Impact of Filler Size and Loading on the Mechanical Performance of Micro and Nano Bio-Composites

Abstract This research explores how the filler size and loading impacts on the mechanical properties of sustainable bio-composites made from recycled polypropylene reinforced with fillers derived from date palm tree agro-residual waste. Two filler types were investigated: micro-scale particles (75 μm) and Nanoscale particles (40–65 nm), each incorporated at varying weight percentages. Mechanical testing, including tensile and flexural strength evaluations, was demonstrated to assess this both impacts (filler size and concentration) on composite the overall performance. The results revealed that micro-filled composites demonstrated high tensile strength, achieving a peak value of 25.2 MPa at 20 %wt., while Nano-filled composites exhibited enhanced flexural strength, reaching 44.3 MPa at 6 %wt. These main results underscore the viatal role of particle size and filler loading in tailoring the mechanical behavior of bio-composites for specific industrial uses. The study supports the valorization of agricultural waste for the development of high-performance, eco-friendly materials suitable for additive manufacturing application.