## 4 Conclusions  
Through melt processing under dynamic conditions, composites based on PP reinforced with long glass fibers (G), thermal power plant ash and thermoplastic elastomer (linear triblock copolymer) (E) were obtained. The effect of the components, both individually and together, on the morphological, thermal, and (nano)mechanical properties of polypropylene reinforced with long glass fibers was analyzed. Each analysis was a necessary step in showcasing the degree of interactions between the components in the studied composites. Firstly, morphstructural analysis showed strong interactions between the components in each composite and confirmed their presence in the polymer matrix. Thermal analysis indicated that the presence of E accelerated the crystallization process by acting as a nucleating agent for PP. From a mechanical point of view, by mixing 20 wt.% E with 25 wt.% G-reinforced PP (PP-25G), an increase in toughness (increase in impact strength and axial strain by 39% and 18%, respectively) was obtained, but at the expense of stiffness, which decreased by approximately 25%. The addition of 5 wt.% treated ash (C) in PP-25G had very little influence on the stiffness (it decreased by less than 10%). On the other hand, the impact strength and tensile strength decreased by 20-30%. The combined effect of toughening with E and stiffening with C was achieved in the PP-G-E-C composite. PP-25G-C-E presented higher impact strength and axial strain compared to PP-25G and even PP-30G, proving good dispersion and interaction among components. Nanomechanical properties of PP-25G-C-E also showed an increase in surface hardness (21-35%) compared to PP-25G and PP-30G, indicating high surface resistance that would be suited for exterior applications in industries such as the automotive industry. Thus, a low-cost yet efficient alternative was developed using polypropylene reinforced with long glass fibers, elastomer and fly ash, with potential for use in industry. The process involved the replacement of a quantity of glass fibers with surface-treated ash and the addition of thermoplastic elastomer, without adversely affecting the specific properties required for the use of such polymer composites in the automotive industry. The process resulted in an enhancement in both toughness and surface properties, making the PP-25G-C-E composite a viable alternative to the regularly used glass fiber-reinforced polypropylene. Due to its increased toughness, composite PP-25G-C-E may find applications in the automotive industry, specifically in car bumpers, which are required to absorb impact energy and have higher resistance to crack initiation. Conceptualization, G.M.T., Z.V. and T.F. ; methodology, Z.V. ; software, G.M.T. ; validation, Z.V. ; formal analysis, C.A.N., M.G., A.I., G.M.T., A.R.G., R.M.I., S.S.-T. and T.F. ; investi \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sample** & **Element** & **\%Weight** & **Standard Deviation, \(\sigma\)** \\ \hline \multirow{8}{*}{PP-25G-C} & C & 22 & 1 \\  & Si & 15.8 & 0.3 \\  & Au & 10.5 & 0.4 \\  & Al & 7.4 & 0.2 \\  & Fe & 3 & 0.2 \\  & Ca & 2.1 & 0.1 \\  & K & 1.5 & 0.1 \\  & Mg & 0.9 & 0.1 \\  & Na & 0.2 & 0.1 \\ \hline \multirow{8}{*}{PP-25G-C-E} & C & 20.9 & 1.5 \\  & Si & 16.5 & 0.4 \\ \cline{1-1}  & Au & 9 & 0.5 \\ \cline{1-1}  & Al & 7.8 & 0.2 \\ \cline{1-1}  & Fe & 5.9 & 0.4 \\ \cline{1-1}  & Ca & 1.4 & 0.1 \\ \cline{1-1}  & K & 1.3 & 0.1 \\ \cline{1-1}  & Mg & 0.8 & 0.1 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: EDX analysis data. gation, Z.V., A.I. and G.M.T. ; resources, J.P. and Z.V. ; data curation, C.A.N., S.S.-T., A.R.G., Z.V. and G.M.T. ; writing--original draft preparation, G.M.T. ; writing--review and editing, M.G., G.M.T., Z.V. and J.P.; visualization, T.F. and G.M.T. ; supervision, Z.V. ; project administration, G.M.T. ; funding acquisition, Z.V., G.M.T. and T.F. All authors have read and agreed to the published version of the manuscript.