## 3 Results and Discussion
### FTIR-ATR Results for TPS/DES Films Obtained via Thermocompression (Test 1)  
FTIR-ATR spectroscopy results for DES, starch and thermoplasticized starch with DES are presented in Figure 3. The analysis was performed to investigate if some derivatization of starch occurred. In Figure 4A, there is a comparison of the TPS plasticized with CCU 1:5 with the unmodified starch. For the TPS there is a band of bending N-H (amide-II region) with a peak at 1624 cm\({}^{-1}\) and stretching C-N (amide-II region) groups at 1458 cm\({}^{-1}\), originating from U in DES. In the TPS, there is a shift in these peaks towards higher wave numbers in comparison with the DES due to a weakening of hydrogen bonds between DES component and the formation of new bonds with the polysaccharide OH groups [5]. There are no new peaks for TPS plasticized with all the CC-based eutectics with different U contents (data not shown). Figure 4B shows the comparison of TPS plasticized with anhydrous betaine and urea with native starch and the plasticizing eutectic. Starch, thermoplasticized with BaU mixture, exhibits a band of bending N-H (amide-II region) with a peak at 1618 cm\({}^{-1}\) and stretching C-N (amide-II region) groups at 1456 cm\({}^{-1}\), originating from U in DES. Moreover, there is a new band at 1732 cm\({}^{-1}\) for DES at 1:3, 1:4 and 1:5 molar ratios of Ba and U associated with a formation of stretching carbamate groups in the base of urethane [35]. Thus, the polysaccharide underwent derivatization with urea from BaU mixtures during thermoprocessing. Behavior in Water and Contact Angle Determination Results for TPS Films Obtained via Thermocompression and Extrusion and Thermocompression (Test 1 and 2)  
The behavior in water of starch plasticized with U-based DES is different than the TPS prepared with a conventional plasticizer like glycerol (Table 4). Figure 3: XRD patterns for the films plasticized with DESs: (**A**) based on CC with different U content; (**B**) TPS/CCU 1:5 after storage at ambient conditions; (**C**) based on Ba with different U content. Due to the highly amorphous structure of TPS/DES materials, their dissolving ability towards polysaccharide and the hygroscopic character of plasticizer, their swelling degree is much higher than that of, e.g., TPS/glycerol, or TPS a with non-dissolving DES [5]. The swelling degree of TPS with CC is lower (154-253%) than that with Ba (371-589%). It can be \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Sample**} & **Swelling** & **Solubility** & **Contact Angle** \\  & **Degree [\%]** & **Degree** & [\({}^{\circ}\)] \\ \hline TPS/CCU 1:2 & 253 (\(\pm\)30.6) & 23.7 (\(\pm\)0.4) & 69 (\(\pm\)2.9) \\ TPS/CCU 1:3 & 154 (\(\pm\)11.7) & 22.3 (\(\pm\)1.2) & 66 (\(\pm\)2.7) \\ TPS/CCU 1:4 & 165 (\(\pm\)8.5) & 22.6 (\(\pm\)1.2) & 72 (\(\pm\)3.6) \\ TPS/CCU 1:5 & 209 (\(\pm\)30.1) & 21.4 (\(\pm\)1.1) & 76 (\(\pm\)4.3) \\ \hline TPS/BaU 1:2 & 371 (\(\pm\)34.4) & 24.7 (\(\pm\)5.8) & 60 (\(\pm\)4.3) \\ TPS/BaU 1:3 & 436 (\(\pm\)30.9) & 27.2 (\(\pm\)1.3) & 90 (\(\pm\)6.7) \\ TPS/BaU 1:4 & 589 (\(\pm\)30.9) & 32.0 (\(\pm\)4.2) & 82 (\(\pm\)7.8) \\ TPS/BaU 1:5 & 426 (\(\pm\)33.8) & 32.5 (\(\pm\)5.0) & 68 (\(\pm\)7.4) \\ \hline eTPS/CCU 1:5 110/100 & & & 95 (\(\pm\)4.0) \\ eTPS/CCU 1:5 110/200 & & & 97 (\(\pm\)8.5) \\ eTPS/BaU 1:5 110/100 & & & 93 (\(\pm\)4.2) \\ eTPS/BaU 1:5 110/200 & & & 72 (\(\pm\)8.2) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Swelling and solubility degrees as well as surface contact angle values of TPS films obtained via thermocompression (TPS) and extrusion and then thermocompression (eTPS). Figure 4: FTIR-ATR spectra for potato granular starch, DES and: (**A**) DES CCU 1:5 and TPS plasticized with this DES; (**B**) DES BaU at 1:2 and 1:5 molar ratio and TPS plasticized with BaU 1:5.  
caused by the presence of a carboxyl group in betaine [37]. Moreover, as FTIR results reveal the occurrence of starch, carbamation can increase the polysaccharide hydrophilicity [43; 44].