Controlled/“living” atom transfer radical polymerization of methyl methacrylate in the synthesis of triblock copolymers from a poly(oxyethylene) macroinitiator

Krishnan, Rajagopal; Srinivasan, K. S. V.

doi:10.1016/s0014-3057(02)00231-8

Cited by 21 publications

(5 citation statements)

References 23 publications

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“…To achieve our aims we required a diblock polymer that was biocompatible and contained a core block that was rich in fluorine. Our prototype design was relatively simple and would include a solubilizing PEG block as a macroinitiator for an ATRP synthesis 13,14,15 . GPC using RI detection generated chromatograms that showed a degree of bimodal character and higher than expected polydispersities.…”

Section: Resultsmentioning

confidence: 99%

“…To achieve our aims we required a diblock polymer that was biocompatible and contained a core block that was rich in fluorine. Our prototype design was relatively simple and would include a solubilizing PEG block as a macroinitiator for an ATRP synthesis − involving a monomer rich in fluorine. The synthesis is shown in Scheme and involves the initial functionalization of Me-PEG-2000 1 with α-bromoisobutyryl bromide (BIBB) 2 to generate the macroinitiator 3 .…”

Section: Resultsmentioning

confidence: 99%

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Increased Oxygen Solubility in Aqueous Media Using PEG–Poly-2,2,2-trifluoroethyl Methacrylate Copolymer Micelles and Their Potential Application As Volume Expanders and As an Artificial Blood Product

Fan

Alghassab

Twyman

2018

ACS Appl. Bio Mater.

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One of the most important functions of blood is to solubilize and distribute oxygen within the body. As such, it is vital that this property is replicated (safely) by any artificial blood product. In this paper, we describe the facile synthesis of a series of simple diblock polymers capable of selfassembling into micellar structures at concentrations around 3×10-3 mg/mL. Using a dissolved oxygen meter, we were able to demonstrate that aqueous solutions of these aggregated structures could retain oxygen and release it (into the aqueous bulk phase). The increased oxygen retention was quantified by measuring the rate of oxygen release and its half-life. These experiments indicated that oxygen retention/binding was dependent on the fluorine concentration. 19 F NMR experiments on a micellar solution saturated with oxygen showed small upfield shifts in the fluorine peaks, which provided qualitative evidence that indicated oxygen binding occurred within the fluorine region of the polymer aggregates. Using a modified enzyme/glucose oxidation assay, we were able to establish that the aqueous oxygen concentrations were 33% higher in a solution of polymer.

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Section: Resultsmentioning

confidence: 99%

“…To achieve our aims we required a diblock polymer that was biocompatible and contained a core block that was rich in fluorine. Our prototype design was relatively simple and would include a solubilizing PEG block as a macroinitiator for an ATRP synthesis − involving a monomer rich in fluorine. The synthesis is shown in Scheme and involves the initial functionalization of Me-PEG-2000 1 with α-bromoisobutyryl bromide (BIBB) 2 to generate the macroinitiator 3 .…”

Section: Resultsmentioning

confidence: 99%

Increased Oxygen Solubility in Aqueous Media Using PEG–Poly-2,2,2-trifluoroethyl Methacrylate Copolymer Micelles and Their Potential Application As Volume Expanders and As an Artificial Blood Product

Fan

Alghassab

Twyman

2018

ACS Appl. Bio Mater.

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“…The rate of activation of a bromo-terminated polymethacrylate chain end is faster than the activation of a 2-bromoisobutyrate PEO chain end. [39,[77][78][79][80][81][82]Typically, halogen exchange procedures [23,24,[35][36][37][38][39] are employed to solve this problem, but they can not be used for systems with low concentrations of catalyst, because of poor initiation efficiency. Motivated by the very good control over the polymerization that is attainable with high amounts Cu (ca.…”

Section: Resultsmentioning

confidence: 99%

“…Motivated by the very good control over the polymerization that is attainable with high amounts Cu (ca. 1,000-30,000 ppm) [23,24,29,[35][36][37][38][39] we initially set out to achieve similar levels of control using only 50 ppm of Cu II /L in solution, following the eATRP procedure under potentiostatic conditions, which requires a three electrode systema Pt mesh working electrode (WE), a Pt mesh counter electrode (CE) (separated from the reaction media using methylated cellulose gel), and a saturated calomel electrode (SCE) reference electrode (RE). In addition, to simplify the procedure, eATRP was carried out under galvanostatic conditions, which only requires a Pt mesh working cathode and an Al wire counter/sacrificial anode.…”

