Enthalpy of swelling of crosslinked copolymers of acrylic acid β-vinyloxyethylamide in water and ethanol

Tazhbaev, E. M.; Мустафин, Е. С.; Burkeev, M. Zh.; Kasenov, B. K.

doi:10.1134/s0036024406080231

Cited by 4 publications

(7 citation statements)

References 2 publications

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“…In the case of the carbon spectrum, the difference is more significant and ranges from 0.05-0.25 ppm. Thus, the formation of supramolecular inclusion complexes is established on the basis of changes in the NMR chemical shifts of the substrate and receptor atoms [28][29][30][31][32][33]. The study by NMR spectroscopy of supramolecular complexes is based on determining the difference in the chemical shifts of 1 H and 13 C of substrates (12)(13)(14) and receptors (β-CD, 2-hydroxypropyl -β-CD) in the free state and in the composition of the complexes as a result of intermolecular interaction.…”

Section: Resultsmentioning

confidence: 99%

“…Hydrazones -N-(diethylamino)benzylidene isonicotinohydrazide (1), N-(2-bromo-3-phenyl)allylidenisonicotinohydrazide (2) and N'-((5-nitrofuran-2-yl) methylene) was chosen as hydrazone substrates isonicotinohydrazide (3). The procedures for the preparation of inclusion complexes of functionally substituted N-benzylidene-and allylidene-isonicotinohydrazide (1-3) with βand hydroxypropyl-β-cyclodextrins were described by us in [29][30][31].…”

Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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Supramolecular inclusion complexes of functionally substituted N-benzylidene-and allylidene-isonicotinohydrazides with oligosaccharides and their properties

Фазылов¹,

Issayeva²,

Mukasheva³

et al. 2020

Bull. of the Kar. Univ. "Chem". Ser.

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Supramolecular inclusion complexes of functionally substituted N-benzylideneand allylidene-isonicotinohydrazides with oligosaccharides and their propertiesThis paper presents the results of a study of the synthesis and structural features of supramolecular inclusion complexes of N-benzylidene-and allylidene-isonicotinohydrazides with cyclic oligosaccharides (with βand 2-hydroxypropyl-β-cyclodextrins). The results of studying the synthesis and structural features of supramolecular inclusion complexes of N-benzylidene and allylideneisonicotinohydrazides with cyclic oligosaccharides (β-and 2-hydroxypropyl-β-cyclodextrins) are presented. The structure of the obtained supramolecular inclusion complexes was studied using one-dimensional 1 H, 13 C and DEPT NMR and two-dimensional spectroscopy of COSY ( 1 H-1 H), HMQC ( 1 H-13 C) and TOCSY ( 1 H-1 H). The formation of supramolecular inclusion complexes was established on the basis of changes in the chemical shifts of the NMR of the substrate and receptor atoms. Based on the analysis of spectral data, the proposed schemes of the obtained supramolecular inclusion complexes are presented. It was found that the interaction of the studied hydrazone substrates with cyclodextrins forms inclusion complexes 1:1 and 1:2 with the entry of the substrate molecule into the internal cavity of the receptor. The resulting products are able to dissolve in water or form stable aqueous dispersions. The antiradical effect of the synthesized supramolecular inclusion complexes with respect to the 2,2-diphenyl-1-picrylhydrazide radical was evaluated. Under the conditions of this test system, antiradical activity was detected in the supramolecular complex of N-(diethylamino)benzylidene-isonicotinohydrazide. The concentration of the complex was determined, capable of reducing the optical density of 100 μM of the test system solution by 50 %.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Supramolecular inclusion complexes of functionally substituted N-benzylidene-and allylidene-isonicotinohydrazides with oligosaccharides and their properties

Фазылов¹,

Issayeva²,

Mukasheva³

et al. 2020

Bull. of the Kar. Univ. "Chem". Ser.

