Improved compositional analysis of block copolymers using Diffusion Ordered NMR Spectroscopy

Viel, Stéphane; Mazarin, Michaël; Giordanengo, Rémi; Phan, Trang N. T.; Charles, Laurence; Caldarelli, Stéfano

doi:10.1016/j.aca.2009.06.049

Cited by 35 publications

(33 citation statements)

References 30 publications

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“…It should be noted that the data are processed with monoexponential fittings. A similar behavior of exponential DOSY processing was also observed by Viel et al for PS‐b‐PEO copolymers where the diffusion coefficients of the PS and PEO blocks were different due to overlapping PS homopolymer.…”

Section: Resultssupporting

confidence: 82%

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Quantitative Studies of Block Copolymers and Their Containing Homopolymer Components by Diffusion Ordered Spectroscopy

Hiller

2019

Macro Chemistry & Physics

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Several polystyrene‐b‐poly(methyl methacrylate) (PS‐b‐PMMA) and polyisoprene‐b‐PMMA (PI‐b‐PMMA) block copolymers are studied with high‐resolution diffusion ordered spectroscopy (DOSY) in order to quantify the amounts and molar masses of the copolymers and the containing homopolymers. These studies are particularly challenging because these homopolymers and one block of the copolymers consist of the same monomer type with different molar masses and compositions and cause a total overlap of these polymer components in the NMR spectra. However, DOSY can be proven as a powerful tool for separation and quantification of these moieties. Whereas exponential fittings only deliver averaged diffusion data, biexponential fittings of the individual magnetization curves can separate the overlapping polymer parts. This DOSY approach can be successfully tested for different blends of PS as well as PS and PS‐b‐PMMA of different molar masses and weighed compositions. The DOSY separation is also compared to size exclusion chromatography (SEC). In the case of the PS‐b‐PMMA and PI‐b‐PMMA block copolymers, DOSY identifies the contaminations with homopolymers, quantifies their individual amounts as well as determines the molar masses of both the copolymers and homopolymers. Two mathematical evaluations are used for quantifying these homopolymers with DOSY. These results are compared with the online coupling of SEC and NMR.

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Section: Resultssupporting

confidence: 82%

“…DOSY can also be used to characterize block copolymers. Barrere et al determined block lengths of copolymers, Viel et al performed the compositional analysis of block copolymers, Natalello et al studied amphiphilic block copolymers, and Yu et al determined the sizes of micelles by DOSY …”

Section: Introductionmentioning

confidence: 99%

Quantitative Studies of Block Copolymers and Their Containing Homopolymer Components by Diffusion Ordered Spectroscopy

Hiller

2019

Macro Chemistry & Physics

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“…1 H NMR, 13 C NMR, and DEPT135 NMR spectra were recorded on a Bruker AC‐400 spectrometer in appropriate deuterated solvents. Diffusion ordered spectroscopy (DOSY) NMR measurements were performed at 298 K on a Bruker Avance III 400 spectrometer in CDCl 3 at room temperature operating at 400.33 MHz and equipped with a 5 mm Bruker multinuclear z ‐gradient direct cryoprobe‐head capable of producing gradients in the z direction with strength 53.5 G cm −1 . For each sample, 3 mg were dissolved in 0.4 mL of CDCl 3 for internal lock and spinning was used to minimize convection effects.…”

Section: Methodsmentioning

confidence: 99%

Dialkylmagnesium‐Promoted Deprotonation of Protic Precursors for the Activated Anionic Ring‐Opening Polymerization of Epoxides

