Ambient Temperature Polymerization of Styrene by Single Electron Transfer Initiation, Followed by Reversible Addition Fragmentation Chain Transfer Control

Subramanian, S. Harihara; Babu, Rajendran Prakash; Dhamodharan, R.

doi:10.1021/ma7021056

Cited by 83 publications

(84 citation statements)

References 15 publications

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“…We found that the molecular weight of PMMA increased linearly with monomer conversion and the molecular weight distribution remained narrow in most cases (Figure 2a) that the polymerization was well-controlled. These results also suggested that the SET-RAFT developed by Dhamodharan et al 28 may not be RAFT at all, but rather SET-LRP initiated by a RAFT reagent, or at a minimum a mixture of the two. It has been reported that Cu(0) can play an important role on the SET-LRP profiles, including the polymerization rate and living behavior.…”

Section: Resultsmentioning

confidence: 80%

“…Recently, Dhamodharan intelligently conducted the polymerization of styrene by SET initiation, followed by RAFT control at ambient temperature. 28 Low-temperature characteristic of SET-LRP was ascribed to its specific mechanism, which was concluded to be an outer-sphere single electron transfer process. 15 In this process, Cu(0) donates an electron to P n /P-X, resulting in a radical-anion [P n /P-X] 3 -.…”

Section: Introductionmentioning

confidence: 99%

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Single-Electron Transfer Living Radical Polymerization (SET−LRP) of Methyl Methacrylate (MMA) with a Typical RAFT Agent as an Initiator

et al. 2009

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A typical reversible addition-fragmentation chain transfer (RAFT) agent, 2-cyanoprop-2-yl 1-dithionaphthalate (CPDN), was used as a single electron transfer-living radical polymerization (SET-LRP) initiator for methyl methacrylate (MMA) polymerization at 25°C. At 1:1 molar ratio of [CPDN] 0 /[Cu(0)] 0 , the apparent rate constants of propagation (k p app ) were 0.037, 0.049, and 0.072 h -1 for [MMA] 0 /[CPDN] 0 of 225/0.2, 225/0.5, and 225/1, respectively. The number-average molecular weight of poly(methyl methacrylate) (PMMA) increased linearly with monomer conversion, and narrow molecular weight distributions (M w /M n <1.50) were found at most cases. At high molar ratio of [CPDN] 0 to [Cu(0)] 0 , such as 1:0.1 in this work, the polymerization was also controllable, whereas it a presented markedly depressed polymerization rate and an obvious induction period. 1 H NMR spectroscope and matrix assisted laser desorption/ionization time-of-flight mass spectrometry confirmed that PMMA chain was end-capped by CPDN species with high fidelity. The tacticity of PMMA from 1 H NMR calculation was about 3.15% isotactic (mm), 29.65% atactic (mr) and 67.20% syndiotactic (rr) triads, consistent with the tacticity distribution for traditional radical polymerizations. Chain extension reactions substantiated further that the obtained PMMA from CPDN mediated SET-LRP was living, and can be reactivated for chain extension reaction. This work demonstrates that a typical RAFT agent can act as a SET-LRP initiator as well as an atom transfer radical polymerization initiator. Furthermore, these results also suggested that the single electron transfer initiation-reversible addition-fragmentation chain transfer control (SET-RAFT) invented by Dhamodharan may not be RAFT at all, but rather SET-LRP initiated by a RAFT reagent, or a combination of SET-LRP and RAFT. Analogously, the exact polymerization process in this work may also proceed in two manners, a fully SET-LRP process and a combination of SET-LRP/RAFT process, which is needed to clarify in the future.

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Section: Resultsmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Single-Electron Transfer Living Radical Polymerization (SET−LRP) of Methyl Methacrylate (MMA) with a Typical RAFT Agent as an Initiator

et al. 2009

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“…RAFT is also applicable to emulsion-polymerization processes (12). Recently, we have also reported on the synthesis of polystyrene Downloaded by [Northwestern University] at 14:59 21 December 2014 using novel heterocycle containing CTAs by RAFT polymerization (13) and also demonstrated the ambient temperature polymerization of styrene by SET initiation followed by RAFT controlled polymerization (14).…”

Section: Introductionmentioning

confidence: 94%

Kinetic Studies on Star Polymerization of Styrene, MA and MMA Using New Three and Four Arm Chain Transfer Agents (CTAs): The Role of R-Group Structure Present in the CTA on RAFT Polymerization

Kannan¹,

Dhamodharan²

2011

Journal of Macromolecular Science, Part A

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Polystyrene, poly(methylacrylate) and poly(methyl methacrylate) four and three-arm stars were synthesized by Reversible Addition Fragmentation chain-Transfer (RAFT) polymerization by using two new dithioester-derived chain transfer agents [CTA or R-S-(C = S)Z]), CTA-1 and CTA-2. CTA-1 is a four arm CTA while CTA-2 is a three-arm CTA. These were easily synthesized from commercially available reagents and were characterized by spectroscopic techniques such as 1 H-NMR, 13 C-NMR, IR and mass spectrometry. It is demonstrated that the two new CTAs enable the growth of arms away from the core (i.e., core first approach). An attempt has been made to study the effect of the structure of the R-group, which is present as the core in the CTA, on the polymerization, by analyzing the detailed kinetics. This study suggests that CTA-2, with a benzylic R group, enables the controlled star polymerization of styrene while CTA-1, with a R group similar in structure to the propagating radical derived from the polymerization of methyl acrylate (MA), enables the controlled polymerization of MA although to a lesser extent. This study also reveals that the temperature of free radical initiated RAFT (star) polymerization should be chosen in such a way that it is a compromise between reasonable rate of homolysis of the initiator and the CTA (R-group).

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“…[20][21][22] Concurrent ATRP and RAFT do not require a constant supply of radicals to compensate for termination processes (as does pure RAFT) because the propagating radicals are not only transferred to other chains by CTAs but also reversibly deactivated by ATRP processes. Therefore, polymers with very high molecular weights exceeding 10 6 but terminated with thiocarbonylthio groups can be obtained.…”

Section: Overview Of Reactions Of Thiocarbonylthio End-groups Radicalmentioning

confidence: 99%

End Group Reactions of RAFT-Prepared (Co)Polymers

et al. 2011

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Ambient Temperature Polymerization of Styrene by Single Electron Transfer Initiation, Followed by Reversible Addition Fragmentation Chain Transfer Control

Cited by 83 publications

References 15 publications

Single-Electron Transfer Living Radical Polymerization (SET−LRP) of Methyl Methacrylate (MMA) with a Typical RAFT Agent as an Initiator

Single-Electron Transfer Living Radical Polymerization (SET−LRP) of Methyl Methacrylate (MMA) with a Typical RAFT Agent as an Initiator

Kinetic Studies on Star Polymerization of Styrene, MA and MMA Using New Three and Four Arm Chain Transfer Agents (CTAs): The Role of R-Group Structure Present in the CTA on RAFT Polymerization

End Group Reactions of RAFT-Prepared (Co)Polymers

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