scholarly journals Ionic-interaction of aqueous and alcoholic poly(vinyl alcohol) in the presence of protons

2019 ◽  
Vol 84 (3) ◽  
pp. 317-326
Author(s):  
Saima Naz ◽  
Rehana Saeed
Keyword(s):  
Acetic Acid ◽  
Vinyl Alcohol ◽  
Entropy Change ◽  
Poly Vinyl Alcohol ◽  
Viscosity Data ◽  
Solvent Mixtures ◽  
Solvent Interactions ◽  
Ion Interactions ◽  
Alcohol Solvent ◽  
Different Temperatures

The ionic-interactions of acetic acid in H2O-PVOH and H2O-Alcohol-PVOH solvent systems were studied at different temperatures by viscosity method. The viscosities of the poly(vinyl alcohol) were increased with the increase in the concentration of poly(vinyl alcohol) and decreased with the increase in the concentration of acetic acid. The viscosity data were used to evaluate the ion-ion interactions and ion-solvent interactions in terms of ?A? and ?B? coefficients of the Jones-Dole equation respectively. The negative values of B-coefficient increased with increase in temperature showed that acid behaves as structure breaker in poly(vinyl alcohol)-solvent mixtures and consequently the values of A-coefficient were decreased with the rise of temperature. Thermodynamic parameters such as energy of activation (Ea*), free energy change of activation (?G*) and entropy change of activation (?S*) were also calculated as a function of acid (CH3COOH) concentration, poly(vinyl alcohol) composition, alcohols, and temperature.

scholarly journals Molecular modeling studies of HIV-1 non-nucleoside reverse transcriptase inhibitors using 3D-QSAR, virtual screening, and docking simulations

2019 ◽  
Vol 84 (3) ◽  
pp. 303-316 ◽  
Author(s):  
Jian-Bo Tong ◽  
Shang-Shang Qin ◽  
Shan Lei ◽  
Yang Wang
Keyword(s):  
Acetic Acid ◽  
3D Qsar ◽  
Entropy Change ◽  
Poly Vinyl Alcohol ◽  
Viscosity Data ◽  
Solvent Mixtures ◽  
Solvent Interactions ◽  
Docking Simulations ◽  
Different Temperatures ◽  
Increasing Temperature

The ionic-interactions of acetic acid in H2O?PVOH and H2O?alcohol? PVOH solvent systems were studied at different temperatures by the viscosity method. The viscosities of the poly(vinyl alcohol) (PVOH) were increased with increasing concentration of PVOH and decreased with the increasing concentration of acetic acid. The viscosity data were used to evaluate the ion?ion interactions and ion?solvent interactions in terms of the A and B coefficients of the Jones?Dole equation, respectively. The negative values of the B-coefficient increased with increasing temperature, showing that the acid behaves as a structure breaker in PVOH?solvent mixtures and consequently, the values of the A-coefficient were decreased with increasing temperature. Thermodynamic parameters, such as energy of activation (Ea*), Gibbs energy change of activation (?G*) and entropy change of activation (?S*) were also calculated as a function of the acid (CH3COOH) concentration, PVOH composition, alcohols and temperature.

Viscometric Study of n-Hexylammonium and n-Octylammonium perchlorates in Binary Non-Aqueous Solvents Probed by a Physicochemical Approach in the Temperature Ranging 298 - 328K at Atmospheric Pressure

2021 ◽  
Vol 37 (3) ◽  
pp. 656-662
Author(s):  
Vivek Pathania ◽  
Shrutila Sharma ◽  
S.K. Vermani ◽  
B.K. Vermani ◽  
Navya Grover ◽  
...  
Keyword(s):  
Entropy Change ◽  
State Theory ◽  
Viscosity Data ◽  
Solvent Interaction ◽  
Solvent Interactions ◽  
Ion Interactions ◽  
Enthalpy And Entropy ◽  
Viscometric Study ◽  
B Coefficients ◽  
Physicochemical Approach

Viscosity data were measured for n-hexyl ammonium perchlorate (C6H13NH3ClO4)(HAP) and n-octylammonium perchlorate (C8H17NH3ClO4) (OAP) in acetonitrile (AN), dimethylsulfoxide (DMSO) and their binary mixtures containing 0, 20, 40, 60, 80 and 100 mol%DMSO at 298, 308, 318 and 328 K in the concentration range 60-350×10-4 mol.dm-3. The data was further examined to evaluate ion-ion and ion-solvent interactions in terms of the Aand B coefficients of the Jones-Dole equation respectively. A and B coefficients for the studied electrolytes came out be to be positive throughout the whole composition range. However, smaller values of A as compare to B reveal the dominance of ion-solvent interaction over ion-ion interactions especially at 60 mol% DMSO in AN-DMSO mixtures. Thermodynamic parameters like free energy, enthalpy and entropy change of activation of the viscous flow have also been evaluated by using Erying transition state theory.

