Sustainable bio-based PET hybrid composites reinforced with organic waste and basalt fibres with antibacterial addition

This study presents the development and characterization of novel hybrid composites based on a bio-based polyethylene terephthalate (bioPET) matrix reinforced with natural and waste-derived fillers-mollusc and eggshell particles, basalt fibres, and titanium dioxide (TiO₂). The composite specimens were produced using the injection moulding technique. The incorporation of these eco-friendly additives aims to enhance the mechanical performance, sustainability, and functionality of the composites. Mechanical tests including tensile, bending, Charpy impact, and low-cycle fatigue experiments were conducted. The addition of basalt fibres significantly improved tensile and flexural moduli, as well as impact resistance. Organic fillers contributed to increased stiffness but often led to brittleness due to weak interfacial bonding. SEM analysis confirmed heterogeneous fracture morphology with varied filler dispersion. Hybrid composites combining waste particles, basalt fibres, and TiO₂ demonstrated synergistic reinforcement effects and stable mechanical behavior under cyclic loading. These findings highlight the potential of bioPET-based hybrid systems for sustainable engineering applications, indicating a promising route toward eco-functional composite materials with potentially enhanced antimicrobial performance due to the presence of TiO₂.