Investigating the Impact of Pistacia Vera L. Bio-filler on the Mechanical Properties of a Synthetic Fiber/Epoxy Composite

The rising demand for sustainable composites has propelled research into agricultural waste as eco-friendly fillers. This work assesses the possible use of Pistacia vera L. (pistachio) shell powder (PBF) as a bio-filler in glass fiber-reinforced epoxy (GFRE) composites, so evaluating its effect on mechanical properties over mass fractions from 0% to 2%. Using compression moulding, composites were created; ASTM criteria were used to test tensile, flexural, and impact strengths. The findings showed a subtle balance: tensile and impact strengths were highest at 1.0% PBF (314 MPa and 36.1 J/cm², respectively), whereas flexural strength steadily dropped with rising PBF content. Higher loadings (>1.0%) caused particle agglomeration and interfacial weaknesses, so compromising performance. Though thorough optimization is crucial to minimize trade-offs in flexural resistance, this work emphasizes the possibility of pistachio shells as partial substitutes for synthetic fillers.