Effect of molecular mass on the optical activity of chitosan

The liquid-crystalline state of cellulose acetates: From past to present. Experience of the Saratov school

“…The effect of mesophasogenic solvent vapors is so large that it is accompanied by a change in not only the supramolecular structure of the cellulose ether but also the three-dimensional organization of the macromolecules [12,15,16,[19][20][21]. Even small amounts of absorbed modifier vapors create conditions for a change in the optical activity of the polymer and wide variation of the specific optical rotation [α] (Fig.…”

“…The character of the effect of mesophasogenic solvents on the structure of the polymer, whether in the form of film, fibre, or powder, is identical: the sorption curves are extremal (Fig. 1a) [11,12], which indicates structural changes in the system [13]. Spontaneous elongation of acetate fibres and films in vapors (Fig.…”

Influence of Physical and Chemical Modification on the Optical Rotatory Dispersion and Biological Activity of Chitosan Films

“…The physical and chemical characteristics of the samples are presented in Table 1. These chitosan samples were chosen for study because the optical activity of their 0.5% solutions in 2% acetic acid was almost the same (Figure 1(b)) [11]. Films made from chitosan in both salt (acetic chitosan) and basic (basic chitosan) forms and films of acetic chitosan modified by heat treatment were the objects of research.…”

“…Comparison of the capabilities of the ORD and CD techniques shows that within the wavelength range outside of the absorption bands of the chromophores (which, for the given aminopolysaccharide, falls within the far UV range), optical rotatory spectroscopy in some cases yields more information on optical activity and its correlation with other physical and chemical parameters of chitosan. For example, fairly recently, the ORD technique was used to reveal a correlation between chitosan's optical activity and its molecular weight and deacetylation degree [11,12], as well as to clarify the character of its biological activity [13]. The influence of metal ions (Ca 2+ , K + , and Na + ) on macromolecular conformation was also shown [14].…”

1-Vinyl-3- and 1-vinyl-5-pyrazolecarboxylic acids. Synthesis and anti-burn activity of their chitosan salts

“…Interestingly, the bending vibrations of the primary amino group are practically lacking, which is indicative of the formation of the chitosan salts with 1-vinylpyrazole carboxylic acids V, VI. In the 1 H NMR spectra of It was noted that practically all functional properties of chitosan depend on its molecular parameters, mainly on the mass (degree of polymerization) [12,13]. From this point of view, introduction of 1vinylpyrazole carboxylic acids in the molecule of chitosan is not a simple substitution because polymerization of the vinyl groups can change the molecular mass of chitosan and thus control its functional properties.…”