Zerovalent Metals in Controlled/“Living” Radical Polymerization

Matyjaszewski, Krzysztof; Coca, Simion; Gaynor, Scott G.; Wei, Mingli; Woodworth, Brian E.

doi:10.1021/ma971258l

Cited by 327 publications

(282 citation statements)

References 29 publications

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“…Further experiments showed that the molar ratio of comonomers also does not strongly effect the MM reactivity. 29 The MM used had M h n ) 5600. For the calculation of M h n and PDI of the pure graft copolymer the unreacted UVlabeled macromonomer was numerically subtracted from the crude copolymer.…”

Section: Resultsmentioning

confidence: 99%

Copolymerization of n-Butyl Acrylate with Methyl Methacrylate and PMMA Macromonomers: Comparison of Reactivity Ratios in Conventional and Atom Transfer Radical Copolymerization

1999

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The reactivity ratios of n-butyl acrylate (nBuA) with methyl methacrylate (MMA) and ω-methacryloyl-PMMA macromonomers (MM) in conventional and atom transfer radical copolymerization (ATRP) have been determined. For the copolymerization of nBuA with MMA, good agreement of the ratios is observed between conventional and controlled radical copolymerization, indicating that chemoselectivities in both processes are similar. The relative reactivity of the MM (1/r nBuA) in conventional copolymerization is significantly lower than that of MMA. It depends on the concentration of the comonomers but is not significantly influenced by the length of the MM. At high concentrations the relative reactivity decreases due to diffusion control of the MM addition. In ATRP the relative reactivity of the MM is much nearer to the value of MMA. This is explained by the different time scales of monomer addition in both processes: whereas the frequency for monomer addition is in the range of milliseconds for conventional polymerizations, it is in the range of seconds in ATRP; thus, diffusion control is less important here. This gives the opportunity to copolymerize at much higher concentrations than in conventional radical copolymerization. In addition, the graft copolymers obtained by ATRP have lower polydispersities.

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Section: Resultsmentioning

confidence: 99%

Copolymerization of n-Butyl Acrylate with Methyl Methacrylate and PMMA Macromonomers: Comparison of Reactivity Ratios in Conventional and Atom Transfer Radical Copolymerization

1999

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“…Cu(0) is known to reduce Cu(II) to Cu(I), thereby increasing [P • ] (cf. Scheme 2a) [15]. The addition of Cu(0) had, in fact, a large effect on the coupling reaction: The GPC curves in Fig.…”

Section: General Observationsmentioning

confidence: 96%

Reactions of polystyrene radicals in a monomer-free atom transfer radical polymerization system

2002

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Polystyrene radicals (PS• ) were produced in high concentration using ω-bromopolystyrene (PS-Br) and α,ω-dibromopolystyrene (Br-PS-Br) in conjunction with Cu(I)Br following the atom transfer technique. A proper choice of the activator system led the PS-Br adduct to a maximum extent of coupling (by recombination), q max = 0.91, as estimated by gel permeation chromatography. On the other hand, the fraction of chains terminated by disproportionation was estimated to be 0.07 ± 0.04 by H NMR. When the radical concentration [PS • ] was not highenough, the chain transfer reaction competed with termination, and q max remained low. For the bifunctional adduct Br-PS-Br, the coupling reaction produced 'polymers' of a variety of chain lengths, whose distribution obeyed the theory of random coupling, when q was lower than about 0.5. The high extent of coupling (q max ≈ 0.9) achievable in short time (< 10 min) suggests practical applicability of this reaction.

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“…279,280 This technique was a logical consequence of earlier work demonstrating that zero-valent metals could reduce the deactivator accumulated in the system 281 and that other reducing agents such as monosaccharides 282 or phenols 283 could be employed for the same purpose. AGET ATRP uses a combination of an alkyl halide (macro)initiator with an active ATRP catalyst in its higher oxidation state (Cu II ) in conjunction with a reducing …”

Section: Decreasing the Amount Of Copper In The Presence Of Environmementioning

confidence: 99%

“Green” Atom Transfer Radical Polymerization: From Process Design to Preparation of Well-Defined Environmentally Friendly Polymeric Materials

2007

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Zerovalent Metals in Controlled/“Living” Radical Polymerization

Cited by 327 publications

References 29 publications

Copolymerization of n-Butyl Acrylate with Methyl Methacrylate and PMMA Macromonomers: Comparison of Reactivity Ratios in Conventional and Atom Transfer Radical Copolymerization

Copolymerization of n-Butyl Acrylate with Methyl Methacrylate and PMMA Macromonomers: Comparison of Reactivity Ratios in Conventional and Atom Transfer Radical Copolymerization

Reactions of polystyrene radicals in a monomer-free atom transfer radical polymerization system

“Green” Atom Transfer Radical Polymerization: From Process Design to Preparation of Well-Defined Environmentally Friendly Polymeric Materials

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