Abstract:Reverse iodine transfer polymerizations (RITP) of 2-h-ydroxyethyl acrylate (HEA) were performed in N,N-dimethylformamide at 75 C using AIBN as initiator. Poly(2-hydroxyethyl acrylate) (PHEA) with M n ¼ 3300 g mol À1 and M w /M n <1.5 were obtained. Homopolymerization of styrene in RITP was also carried out under similar conditions using toluene as solvent. The resulting iodopolystyrene (PS-I) with (M n, SEC ¼ 607 g mol À1 , polydispersity index (PDI) ¼ 1.31) was used as a macroinitiator for the synthesis of am… Show more
“…The strong signals at 3.55 and 4.05 ppm are attributed to the methylene (–CH 2 ) protons of the hydroxyethyl group (d and e) and the signal at 4.8 ppm corresponds to the –OH of hydroxyethyl group. The presence of peaks belonging to styrene and HEA are consistent with the literature data reported for the copolymerization of PS- b -PHEA 27 , 29 . Figure 3 1 H NMR spectrum of ( a ) PS-SG1 macroinitiator in CDCl 3 and ( b ) PS- b -PHEA in DMSO-d 6 .…”
Section: Resultssupporting
confidence: 91%
“…In the FTIR spectrum of PS the aromatic (C=C stretching) band produced three peaks at 1602, 1492, and 1451 cm −1 , the aromatic (C–H) bands was observed at 740 cm −1 , and aliphatic band (C–H stretching) appeared at 3024 cm −1 . The FTIR spectrum of PS- b -PHEA exhibits new stretching bands at 3432, 1714, and 1160 cm −1 , which are assigned to (–OH), –C=O, and C–O of PHEA, respectively 27,33 . These FTIR spectroscopy results are clear evidence of the copolymerization of styrene and HEA by NMP.Figure 4FTIR spectra of PS and PS- b -PHEA.…”
Section: Resultsmentioning
confidence: 99%
“…Compared to other synthesis methods, NMP is an unimolecular technique involving only one alkoxyamine initiator with no additional controller and no purification step 25 , 26 . Recently, PS- b -PHEA could be synthetized by different CRP methods including NMP with TEMPO-and TIPNO-based nitroxide 27 – 31 . But to the best of our knowledge, only short PHEA blocks not exceeding 50 wt.…”
The high failure strain of thermoplastic elastomers (TPEs) is a very desirable feature for rechargeable Li-ion batteries by improving the lifetime of high specific capacity anode materials that undergo mechanical fractures induced by large volume variations. In this work, poly(styrene-b-2-hydroxyethyl acrylate) called PS-b-PHEA was synthesized by a nitroxide meditated polymerization method. Owing to the use of a specific polystyrene macroinitiator (SG1), a suitable TPE copolymer with long hydroxyethyl acrylate blocks to ensure good mechanical properties is obtained for the first time. We show that the electrochemical properties of the PS-b-PHEA-coated SnSb anode are drastically improved by suppressing the crack formation at the surface of the electrode. Indeed, electrochemical characterization revealed that a high and stable gravimetric capacity over 100 cycles could be achieved. Moreover, excellent capacity reversibility was achieved when cycled at multiple C-rates and fast kinetics confirming the strong protection role of the polymer. The advanced chemical and mechanical properties of PS-b-PHEA open up promising perspectives to significantly improve the electrochemical performance of all electrodes that are known to suffer from large volume variations.
“…The strong signals at 3.55 and 4.05 ppm are attributed to the methylene (–CH 2 ) protons of the hydroxyethyl group (d and e) and the signal at 4.8 ppm corresponds to the –OH of hydroxyethyl group. The presence of peaks belonging to styrene and HEA are consistent with the literature data reported for the copolymerization of PS- b -PHEA 27 , 29 . Figure 3 1 H NMR spectrum of ( a ) PS-SG1 macroinitiator in CDCl 3 and ( b ) PS- b -PHEA in DMSO-d 6 .…”
Section: Resultssupporting
confidence: 91%
“…In the FTIR spectrum of PS the aromatic (C=C stretching) band produced three peaks at 1602, 1492, and 1451 cm −1 , the aromatic (C–H) bands was observed at 740 cm −1 , and aliphatic band (C–H stretching) appeared at 3024 cm −1 . The FTIR spectrum of PS- b -PHEA exhibits new stretching bands at 3432, 1714, and 1160 cm −1 , which are assigned to (–OH), –C=O, and C–O of PHEA, respectively 27,33 . These FTIR spectroscopy results are clear evidence of the copolymerization of styrene and HEA by NMP.Figure 4FTIR spectra of PS and PS- b -PHEA.…”
Section: Resultsmentioning
confidence: 99%
“…Compared to other synthesis methods, NMP is an unimolecular technique involving only one alkoxyamine initiator with no additional controller and no purification step 25 , 26 . Recently, PS- b -PHEA could be synthetized by different CRP methods including NMP with TEMPO-and TIPNO-based nitroxide 27 – 31 . But to the best of our knowledge, only short PHEA blocks not exceeding 50 wt.…”
The high failure strain of thermoplastic elastomers (TPEs) is a very desirable feature for rechargeable Li-ion batteries by improving the lifetime of high specific capacity anode materials that undergo mechanical fractures induced by large volume variations. In this work, poly(styrene-b-2-hydroxyethyl acrylate) called PS-b-PHEA was synthesized by a nitroxide meditated polymerization method. Owing to the use of a specific polystyrene macroinitiator (SG1), a suitable TPE copolymer with long hydroxyethyl acrylate blocks to ensure good mechanical properties is obtained for the first time. We show that the electrochemical properties of the PS-b-PHEA-coated SnSb anode are drastically improved by suppressing the crack formation at the surface of the electrode. Indeed, electrochemical characterization revealed that a high and stable gravimetric capacity over 100 cycles could be achieved. Moreover, excellent capacity reversibility was achieved when cycled at multiple C-rates and fast kinetics confirming the strong protection role of the polymer. The advanced chemical and mechanical properties of PS-b-PHEA open up promising perspectives to significantly improve the electrochemical performance of all electrodes that are known to suffer from large volume variations.
