Chemistry, Physics and Technology of Surface

ISSN 2518-1238 (Online), ISSN 2079-1704 (Print)

In order to create nanocomposites based on polar polycondensing polymers with montmorillonite, a new method of layered silicate surface modification has been developed. Modification is carried out by ion exchange of inorganic cations on the montmorillonite surface with organicones.

We used the natural montmorillonite of the Askania deposit (Georgia). Natural montmorillonite was transferred to the sodium form by treatment with sodium carbonate, to ensure the maximum exchange capacity of the mineral surface.

The exchange capacity on the surface of montmorillonite sodium form was determined by analysis of the adsorption of the methylene blue by photocolorimetry. The new synthesized modifier oligourethaneamineammonium chloride, simultaneously comprising polar urethane fragments and reactive amino groups, has been used for montmorillonite modification.

The synthesis of oligourethaneamineammonium chloride was carried out in two stages without isolation of intermediate products, with the formation of a modifier solution of a given concentration. The content of amino groups in the modifier was determined by acid-base titration method. The amount of adsorbed oligourethaneamineammonium chloride was determined by the thermogravimetric analysis. The increase in interlayer distance, due to montmorillonite modification, was determined by X-ray analysis. The urethane fragments in the composition of the new modifier provide swelling in polar aprotic solvents, which contributes to the process of nanoparticle separation, the diffusion of polar monomer into the interlayer space and the formation of hydrogen bonds between the modified surface and polymer matrix. The presence of available amino groups located at the end of the oligomer molecules contributes to the formation of a chemical bond with the polymer matrix during the polycondensation processes. The formation of physical and chemical bonds with the polar polycondensing polymer matrix promotes the increase of nanocomposite operational properties, in particular, physic-mechanical ones.

The increase of the tensile strength of the polyepoxide based nanocomposite was found by a factor of 2.1 compared with the initial polymer matrix at montmorillonite concentration of 2 wt. %.

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