Telegeev I. Synthesis and properties of nanosilica modified by methyl methacrylate compounds as fillers of poliepoxy composites

Thesis is devoted to the sorption, chemical and combined modification of nanosilica by methyl methacrylate oligomers and methyl methacrylate silane coupling agents in gas dispersion medium. It was shown that the interaction of methyl methacrylate alkoxysilane (PMTMS) with the surface of nanosilica in pseudo-liquid state achieved complete replacement of free silanol groups of all nanosilicas types regardless of their dispersion and aggregation. From the ratio of modifier used and the degree of substitution of surface silanol groups it was calculated that approximately 55% of the molecules under the experimental conditions interact with the hydrophilic surface free silanol groups in a 1:1 ratio, and 45% - 1:2. It was established that the adsorbed molecules of methyl methacrylate oligomers interact with the surface of silica through the formation of hydrogen bonds with the free silanol groups. By means of IR spectroscopy, thermogravimetry, temperature-programmed desorption mass spectrometry and water adsorption was showed that regardless of the input sequence modifiers structure of the surface layer in all cases almost identical. It can be seen as a manifestation of the phenomenon of self-organization in a surface layer. It was shown that the introduction of synthesized fillers improves mechanical strength of composite materials. The results show that nanosilica surface modification by methyl methacrylate alkoxysilanes and oligomers allows obtaining promising filler for polymeric materials.