Influence of molar mass of polymer on the solvent activity for binary system of poly N-vinylcaprolactam and water

Foruotan, Masumeh; Zarrabi, Mona

doi:10.1016/j.jct.2008.11.010

Cited by 6 publications

(2 citation statements)

References 25 publications

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“…Water activity in the presence of PVCap is calculated using the Flory–Huggins theory . The details of measurement and thermodynamic modeling of water activity in the presence of PVCap is given by Foruotan and Zarrabi . It was understood that at concentrations of PVCap used in this work, i.e., 0.5 wt %, the water activity can be assumed approximately unity.…”

Section: Thermodynamic Modelmentioning

confidence: 99%

Effect of EMIM-BF₄ Ionic Liquid on Dissociation Temperature of Methane Hydrate in the Presence of PVCap: Experimental and Modeling Studies

et al. 2018

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Most of the studies done on kinetic hydrate inhibitors (KHIs) are related to the effect of KHIs on hydrate formation, and there are a limited number of research works on hydrate dissociation conditions in the presence of KHIs. In the subject of hydrate remediation, knowing the effects of KHIs on hydrate dissociation conditions is necessary. In this work, first, the effect of the presence of poly vinyl caprolactam (PVCap) as a KHI on methane hydrate dissociation conditions has been studied and the results show that dissociation temperature of methane hydrate in the presence of PVCap is higher than the noninhibited system and increases hydrate stability conditions. Then, at the second stage, the effects of EMIM-BF4 as a synergist for PVCap on methane hydrate dissociation conditions have been investigated. Different concentrations of EMIM-BF4 and PVCap have been studied, and a thermodynamic model has been developed to predict hydrate dissociation temperature. The experiments reveal that adding EMIM-BF4 to an aqueous solution of PVCap does not have a significant effect on methane hydrate dissociation conditions. The model has been developed based on the fact that the presence of PVCap changes the large to small cavity ratios, L/S, from its theoretical value, i.e. 3/1. It has been assumed that the number of small cavities to water molecules for methane hydrates in the presence of PVCap depends on PVCap concentration. A correlation is proposed to indicate this dependence. Different activity coefficient models have been tested to calculate water activity in the presence of PVCap and IL. The agreement between the experimental data and model results is found to be satisfactory.

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Section: Thermodynamic Modelmentioning

confidence: 99%

Effect of EMIM-BF₄ Ionic Liquid on Dissociation Temperature of Methane Hydrate in the Presence of PVCap: Experimental and Modeling Studies

et al. 2018

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“…Due to the rather low latent heat of transition (−1.7 kJ/mol), hydrated PVCL macromolecules may be used as highly sensitive detectors of water associates and interactions, which are affected by the polarization action of high polar amide CO groups and by specific configurational and conformational structures. , Additionally, the colloidal mesoglobules formed by PVCL linear chains were proven to be stable for several days due to the presence of the hydrophilic outer surface. , Fluorescence and small-angle neutron scattering (SANS) investigations showed that PVCL undergoes a conformational change from an expanded coil to a compact globule at its LCST, but with a reducing magnitude compared to PNIPAM. , According to absorption millimeter-wave measurements, the association of hydrophobic groups in PVCL upon coil-to-globule transition causes an apparent decrease in the relative hydration number . Some theoretical models − have also been proposed to interpret the competition of the hydrophobic and hydrophilic effects of PVCL, e.g., the simplest HP side-chain model of an amphiphilic polymer consisting of hydrophobic (H) strings and hydrophilic (P) beads. However, the also-existing hydrophobic groups in side chains of PVCL make the case more complicated.…”

Section: Introductionmentioning

confidence: 99%

Infrared Spectroscopic Insight into Hydration Behavior of Poly(N-vinylcaprolactam) in Water

2011

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IR spectroscopy in combination with two-dimensional correlation spectroscopy (2DCOS) and the perturbation correlation moving window (PCMW) technique is employed to illustrate the dynamic hydration behavior of poly(N-vinylcaprolactam) (PVCL) in water, which exhibits a typical type I continuous lower critical solution temperature (LCST) behavior. PCMW easily determined the transition temperature to be ca. 43.5 °C during heating and ca. 42.5 °C during cooling and the transition temperature range to be 39.5-45 °C. On the other hand, 2DCOS was used to discern the sequence order of different species in PVCL and concluded that hydrogen bonding transformation predominates at the first stage below LCST while hydrophobic interaction predominates at the second stage above LCST. In combination with molecular dynamics simulation results, we find that there exists a distribution gradient of water molecules in PVCL mesoglobules ranging from a hydrophobic core to a hydrophilic surface. Due to the absence of self-associated hydrogen bonds and topological constraints, PVCL mesoglobules would form a "sponge-like" structure which can further continuously expel water molecules upon increasing temperature, while poly(N-isopropylacrylamide) (PNIPAM) with self-associated hydrogen bonds forms mesoglobules with a "cotton-ball-like" structure without an apparent distribution gradient of water molecules and does not change much upon increasing temperature.

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Solvents and Solutes: Interaction, Dissolution, Power

2024

Handbook of Solvents, Volume 1

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Influence of molar mass of polymer on the solvent activity for binary system of poly N-vinylcaprolactam and water

Cited by 6 publications

References 25 publications

Effect of EMIM-BF₄ Ionic Liquid on Dissociation Temperature of Methane Hydrate in the Presence of PVCap: Experimental and Modeling Studies

Effect of EMIM-BF₄ Ionic Liquid on Dissociation Temperature of Methane Hydrate in the Presence of PVCap: Experimental and Modeling Studies

Infrared Spectroscopic Insight into Hydration Behavior of Poly(N-vinylcaprolactam) in Water

Solvents and Solutes: Interaction, Dissolution, Power

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Influence of molar mass of polymer on the solvent activity for binary system of poly N-vinylcaprolactam and water

Cited by 6 publications

References 25 publications

Effect of EMIM-BF4 Ionic Liquid on Dissociation Temperature of Methane Hydrate in the Presence of PVCap: Experimental and Modeling Studies

Effect of EMIM-BF4 Ionic Liquid on Dissociation Temperature of Methane Hydrate in the Presence of PVCap: Experimental and Modeling Studies

Infrared Spectroscopic Insight into Hydration Behavior of Poly(N-vinylcaprolactam) in Water

Solvents and Solutes: Interaction, Dissolution, Power

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Product

Resources

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Effect of EMIM-BF₄ Ionic Liquid on Dissociation Temperature of Methane Hydrate in the Presence of PVCap: Experimental and Modeling Studies

Effect of EMIM-BF₄ Ionic Liquid on Dissociation Temperature of Methane Hydrate in the Presence of PVCap: Experimental and Modeling Studies