## 3 Results and Discussion  
### Thermogravimetric Analysis  
For compositions containing tri-layers deposited with the layer-by-layer method, with the increased number of layers, the temperature of 5% mass loss decreased, independently of the employed substrate (Figure 2). The highest values were observed for the 5L and 5 LMMT samples. The thermogravimetry (TG) curves demonstrating the first and the second step of thermal degradation for all samples did not exhibit significant differences. The analysis of the parameters of thermal degradation showed that in the low-temperature range, the thermal stability decreases with the increase in the number of deposited layers. It was also concluded that the application of any number of layers by the LBL method on the surface of PA6/MMT composites did not affect their thermal stability above 440 \({}^{\circ}\)C. The adsorption of five layers on the pure matrix as well as 10 layers on the nanocomposite allowed for obtaining the largest amount of charred residues in comparison to the rest of the analyzed materials (Table 1). In those materials, a relationship between the decreased mass of the obtained residue and an increase in the number of layers deposited on the surface occurred. Analogously to the results obtained by other research teams [29,30], such results suggest that the application of the triple layers might have a positive impact on the flame retardancy of the pure and filled polyamide matrix, respectively. The barrier effect was particularly pronounced with the application of the least number of deposited layers (5L). The adsorption of the tri-layers on the surface of polyamide materials could reduce the air permeability into the interior of the composite, as a result of which the greater mass of residue in comparison to the reference material was noted. It was concluded that the deposition of layers may have affected the mechanism of thermal degradation of the analyzed compositions, but did not alter the number of steps. In order to present the influence of the number of deposited tri-layers on the overall thermal stability of the obtained materials, the column graph detailing the values of the additional thermogravimetric index, OSE (_overall stabilization effect_) (Figure 3), calculated on the basis of the formula (1) given below [31], was created:  
\[\text{OSE}=\sum_{30}{}^{600}\text{(mass\% PA6/MMT at T temperature-mass\% pure PA6 at T temperature)} \tag{1}\] \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Sample** & **T\% (\({}^{\circ}\)C)** & **T\% (\({}^{\circ}\)C)** & **T\% (\({}^{\circ}\)C)** & **T\% (\% C)** & **T\({}_{\text{max}}\) (\({}^{\circ}\)C)** & **Residue at 600 \({}^{\circ}\)C (\%)** \\ \hline
**REF** & 374 & 391 & 412 & 440 & 445 & 0.9 \\
**5L** & 383 & 399 & 417 & 442 & 454 & 2.4 \\
**10L** & 381 & 399 & 418 & 442 & 449 & 1.8 \\
**15L** & 377 & 395 & 412 & 439 & 450 & 1.5 \\ \hline
**REFMMT** & 336 & 384 & 409 & 438 & 445 & 1.8 \\
**5 LMMT** & 379 & 395 & 418 & 444 & 454 & 2.0 \\
**10 LMMT** & 373 & 397 & 418 & 444 & 460 & 2.6 \\
**15 LMMT** & 372 & 403 & 421 & 445 & 453 & 2.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Temperatures at which 5%, 10%, 20%, and 50% mass loss occurs for the PA6 and the PA6/MMT nanocomposites stabilized with triple layers. Figure 2: Thermograms of the materials with 5, 10, and 15 triple layers, deposited on the surface of (**A**) the PA6 and (**B**) the PA6/MMT nanocomposites. The purpose of the OSE index is to assess the materials' thermal stability in the whole measurement range since its value is determined on the basis of the surface area below the mass loss curve as a function of temperature. The positive values of the OSE index indicate that all the samples with deposited triple layers are more thermally stable than polyamide 6. The negative value observed for the REFMMT material confirms the existence of the destabilization effect caused by the implementation of the nanofiller in the form of montmorillonite.