RAFT Polymerization with Phthalimidomethyl Trithiocarbonates or Xanthates. On the Origin of Bimodal Molecular Weight Distributions in Living Radical Polymerization

2006 ◽  
Vol 39 (16) ◽  
pp. 5307-5318 ◽  
Author(s):  
Almar Postma ◽  
Thomas P. Davis ◽  
Guoxin Li ◽  
Graeme Moad ◽  
Michael S. O'Shea
Keyword(s):  
Molecular Weight ◽  
Radical Polymerization ◽  
Raft Polymerization ◽  
Living Radical Polymerization ◽  
Molecular Weight Distributions ◽  
Weight Distributions

scholarly journals Aqueous Photo-Living Radical Polymerization of Sodium Methacrylate Using a Water-Soluble Nitroxide Mediator

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Eri Yoshida
Keyword(s):  
Molecular Weight ◽  
Radical Polymerization ◽  
Linear Correlation ◽  
Linear Increase ◽  
Living Radical Polymerization ◽  
Water Soluble ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Sodium Methacrylate

The aqueous photo-living radical polymerization of sodium methacrylate (NaMA) was attained using 2,2′-azobis2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]-propionamide (V-80) as the initiator and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (HTEMPO) as the mediator in the presence of (4-fluorophenyl)diphenylsulfonium triflate (FS). The polymerization was carried out in water at room temperature by irradiation using a high-pressure mercury lamp. Whereas the polymerization by V-80 and/or FS in the absence of HTEMPO produced polymers with very high molecular weights and broad molecular weight distributions, the HTEMPO-mediated polymerization provided still lower-molecular-weight distributions using both V-80 and FS. The first-order time-conversion plots had an induction period up to 2.5 h; however, they thereafter showed a linear increase. The conversion-molecular weight plots also exhibited a linear correlation. A linear correlation was also obtained for the plots of the molecular weights versus the reciprocal of the initiator concentration. Based on these three correlations, it was found that the HTEMPO-mediated photopolymerization proceeded by a living mechanism.

Precise synthesis of poly(N-acryloyl amino acid) through photoinduced living polymerization

2018 ◽  
Vol 9 (20) ◽  
pp. 2733-2745 ◽  
Author(s):  
Guofeng Li ◽  
Wenli Feng ◽  
Nathaniel Corrigan ◽  
Cyrille Boyer ◽  
Xing Wang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Radical Polymerization ◽  
Living Polymerization ◽  
Living Radical Polymerization ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Weight Distributions

A library of N-acryloylamino acid polymers with controlled molecular weights and narrow molecular weight distributions (Mw/Mn < 1.20) was created by a universal and versatile photoinduced living radical polymerization technique.

Tertiary amine catalyzed photo-induced controlled radical polymerization of methacrylates

2015 ◽  
Vol 6 (30) ◽  
pp. 5362-5368 ◽  
Author(s):  
Qiang Fu ◽  
Thomas G. McKenzie ◽  
Shereen Tan ◽  
Eunhyung Nam ◽  
Greg G. Qiao
Keyword(s):  
Molecular Weight ◽  
Radical Polymerization ◽  
Uv Irradiation ◽  
Tertiary Amine ◽  
Controlled Radical Polymerization ◽  
Low Molecular Weight ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
End Group

A novel tertiary amine catalyst and trithiocarbonate synergistic photo-induced controlled radical polymerization of methacrylates has been realized under mild UV irradiation, yielding polymethacrylates with low molecular weight distributions and excellent end-group fidelity.

scholarly journals Tuning the molecular weight distribution from atom transfer radical polymerization using deep reinforcement learning

2018 ◽  
Vol 3 (3) ◽  
pp. 496-508 ◽  
Author(s):  
Haichen Li ◽  
Christopher R. Collins ◽  
Thomas G. Ribelli ◽  
Krzysztof Matyjaszewski ◽  
Geoffrey J. Gordon ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Reinforcement Learning ◽  
Atom Transfer Radical Polymerization ◽  
Radical Polymerization ◽  
Weight Distribution ◽  
In Silico ◽  
Atom Transfer ◽  
Polymer Molecular Weight ◽  
Molecular Weight Distributions ◽  
Weight Distributions

Combination of deep reinforcement learning and atom transfer radical polymerization gives precise in silico control on polymer molecular weight distributions.

scholarly journals Further Effects of Chain-Length-Dependent Reactivities on Radical Polymerization Kinetics

2007 ◽  
Vol 60 (10) ◽  
pp. 754 ◽  
Author(s):  
Johan P. A. Heuts ◽  
Gregory T. Russell ◽  
Gregory B. Smith
Keyword(s):  
Molecular Weight ◽  
Radical Polymerization ◽  
Chain Length ◽  
Chain Transfer ◽  
Transfer Constant ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
A Chain ◽  
Chain Transfer Constant ◽  
Independent Chain

In the present paper, we finalize some threads in our investigations into the effects of chain-length-dependent propagation (CLDP) on radical polymerization kinetics, confirming all our previous conclusions. Additionally, and more significantly, we uncover some unexpected and striking effects of chain-length-dependent chain transfer (CLDTr). It is found that the observed overall rate coefficients for propagation and termination (and therefore the rate of polymerization) are not significantly affected by whether or not chain transfer is chain-length dependent. However, this situation is different when considering the molecular weight distributions of the resulting polymers. In the case of chain-length-independent chain transfer, CLDP results in a considerable narrowing of the distribution at the low molecular weight side of the distribution in a chain-transfer controlled system. However, the inclusion of both CLDP and CLDTr yields identical results to classical kinetics – in these latter two cases, the molecular weight distribution is governed by the same chain-length-independent chain transfer constant, whereas in the case of CLDP only, it is governed by a chain-length-dependent chain transfer constant that decreases with decreasing chain length, thus enhancing the probability of propagation for short radicals. Furthermore, it is shown that the inclusion of a very slow first addition step has tremendous effects on the observed kinetics, increasing the primary radical concentration and thereby the overall termination rate coefficient dramatically. However, including possible penultimate unit effects does not significantly affect the overall picture and can be ignored for the time being. Lastly, we explore the prospects of using molecular weight distributions to probe the phenomena of CLDP and CLDTr. Again, some interesting insights follow.

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