“…This could help in overcoming the disadvantages in the synthesis and storage process of CTAs . RITP has successfully been used for polymerization of various monomers such as acrylates, styrene, vinyl acetate (VAc), methacrylates and copolymers …”
Homo-and copolymers of vinyl esters including vinyl acetate (VAc) and vinyl benzoate (VBz) were synthesized via the reverse iodine transfer radical polymerization technique. Polymerization was carried out in the presence of iodine as the in situ generator of the transfer agent and 2,2 ′ -azobis(isobutyronitrile) as the initiator at 70 ∘ C. Reverse iodine transfer radical homopolymerization of VAc and VBz led to conversions of 76 and 57%, number-average molecular weights of 8266 and 9814 g mol −1 and molecular weight distributions of 1.58 and 1.49, respectively. The microstructure of the synthesized polymers was investigated in detail using gel permeation chromatography, 1 H NMR, 13 C NMR and distortionless enhancement of polarization transfer (135 ∘ decoupler pulse) techniques. Relatively narrow molecular weight distribution and controlled and predictable trend of molecular weight versus conversion were observed for the synthesized polymers, showing that reverse iodine transfer radical homo-and copolymerization of VAc and VBz proceeded with controlled characteristics. Results of molecular weight and its distribution along with the 1 H NMR spectra recorded for homo-and copolymers indicated that side reactions can occur during the course of polymerization with a significant contribution when VAc, even in a small amount, was present in the reaction mixture. This can result in polymer chains with aldehyde dead end and broadening of the molecular weight distribution.
“…Clement et al used NMP for synthesizing poly( d , l ‐lactide)(PLA)‐b‐PHEA biocompatible block copolymers. Reverse iodine transfer polymerization (RITP) allowed synthesizing PS‐b‐PHEA block copolymers . Poly( N ‐isopropylacrylamide) (PNIPAM), poly(vinylidene chloride‐co‐methyl acrylate) or bovine serum albumin (BSA) macro‐RAFT agents were used for synthesizing PHEA containing block copolymers.…”
Triple hydrophilic asymmetric poly(2-hydroxyethyl acrylate)-b-poly(ethylene oxide)-b-poly(2-hydroxyethyl acrylate) (PHEA-b-PEO-b-PHEA) triblock copolymers are obtained by copper(0) catalyzed reversible deactivation radical polymerization (RDRP). Copper wire catalyzed polymerization of HEA from large PEO ( M n = 35 000 g mol −1 ) macroinitiator in dimethylsulfoxide or in water fails to reach high monomer conversion in a controlled manner contrary to what is previously published with a shorter PEO macroinitiator. Catalysis by nascent Cu(0) particles generated by disproportionating CuBr in water allows rapid polymerization and high monomer conversion with a rather good control of both dispersity and HEA block length. Model disproportionation experiment shows that HEA infl uences the disproportionation/ comproportionation equilibrium. Larger quantities of HEA lead to higher apparent rate constants and less disproportionation of CuBr which is in agreement with the supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) mechanism and not with the single electron transfer-living radical polymerization (SET-LRP) mechanism.to synthesize amphiphilic diblock [ 2 ] (AB) or triblock [ 3 ] (BAB) copolymers bearing cross-linkable moieties on the hydrophobic B-blocks. These block copolymers self-assembled in aqueous solution and formed star-like [ 2,4,5 ] or fl owerlike [ 3,6 ] polymeric micelles that could be rendered permanent by in situ photo-cross-linking.Reversible deactivation radical polymerization (RDRP) techniques have been shown to allow synthesis of PHEA in a controlled manner, both in the bulk and in solution. PHEA homopolymers are readily synthesized by nitroxide mediated polymerization (NMP), [ 7 ] reversible addition fragmentation chain transfer (RAFT), [ 8,9 ] atom transfer radical polymerization (ATRP), [ 10 ] and RDRP catalyzed by copper(0) associated to copper halides [ 11,12 ] (usually called
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