# Comparison of the Properties and Structure of Montmorillonite Modified with Polyvinylpyrrolidone
###### Abstract  
The modification method of aluminosilicate clays and the modifier content have a decisive influence on the structure and properties of the obtained nanocomposites. Therefore, the development and research of new techniques of nanocdays modification are of great importance for polymer nano-chemistry. The work studied the modification of montmorillonite (MMT) using polyvinylpyrrolidone (PVP) in an aqueous colloidal solution with the subsequent separation of three separate fractions of the solution according to the previously developed method. The influence of the initial mass ratio of components (MMT/PVP) on the structure and thermal properties of the modified MMT in each solution layer was determined. Scanning electron microscopy (SEM), X-ray diffraction (XRD), thermal gravimetry (TG), differential scanning calorimetry (DSC), and Fourier-transform infrared (FTIR) spectroscopy were used for research. It was established that the mass ratio of components in the initial solution has almost no effect on the structure of MMT in the top and middle solution layers, but significantly affects the yield of final products. Different structures can be obtained in the bottom layer of the solution. Still, intercalated MMT was obtained exclusively at the mass ratio of MMT/PVP = 1:2. In addition, the work investigated the structure and thermal properties of modified montmorillonite with the same PVP content, and it has been proven that such composites have dissimilar structures and properties when obtained by different methods. mottmorillonite; polyvinylpyrrolidone; modification in solution; structure; intercalation; exfoliation; floccation 2024 20  
most common nanofillers are carbon nanotubes, graphene, chitosan and silica nanoparticles, starch nanocrystals, cellulose nanofibers, and layered silicates [4; 7; 8; 9; 10]. [PERSON] et al. [11] analyzed the structure and properties of various composites based on biodegradable polymers and bentonite clays and showed their potential for multifunctional applications. Including bentonite clay in biodegradable polymers can lead to increased crystallinity and thermal stability due to the creation of a thermal barrier and significantly increase the tensile strength, impact strength, and stiffness of composites. Such bio(nano) composites are versatile and promising in various industrial applications such as packaging, energy storage, electromagnetic shielding, and electronics, including flexible electronics. Layered clay minerals were first used in the 1980s to produce nylon-clay nanocomposite using MMT [12; 13]. Due to the successful development of nylon-MMT nanocomposite, clay minerals of various structural types have been widely used as fillers for the development of functional materials based on thermoplastic [2; 10; 11] and thermoset polymers [14; 15]. Anisotropic shapes of crystalline structures, such as lamellar nanoparticles with different aspect ratios, are believed to lead to diverse/controllable functions of the resulting hybrid materials [1; 16; 17]. The degree of dispersion of such nanoparticles in the polymer matrix is a crucial parameter that determines the properties of the obtained nanocomposites [18]. In turn, the degree of dispersion depends on the affinity between the polymer and the clay mineral. This affinity is increased by modification of the outer and inner (interlayer space of layered silicates) surfaces of clay mineral particles [18; 19; 20; 21; 22; 23]. Natural and synthetic water-soluble polymers are widely used for \"eco-modification\" of layered silicates, namely polysaccharides, alginates, cellulose, gelatin [24; 25; 26; 27], as well as PVP, polyvinyl alcohol (PVA), polyacrylamide (PAA), polyethylene glycol. (PEG) [1; 21; 28]. These polymers are applied to stabilize nanoparticles (prevent aggregation), improve their dispersion in solvents, and, as a protective layer for growing nanoparticles of the required morphology [29; 30; 31]. [PERSON] et al.