Macromonomers with Activated Allyl End Groups: Synthesis and Copolymerization

Rizzardo, Ezio; Harrison, D. S.; Laslett, Robert; Meijs, Gordon F.; Morton, T C; Thang, San H.

doi:10.1007/978-3-642-84115-6_11

Cited by 18 publications

(17 citation statements)

References 6 publications

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“…There were good reasons to revisit CCT in the early 90s. CCT got its second wind when Berge, Darmon, and Antonelli 33 at DuPont and Ezzio Rizzardo et al 34 at CSIRO (Australia) independently discovered that polymethacrylate oligomers obtained by CCT work very well as additionfragmentation chain-transfer (AFCT) agents. After several years of investigating the radical copolymerization of P n ϭ with different monomers, 35 they found that the reason for the poor copolymerization of macromonomers obtained via CCT with methacrylic monomers is not because the double bond in them is unreactive.…”

Section: Time For a Movementioning

confidence: 98%

The 25th anniversary of catalytic chain transfer

Gridnev¹

2000

J. Polym. Sci. A Polym. Chem.

112

102

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Section: Time For a Movementioning

confidence: 98%

The 25th anniversary of catalytic chain transfer

Gridnev¹

2000

J. Polym. Sci. A Polym. Chem.

112

102

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“…acrylates, Sty, AN, acrylamide) to afford graft copolymers. [7,51] In contrast, little [7] or no [51] copolymerization was observed with the more sterically hindered methacrylates (e.g. see Table 2).…”

Section: Reversible Addition]fragmentation Chain Transfer Polymerizatmentioning

confidence: 99%

“…Based on the above observations, we proposed a general mechanism to explain the results of copolymerization of methacrylate macromonomers with various monomers (Scheme 19). [51] The addition of propagating radical 1 to methacrylate macromonomer 2 in Scheme 19 is expected to occur readily to give adduct radical 3. [7,51] The adduct radical 3 can react by one of three different pathways: (a) it can add to monomer which would result in the macromonomer becoming incorporated into the polymer backbone (yielding a graft copolymer), (b) it can revert to the starting species in which case the propagating radical 1 can continue to grow by further addition of monomer, or (c) it can fragment, by b-scission, and in so doing generates a polymeric re-initiating radical 5 and a new alkene terminated oligomer 4 whose backbone is based on the propagating radical 1.…”

Section: Reversible Addition]fragmentation Chain Transfer Polymerizatmentioning

confidence: 99%

“…The lack of macromonomer copolymerization with MMA suggests that propagation of adduct radical 3 is severely limited. [51] Indeed, the large van der Waals interactions between a bulky radical 3 approaching a hindered methacrylate monomer is likely to be the reason for propagation of radical 3 to be unfavourable. Ultimately, the favoured route and the path forward is through fragmentation by b-scission.…”

Section: Reversible Addition]fragmentation Chain Transfer Polymerizatmentioning

confidence: 99%

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On the Origins of Nitroxide Mediated Polymerization (NMP) and Reversible Addition–Fragmentation Chain Transfer (RAFT)

Rizzardo¹,

Solomon²

2012

Aust. J. Chem.

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The early experiments on radical polymerization, which were to lead to a study of nitroxide trapping of the initiation step and the interest in defect groups, particularly the macromonomers formed by termination by disproportionation, are discussed. Results from the nitroxide trapping clearly show that the initiation step ranges from simple clean addition to the head of the monomer, to complex addition/abstraction reactions. Careful selection of the monomer/initiation system is emphasized with particular reference to two common monomers, styrene and methyl methacrylate, and two initiating radicals, t-butoxy and benzoyloxy. The discovery of nitroxide mediated polymerization (NMP) from observations made during the nitroxide trapping work is reported and the ability to have a living radical system demonstrated with numerous examples. Similarly, the study of the copolymerization of macromonomers, formed by disproportionation of the propagating chains, is discussed with the discovery of b-scission and an early form of addition-fragmentation reported. The evolution of reversible addition-fragmentation chain transfer (RAFT) to a highly versatile and commercially attractive radical system is reported and the detailed chemistry behind the discovery of this living radical system discussed. Both NMP and RAFT enable the synthesis of structures not previously possible by radical polymerization and in some cases not possible by any other process.

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“…[3,4,[11][12][13] MMA-2 behaves as a non-polymerizable AFCT agent in the presence of homopolymerizable monomer, and some copolymerization may occur in competition with fragmentation. [12,14,15] Thus, addition to the AFCT agent competes with homopolymerization of the monomer, whereas the b-fragmentation step of the adduct radical competes with cross propagation of the adduct radical, and each AFCT step also competes with bimolecular termination. When AFCT is the dominating end forming reaction instead of bimolecular termination, unsaturated end groups are quantitatively introduced into the polymer, and the competition of AFCT with homopolymerization of the monomer and cross propagation governs the molecular weight.…”

Section: Introductionmentioning

confidence: 99%

Reactivities of ω‐Unsaturated Methacrylate Oligomers toward tert‐Butoxy Radicals: Investigation of the Effect of Degree of Polymerization and Ester Alkyl Group

Sato

Zetterlund

Yamada

et al. 2003

Macro Chemistry & Physics

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The reactivities of ω‐unsaturated methacrylate oligomers (RMA‐n; n = 2–5) toward tert‐butoxy radicals (t‐BuO·) as a model of the addition step in addition‐fragmentation chain transfer (AFCT) have been investigated by the nitroxide trapping technique in combination with HPLC and electrospray ionization mass spectrometry. The ratio of the rate coefficients for the addition of ω‐unsaturated methyl methacrylate oligomers (MMA‐n) to t‐BuO· to the β‐fragmentation of t‐BuO· (kadd/kβ), where kβ can be treated as a constant, has been shown to decrease with increasing n due to increased steric hindrance of the α‐substituents. However, the value of kadd/kβ reaches a constant value at n = 3–4, and the greatest extent of suppression of the addition rate compared with MMA is less than a factor of four. Comparison of the values of kadd/kβ for ω‐unsaturated cyclohexyl methacrylate oligomers (CHMA‐n; n = 2 and 3) with MMA‐n revealed that the extent of suppression increased with increasing n without regard to the ester alkyl group. Hydrogen abstraction by t‐BuO· from RMA‐n appears to occur mainly at the ester alkyl groups, and the extent is much greater from CHMA‐n than from MMA‐n.

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Macromonomers with Activated Allyl End Groups: Synthesis and Copolymerization

Cited by 18 publications

References 6 publications

The 25th anniversary of catalytic chain transfer

The 25th anniversary of catalytic chain transfer

On the Origins of Nitroxide Mediated Polymerization (NMP) and Reversible Addition–Fragmentation Chain Transfer (RAFT)

Reactivities of ω‐Unsaturated Methacrylate Oligomers toward tert‐Butoxy Radicals: Investigation of the Effect of Degree of Polymerization and Ester Alkyl Group

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