The rheological behavior of acetate and succinimide of chitosan in mixed solvents was investigated. It is shown that the replacement of a part of the solvent by two- or three-atom alcohols is accompanied by an increase in the relative and dynamic viscosity of the succinimide chitosan solution, an earlier formation of the net of links, a transition from viscoelastic systems to elastoviscous ones at lower polymer concentration values and an increase in the relaxation time.
An innovative nanosized natural pesticide based on neem seeds was developed. The resulting nanobiopesticide (NBP) was synthesised by entangling neem seed extract on chitosan cross-linked with succinic anhydride via ultrasonic treatment following purification. Fourier-transform infrared (FTIR), ultraviolet-visible (UV-Vis) and dynamic light scattering (DLS) spectrophotometers were used to characterise the resulting NBP, and its stability was observed against changes in pH, temperature and UV radiation.
Enzymatic destruction of film materials on the basis of chitosan and antibiotics was analyzed. It was established that presence of drugs in a film sample caused a decrease in the rate of destruction of chitosan and led to a potentially longer service life of film material on the wound surface.
Phosphorylated zeolite-A/chitosan composites were prepared and characterized as an alternative material for proton exchange membrane fuel cell (PEMFC). Their applicability was demonstrated by mechanical properties, swelling property, proton conductivity, methanol permeability, and thermal resistance. Chitosan was prepared from shrimp shell waste by deproteination, demineralization, and deacetylation. Chitosan was modified using zeolite A in the various concentrations.
We propose an approach to the preparation of viscoelastic systems based on chitosan without crosslinking agents. It is the formation of an additional network of physical links by introducing a low molecular weight modifier – ethanol or glycerol. It turns out that gelation of chitosan in the solution is accompanied by the formation of additional meshes of physical links, nodes or aggregates of chitosan macromolecules formed in a mixed solvent of acetic acid-water-glycerol or acetic acid-waterethanol.
Chitosan films were obtained in the salt form and in the hydroxide form. Films were prepared by dry method of forming. For the production of films chitosan from mycelium biomass waste of fungus Aspergillus Niger was used. The effect of heat treatment on the structure and solubility of chitosan films was studied. It was established that during the heat treatment of the films the process of amidation takes place, which in turn leads to the structure ordering and reduces the solubility of the films.
Via radical reactions of chitosan and 5-tert-butylperoxy-5-methyl-1-hexen-3-in peroxychitosanes with ditertiary peroxide fragments were synthesized. They can be used as macroinitiator and coemulsifiers for emulsion polymerization of vinyl monomers. Latex polymers obtained antibacterial properties. Polymeranalogical interaction of chitosan with tert-butylperоxymethyl ester of butendicarbon acid yields in peroxychitosanes with controlled quantity of primary-tertiary peroxide fragments. New pH-sensitive smart hydrogels with antibacterial properties were created on their basis.
Through the process of modification of chitosan films obtained from solutions in acetic acid, the possibility of obtaining iodine polymer films with controlled release of iodine has been shown.
Chitosan films obtained from solutions in acetic acid and containing the antibiotics – cephazolin and cephotoxim – have been investigated and the principal possibility of regulating their transport properties as regards the medicinal preparations release has been demonstrated. This regulation can be carried out by films thermal modification consisting in heating of the formed films at the temperature of about 393 K and their treatment with sodium dodecylsulphate solution.
The kinetics of controlled release of medicinal substances from chitosan films has been investigated. Correlation between values of diffusion coefficients and the sedate indicator characterizing diffusion of medicinal substance from a film and shares of medicinal substance connected with a polymeric chain has been established. With the increase in amount of the entered medicinal substance the rate of release of medicines decreases.