Preparation of poly(ethylene oxide)‐<i>block</i>‐poly(isoprene) by nitroxide‐mediated free radical polymerization from PEO macroinitiators

Wegrzyn, Jakub K.; Stephan, Thomas; Lau, Ryan; Grubbs, Robert B.

doi:10.1002/pola.20756

Cited by 69 publications

(87 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These properties make polyisoprene an attractive target for controlled/living radical polymerization, and several groups have applied reversible addition‐fragmentation chain transfer polymerization (RAFT)8–11 or nitroxide‐mediated radical polymerization (NMP)3, 12–19 to the synthesis of functional and block copolymers containing polyisoprene.…”

Section: Introductionmentioning

confidence: 99%

Use of Solvent Effects to Improve Control Over Nitroxide‐Mediated Polymerization of Isoprene

Harrisson¹,

Couvreur²,

Nicolas³

2012

Macromol. Rapid Commun.

View full text Add to dashboard Cite

The use of 1,4-dioxane or pyridine as solvents for the polymerization of isoprene mediated by the acid-functional SG1-based alkoxyamines N-(2-methylpropyl)-N-(1-diethylphosphono-2,2-dimethylpropyl)-O-(2-carboxylprop-2-yl)hydroxylamine (BlocBuilder MA) and N-(2-methylpropyl)-N-(1-diethylphosphono-2,2-dimethylpropyl)-O-(2-carboxyleth-2-yl)hydroxylamine results in an increase in the rate of consumption of the initiator and narrower molecular weight distributions of the resulting polymer. In pyridine, an improved control of the polymerization was also obtained for a non-acid-functional initiator, and the overall rate of polymerization increased. These effects are likely to be the result of the disruption of intramolecular hydrogen bonding and, in the case of pyridine, stabilization of the polar SG1 free radical.

show abstract

Section: Introductionmentioning

confidence: 99%

Use of Solvent Effects to Improve Control Over Nitroxide‐Mediated Polymerization of Isoprene

Harrisson¹,

Couvreur²,

Nicolas³

2012

Macromol. Rapid Commun.

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 99%

“…Controlled radical polymerization of isoprene was initially reported using nitroxide mediated polymerization (NMP) 9, 44, 48-49. Diblock copolymers of PEO- b -PIp have been successfully prepared by Grubbs via NMP methods using a PEO macro-initiator 9, 44. The solution-state properties of nanoassemblies derived from di- and triblock copolymers that include PEO and PIp segments have been investigated, including the formation of micelles and stable vesicles with small molecule additives,8, 21, 50 or the formation of unusual assemblies with unique properties when thermoresponsive intermediate blocks were incorporated 9.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Isoprene Chain Extension from PEO Macromolecular Chain Transfer Agents for the Preparation of Dual, Invertible Block Copolymer Nanoassemblies

et al. 2010

View full text Add to dashboard Cite

Two RAFT-capable PEO macro-CTAs, 2 and 5 kDa, were prepared and used for the polymerization of isoprene which yielded well-defined block copolymers of varied lengths and compositions. GPC analysis of the PEO macro-CTAs and block copolymers showed remaining unreacted PEO macro-CTA. Mathematical deconvolution of the GPC chromatograms allowed for the estimation of the blocking efficiency, about 50% for the 5 kDa PEO macro-CTA and 64% for the 2 kDa CTA. Self assembly of the block copolymers in both water and decane was investigated and the resulting regular and inverse assemblies, respectively, were analyzed with DLS, AFM, and TEM to ascertain their dimensions and properties. Assembly of PEO-b-PIp block copolymers in aqueous solution resulted in well-defined micelles of varying sizes while the assembly in hydrophobic, organic solvent resulted in the formation of different morphologies including large aggregates and well-defined cylindrical and spherical structures.

show abstract

“…Alkoxyamines were first used by Hawker and coworkers36, 37 as initiators in nitroxide‐mediated controlled/living radical polymerization. Research on the application of nitroxide‐mediated controlled/living radical polymerization is still ongoing in the preparation of various functional block copolymers 38–40. The homolysis of alkoxyamine has already been well studied by Fischer and a coworker41–43 and Fukuda and coworkers 44, 45.…”

Section: Introductionmentioning

confidence: 99%

Kinetic analysis of the cross reaction between dithioester and alkoxyamine by a Monte Carlo simulation

Han

et al. 2006

J. Polym. Sci. A Polym. Chem.

View full text Add to dashboard Cite

A model reaction of dithioester and alkoxyamine is proposed to probe the reversible addition–fragmentation chain transfer (RAFT) process. The kinetics of the model reaction is analyzed and compared with that of pure alkoxyamine homolysis with a Monte Carlo simulation. Although the pure alkoxyamine obeys the law of persistent radical effect, the model reaction results in higher concentration of the persistent radical during the main period of the reaction. However, for a very fast RAFT process or a very low addition rate constant, the time dependence of the persistent radical concentration is quite close to that of pure alkoxyamine. Furthermore, the cross termination between the intermediate and alkyl radicals causes a retardation effect for the model reaction when the intermediate is relatively long‐lived. The Monte Carlo simulation indicates that it is feasible to measure the individual rate constants of the RAFT process, such as the rate constant of addition, with a large excess of alkoxyamine. In addition, the special feature of the system with different leaving groups in the alkoxyamine and dithioester is also discussed. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 374–387, 2007

show abstract

Preparation of poly(ethylene oxide)‐block‐poly(isoprene) by nitroxide‐mediated free radical polymerization from PEO macroinitiators

Cited by 69 publications

References 36 publications

Use of Solvent Effects to Improve Control Over Nitroxide‐Mediated Polymerization of Isoprene

Use of Solvent Effects to Improve Control Over Nitroxide‐Mediated Polymerization of Isoprene

Evaluation of Isoprene Chain Extension from PEO Macromolecular Chain Transfer Agents for the Preparation of Dual, Invertible Block Copolymer Nanoassemblies

Kinetic analysis of the cross reaction between dithioester and alkoxyamine by a Monte Carlo simulation

Contact Info

Product

Resources

About