Roos

Wirotius

Carlotti

2017

Macro Chemistry & Physics

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A family of extremely strong Brönsted bases called phosphazene superbases, [13] was also employed as effective organic catalysts or promoters for the polymerization of various types of monomers, including epoxides. [14][15][16][17][18][19][20][21][22] Due to their high basicity, non-nucleophilic nature, good solubility in a wide range of solvents, and easy handling, phosphazene bases can be readily used to turn protic moieties into nucleophilic initiating sites through deprotonation or activation of weak nucleophiles. Hydroxyl groups were the most commonly employed protic moieties due to their wide variety and high availability. Some recent reports have also demonstrated the deprotonation of other protic precursors, i.e., thiol, [23][24][25][26] amide, [27][28][29] and carboxylic acid [30] for effective polymerizations of cyclic monomers with mostly t-BuP 4 superbase. The obtention of hydroxy telechelic poly(propylene oxide) appears still limited by transfer to monomer reactions, giving chains initiated by an allyloxy group and limiting the molar masses. Their present high cost may also limit their use in industry.Besides, some studies have shown that a simple dibutylmagnesium (Bu 2 Mg) enables the synthesis of polyesters by ring-opening polymerization of lactides or lactones with residual transesterification side reactions. [31][32][33][34][35] Alcohols with different steric bulk and acidity, including iPrOH, PhCH 2 OH, Ph 2 CHOH, and Ph 3 COH, were employed with Bu 2 Mg to form magnesium alkoxides. The generated system was shown to improve the polymerizability of cyclic esters in dilute solutions by increasing the molar masses and narrowing the dispersity values where alcohols acts as control transfer agents. [36][37][38][39] We demonstrated in a previous work that propylene oxide can be polymerized with magnesium alkoxides (ROMgX) prepared from Grignard precursors in combination with triisobutylaluminum. [40] Starting from an alcohol, Grignard reagents were used as sustainable deprotonating agents for the generation of alkoxides of magnesium halide. The so-formed active species were able to initiate and poly merize propylene oxide in a controlled way. Competitive initiations were nevertheless observed. The main one was coming from the halide of the Grignard. The work presented in this article concerns a halide-free system based on dialkylmagnesium compounds used as deprotonating agents of protic

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“…Whatever the grafting ratio and the grafted chain lengths, the 13 C CPMAS data proved the presence of both CA and PS in the samples. DOSY-NMR has already been successfully used to prove the formation of block copolymers [31][32][33] and graft copolymers. Two model grafted copolymers, namely CA-g-PS(20%, 13000) and CA-g-PS(3%, 21000) were analysed by DSC as well ( Figure 8).…”

Section: Characterization Of the Grafted Copolymermentioning

confidence: 99%

Synthesis of polystyrene-grafted cellulose acetate copolymers via nitroxide-mediated polymerization

et al. 2015

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Cellulose acetate-g-polystyrene (CA-g-PS) grafted copolymers have been synthesized by nitroxidemediated\ud polymerization (NMP) under homogeneous conditions by using the 1,2-intermolecular radical\ud addition (1,2-IRA) methodology to introduce the SG1-based alkoxyamine BlocBuilder MA (BB) on the\ud polysaccharide backbone. A preliminary study conducted on model sugar-based alkoxyamines proved that\ud whatever the position of the alkoxyamine on the sugar unit, the number of sugar units and the presence\ud of OH groups, one could expect a controlled/living polymerization process. This was confirmed by the\ud graft polymerization of styrene from the BB-modified cellulose acetate backbone with two different grafting\ud ratios (3 and 20%) and different grafted chain lengths (40 000 and 80 000 g mol−1 targeted Mn). The\ud grafted copolymers were carefully analyzed, in particular, by DOSY NMR to confirm their grafted\ud structure

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Improved compositional analysis of block copolymers using Diffusion Ordered NMR Spectroscopy

Cited by 35 publications

References 30 publications

Quantitative Studies of Block Copolymers and Their Containing Homopolymer Components by Diffusion Ordered Spectroscopy

Quantitative Studies of Block Copolymers and Their Containing Homopolymer Components by Diffusion Ordered Spectroscopy

Dialkylmagnesium‐Promoted Deprotonation of Protic Precursors for the Activated Anionic Ring‐Opening Polymerization of Epoxides

Synthesis of polystyrene-grafted cellulose acetate copolymers via nitroxide-mediated polymerization

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