# Preparation and Characterization of Hybrid Nanocomposites for Dental Applications
## 2 Materials and Methods
### Preparation of Polymer Nanocomposites Containing Mineral Nanofilers
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Sample** & **E\({}_{\text{t}}\) (GP)** & **\({}_{\text{t}}\) (MP)** & \({}_{\text{t}}\) (PS)** & **\({}_{\text{t}}\) (CP)** & \({}_{\text{t}}\) (MP)** & \({}_{\text{t}}\) (MP) & \({}_{\text{t}}\) (PS) & **H\({}_{\text{t}}\) (SD\({}^{\text{t}}\))** & **KC (J/m)** & \({}_{\text{t}}\) (PS)** \\ \hline Base & 3.58 \(\pm\) 0.34 & 39.29 \(\pm\) 0.88 & 1.72 \(\pm\) 0.15 & 2.23 \(\pm\) 0.17 & 54.67 \(\pm\) 5.90 & 281 \(\pm\) 0.28 & 84 \(\pm\) 1 & 12.4 \(\pm\) 1.2 & 1.37 \(\pm\) 0.004 & 21489 \(\pm\) 3.80 \\ \hline \({}_{10}\)HNTs & 3.80 \(\pm\) 0.32 & 24.93 \(\pm\) 2.13 & 1.05 \(\pm\) 0.09 & 2.48 \(\pm\) 0.11 & 42.21 \(\pm\) 4.54 & 1.76 \(\pm\) 0.27 & 78 \(\pm\) 4.49 \(\pm\) 0.4 & 1.124 \(\pm\) 0.001 & 23311 \(\pm\) 1.72 \\ \({}_{25}\)Si\({}_{4}\)NETs & 2.99 \(\pm\) 0.11 & 21.93 \(\pm\) 2.07 & 6.99 \(\pm\) 2.23 & 6.27 \(\pm\) 0.12 & 2.28 \(\pm\) 0.38 & 72.76 \(\pm\) 3.12 & 1.25 \(\pm\) 0.03 & 2.175 \(\pm\) 0.004 & 2112.6 \(\pm\) 6.79 \\ \({}_{55}\)HNTs & 2.84 \(\pm\) 0.29 & **27.89 \(\pm\) 1.55** & **1.54 \(\pm\) 0.11** & **2.23 \(\pm\) 0.17** & **44.74 \(\pm\) 6.44** & **2.02 \(\pm\) 0.27** & **85.1** \(\pm\) **4.74** \(\pm\) **0.137 \(\pm\) **0.017** & **20.92 \(\pm\) 0.87** \\ \({}_{75}\)Ni\({}_{4}\)NETs & 3.69 \(\pm\) 0.31 & 25.53 \(\pm\) 2.07 & 0.87 \(\pm\) 0.08 & 2.58 \(\pm\) 0.11 & 45.77 \(\pm\) 3.13 & 1.78 \(\pm\) 0.17 & 77.8 \(\pm\) 4.8 \(\pm\) 0.27 & 1.125 \(\pm\) 0.004 & 22425 \(\pm\) 1.186 \\ \({}_{10}\)HNTs & 3.77 \(\pm\) 0.33 & 29.20 \(\pm\) 1.99 & 1.37 \(\pm\) 0.19 & 2.63 \(\pm\) 0.04 & 38.54 \(\pm\) 0.56 & 1.58 \(\pm\) 0.31 & 84 \(\pm\) 1 & 3.9 \(\pm\) 0.11 & 1.441 \(\pm\) 0.001 & 2111.02 \(\pm\) 13.59 \\ \hline \hline \end{tabular}  
* E\({}_{\text{F}}\)—tensile modulus; \(\alpha_{\text{B}}\)—stress at break; \(\epsilon_{\text{B}}\)—elongation at break; E\({}_{\text{F}}\)—flexural modulus; \(\sigma_{\text{M}}\)—flexural strength; \(\epsilon_{\text{M}}\)—bending deformation; H—hardness; KC—impact strength; \(\rho\)—hydrostatic density; \(\Delta\)V\({}_{\text{red}}\)—relative volume loss.  
\end{table} 
Table 1: Selected properties of base material and acrylic-based composites with variable HNTs content. to carry out the modification, the mixture of gelatin and halloysite was subjected to the ultrasonic field at the frequency of 250 kHz in demineralized water, in the mass ratio of gelatin to halloysite of 1:2. The reaction was carried out at 80 \({}^{\circ}\)C for 3 h. After the reaction was complete, the water was removed (by evaporation) and the dry product was made into a fine powder--milled on a ball mill (Scheme 1). The halloysite modified with natural polymer (HNT-g) (5 mass%) was introduced into (MM/mMM) by creating a homogeneous dispersion in a high shear mixer and then subjected to bulk polymerization (at 60 \({}^{\circ}\)C for 3600 s, then at 100 \({}^{\circ}\)C for 3600 s). Nevertheless, the modification of HNTs by gelatin was carried out to improve the quality of dispersion and compatibility between components of the composite, but unfortunately it adversely affected water absorption. That is why, in the third stage of work, nanocomposites based on MM/mMM and 5% of ATH modified with silane (ATH-sil) (Evonik, Germany) was prepared in the form of a powder. This composite was made for comparative purposes to a hybrid composite. The aim of this work, apart from the presented solutions, is the preparation via bulk polymerization (at 60 \({}^{\circ}\)C for 3600 s, and then 100 \({}^{\circ}\)C for 3600 min) of polymer hybrid composites based on MM/mMM containing two types of fillers:  
* 2.5% HNT + 2.5% ATH-sil and
* 2.5% HNT-g + 2.5% ATH-sil.