ARGET ATRP

ARGET ATRP has been successfully applied for polymerization of methyl methacrylate, ft-butyl acrylate and styrene in the presence of Sn(EH)2 (10 mol% vs. alkyl halide initiator or 0.07 mol% vs. monomer) [164,165]. For all monomers, polymerizations were well controlled using between 10 and 50 ppm of copper complexes with highly active TPMA and Me6TREN ligands. ARGET ATRP has also been utilized in the synthesis of block copolymers (poly(n-butyl acrylate)— -polystyrene and polystyrene-Z -poly(n-butyl acrylate) [164,165] and grafting... 

The effect of polydispersity of primary chains on experimental gel points was also studied by using activators regenerated by electron transfer (ARGET) ° ATRP for the copolymerization of MA and EGDA. Decreasing the copper concentration from tens of ppm to a few ppm increased the polydispersity of primary chains from M /Mn = 1.1 to 2.0, which accelerated the experimental gel point during the copolymerization of monomer and crosslinker. 

Synthesis of Polystyrene-A-Poly( -Butyl Acrylate) (PSt-ft-P BA) via ARGET ATRP... 

The ARGET ATRP method was chosen for extension of PSt macroinitiator with /BA. This technique provides higher control over the polymerization of acrylates than ICAR ATRP (13, 23). It uses Sn(EH)2 or other non-radical... 

Figure 3. GPC traces of PSt and resulting PSt-b-PtBA block copolymers prepared by ARGET ATRP. General experimental conditions tBA/PSt/CuBr2/TPMA/Sn(EH)2 = 150/1/0.0075/0.05/0.05, in anisole (1.0vA>vs.

ARGET/ICAR ATRP, for the first time, has made possible the simultaneous control of both molecular weight and PDI. It was shown that vaiying the amount of copper during ARGET ATRP of methyl methacrylate... 

ARGET ATRP should allow direct preparation of block copolymers in existing large scale industrial equipment, publication No. WO/2007/075817 (International Application No. PCT/US2006/048656). Furthermore, it is envisioned that no catalyst removal step is required for many applications. 

Hansson S, Ostmark E, Carlmark A, Malmstrom E (2009) ARGET ATRP for versatile grafting of cellulose using various monomers. ACS Appl Mater Interfaces 1 2651-2659... 

FIGURE 11.9 Synthesis of /methacrylate (co)polymers by living and controlled polymerizations (a) group transfer polymerization according to Reference 55 (b) ARGET ATRP (c) polymerization of lluoroacrylates by RAFT according to References 87 and 98. 

To summarize, it can be stated that both free radical copolymerization and ATRP can be applied successfully to synthesize random copolymers of MMA with sfMA. First copolymerization experiments with ARGET-ATRP in BFMB as well as in SCCO2 according to Schreiber et al. [70] showed the applicability of the method further optimization is necessary. 

Kwak, Y, Magenau, A.J.D., Matyjaszewski K. 2011. ARGET ATRP of Methyl Acrylate with Inexpensive Ligands and ppm Goncentrations of Gatalyst. Macromolecules 44 811-819. 

Activators regenerated by electron transfer (ARGET) ATRP is another promising method, which reduces Cu(II)Xj to Cu(I)X with chemical reducing agents such as ascorbic acid or Snlethylhexanoate) [103]. 

Kwak Y Magenau AID, Matyjaszewski K. ARGET ATRP of methyl acrylate with inexpensive hgands and ppm concentrations of catalyst. Macromolecules 2011 44 811-819. 

Burdynska J, Cho HY, MueUer L, Matyjaszewski K. Synthesis of star polymers using ARGET ATRP. Macromolecules 2010 43 9227-9229. 

Table 3.1 Characterization of linear PSt prepared by normal and ARGET ATRP...

Ma, W., Otsuka, H., Takahara, A., 2011a. Poly(methyl methacrylate) grafted imogoUte nano-tuhes prepared through surface-initiated ARGET ATRP. Chemical Communications 47, 5813-5815. 

A variation of a reverse ATRP was developed using Cu(0) to provide the ability to start with stable aaive Cu(II) catalyst precursors (cf Section 3.12.3.4 on activator regenerated by electron transfer (ARGET) ATRP). This allows for a simple experimental setup without problems associated with oxidation of a readily oxidized Cu(I) complex. Reduction of the higher oxidation state transition metal with Cu(0), in any solid state, occurs quickly in most cases to form the Cu(I) catalysts. This simple procedure to initiate an ATRP was used subsequently by Percec when examining RP of butyl methacrylate initiated with sulfonyl chlorides. ... 

Note that, as with SR NI, the formation, or addition, of Mt in any form to the reaction medium does not change the mechanism but only the manner of attaining the equilibrium conditions and the rate of polymerization.However, it should be noted that Mt can act as a supplemental initiator and may increase the absolute concentration of catalyst in the reartion medium. Other transition metals have been used to reduce the concentration of the deactivator in ARGET ATRP including metallic zinc, magnesium, and iron. ... 

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