Structural investigations of acrylonitrile–vinyl acid copolymers by NMR spectroscopy

Bajaj, P.; Sreekumar, T. V.; Sen, Kushal; Kumar, Rajeev; Brar, A. S.

doi:10.1002/app.11779

Cited by 17 publications

(6 citation statements)

References 16 publications

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“…However, the resolution of the −CN splitting in the copolymer of acrylonitrile becomes broad due to the overlapping of the compositional sequence of the comonomers units. 20 Thus, the signal due to the resonance of the carbon atom on nitrile (−CN) functionality is observed at 121.499 ppm in the present copolymer. Similarly, the signal due to the resonance of the carbon atom on methylene (−CH 2 ) of the homopolyacrylonitrile and homopolyvinylpyrrolidone ring at 33.3 ppm 21 and 30.3 ppm, 22 respectively, merges to a strong single peak at 31.208 ppm in the copolymer.…”

Section: Introductionmentioning

confidence: 69%

“…The homopolyacrylonitrile (PAN) has been reported to show a well resolved triplet in the −CN region at 118.8–120.10 ppm. However, the resolution of the −CN splitting in the copolymer of acrylonitrile becomes broad due to the overlapping of the compositional sequence of the comonomers units . Thus, the signal due to the resonance of the carbon atom on nitrile (−CN) functionality is observed at 121.499 ppm in the present copolymer.…”

Section: Resultsmentioning

confidence: 99%

“…The formation of the copolymer of AN and NVP was also evident from NMR analysis as shown in Figure 1b. The homopolyacrylonitrile (PAN) has been reported 20 to show a well resolved triplet in the −CN region at 118.8− 120.10 ppm. However, the resolution of the −CN splitting in the copolymer of acrylonitrile becomes broad due to the overlapping of the compositional sequence of the comonomers units.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Sorption and Permeation of Acetonitrile–Water Mixtures through Nanoclay-Filled Copolymer Membranes

Choudhury

Ray

2019

Ind. Eng. Chem. Res.

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Several hydrophilic membranes were prepared by solvent casting from filled copolymers. These filled copolymers were synthesized by free radical polymerization of acrylonitrile (AN) and N-vinylpyrrolidone (NVP) monomers in different comonomer ratios (AN/NVP) in the presence of a nanosized clay. The membrane polymers were analyzed by NMR, Fourier transform infrared spectroscopy, X-ray diffraction, differential thermal and thermogravimetric analyses, scanning electron microscopy, mechanical properties, and dynamic mechanical analysis for characterization of its structural configuration, functionalities, copolymer composition, distribution of clay in the copolymer, and the strength and stability of the membrane under dynamic and thermal stress. The sorption and pervaporation of acetonitrile–water mixtures through these membranes were studied at varied copolymer compositions, mass % of clay, feed concentrations of water, and feed temperatures. Sorption data were analyzed by binary and ternary solvent/membrane interaction parameters while the diffusion coefficient of solvents through the membranes was determined by a solution-diffusion model. The synthesis and process variables were optimized by a central composite design of the response surface methodology with flux and separation factor as output responses. The membrane prepared with the AN/NVP mole ratio of 12:1 and 1 mass % nanoclay showed the optimized flux and separation factor of 160 g/m2 h and 196, respectively for 90 mass % acetonitrile in feed which was dehydrated to 95.6 mass % after pervaporation. The long-term stability of the membrane was also evaluated. Comparison of tensile properties of unused and used membranes confirmed mechanical stability of the membrane while FTIR analysis revealed that there was no change in structure or composition of the membrane after prolonged use.

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Section: Introductionmentioning

confidence: 69%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Analysis of Sorption and Permeation of Acetonitrile–Water Mixtures through Nanoclay-Filled Copolymer Membranes

Choudhury

Ray

2019

Ind. Eng. Chem. Res.

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“…By contrary, a little higher molecular weight can be obtained by the same prescription in solvent–water polymerization system since water has a near‐zero chain transfer coefficient [23]. The polymer dispersity index (PDI) of 85/15 AN/MA is about 2.0, which is lower than that reported in the literature [24]. The narrow PDI is beneficial for developing high mechanical strength sheet.…”

Section: Resultsmentioning

confidence: 99%

Structures and properties of thermoregulated acrylonitrile–methyl acrylate sheet containing microphase change materials

Han

Gao

Zhang³

et al. 2013

Polymer Composites

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A series of melt processable poly(acrylonitrile-methyl acrylate) copolymers with a feeding ratio of 85/15 mol% (abbreviated as 85/15 AN/MA below) containing 0-25 wt% of microencapsulated phase change materials (micro-PCMs) were synthesized by aqueous precipitation polymerization. The number average sequence lengths (NASLs) and tacticity of 85/15 AN/MA were determined using 13 C-NMR. The results showed that the NASL of contiguous AN sequences is 10.00 and the tacticity is atactic with approximately 51% m and 49% r diads (the relative orientation of two adjacent cyanogroup). 85/15 AN/MA containing various contents of micro-PCMs were processed into sheets in melt condition at 2108C and 20 MPa. The structures and properties of the copolymers and sheets containing micro-PCMs were studied by using Fourier transform infrared spectroscopy, nuclear magnetic resonance ( 1 H-NMR), scanning electron microscopy, differential scanning calorimetry, gel permeation chromatography, X-ray diffraction, and dynamic mechanical analysis. The composition of AN/MA copolymer agreed well with its monomer feed ratio. The melting enthalpy of the sheets containing 25 wt% of micro-PCMs was approximately 25 J/g, which increased steadily as the micro-PCMs content increased. The modulus of the sheets decreased with the micro-PCMs content increased. The glass transition temperature (T g ) of the sheets was in the range of 79.7-81.78C, which also increased with the micro-PCMs content increasing. POLYM. COMPOS., 34:641-649, 2013. ª

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“…The spun fibers were drawn in a coagulation bath and subsequently washed with water. In order to facilitate the formation of domains, the spun fibers were annealed in a taut condition at 120 • C for a period of 2 h. This temperature was chosen to avoid both the anhydride formation in acrylic acid segments (which starts at ∼170 • C) and cyclization of the adjacent acrylonitrile groups, which occurs at >220 • C [27,28]. An attempt was made to keep the diameter of fibers from all the copolymers uniform at 120 ±3 μm so that their properties may be directly compared.…”

Section: Solution Spinning Of the Stimuli Sensitive Fibers And Heat T...mentioning

confidence: 99%

The effect of distribution of monomer moiety on the pH response and mechanical properties of poly(acrylonitrile-co-acrylic acid) copolymers

Sahoo¹,

Jassal²,

Agrawal³

2010

Smart Mater. Struct.

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The pH response and mechanical properties of copolymer-based hydrogels such as poly(acrylonitrile-co-acrylic acid) are usually attributed to their chemical composition. In this study, it has been shown that the architecture of the polymer chains, i.e. the distribution of comonomers in the macromolecules, also plays a major role in controlling these properties. A series of four poly(acrylonitrile-co-acrylic acids) with fixed composition (i.e. ∼30 mol% acrylic acid moieties) were synthesized, where the block lengths of both AN (acrylonitrile) and AAc (acrylic acid) moieties in the copolymers were varied by controlling the feeding pattern of the monomers during free radical copolymerization. These copolymers were then converted into fine fibers of the same dimensions. The monomer distribution in the four copolymers was estimated using quantitative carbon 13 C nuclear magnetic resonance (NMR) and related to the mechanical and pH response properties of the resultant fibers. The pH response of the fibers with similar composition increased dramatically as the block length of the AAc moiety was increased, while the mechanical properties increased as a direct function of the block length of the AN moieties.The fiber's response at pH 10 in terms of the change in length increased by ∼four times while its response rate increased by ∼50 times with the increase in block length of the AAc moiety. On the other hand, the tensile properties and retractive stress increased by ∼four times with the increase in the block length of the AN moiety.

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Structural investigations of acrylonitrile–vinyl acid copolymers by NMR spectroscopy

Cited by 17 publications

References 16 publications

Analysis of Sorption and Permeation of Acetonitrile–Water Mixtures through Nanoclay-Filled Copolymer Membranes

Analysis of Sorption and Permeation of Acetonitrile–Water Mixtures through Nanoclay-Filled Copolymer Membranes

Structures and properties of thermoregulated acrylonitrile–methyl acrylate sheet containing microphase change materials

The effect of distribution of monomer moiety on the pH response and mechanical properties of poly(acrylonitrile-co-acrylic acid) copolymers

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