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A porous, thermostable composite material was developed from natural powders that form a cordierite matrix on sintering and a filler -fibrous nanostructure aluminum oxide powder with high porosity and reactivity. It was found that incorporation of the nanocrystalline aluminum oxide filler in the composite with the cordierite matrix causes the formation of a polyporous structure that increases the porosity and thermal stability and improves the heat-insulating properties of the material.Porous thermostable ceramic materials with low TCLE are required for fabricating refractories, thermal insulation, catalyst supports, and filters for hot liquids and gases used in industry [1,2]. One of these materials is a cordierite-based ceramic. However, in addition to the valuable physicomechanical properties, cordierite has a drawback -a narrow temperature range of existence, as it decomposes into mullite and other silicate compounds at temperatures above 1420 -1450°C, and this has led to a search for ways of obtaining cordierite at low sintering temperatures by activating the initial components (US Patent No. 532282) [3] or by adding modifiers. Since the thermal stability of ceramic articles is a function of the composition, pore structure, and TCLE of the material, components which form a ceramic with a low TCLE on sintering are selected as the initial substances and blowing agents are incorporated as additives [4,5]. In other cases, polydisperse powders are used to form uniform slit pores in the ceramic for fabricating porous thermostable materials. However, this method does not result in formation of a highly porous and strong material [6].We wanted to obtain a porous thermostable composite made of natural minerals and industrial powders that form a cordierite matrix on sintering, to use fibrous nanocrystalline aluminum oxide powder with high reactivity as the modifying filler, and to study the structure, thermophysical, and physicomechanical properties of the composite.A charge of Granitik-Vesko clay from the Veselovskoe deposit, talc from the Onotsk deposit, and industrial alumina in the ratio of components that corresponds to the composition of cordierite was prepared for fabricating the cordierite matrix. Fibrous nanocrystalline aluminum oxide powder with the structure of a-corundum, ground and passed through a 0.08 mm sieve was used as the filler; it was a finely disperse white substance with particles 10 -15 mm long and 3 -5 mm in diameter. The powder particles consisted of 40 -45 nm nanograins of aluminum oxide. The bulk density of the powder was 510 kg/m 3 , the pycnometric density was 3750 kg/m 3 , and the specific surface area was 43 m 2 /g.The oxide fibers used to make the powder were synthesized by saturating hydrated cellulose powder with an aqueous solution of aluminum chloride followed by drying and heat treatment conducted in special conditions. Water and organic products of thermolysis of the polymer were removed during heat treatment, the salts homogeneously distributed in the cellulose chain were disso...

Dissolution of acrylamide anionic (co)polymers in saline solutions (potassium and sodium chlorides) with concentration of 3.4 mol/l was studied by atomic absorption spectroscopy, optical microscopy, gel-test and capillary viscosimetry. It has been established that with increasing in the content of ionogenic groups and the transition from sodium chloride to potassium chloride solutions the dissolution rate of (co)polymer increases. The concentration of cations of low molecular weight electrolytes is higher in the swollen polymer phase than in the solution in the swelling stage of polymers, the difference in the counter ion content decreases with increasing dissolution time. Comparative analysis of the Huggins constant and the hydrodynamic radii of acrylamide (co)polymers has showed that increase in the interaction in polymer-solvent system is accompanied by the increase in size of macromolecular coils. The Kuhn segment of polymer macromolecules is higher in sodium chloride solutions than in potassium chloride solutions and increases with the decrease in ionogenic group content.