## 3 Results and Discussion
### Structural and Morphological Consequences of Processing
#### 3.1.3 Thermo-Oxidative Stability
Regarding the peak, \(T_{p}\) was moved towards lower temperatures due to the PLA chain scission during processing. While injection molding promoted a more severe reduction of \(T_{p}\) in the PLA-1500 compositions, the PLA-400-based materials were more labile to the stage of compression molding. PEG with higher molar mass and lower plasticizing yield seemed to result in slightly more degradation during injection molding when significant mechanical and thermal stresses \begin{table}
\begin{tabular}{c c c c c c c} \hline  & & \(T_{o}\) & \(T_{p}\) & \(T_{o}\) & \(T_{p}\) \\  & & **C\({}^{\circ}\)C** & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)C)** & **(\({}^{\circ}\)C)** \\ \hline \multirow{3}{*}{PLA} & \(P\) & 332.1 (\(\pm\)0.6) & 355.6 (\(\pm\)1.7) & & & \\  & \(D\) & 333.0 (\(\pm\)2.1) & 354.3 (\(\pm\)0.3) & & & \\  & \(F\) & 332.4 (\(\pm\)4.2) & 355.9 (\(\pm\)1.8) & & & \\ \hline \multirow{3}{*}{PLA-400} & \(C\) & 330.5 (\(\pm\)1.1) & 357.0 (\(\pm\)2.7) & & \(C\) & 333.0 (\(\pm\)1.3) & 358.4 (\(\pm\)1.8) \\  & \(D\) & 333.1 (\(\pm\)1.4) & 355.0 (\(\pm\)2.4) & PLA-1500 & \(D\) & 324.7 (\(\pm\)0.1) & 353.5 (\(\pm\)2.6) \\  & \(F\) & 326.3 (\(\pm\)2.0) & 356.2 (\(\pm\)0.5) & & \(F\) & 326.3 (\(\pm\)0.2) & 351.0 (\(\pm\)1.7) \\ \hline \multirow{3}{*}{PLA-400-NFC1} & \(C\) & 334.8 (\(\pm\)2.7) & 359.9 (\(\pm\)0.6) & & \(C\) & 333.9 (\(\pm\)3.4) & 359.6 (\(\pm\)1.1) \\  & \(D\) & 334.9 (\(\pm\)1.5) & 359.5 (\(\pm\)1.3) & PLA-1500-NFC1 & \(D\) & 331.2 (\(\pm\)1.2) & 356.2 (\(\pm\)0.3) \\  & \(F\) & 323.5 (\(\pm\)0.7) & 355.5 (\(\pm\)0.3) & & \(F\) & 327.4 (\(\pm\)2.0) & 356.0 (\(\pm\)1.5) \\ \hline \multirow{3}{*}{PLA-400-NFC3} & \(C\) & 337.6 (\(\pm\)1.2) & 359.4 (\(\pm\)1.4) & & \(C\) & 334.6 (\(\pm\)1.5) & 358.5 (\(\pm\)0.5) \\  & \(D\) & 330.8 (\(\pm\)2.6) & 357.2 (\(\pm\)0.8) & PLA-1500-NFC3 & \(D\) & 330.0 (\(\pm\)2.2) & 352.2 (\(\pm\)3.0) \\  & \(F\) & 317.9 (\(\pm\)1.9) & 349.6 (\(\pm\)2.9) & & \(F\) & 326.3 (\(\pm\)1.9) & 351.9 (\(\pm\)2.7) \\ \hline \multirow{3}{*}{PLA-400-NFC5} & \(C\) & 332.8 (\(\pm\)0.4) & 357.9 (\(\pm\)0.4) & & \(C\) & 331.3 (\(\pm\)0.3) & 356.2 (\(\pm\)0.2) \\  & \(D\) & 329.7 (\(\pm\)1.7) & 354.5 (\(\pm\)1.1) & PLA-1500-NFC5 & \(D\) & 329.9 (\(\pm\)0.6) & 352.2 (\(\pm\)1.3) \\ \cline{1-1}  & \(F\) & 319.3 (\(\pm\)1.6) & 350.1 (\(\pm\)1.3) & & \(F\) & 330.2 (\(\pm\)1.2) & 351.2 (\(\pm\)0.8) \\ \hline \end{tabular}
\end{table} 
Table 2: Thermo-oxidative decomposition parameters for the bionanocomposites after the subsequent compounding stages and dog-bone and film specimen preparation: onset (\(T_{o}\)) and peak (\(T_{p}\)) temperatures. \(P\) stands for pellet, \(C\) for compounding, \(D\) for dog-bone, and \(F\) for film specimens. were applied. Finally, the contribution of low percentages of NFC (1 and 3 wt%) buffered the decrease of \(T_{p}\) due to reprocessing compared to their PLA-PEG counterparts. NFC promoted a neat increase of \(T_{p}\) in both PLA-400-NFC and PLA-1500-NFC nanocomposites after injection molding, which was still visible in the compression-molded films, particularly in the PLA-1500-NFC compositions. Overall, the successive processing stages reduced the thermo-oxidative stability of the bionanocomposites, especially in terms of the onset and peak decomposition temperatures of PLA. It was also pointed out that the use of PEG involved its own degradation process with temperatures in the vicinities of 245 \({}^{\circ}\)C that may be considered the limiting temperature during service for these materials. Although using NFC in the plasticized bionanocomposites still resulted in lower thermo-oxidative stability than pure PLA, low percentages (1 and 3 wt%) contributed to retarding the launch of the PEG decomposition and even increased both onset and peak temperatures of PLA. This performance was more relevant the higher the molar mass of PEG.