The electrospinning behavior of poly(vinyl alcohol) in DMSO–water binary solvent mixtures

RSC Advances ◽  
2016 ◽  
Vol 6 (105) ◽  
pp. 102947-102955 ◽  
Author(s):  
Deepika Gupta ◽  
Manjeet Jassal ◽  
Ashwini K. Agrawal
Keyword(s):  
Ternary System ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Binary Solvent ◽  
Solvent Mixtures ◽  
Binary Solvent Mixtures ◽  
Polymer Interactions ◽  
Solvent Solvent

The fiber diameters obtained from PVA–DMSO–water ternary system are the result of the interplay between the solvent–solvent and solvent–polymer interactions.

scholarly journals Study of Physical Properties for Sodium acetate with Water and Water - Acetone mixtures at Different Temperatures

2017 ◽  
Vol 27 (4) ◽  
Author(s):  
Ahmed Mohammed Abbas ◽  
Zainab Wajdi Ahmed ◽  
Alaa Fadhil Sulaiman ◽  
Issam AbdalKreem AbdalLatif
Keyword(s):  
Sodium Acetate ◽  
Apparent Molal Volume ◽  
Viscosity Data ◽  
Partial Molal Volume ◽  
Molal Volume ◽  
Solvent Interactions ◽  
Acetone Water ◽  
Thermodynamic Activation Parameter ◽  
Different Temperatures ◽  
Apparent Molal Compressibility

In this study binary and ternary solutions are prepared by using the sodium acetate concentrations (0.1, 0.125, 0.2, 0.25, 0.4, 0.5, 0.8, 1 M) in water and acetone –water mixtures .The important parameters such as apparent molal volume, the partial molal volume transfer,  apparent  molal compressibility, free energy of activation of viscous flow and thermodynamic activation parameter (enthalpy and entropy) determined of sodium acetate in water , 20%, 40% ,60% and 80% V/V acetone –water mixtures at 298.15K, 303.15K, and 308.15K from density and viscosity measurements espectively. The limiting apparent molal volumes and experimental slopes were derived from the Masson equation, have been interpreted in terms of solute–solvent and solute–solute interactions  respectively. The viscosity data were analyzed using theJones–Dole equation and the derived parameter B - coefficient has also been interpreted in terms of solute–solvent interactions in the solutions. 

scholarly journals Morphological and Thermal Properties of Poly(Vinyl Alcohol)/Layered Double Hydroxide Hybrid Nanocomposite Fibers

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
A. F. Al Naim ◽  
J. Mazher ◽  
S. S. Ibrahim
Keyword(s):  
Crystal Structure ◽  
Heat Treatment ◽  
Layered Double Hydroxide ◽  
Vinyl Alcohol ◽  
Separation Distance ◽  
Molecular Vibration ◽  
Poly Vinyl Alcohol ◽  
Rapid Weight Loss ◽  
Different Temperatures ◽  
Double Hydroxide

Nanolayered particulate of Zn-based layered double hydroxide (LDH) was prepared by a low temperature greener sol-gel method. X-ray diffraction (XRD) studies were performed on the particles annealed at different temperatures. Hexagonal crystal structure of the as-grown LDH particulates was observed. The crystal structure was modified to tetragonal structure of layered double oxide (LDO) on annealing at 250°C. Rietveld fittings showed a collapse of interlayer separation distance along the preferred orientation of the LDH particles as a result of heat treatment. Further, LDH particles were used as fillers of electrospun poly(vinyl alcohol) (PVA) fibers. Heat treatment of the polymer fibers was also performed at different temperatures, and thermal changes were studied by thermogravimetric analysis (TGA), Raman spectroscopy, and scanning electron microscopy (SEM) techniques. Improved interaction of fibers with LDH nanoparticles was observed and ascribed to LDH-related LDO phase transformation at higher temperature. Thermal mechanisms of the rapid weight loss in filled fibers were discussed in comparison to the pure PVA fiber losses. Experimental Raman frequencies of the composite fibers were compared with the calculated Raman modes of the enol and ZnO monomers. The molecular vibration frequencies were found to differ significantly due to heat treatment. Finally, the role filler in the faster and greener thermal decomposition of polymeric fibers was also discussed in the present work.

Rheological properties of pectin, poly(vinyl alcohol) and their blends in aqueous solutions

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Katarzyna Lewandowska ◽  
Aldona Dąbrowska ◽  
Halina Kaczmarek
Keyword(s):  
Aqueous Solutions ◽  
Rheological Properties ◽  
Vinyl Alcohol ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
Concentric Cylinder ◽  
Water Soluble Polymer ◽  
Flow Measurements ◽  
Result Show ◽  
Different Temperatures

AbstractThe new blends composed of natural polysaccharide - pectin and synthetic water soluble polymer - poly(vinyl alcohol) (PVA) are attractive materials due to their biocompatibility, non-toxicity and biodegradability. In this work the rheological properties of aqueous solutions of pectin (PEC), poly(vinyl alcohol) and their mixtures at various weight ratios (70/30, 50/50, 30/70) have been investigated. Flow measurements were carried out using a rotary viscometer with concentric cylinder at different temperatures (20-70 ºC) and shear rates (24- 1234 s-1). The flow parameters and energy of activation have been calculated from the flow curves and Arrhenius plots, respectively. It was found that studied polymer solutions exhibited non-Newtonian behavior, moreover, the flow properties were dependent on the blend composition. The result show that practically there was no thixotropy in studied system but some interactions between PVA and pectin in water occurred.

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