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Accessing chain length dependent termination rate coefficients of methyl methacrylate (MMA) via the reversible addition fragmentation chain transfer (RAFT) process
Johnston-Hall, Geoffrey, Theis, Alexander, Monteiro, Michael J., Davis, Thomas P., Stenzel, Martina H. and Barner-Kowollik, Christopher (2005-10-24) Accessing chain length dependent termination rate coefficients of methyl methacrylate (MMA) via the reversible addition fragmentation chain transfer (RAFT) process. Macromolecular Chemistry And Physics, 206 20: 2047-2053.
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| Author(s) |
Johnston-Hall, Geoffrey
Theis, Alexander
Monteiro, Michael J.
Davis, Thomas P.
Stenzel, Martina H.
Barner-Kowollik, Christopher
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| Title |
Accessing chain length dependent termination rate coefficients of methyl methacrylate (MMA) via the reversible addition fragmentation chain transfer (RAFT) process
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| Journal name |
Macromolecular Chemistry And Physics
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| Publication date |
2005-10-24
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| Volume number |
206
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| Issue number |
20
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| ISSN |
1022-1352
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| Start page |
2047
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| End page |
2053
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| Total pages |
7
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| Place of publication |
Weinheim
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| Publisher |
Wiley-V C H Verlag Gmbh
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| Collection year |
2005
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| Subject |
C1
250501 Synthesis of Macromolecules
680303 Polymeric materials (e.g. paints)
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| Abstract |
The RAFT-CLD-T methodology is demonstrated to be not only applicable to 1-substituted monomers such as styrene and acrylates, but also to 1,1-disubstituted monomers such as MMA. The chain length of the terminating macromolecules is controlled by CPDB in MMA bulk free radical polymerization at 80 degrees C. The evolution of the chain length dependent termination rate coefficient, k(t)(i,i), was constructed in a step-wise fashion, since the MMA/CPDB system displays hybrid behavior (between conventional and living free radical polymerization) resulting in initial high molecular weight polymers formed at low RAFT agent concentrations. The obtained CLD of k(t) in MMA polymerizations is compatible with the composite model for chain length dependent termination. For the initial chain-length regime, up to a degree of polymerization of 100, k(t) decreases with alpha (in the expression k(t)(i,i) = k(t)(0) . i(-alpha)) being close to 0.65 at 80 degrees C. At chain lengths exceeding 100, the decrease is less pronounced (affording an alpha of 0.15 at 80 degrees C). However, the data are best represented by a continuously decreasing nonlinear functionality implying a chain length dependent alpha.
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| Keyword(s) |
Polymer Science
Kinetics
Living Polymerization
Methyl Methacrylate
Reversible Addition Fragmentation Chain Transfer Polymerization
(raft)
Termination Rate Coefficient
Free-radical Polymerization
Pulsed-laser Polymerization
Propagation Rate Coefficients
Rate-constant
Analytical Expression
Kinetics
Styrene
Bulk
25-degrees-c
Acrylate
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| Additional Notes |
DOI: 10.1002/macp.200500354
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