## 3 Results and Discussion
### Thermogravimetric Analysis (TGA)  
TGA of the dry extracts (DCM, iPr) was performed to analyze the content of the components of the nano rubber particles. Furthermore, experiments were performed for selected sediments with fractions <25 \(\upmu\)m, 25-40 \(\upmu\)m, 40-100 \(\upmu\)m, 100-250 \(\upmu\)m, and 250 \(\upmu\)m-1 mm to ascertain the presence of organic and other compounds, which were washed with both dichloromethane and isopropanol. The analysis was conducted under inert gas and air atmospheres. From the TGA data, the residue mass and temperatures corresponding to the maximum decomposition rates (T\({}_{\text{max}}\)) were determined. In Figure 8, thermograms of dry extracts for analysis conducted in the nitrogen atmosphere (Figure 8A) and air atmosphere (Figure 8B) are presented. In the nitrogen atmosphere, a one-step decomposition of the dichloromethane extract is observed with a T\({}_{\text{max}}\) = 445.8 \({}^{\circ}\)C, corresponding to the thermal degradation of polymers (nano rubber). Thermal analysis results indicate that washing with dichloromethane effectively enabled the extraction of nanoparticles. Based on the literature analysis, it was determined that T\({}_{\text{max}}\) for SBR rubbers is approximately 449 \({}^{\circ}\)C [41] and, for EPDM rubbers, T\({}_{\text{max}}\) = 409 \({}^{\circ}\)C [42]. In the conducted analyses in this article, it is not possible to unequivocally determine the qualitative composition of the rubber due to the diverse composition of the collected samples. The residual residue mainly consists of black carbon and other fillers. A multi-step curve profile is observed for the isopropanol extract, resulting from the extraction of a wide range of compounds. In the initial stage, the elimination of volatile substances such as organic solvents is observed. In the temperature range of 200-500 \({}^{\circ}\)C, the greatest mass loss, exceeding 55%, is observed, which is attributed to the overlapping thermal processes occurring in the tested samples. Degradation of polymers and medium-volatile materials such as elastomers and curing agents is observed within this temperature range [43]. Additives present in the tire composition, such as oils (including naphthenic oil, parafinic oil, and highly aromatic oil), plasticizers, low molecular weight oligomers, emulsifiers, waxes, and antioxidants, undergo a process of evaporation due to the elevated temperature. Above the temperature of 550 \({}^{\circ}\)C, decomposition of remaining inorganic compounds (non-volatile materials, metal oxides, etc.) occurs. In the range of 720-820 \({}^{\circ}\)C (T\({}_{\text{max}}\) = 769.6 \({}^{\circ}\)C), a peak is observed, likely originating from the decomposition of calcium carbonate to calcium oxide, indicating the presence of carbonate material [44]. In some cases, calcium carbonate is used as an additive in rubber mixtures. During thermal analysis in an oxidizing atmosphere for chloromethane extract, initially, desorption of volatile compounds is observed. Subsequently, similar to what occurred in an inert atmosphere, polymer degradation is observed. Additionally, in the air atmosphere, an additional peak was observed on the DTG curve at T\({}_{\text{max}}\) = 538.8 \({}^{\circ}\)C originating from the combustion of carbon black, extracted solely using DCM [45]. It has been observed that in the case of extracts obtained using dichloromethane, a high content of carbon black is observed, whereas in the case of extracts obtained solely using isopropanol, lighter molecules present in the rubber composition, such as plasticizers, oils, etc., are washed away. Figures 9 and 10 present thermogravimetric curves for the SZY, UMU, BIS, and CZT2 sediments. A multi-stage decomposition is observed, which is a result of the complex nature of the samples in terms of their varied compositions, types, and collection locations (Tables 6 and 7). The analysis of the SZY and UMU samples, collected as sand from areas near busy streets, shows similar degradation mechanisms (five-stage sample decomposition).