## 3 Results and Discussion  
### Materials Characterization  
As noted above, two types of TiO\({}_{2}\) of \(d_{\text{av}}\) = 46 nm and 100 nm in size and different relative contents of rutile and anatase polymorphs were studied as nanofillers. The elemental analysis of TiO\({}_{2}\) nanopowders, as expected, confirmed their purity (Table 1). According to the calculations, the theoretical elemental Ti content in TiO\({}_{2}\) should be 59.95%. This value is slightly below the theoretical content because, as is known, TiO\({}_{2}\) nanoparticles have OH groups on the surface and inside the particles [51; 52; 53]. The TiO\({}_{2}\) particle sizes were determined by a transmission electron microscope (TEM) examination. In the images for two types of nanoparticles (Figure 2a,c), subspherical particles and polyhedrons were observed (probably due to the presence of two TiO\({}_{2}\) polymorphs). It can be seen that the nanoparticles with an average diameter of 46 nm are in a strongly aggregated state, in contrast to the larger ones. The distribution histograms plotted from the images (Figure 2b,d) show a fairly wide range of particle sizes, and their average diameter was 44 nm and 104 nm. The selected area electron diffraction (SAED) patterns (Figure 3a,b) indicate the presence of two TiO\({}_{2}\) polymorphs of anatase and rutile. The brookite signals are mostly close to anatase and rutile signals. The absence of signals of the atomic planes (hkl) 211, 221, and 302 of brookite, which do not match the atomic planes of other polymorphs, makes it possible to conclude that it is absent in the nanoparticle composition. The study of the obtained TiO\({}_{2}\)/EP nanocomposites using a scanning electron microscope showed the formation of large aggregates in the case of the composite with TiO\({}_{2}\) (\(d_{\text{av}}\) = 46 nm) even at their low content (1 wt. %). As can be seen from Figure 4a, which shows an SEM image of particle aggregates in System I, such clusters can be several times larger than the original TiO\({}_{2}\). This fact is described in more detail in a previous paper [54], and is consistent with other authors [45; 55; 56]. On the contrary, in System II (\(d_{\text{av}}\) = 100 nm), the particles are uniformly distributed throughout the polymer and there are no large aggregates (Figure 4b). This difference can be explained by the active aggregation of smaller particles due to their higher surface energy compared to larger particles. \begin{table}
\begin{tabular}{c c c} \hline \(d_{\text{av}}\) TiO\({}_{2}\), nm & Ti, wt. \% (Calc.) & Ti, wt. \% (Exp.) \\ \hline
46 & 59.95 & 59.54 \(\pm\) 0.06 \\
100 & 59.95 & 59.59 \(\pm\) 0.01 \\ \hline \end{tabular}
\end{table} 
Table 1: Results of elemental analysis of TiO\({}_{2}\) nanopowders. Figure 3: SAED patterns of the as-synthesized TiO\({}_{2}\) samples: \(d_{\rm av}\) = 46 nm (**a**), and \(d_{\rm av}\) = 100 nm (**b**). The following symbols are used: A—anatase, R—rutile, and B—brucite. The numbers in parentheses correspond to the hkl indices of the atomic planes. Figure 2: TEM results of the as-synthesized TiO\({}_{2}\) samples. For the \(d_{\rm av}\) = 46 nm sample: TEM image (**a**), and size distribution histogram (**b**). For the \(d_{\rm av}\) = 100 nm sample: TEM image (**c**), and size distribution histogram (**d**). The phase composition of the synthesized TiO\({}_{2}\)/EP was investigated by XRD (Figure 5). A typical diffraction pattern was observed for the original nanopowders, which confirmed the presence of the anatase (JCPDS card no. 21-1272 or RRUFF ID R060277.9) and rutile (JCPDS card no. 21-1276 or RRUFF ID R110109.9) polymorphic modifications of TiO\({}_{2}\)[57; 58; 59]. The observed difference in the intensities of the anatase (20 = 25.3, 37.8, 48.0, 53.9, 55.0, and 62.7 deg.) and rutile (20 = 27.5, 36.1, 41.6, 44.0, 54.3, 56.6, and 64.1 deg.) peaks are due to the different relative contents of anatase and rutile in the samples of \(d_{\mathrm{av}}\) = 46 and 100 nm in size. The third TiO\({}_{2}\) polymorph, brookite (JCPDS card no.