Section: Resultsmentioning

confidence: 99%

“…[23,24,[35][36][37] Triblock copolymers with narrow MWD (M w /M n = 1.111.30) were prepared using a difunctional PEO macroinitiator but also required a high concentration of catalyst, at least 10,500 ppm. [23,38,39] Recently, new ATRP procedures with low concentration of Cu-based catalysts were developed. They include activators regenerated by electron transfer (ARGET), [40][41][42][43][44][45] initiators for continuous activator regeneration (ICAR), [40,46,47] or supplemental activators and reducing agents (SARA) [48][49][50][51][52] ATRP methods.…”

Section: Introductionmentioning

confidence: 99%

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A simplified electrochemically mediated ATRP synthesis of PEO-b-PMMA copolymers

Chmielarz

Sobkowiak

Matyjaszewski

2015

Polymer

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Poly(ethylene oxide)-block-poly(methyl methacrylate) amphiphilic copolymers were prepared via electrochemically mediated atom transfer radical polymerization (eATRP) utilizing only 50 ppm of Cu II complex, rather than previously reported concentrations of catalyst of ca. 1,000-30,000 ppm. The copolymers were also prepared via a simplified electrochemically mediated ATRP (seATRP) procedure utilizing an aluminum wire sacrificial anode as a counter electrode, which was directly immersed into the reaction flask, without the need fo its separation. This seATRP system works under both potentiostatic and galvanostatic conditions. In each case the polymerization results showed similar molecular weight evolution while maintaining a narrow molecular weight distribution throughout the reactions. The successful chain extension and formation of block copolymers confirmed the living nature of the poly(alkyl methacrylates) prepared by eATRP and seATRP.

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Synthesis and characterization of amphiphilic block copolymers of methyl methacrylate with poly(ethylene oxide) macroinitiators formed by atom transfer radical polymerization

Krishnan

Srinivasan

2005

J of Applied Polymer Sci

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Amphiphilic ABA triblock copolymers of poly(ethylene oxide) (PEO) with methyl methacrylate (MMA) were prepared by atom transfer radical polymerization in bulk and in various solvents with a difunctional PEO macroinitiator and a Cu(I)X/N,N,NЈ,NЉ,NЉ-pentamethyldiethylenetriamine catalyst system at 85°C where XϭCl or Br. The polymerization proceeded via controlled/living process, and the molecular weights of the obtained block copolymers increased linearly with monomer conversion. In the process, the polydispersity decreased and finally reached a value of less than 1.3. The polymerization followed firstorder kinetics with respect to monomer concentration, and increases in the ethylene oxide repeating units or chain length in the macroinitiator decreased the rate of polymerization. The rate of polymerization of MMA with the PEO chloro macroinitiator and CuCl proceeded at approximately half the rate of bromo analogs. A faster rate of polymerization and controlled molecular weights with lower polydispersities were observed in bulk polymerization compared with polar and nonpolar solvent systems. In the bulk polymerization, the number-average molecular weight by gel permeation chromatography (M n,GPC ) values were very close to the theoretical line, whereas lower than the theoretical line were observed in solution polymerizations. The macroinitiator and their block copolymers were characterized by Fourier transform infrared spectroscopy, 1 H-NMR, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, thermogravimetry (TG)/differential thermal analysis (DTA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). TG/DTA studies of the homo and block copolymers showed two-step and multistep decomposition patterns. The DSC thermograms exhibited two glass-transition temperatures at Ϫ17.7 and 92°C for the PEO and poly(methyl methacrylate) (PMMA) blocks, respectively, which indicated that microphase separation between the PEO and PMMA domains. SEM studies indicated a fine dispersion of PEO in the PMMA matrix.

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Controlled/“living” atom transfer radical polymerization of methyl methacrylate in the synthesis of triblock copolymers from a poly(oxyethylene) macroinitiator

Cited by 21 publications

References 23 publications

Increased Oxygen Solubility in Aqueous Media Using PEG–Poly-2,2,2-trifluoroethyl Methacrylate Copolymer Micelles and Their Potential Application As Volume Expanders and As an Artificial Blood Product

Increased Oxygen Solubility in Aqueous Media Using PEG–Poly-2,2,2-trifluoroethyl Methacrylate Copolymer Micelles and Their Potential Application As Volume Expanders and As an Artificial Blood Product

A simplified electrochemically mediated ATRP synthesis of PEO-b-PMMA copolymers

Synthesis and characterization of amphiphilic block copolymers of methyl methacrylate with poly(ethylene oxide) macroinitiators formed by atom transfer radical polymerization

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