The optimal conditions of cellulose acetate sulfate (CAS) homogeneous synthesis with the yield of 94–98 wt.% have been determined. CAS was confirmed to have an even distribution of functional groups along the polymer chain. The polymer was characterized by an exceptionally high water solubility (up to 70 wt.%). The isothermal diagrams of its solubility in water-alcohol media have been obtained. CAS aqueous solutions stability, electrolytic, thermal, and viscous properties have been defined. The main hydrodynamic characteristics such as intrinsic viscosity, Huggins constant, and crossover concentration have been evaluated. The parameters of polymer chain thermodynamic rigidity have been calculated. The formation of liquid crystalline structures in concentrated CAS solutions has been confirmed. CAS was recommended to be used as a binder for the medicinal forms of activated carbon and carbon sorbent for water treatment, hydrophilic ointment foundation.

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661.728.014:532.78 With the method of homogeneous synthesis, various salt forms of cellulose sulfate-acetate containing Li + , Na + , K + , Ca 2+ , Mg 2+ , Zn 2+ , and Co 2+ as compensating cations have been obtained. The flow curves, the concentration and temperature dependences of the shear viscosity of aqueous solutions of cellulose sulfateacetate have a form characteristic of liquid-crystal systems. For solutions of all salts except for potassium salt, spontaneous formation of the anisotropic phase in the form of individual spherulites, spherulite bands, structures of the fingerprint type, and other more complex formations has been registered. A new hydrodynamic criterion that permits predicting the realization of lyotropic mesomorphism in solutions of cellulose derivatives is proposed.At the Scientific-Research Institute of Physicochemical Problems of the Belarusian State University, for the first time a polymer electrolyte containing in each anhydroglucose link an acetate and a sulfate group and, as compensating counterions, one-and two-charge cations Li + , Na + , K + , Ca 2+ , Mg 2+ , Zn 2+ , and Co 2+ has been synthesized and isolated from solution of cellulose sulfate-acetate (CSA) in the salt form.Synthesized salts of cellulose sulfate-acetate are characterized by a high solubility in water (up to 70 mass %). High-concentration aqueous solutions of salt forms of CSA, except for potassium salt, exhibit stable birefringence. In the stationary state and in flowing they opalesce, changing their color from yellow-red to violet, which is one of the outward signs of the cholesteric mesophase formation [1][2][3].To register and predict the liquid crystalline (LC) ordering of cellulose sulfate-acetate salts, we have made rheological, polarization-microscopic, and hydrodynamic studies of their aqueous solutions in a wide range of concentrations.Experimental. Cellulose sulfate-acetate in the salt form was obtained by the method of homogeneous synthesis [4]. The degree of substitution (DS) for sulfate and acetate groups was, respectively, 0.9-1.0 and 0.8-1.0, and the polymer molecular mass was 46,000.Solutions of CSA salts were prepared by dissolving polymer samples previously dried to a constant mass at a temperature of 60 2 o C in water, water-salt and water-alcohol media at a different ratio of components. The dissolution process was considered to be completed under the condition of the absence of undissolved polymer fragments from the optical microscope field of view. Concentrated viscous solutions of CSA were deaerated for 48 h. The concentration of prepared solutions was refined by the gravimetric method [5]. To register the isotropic-anisotropic phase transition, a drop of the prepared solution was placed on a microscope slide and pressed by a cover glass. Then the thin solution layer obtained was observed in polarized light with an "Amplival" optical microscope equipped with two polaroids. The observed structural changes were recorded on a film by means of a photographic attachment. Rheological studies of ...

A "green" method to synthesize new composite membranes from a cellulose solution in phosphoric acid on various ultrafiltration substrates is proposed. The method can be used in industry; it differs from the conventional viscose method for producing cellophane and other known methods for synthesizing cellulose-based gas separation membranes by the absence of gaseous emissions and wastewater. The structure of the synthesized samples is studied by electron microscopy, X-ray diffraction, and thermal analysis (DSC). Analysis of the mechanical properties of the samples shows that the new membranes have better mechanical characteristics than those of homogeneous pure cellulose films synthesized in this study and commercial cellophane films. The gas transport properties of new membranes with respect to O 2 , N 2 , CO 2 , CH 4 , and He are studied. It is found that the proposed membrane synthesis method provides the formation of uniform dense gas separation layers of cellulose; the membranes show a three orders of magnitude higher gas permeability than that of cellophane films. It is shown that the highest ideal selectivity is exhibited by membranes with a gas separation layer of cellulose on viscose fabric substrates.

The study of the rheological properties of aqueous solutions of corn starch (CS) blends with sodium alginate (SA) and agar-agar (AA) as well as the physical and mechanical properties of bicomponent films on their basis has been carried out. The data show that adding of both polymers to starch solution causes an increase in viscosity which is higher in the case of SA. Activation energy for viscosity flow of solutions of CS blended with SA has minimum value at CS:SA ratio = 98:2. The above mentioned dependence is not typical for AA, as flow activation energy in this case raises steadily with the growth of AA content in the solution, like viscosity of the CS:AA. The extreme behavior of polymer blends with low content of one of the polymers is described in terms of mutual solubility or thermodynamic compatibility. There is a tendency that mechanical properties and water solubility increase with the increasing of SA and AA polymers in corn starch matrix. Obtained data evidence the benefits of bicomponent films production instead of starch-based films.