Valorization of Distilled Paint Waste as a Modifier of Polymer Matrices Based on ABS, PP and PS

This study evaluates the feasibility of incorporating a specific batch of distilled paint waste into acry-lonitrile–butadiene–styrene (ABS), polypropylene (PP), and polystyrene (PS) matrices at nominal feed contents of 10, 20, and 30 wt.%. After drying and grinding, the waste was compounded by extrusion and specimens were produced by injection molding. Melt-flow behavior, density, impact and tensile properties, thermal stability, thermal transitions, and dynamic-mechanical response were investigated. The effect of waste addition was strongly matrix dependent. In PS, MFR increased from 9.52 to 24.85 g/10 min between neat PS and the 30 wt.% nominal formulation, while Tg decreased from 106.4 to 81.6 °C. TGA showed non-monotonic, matrix-dependent changes in thermal stability. Mechanical performance generally deteriorated with increasing nominal waste content; for ABS, tensile strength decreased from 42.21 to 26.17 MPa and impact strength from 17.51 to 0.23 kJ/m2. DMA confirmed matrix-dependent changes in stiffness and relaxation behavior. The results show that the investigated waste batch can be processed with all three ther-moplastic matrices, but increasing waste addition involves clear mechanical and thermal trade-offs.