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“…This chemisorption significantly contributes to the hysteresis observed between sorption and desorption. Nevertheless, this irreversibility can also be attributed to an absorption of ethanol accompanied by a swelling of the material as in the case of some polymers. , …”

Section: Resultsmentioning

confidence: 99%

Sorption Equilibria of Ethanol on Cork

Lequin

Chassagne

Karbowiak

et al. 2013

J. Agric. Food Chem.

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We report here for the first time a thermodynamic study of gaseous ethanol sorption on raw cork powder and plate. Our study aims at a better understanding of the reactivity of this material when used as a stopper under enological conditions, thus in close contact with a hydroethanolic solution, wine. Sorption−desorption isotherms were accurately measured by thermogravimetry at 298 K in a large range of relative pressures. Sorption enthalpies were determined by calorimetry as a function of loading. Sorption−desorption isotherms exhibit a hysteresis loop probably due to the swelling of the material and the absorption of ethanol. Surprisingly, the sorption enthalpy of ethanol becomes lower than the liquefaction enthalpy as the filling increases. This result could be attributed to the swelling of the material, which would generate endothermic effects. Sorption of SO₂ on cork containing ethanol was also studied. When the ethanol content in cork is 2 wt %, the amount of SO₂ sorbed is divided by 2. Thus, ethanol does not enhance the sorption rate for SO₂ but, on the contrary, decreases the SO₂ sorption activity onto cork, probably because of competitive sorption mechanisms.

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“…It is well known that the entropy of mixing between polymers and water decreases because of the formation of cage structures and the enhancement of the order degree of water molecules. Therefore, Δ S was negative, and Δ H was also negative because of the formation of hydrogen bonds and the previous exothermic swelling process 35–37. According to Δ G = Δ H − T Δ S , Δ G is defined as Gibbs free energy; Δ H is defined as enthalpy and Δ S is defined as entropy, an increase in the temperature leads to larger negative T Δ S values, and the Δ G values are then increased; this is disadvantageous for the swelling of the hydrogels.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, characterization, and swelling kinetics of pH‐responsive and temperature‐responsive carboxymethyl chitosan/polyacrylamide hydrogels

Wei

Luo

Feng

et al. 2012

J of Applied Polymer Sci

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A novel pH‐ and temperature‐responsive hydrogel composed of carboxymethyl chitosan (CMC) and polyacrylamide (PAM) semi‐interpenetrating polymer networks (semi‐IPNs) was synthesized by a crosslinking copolymerization route in the presence of N,N‐methylene bisacrylamide and potassium persulfate. The structure of the CMC/PAM hydrogels was characterized by Fourier transform infrared spectroscopy, and the morphologies were observed by scanning electron microscopy. The swelling kinetics investigations demonstrated that the equilibrium swelling ratios (ESRs) of the semi‐IPN hydrogels depended on the compositional ratios, pH values of the buffer solutions, and temperature. The ESR values increased with increasing CMC contents and pH values; this was in agreement with the maximum theoretical water contents fitted by the swelling kinetic data. The CMC/PAM hydrogels complied with Fickian behavior at pH 1.4 and non‐Fickian behavior at pH 11.7 in the buffer solutions. These hydrogels displayed thermosensitivities that were different from those of common thermoresponsive gels. The swelling was enhanced when the temperature of the media was increased up to 40°C; this was followed by a reduction. Therefore, the swelling behavior of the CMC/PAM hydrogels could be controlled and modulated by means of the compositional ratios of CMC to acrylamide, pH values of the buffer solutions, and temperature. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

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Enthalpy of swelling of crosslinked copolymers of acrylic acid β-vinyloxyethylamide in water and ethanol

Cited by 4 publications

References 2 publications

Supramolecular inclusion complexes of functionally substituted N-benzylidene-and allylidene-isonicotinohydrazides with oligosaccharides and their properties

Supramolecular inclusion complexes of functionally substituted N-benzylidene-and allylidene-isonicotinohydrazides with oligosaccharides and their properties

Sorption Equilibria of Ethanol on Cork

Synthesis, characterization, and swelling kinetics of pH‐responsive and temperature‐responsive carboxymethyl chitosan/polyacrylamide hydrogels

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