the shape and size of macromolecules of carboxymethyl starch in diluted solutions

Abstract

Carboxymethyl starch samples were prepared by etherification in heterogeneous media. Three samples were prepared from corn starch and three samples from potato starch. Degree of substitution of prepared samples ranged from 0.40 to 1.10. The samples were investigated by static and dynamic light scattering and viscosity of diluted solution in 0.10 M NaCl as solvent at 25 C. The values of molar mass, MW, radius of gyration, Rg, hydrodynamic radius, Rh, and limited viscosity number, [η] were determined. It was found that the samples are similar to each other regardless of the type of starch and the degree of substitution. Fractal dimension, df, was equal to 2.380 (Rg - MW) and 2.406 (Rη - MW), while parameter was 1.195. The values of fractal dimension and parameter are characteristic values for the behavior of branched clusters in thermodynamically good solvents

Viscosity changes of aqueous carboxymethyl starch by partial crosslinking and montmorillonite addition

“…Chemical modification of starch is performed to overcome the shortcomings of native starch such as insolubility in cold water, uncontrolled or hardly controlled viscosity of aqueous solution, tendency to retrogradation and so forth. [1][2][3] The solubility in cold water can be ensured in various ways, for example, by introduction of anionic groups into starch macromolecules via carboxymethylation [1][2][3] or succination. 4 The properties of carboxymethyl starch (CMS) solutions are determined mainly by the degree of substitution (DS) and botanical origin of starch.…”

Carboxymethyl Starch/Montmorillonite Aqueous Dispersions: The Effect of Components and Mixing Method on Rheoviscometric Characteristics

“…Chemical modification of starch has been performed to overcome the shortcomings of native starch, such as insolubility in cold water, excessive or uncontrolled viscosity after heating, and tendency to retrogradation. 1 The water solubility could be improved by introducing ionogenic groups into starch macromolecules, for example, via carboxymelthylation. 2 The properties of carboxymethyl starch (CMS) solution (viscosity, dissolution rate, etc.)…”

Carboxymethyl Starch/Medium Chain Fatty Acid Compositions: Rheological Changes During Storage and Selected Film Properties

“…[1,2] Moreover, its aqueous solutions can be used as binders for sand foundry [3][4][5] wood, [6] drilling mud, [7,8] DOI: 10.1002/star.201900240 or production of electrorheological fluids. [9,10] Viscosity of CMS solutions is a very important factor in many applications and it can be regulated by, for example, optimization of starch etherification parameters, [11,12] slight crosslinking [13,14] or additive incorporation, for example clays, into solutions. [13,15] CMS is safe and non-toxic, so it can be used for cosmetics or medicine.…”