The research is devoted to the development and modification of wood–polymer composites (WPCs), which combine the properties of wood and polymers and have promising applications in construction and other industries. The study considers the use of mineral fillers (fly ash, phosphogypsum) and organic modifiers (stearic acid, epoxidized soybean oil).
The aim of the work is to develop technologies for producing composites with high strength, durability, and resistance to external influences. Experimental studies were conducted to evaluate the effect of additives on the physico mechanical, technological, and performance properties of the materials.
It was established that the introduction of stearic acid in the amount of 0.8–1.25 wt.% improves flexural strength (up to 51.3 MPa, +20%) and impact strength (+37%), while reducing water absorption and the coefficient of linear thermal expansion. Optimization of its content enhances the stability and productivity of the extrusion process.
For the first time, it was shown that the addition of 0.5 wt.% epoxidized soybean oil significantly improves composite properties: impact strength increases almost threefold (up to 20.0 kJ/m²), flexural strength rises to 50.8 MPa, and the coefficient of thermal expansion decreases by 15%. Further increase in its content leads to deterioration of mechanical properties, which determines the optimal level of modification.
Replacing calcite with fly ash reduces water absorption, thermal expansion, and shrinkage, while increasing flexural strength (up to 55.8 MPa). At the same time, impact strength decreases more than twofold, which must be considered in practical applications. The use of phosphogypsum as an alternative filler ensures the stability of composite properties and reduces product cost, opening new opportunities for environmentally oriented production.
Regression models confirmed the significant influence of modifiers, while the interaction between epoxidized soybean oil and fly ash proved statistically insignificant, indicating an additive nature of their effects.
The developed highly filled composites with hybrid fillers combine environmental friendliness and economic efficiency, utilizing mainly waste and secondary materials. They are characterized by high strength, resistance to thermal deformation and water, durability, and resistance to biological factors. This makes them suitable for outdoor structures (terraces, fences, facades) as well as for furniture production.
The developed formulation was successfully tested under industrial conditions. The experimental batch confirmed the stability of properties, economic efficiency, and environmental feasibility of the approach. Implementation provided reduced production costs, lower energy consumption, and minimal expenses for technology adaptation, demonstrating readiness for serial application and competitiveness in the finishing materials market.
The results of the study possess scientific novelty and practical significance for the creation of environmentally safe, stable, and technologically efficient materials that meet modern requirements of sustainable development.
