Nanocomposites and nanomaterials

Influence of a modification method on structure and properties of aminopropylsilica 
Goncharuk O.V.1, Pakhlov E.M.1, Sternik D.2, Voronin E.F.1, Deryło-Marczewska A.2 , Gun'ko V. M.1
1 Chuiko Institute of Surface Chemistry, NASU, 17 General Naumov Str., 03164 Kyiv, Ukraine. 
E-mail: iscgoncharuk@meta.ua
2 Faculty of Chemistry, Maria Curie-Sklodowska University, M.C. Sklodowska Sq.3, 20031 Lublin, Poland.

Modification of a silica surface by grafting various functional groups is one of effective ways to control the properties of the surface during subsequent interactions with high- or low- molecular weight polar or nonpolar compounds. The substitution of silanol groups for amino propyl groups allows one to enhance
	
Fig. 1. FTIR-ATR spectra of unmodified and modified silicas	
	
Fig. 2. Incremental pore size distributions of unmodified and modified silicas	
the interactions with certain functional groups of polymers due to a greater specificity. In the current work, the modification of fumed silica was carried out with 3-aminopropyldiethoxymethylsilane (APDMS) using (i) gas-phase synthesis in the absence of a solvent, and (ii) gas-phase mechano-sorption modification (GMSM) with the presence of alcohol and water as solvents. The presence of bands at 3376 and 3312 cm-1 corresponding to NH2 stretching vibrations and a decrease in the intensity of a band at 3750 cm-1 of free silanols (Fig. 1) indicate that the reaction of ethoxy groups with silanols is complete. Incremental pore size distributions (Fig. 2) calculated from low-temperature nitrogen adsorption- desorption isotherms show that the texture of the samples is slightly changed due to the modification in the gas phase (solvent is absent), while GMSM causes more noticeable structure changes.