viscosity

Alkaline Hydrolysis Kinetics and Physico-Chemical Properties of Acrylic Copolymers Based on Acrylic Acid, Its Esters and Vinyl Acetate

Kinetic regularities of the alkaline hydrolysis of copolymers of methyl acrylate, butyl acrylate, vinyl acetate and acrylic acid of several chemical compositions under various conditions were studied by IR spectrometry. The initial rate of alkaline hydrolysis and the limiting conversion degree were shown to increase with increasing concentrations of the components of the reaction mass and temperature.

Ionic Aggregation of Macromolecules as the Cause of the Kinetic (Non)Stability of Physicochemical Properties of Chitosan Solutions

Hydrodynamic, optical, colloid-flocculating, film-forming and structural morphological properties of diluted chitosan solutions (50–640 kDa) in acetate buffer (0.33 М СН3СООН + 0.2 М СН3СOONa), both initial ones and stored for ~1,850 days, were studied. It has been established that the decrease in the intrinsic viscosity of solutions over time is manifested for the reprecipitated and high-molecular-weight samples of chitosan to a greater degree. The viscosity drop effect is not affected by the use of untreated or sterile degassed distilled water to dissolve the polymer.

Viscous Degradation of Acidic Chitosan Solutions and its Ionic Probe Study

A review of the literature on the phenomenon of aging (a significant drop in viscosity over time) of acidic chitosan solutions is given. A study was made on acetic acid (2%) solutions of chitosan of two viscosity-average molecular weights (200 and 46 kDa) by ion probing (addition of a KI solution). It has been indirectly confirmed that the motion of the probing ions in an electric field disturbs part (about a quarter) of the average macromolecule rather than the whole one.