Synthesis and reactivity of α,ω-homotelechelic polymers by Cu(0)-mediated living radical polymerization (original) (raw)
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Copper(0)-mediated radical polymerisation in a self-generating biphasic system
Polymer Chemistry, 2013
Herein, we demonstrate the synthesis of well-defined poly(n-alkyl acrylate)s via copper (0)-mediated radical polymerisation in a self-generating biphasic system. During the polymerisation of n-butyl acrylate in DMSO the polymer phase separates to yield a polymer-rich layer without trace of copper salts (XPS analysis). The poly(n-butyl acrylate) has been characterized by a range of techniques, including GPC, NMR and MALDI-TOF, to confirm both the controlled character of the polymerisation and the end group fidelity. Moreover, we have successfully chain extended poly(n-butyl acrylate) in this biphasic system several times with n-butyl acrylate to high conversion without intermediate purification steps. A range of other alkyl acrylates have been investigated and the control over the polymerisation is lost as the hydrophobicity of the polymer increases as the alkyl chain length increases indicating that it is important for the monomer to be soluble in the polar solvent.
Controlled/living radical polymerization: Features, developments, and perspectives
Recent mechanistic developments in the field of controlled/living radical polymerization (CRP) are reviewed. Particular emphasis is placed on structure-reactivity correlations and ''rules'' for catalyst selection in atom transfer radical polymerization (ATRP), for chain transfer agent selection in reversible addition-fragmentation chain transfer (RAFT) polymerization, and for the selection of an appropriate mediating agent in stable free radical polymerization (SFRP), including organic and transition metal persistent radicals. Novel methods of fine tuning initiation, activation, and deactivation processes for all techniques are discussed, including activators regenerated by electron transfer (ARGET) and initiators for continuous activator regeneration (ICAR) ATRP, whereby Cu catalyst concentrations in ATRP can be lowered to just 10 ppm. Progress made in each technique related to the synthesis of both high and low molecular weight polymers, end functional polymers, block copolymers, expanding the range of polymerizable monomers, synthesis of hybrid materials, environmental issues, and polymerization in aqueous media is thoroughly discussed and compared. r
Journal of Polymer Science Part A: Polymer Chemistry, 2005
ABA block copolymers containing poly(methyl acrylate) (PMA) as the A segment and poly(vinyl chloride) (PVC) as the B segment (PMA-b-PVC-b-PMA) were synthesized by the Cu(0)/tris(2-dimethylaminoethyl)amine (Me 6 -TREN)-catalyzed living radical block copolymerization of methyl acrylate (MA) initiated with ␣,-di(iodo)poly(vinyl chloride) [␣,-di(iodo)PVC] in dimethyl sulfoxide (DMSO) at 90, 50, and 25°C. 1,1-Chloroiodoethane, a model compound for the chain ends of the ␣,-di(iodo)PVC macroinitiator, was used as an initiator for the Cu(0)/Me 6 -TREN-catalyzed living radical polymerization of MA in DMSO at 70, 50, and 25°C. Ultrafast block copolymerization and living radical polymerization methods for MA and other acrylates were discovered. These ultrafast methods provided access to the synthesis of PMA-b-PVA-b-PMA in reaction times, which depended on the temperature range, of 3-20 min.
Chemistry – A European Journal, 2012
The field of transition‐metal‐mediated controlled/“living” radical polymerization (CLRP) has become the subject of intense discussion regarding the mechanism of this widely‐used and versatile process. Most mechanistic analyses (atom transfer radical polymerization (ATRP) vs. single‐electron transfer living radical polymerization (SET‐LRP)) have been based on model experiments, which cannot correctly mimic the true reaction conditions. We present, for the first time, a determination of the [CuIBr]/[L] (L=nitrogen‐based chelating ligand) ratio and the extent of CuIBr/L disproportionation during CLRP of methyl acrylate (MA) in dimethylsulfoxide (DMSO) with Cu0 wire as a transition‐metal catalyst source. The results suggest that Cu0 acts as a supplemental activator and reducing agent of CuIIBr2/L to CuIBr/L. More importantly, the CuIBr/L species seem to be responsible for the activation of SET‐LRP.
Journal of Polymer Science Part A-polymer Chemistry, 2005
α,ω-Di(iodo)poly(vinyl chloride)s with number-average molecular weights (Mn's) of 2100–29,800 and weight-average molecular weight/number-average molecular weight (Mw/Mn) ratios of 1.66–2.16 were synthesized by the single-electron-transfer/degenerative-chain-transfer mediated living radical polymerization of vinyl chloride initiated with CHI3 and catalyzed by Na2S2O4. These α,ω-di(iodo)poly(vinyl chloride)s were used as initiators for the metal-catalyzed living radical block copolymerization of methyl methacrylate mediated by CuCl/2,2′-bipyridine. Poly(methyl methacrylate)-b-poly(vinyl chloride)-b-poly(methyl methacrylate) block copolymers with Mn values of 36,500–95,700 and Mw/Mn values lower than 1.20 were synthesized by this novel and general synthetic method. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1478–1486, 2005
Chem. Commun., 2015
A photo-polymerization protocol, utilizing a pre-formed and wellcharacterized Cu(II) formate complex, [Cu(Me 6 -Tren)(O 2 CH)](ClO 4 ), mediated by UV light is described. In the absence of additional reducing agents and/or photosensitizers, ppm concentrations of the oxidatively stable [Cu(Me 6 -Tren)(O 2 CH)](ClO 4 ), furnish nearquantitative conversions within 2 h, yielding poly(acrylates) with low dispersities (B1.10) and exceptional end-group fidelity, capable of undergoing in situ chain extension and block copolymerization.