Preparation and properties of silicon- and titanium-containing hybrid nanocomposite films based on ethyl cellulose

Nanocomposite hybrid films containing silicon and titanium compounds in the polymer matrix are prepared through the sol-gel method via the hydrolytic polycondensation of Si and Ti alkoxides (tetraethoxysilane and titanium tetrabutoxide) in the THF solution of a hydrophobic polymer, ethyl cellulose. Their structure and properties are studied with the use of a complex of physicochemical methods. During the hydrolysis of tetraethoxysilane and the subsequent polycondensation of the reaction products, silicon atoms are incorporated into the polymer and form -O-Si-O-bonds involving hydroxyl groups of ethyl cellulose. In the sol-gel method, titanium alkoxide yields nanosized particles of titanium dioxide that play the role of fillers in the polymer matrix. Titanium-containing films show solubility in THF and, after prolonged contact with the solvent, precipitate titanium dioxide from the solution. Hybrid films containing silicon are insoluble owing to the formation of a chemical network between polymer molecules and Si-OH groups of the products of hydrolysis of silicon alkoxide, as confirmed by the IR data. It is shown that the amounts and types of alkoxides and the diameters of the structures formed in the polymer matrix via the sol-gel procedure affect the hydrophilicity levels of ethyl cellulose hybrid films and their abilities to swell in water and aqueous solutions of organic dyes (brilliant blue and methylene blue). Ethyl cellulose hybrid films are hydrophilic, and they facilitate the removal of dye molecules from aqueous solutions. The best properties are featured by the films containing nanosized particles of titanium dioxide in the polymer matrix. © 2013 Pleiades Publishing, Ltd

Formation of the liquid crystal state of cellulose diacetate in nitromethane vapor: A fourier IR study

The structure, intra- and intermolecular interactions, and conformations of macromolecules in cellulose diacetate films under the conditions of formation of the liquid crystal state in the course of nitromethane vapor sorption were studied by Fourier IR spectroscopy and polarization microscopy. The number of intramolecular hydrogen bonds stabilizing the rigid helical conformation of the macromolecules is preserved in the process. The anisotropic structure of cellulose diacetate films is also preserved after desorption of the sorbed solvent vapor. © Pleiades Publishing, Ltd., 2012

Thermodynamic parameters of the interaction of cellulose ethers with low-molecular-mass liquids

The thermodynamic analysis of the interaction of methyl cellulose, cyanoethyl cellulose, cyano- ethyl hydroxyethyl cellulose, and hydroxyethyl cellulose with low-molecular-mass liquids is performed via the method of static sorption. A correlation is found between the thermodynamic parameters and the chem- ical structures of the components. © Pleiades Publishing, Ltd., 2012