# Comparison of the Properties and Structure of Montmorillonite Modified with Polyvinylpyrrolidone
## 4 Conclusions  
The paper examines the influence of the ratio of components on the MMT modification process, which consists of mixing, under the ultrasound, aqueous colloidal solutions of MMT and PVP and selecting individual fractions formed during the settling of the resulting solution. Different structures and yields of target products can be obtained depending on the ratio of the initial components. In particular, intercalated MMT can be obtained only in the bottom layer of the solution at the MMT:PVP ratio 1:2. At other ratios of components (MMT:PVP = 4:1, 3:1, 2:1, 1:1), MMT with PVP molecules adsorbed on the surface is formed in the bottom layer of the solution. In the middle and top layers of the solution, flocculated and exfoliated MMT are formed, respectively, regardless of the ratio of components in the  
Figure 11: SEM images of MMT (**a**); PVP (**b**); MMT/PVP = 1:12 (**c**); MMT/PVP-top at the MMT:PVP ratio 1:2 (**d**). original mixture. The most optimal MMT:PVP ratio can be considered 1:2 because only with this ratio can you obtain three types of modified MMT (intercalated, flocculated, and exfoliated) from one prepared solution. A comparative analysis of two exfoliated MMT/PVP nanocomposites (MMT/PVP = 1:12 and MMT/PVP-top at the MMT:PVP ratio 1:2) with the same PVP content (about 93 wt%), obtained by different methods, showed differences in their structure and thermal behavior. In particular, the formation of mostly exfoliated MMT structures in these samples was confirmed by SEM, TGA, FTIR, DSC, and XRD. However, in the MMT/PVP-top sample, in contrast to MMT/PVP = 1:12, a small number of intercalated MMT structures were detected. It had a positive effect on the heat resistance of this sample and increased its glass transition temperature. In the MMT/PVP = 1:12 nanocomposite, MMT is completely exfoliated with a uniform distribution of MMT sheets between PVP macromolecules as, a result, its heat resistance is lower than that of the MMT/PVP-top, and its glass transition temperature is even 2.8\({}^{\circ}\)C lower than that of the original PVP. Each type of modified MMT can be further used to modify polymers, including biodegradable ones, to obtain nanocomposites for various purposes. Preliminary studies of the influence of exfoliated MMT (MMT/PVP-top) on the polyethylene (PE) stretch film properties were conducted. It was established that adding a small amount of MMT/PVP-top to PE increases the adhesive properties of the stretch film and allows the use of a much smaller amount of special glue during extrusion. Intercalated and flocculated MMT, for example, significantly changes the MFR of the biopolymer polybutylene succinate (PBS) and improves the optical and mechanical properties of PBS-based films. The following works will be devoted to a detailed study of the influence of the obtained modified montmorillonite on the properties of various polymers. Conceptualization, V.K. ; methodology, V.K., R.M. and O.K. ; validation, K.B., R.M. and L.D. ; formal analysis, V.K. and O.K. ; investigation, V.K., L.D. and O.K. ; resources, L.D. and K.B. ; writing--original draft preparation, V.K. ; writing--review and editing, V.K., L.D., R.M. and K.B. ; visualization, V.K. and O.K. ; supervision, K.B. ; project administration, V.K. and L.D. All authors have read and agreed to the published version of the manuscript. This research was funded by the European Union's programme for research and innovation Horizon Europe under the Marie Sklodowska-Curie Action grant agreement No 101129698-PROMATAI-Horizon-MSCA-2022-SE-01. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or European Research Executive Agency. Neither the European Union nor the granting authority can be held responsible for them. Not applicable. The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy.