Influence of manufacturing processes on the physicochemical and mechanical properties of composites reinforced with palm fibers

Bio-composites represent a class of materials offering attractive mechanical and environmental properties for a range of industrial and biomechanical applications. This study investigates the influence of extrusion processing parameters on the physicochemical and mechanical properties of polypropylene biocomposites reinforced with date palm fibers. The composites were fabricated using varying extrusion conditions, including temperature zones (TS3: 210–240 °C; TS2: 160–200 °C), screw speeds (35–45 RPM), and fiber dosages (5–15 wt.%). Advanced characterization techniques: Dynamic Mechanical Analysis, Differential Scanning Calorimetry, Thermogravimetric Analysis, and Digital microscopy, were employed to evaluate crystallinity, thermal stability, and microstructure. Results revealed that higher screw speeds (45 RPM) and moderate temperatures (TS3 = 210 °C, TS2 = 160 °C) enhanced crystallinity (up to 21.74%) and mechanical rigidity, attributed to improved polymer chain alignment and fiber dispersion. Conversely, increased fiber dosage (15%) reduced crystallinity due to filler-induced disruption of polymer crystallization but improved thermal stability by acting as a barrier against porous. The Thermogravimetric Analysis demonstrated that fiber-reinforced composites exhibited gradual mass loss compared to pure Polypropylene, while Dynamic Mechanical Analysis highlighted superior energy dissipation (loss modulus) in formulations with optimized parameters. Microscopy identified surface defects (e.g., sharkskin) at lower temperatures, mitigated by elevated processing conditions. This study provides actionable insights for tailoring extrusion parameters to balance crystallinity, thermal resistance, and mechanical performance, advancing the development of sustainable biocomposites for automotive and industrial applications.