Viscosimetric studies of chitosan nitrate and chitosan chlorhydrate in acid free NaCl aqueous solution

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Cristóbal Lárez Velásquez ◽  
Joel Sánchez Albornoz ◽  
Enrique Millán Barrios
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Aqueous Medium ◽  
Intrinsic Viscosity ◽  
Free Acid ◽  
Film Formation ◽  
Stiffness Parameter ◽  
Low Ionic Strength

AbstractTwo salts of the biopolymer chitosan were prepared in aqueous medium by employing an excess of HCl or HNO3 in order to ensure neutralization of all NH2-chitosan groups. Chitosan salts were extensively dialyzed in dionised water and dried at 40 ºC until film formation. The films were characterized by thermogravimetry, FTIR and conductimetric tritration. QH+Cl− and QH+NO3− salts were viscosimetrically evaluated in free acid aqueous solutions in the presence of NaCl to control ionic strength of the medium. Unexpected high intrinsic viscosity values were obtained at low ionic strength when QH+NO3− salt were evaluated. Smidsrod´s approach was employed to estimate the stiffness parameter of both salts and B = 0.084 and 0.120 for QH+Cl− and QH+NO3−, respectively, were obtained.

Challenges in Determining Intrinsic Viscosity Under Low Ionic Strength Solution Conditions

2017 ◽  
Vol 34 (4) ◽  
pp. 836-846 ◽  
Author(s):  
Mariya A. Pindrus ◽  
Steven J. Shire ◽  
Sandeep Yadav ◽  
Devendra S. Kalonia
Keyword(s):  
Ionic Strength ◽  
Intrinsic Viscosity ◽  
Low Ionic Strength

The aggregation and reaction with oxygen of the tetrasodium salt of cobalt phthalocyanine-4,4',4'',4'''-tetrasulphonic acid

1973 ◽  
Vol 26 (2) ◽  
pp. 319 ◽  
Author(s):  
LC Gruen ◽  
RJ Blagrove
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Molecular Oxygen ◽  
Absorption Spectra ◽  
Alkaline Solution ◽  
Cobalt Phthalocyanine ◽  
Visible Absorption ◽  
Reversible Addition ◽  
Dimeric Form ◽  
Low Ionic Strength

The reversible addition of molecular oxygen to the tetrasodium salt of cobalt phthalocyanine-4,4?,4?,4??-tetrasulphonic acid in aqueous solution has been confirmed. Visible absorption spectra of the monomeric and dimeric species and of the oxygen adduct have been determined. A monomer-dimer system prevails at neutral pH, low ionic strength, and low dye concentrations. The oxygen adduct and the dimeric form of the dye predominate in alkaline solution.

Size distribution analysis of colloid generated from compacted bentonite in low ionic strength aqueous solutions

2014 ◽  
Vol 95 ◽  
pp. 284-293 ◽  
Author(s):  
Nairoby Albarran ◽  
Claude Degueldre ◽  
Tiziana Missana ◽  
Ursula Alonso ◽  
Miguel García-Gutiérrez ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Size Distribution ◽  
Distribution Analysis ◽  
Compacted Bentonite ◽  
Low Ionic Strength

THE DISSOCIATION OF α- AND β-LIPOVITELLIN IN AQUEOUS SOLUTION: PART I. EFFECT OF pH, TEMPERATURE, AND OTHER FACTORS

1962 ◽  
Vol 40 (3) ◽  
pp. 363-372 ◽  
Author(s):  
R. W. Burley ◽  
W. H. Cook
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Thermodynamic Data ◽  
Equilibrium Constants ◽  
Effect Of Ph ◽  
Reversible Dissociation ◽  
Lipoprotein Concentration ◽  
Irreversible Aggregation ◽  
Increasing Temperature

The effect of pH, temperature, ionic strength, and lipoprotein concentration on the reversible dissociation of α- and β-lipovitellin in aqueous solutions above pH 6 has been examined by ultracentrifugal measurements. Under otherwise similar conditions α- and β-lipovitellin are 50% dissociated at pH 10.5 and 7.8, respectively. Both lipovitellins undergo an irreversible aggregation above about pH 11; β-lipovitellin is sometimes converted to a non-dissociable form upon aging. Dissociation of both lipovitellins decreases with increasing ionic strength and increasing temperature. Although the ultracentrifugal method has limitations, provisional equilibrium constants and thermodynamic data were obtained from it that are comparable with those obtained for certain protein systems.

Coordinating Properties of Aromatic and Aliphatic Sulfur with Bivalent Metals in Aqueous Solution. A Calorimetric Study

1979 ◽  
Vol 32 (4) ◽  
pp. 709 ◽  
Author(s):  
R Aruga
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Complex Formation ◽  
Aqueous Medium ◽  
Formation Constants ◽  
Calorimetric Study ◽  
Thermodynamic Quantities ◽  
Direct Calorimetry ◽  
Bivalent Metals

Heats and entropies of complex formation of the thiophen-2-carboxylate ion with Ni2+, Cu2+, Zn2+ and Cd2+ have been determined by direct calorimetry, the formation constants being known from the literature. The measurements were carried out in aqueous medium at 25�C and an ionic strength of 1. The values of the thermodynamic quantities for thiophen-2-carboxylate, compared with those for (ethylthio)acetate and (phenylthio)acetate obtained previously, indicate a greater tendency for aromatic sulfur to form bonds with the above metals than for aliphatic sulfur. The causes of this behaviour are discussed.

Synthesis of nanometric TiO2 in aqueous solution by soft chemistry: obtaining of anatase, brookite and rutile with controlled shapes

2004 ◽  
Vol 822 ◽  
Author(s):  
Magali Koelsch ◽  
Sophie Cassaignon ◽  
Jean-Pierre Jolivet
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Aqueous Medium ◽  
Crystalline Structure ◽  
Soft Chemistry ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Nanometric Particles ◽  
Size And Morphology ◽  
Hcl Medium

AbstractNanometric particles of titania, exhibiting anatase, brookite or rutile polymorphs, were synthesized by thermohydrolysis of TiCl4 in aqueous medium. The adjustement of physico-chemical parameters (acidity, ionic strength, anions, temperature) allows to tune the crystalline structure, the size and the morphology of the particles. Brookite results from the precipitation of titanium in HCl, HBr or HNO3 whereas anatase is formed in H2SO4 medium. Adding salts in HCl medium leads to ionic strength or complexation effect. Varying the temperature of thermohydrolysis implies modification on yield, size and morphology of the particles.

Precollapse of T7 DNA by spermidine at low ionic strength: A linear dichroism and intrinsic viscosity study

Biopolymers ◽  
1984 ◽  
Vol 23 (12) ◽  
pp. 2835-2851 ◽  
Author(s):  
Walter A. Baase ◽  
Paul W. Staskus ◽  
Stuart A. Allison
Keyword(s):  
Ionic Strength ◽  
Intrinsic Viscosity ◽  
Linear Dichroism ◽  
Viscosity Study ◽  
Low Ionic Strength
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