymer synthesis. A combination of nitroxide-mediated and copper-catalyzed living radical polymerizations, for example, gives graft copolymers G-6, where the main chain is prepared by the former.432 The chlorobenzyl unit in the copolymer is not active during the polymerization but, upon copper catalysis, it can initiate living radical polymerizations of styrene and methacrylates. 

Wang resin has been transformed into an initiator for copper(I)-mediated living radical polymerization of methacrylates. The immobilized initiator was characterized by gel phase C NMR, and solid-state CPMAS C NMR using two different spinning frequencies as well as a TOSS pulse sequence. ... 

This contribution reports on the use of NMR spectroscopy to follow copper(I) mediated living radical polymerization. Carrying out the polymerizations within the cavity of the NMR spectrometer allows the reaction to be closely monitored. This gives extensive information on both the polymerization kinetics and on the nature of the catalyst. 

Haddleton and Ohno reported on maltodextrin modified polymers via copper(I)-mediated living radical polymerization [125]. Comblike structures based on polystyrene with amylose entities were synthesized by Kobayashi et al. [126] and bottle-brush-like structures by Kakuchi and coworkers [127]. 

Haddleton DM, Perrier S, Bon SAP. Copper(I)-mediated living radical polymerization in the presence of oxyethylene groups online H NMR spectroscopy to investigate solvent effects. Macromolecules 2000 33 8246-8251. 

In addition, Cui-N-propyl-2-pyridylmethanimine mediated "living" radical polymerization of vinyl monomers by use of l-butyl-3-methylimidazolium hexafluorophosphate as solvent has been reported (Carmichael et al., 2000). It has been pointed out that the rate of polymerization was enhanced in comparison to other polar/coordinating solvents. Moreover, the polymerization product was made copper free by a simple solvent wash, which avoids the contamination of the polymer product by the catalyst. Other atom transfer radical polymerizations in ionic liquids have recently been reported (Sarbu Matyjaszewski, 2001 Biendron Kubisa, 2001). 

Controlled/ Living radical polymerization (CRP) of vinyl acetate (VAc) via nitroxide-mediated polymerization (NMP), organocobalt-mediated polymerization, iodine degenerative transfer polymerization (DT), reversible radical addition-fragmentation chain transfer polymerization (RAFT), and atom transfer radical polymerization (ATRP) is summarized and compared with the ATRP of VAc catalyzed by copper halide/2,2 6 ,2 -terpyridine. The new copper catalyst provides the first example of ATRP of VAc with clear mechanism and the facile synthesis of poly(vinyl acetate) and its block copolymers. 

VAc has been successfully polymerized via controlled/ living radical polymerization techniques including nitroxide-mediated polymerization, organometallic-mediated polymerization, iodine-degenerative transfer polymerization, reversible radical addition-fragmentation chain transfer polymerization, and atom transfer radical polymerization. These methods can be used to prepare well-defined various polymer architectures based on PVAc and poly(vinyl alcohol). The copper halide/t is an active ATRP catalyst for VAc, providing a facile synthesis of PVAc and its block copolymers. Further developments of this catalyst will be the improvements of catalytic efficiency and polymerization control. 

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