"Nanocomposites and nanomaterials"

Functionalization of montmorillonite nanoparticles and synthesis of oligomer on their surface
Gonchar O.M., Travinska T.V., Savelyev Yu.V.
Institute of Macromolecular Chemistry, NAS of Ukraine, Kharkovskoe shosse,48, 02160 Kiev, Ukraine. 
E-mail: lexgon@ukr.net

Organophilization of the surface of silicate nanoparticles is important for the production of polymeric organo/inorganic nanocomposites with montmorillonite (Mt) and other layered silicates based on polar polymers. This is achieved by modifying the surface of Mt nanoparticles with organic cations of different nature. Common modifiers used for organic modification of Mt are cations of Quaternary organic ammonium salts [1], cations of Quaternary salts of phosphonium [2], diamines and amino acids. Mt, modified with organic cations, is dispersed in the polymer matrix, where it acts as a strengthening agent, improving the properties of the polymeric material. In the case of polar polymers such as polyurethanes, polyamides, polyepoxides, Mt modified with aliphatic surfactants does not lead to delamination in the polymer matrix. This is due to the lack of sufficient quality interaction between the nanofiller and the polar polymer matrix [8-10]. In order to create organoclay with a functionalized surface for use as a nanofiller in the creation of organic/inorganic nanocomposites based on polar polymers, a method of modification of Mt with cationic oligourethane (oligourethanamine ammonium chloride (OUAAC)) was developed. Aromatic and aliphatic diisocyanate addition reactions, as well as sequential addition of aromatic diisocyanate, glycerol, and again diisocyanate, were performed in a suspension of amino-functionalized modified Mt. Thus, the possibility of synthesis on the surface of Mt nanoparticles of an organic layer with the required structural hierarchy is demonstrated. This method can also be used for matrix synthesis of the oligomer on Mt nanoparticles. he interlayer distance of all types of the obtained modified Mt was determined by the WAXS method, and the addition of diisocyanates corresponding to the content of amino groups was proved by thermogravimetric analysis.

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