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Norbornenyl-based RAFT agents for the preparation of functional polymers via thiol-ene chemistry

Milan M. Stamenović UGent, Pieter Espeel UGent, Wim Van Camp UGent and Filip Du Prez UGent (2011) MACROMOLECULES. 44(14). p.5619-5630
abstract
A synthetic platform for the preparation of various norbornenyl (Nb) containing reversible addition fragmentation chain transfer (RAFT) agents has been developed. The design of the chain transfer agents (CTAs) is based on the desymmetrization of alpha,alpha'-dibromo-p-xylene by monosubstitution with an alkoxide anion and subsequent replacement of the residual bromine atom in the benzylic bromide to create several series of RAFT CTA including trithiocarbonate, xanthate and dithiobenzoate CTAs, allowing for the possibility to introduce other functional groups besides Nb, such as an allyl group. While a norbomene functionality was chosen as most reactive functional group toward thiols in radical-mediated thiol-ene chemistry, an ally] group was introduced for the sake of direct comparison of the double bond reactivity in the thiol-ene reaction. Control of the radical polymerization of acrylates, styrene and vinyl acetate has been achieved by using this novel family of CTAs. The results indicate that the Nb group remained intact at low monomer conversions (e.g., below 50% for styrene and vinyl acetate, below 30% for acrylates) and at optimal reaction temperatures (e.g., 70 degrees C for styrene and vinyl acetate, 62 and 65 degrees C for 1-ethoxyethyl acrylate and methyl acrylate, respectively), while the monomer-to-CTA ratio was kept high. Polymers with high end-group fidelity were modified with a series of thiol-containing compounds, leading to alpha-semitelechelics with different chain-end structures. While allyl-containing polymers exhibited a significantly lower reactivity, modification of the Nb-containing semitelechelics was rapid and fully accomplished under the same reaction conditions. However, for the given conditions, dodecanethiol and benzyl mercaptan showed a lower reactivity toward Nb-containing polymers, as evidenced by the obtained modification efficiency of 70% and 45%, respectively.
Please use this url to cite or link to this publication:
author
organization
year
type
journalArticle (original)
publication status
published
subject
keyword
RING-OPENING METATHESIS, TRANSFER RADICAL POLYMERIZATION, CLICK-CHEMISTRY, BLOCK-COPOLYMERS, MOLECULAR BRUSHES, POLY(ACRYLIC ACID), VINYL-ACETATE, MODULAR SYNTHESIS, ROMP, FRAGMENTATION-CHAIN-TRANSFER
journal title
MACROMOLECULES
Macromolecules
volume
44
issue
14
pages
5619 - 5630
Web of Science type
Article
Web of Science id
000292850100012
JCR category
POLYMER SCIENCE
JCR impact factor
5.167 (2011)
JCR rank
5/78 (2011)
JCR quartile
1 (2011)
ISSN
0024-9297
DOI
10.1021/ma200799b
language
English
UGent publication?
yes
classification
A1
copyright statement
I have transferred the copyright for this publication to the publisher
id
1909274
handle
http://hdl.handle.net/1854/LU-1909274
date created
2011-09-27 13:43:42
date last changed
2011-09-28 15:33:56
@article{1909274,
  abstract     = {A synthetic platform for the preparation of various norbornenyl (Nb) containing reversible addition fragmentation chain transfer (RAFT) agents has been developed. The design of the chain transfer agents (CTAs) is based on the desymmetrization of alpha,alpha'-dibromo-p-xylene by monosubstitution with an alkoxide anion and subsequent replacement of the residual bromine atom in the benzylic bromide to create several series of RAFT CTA including trithiocarbonate, xanthate and dithiobenzoate CTAs, allowing for the possibility to introduce other functional groups besides Nb, such as an allyl group. While a norbomene functionality was chosen as most reactive functional group toward thiols in radical-mediated thiol-ene chemistry, an ally] group was introduced for the sake of direct comparison of the double bond reactivity in the thiol-ene reaction. Control of the radical polymerization of acrylates, styrene and vinyl acetate has been achieved by using this novel family of CTAs. The results indicate that the Nb group remained intact at low monomer conversions (e.g., below 50\% for styrene and vinyl acetate, below 30\% for acrylates) and at optimal reaction temperatures (e.g., 70 degrees C for styrene and vinyl acetate, 62 and 65 degrees C for 1-ethoxyethyl acrylate and methyl acrylate, respectively), while the monomer-to-CTA ratio was kept high. Polymers with high end-group fidelity were modified with a series of thiol-containing compounds, leading to alpha-semitelechelics with different chain-end structures. While allyl-containing polymers exhibited a significantly lower reactivity, modification of the Nb-containing semitelechelics was rapid and fully accomplished under the same reaction conditions. However, for the given conditions, dodecanethiol and benzyl mercaptan showed a lower reactivity toward Nb-containing polymers, as evidenced by the obtained modification efficiency of 70\% and 45\%, respectively.},
  author       = {Stamenovi\'{c}, Milan M. and Espeel, Pieter and Van Camp, Wim and Du Prez, Filip},
  issn         = {0024-9297},
  journal      = {MACROMOLECULES},
  keyword      = {RING-OPENING METATHESIS,TRANSFER RADICAL POLYMERIZATION,CLICK-CHEMISTRY,BLOCK-COPOLYMERS,MOLECULAR BRUSHES,POLY(ACRYLIC ACID),VINYL-ACETATE,MODULAR SYNTHESIS,ROMP,FRAGMENTATION-CHAIN-TRANSFER},
  language     = {eng},
  number       = {14},
  pages        = {5619--5630},
  title        = {Norbornenyl-based RAFT agents for the preparation of functional polymers via thiol-ene chemistry},
  url          = {http://dx.doi.org/10.1021/ma200799b},
  volume       = {44},
  year         = {2011},
}

Chicago
Stamenović, Milan M., Pieter Espeel, Wim Van Camp, and Filip Du Prez. 2011. “Norbornenyl-based RAFT Agents for the Preparation of Functional Polymers via Thiol-ene Chemistry.” Macromolecules 44 (14): 5619–5630.
APA
Stamenović, M. M., Espeel, P., Van Camp, W., & Du Prez, F. (2011). Norbornenyl-based RAFT agents for the preparation of functional polymers via thiol-ene chemistry. MACROMOLECULES, 44(14), 5619–5630.
Vancouver
1.
Stamenović MM, Espeel P, Van Camp W, Du Prez F. Norbornenyl-based RAFT agents for the preparation of functional polymers via thiol-ene chemistry. MACROMOLECULES. 2011;44(14):5619–30.
MLA
Stamenović, Milan M., Pieter Espeel, Wim Van Camp, et al. “Norbornenyl-based RAFT Agents for the Preparation of Functional Polymers via Thiol-ene Chemistry.” MACROMOLECULES 44.14 (2011): 5619–5630. Print.