Eco-Friendly Polypropylene Composite Reinforced with Natural Fillers: Mechanical Properties and Wear Resistance

¹ Laboratoire de Mécanique, Matériaux et Procédés, Ecole Nationale Supérieure d’Ingénieurs de Tunis, Université de Tunis, 5, Avenue Taha Husseïn, Montfleury, Tunis 1008, Tunisia
² Institut Préparatoire aux Etudes d’Ingénieurs d’El-Manar, Université d’El-Manar, B.P 244, CNRS, UMR 5223, Tunis 2092, Tunisia
³ Composite Materials and Clay Minerals Laboratory, National Center for Research in Materials Science, Technopole of Borj Cedria, Slimane 8027, Tunisia
⁴ Laboratoire Mécanique Appliquée et Ingénierie (LR-MAI)-ENIT, Tunisie
⁵ Team of Research Applied to Polymers, ENSEM, Morocco

^* Corresponding author E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Natural composite materials are gaining interest due to their low cost, recyclability, and availability. This study examines hemp-polypropylene (HPP) composites, where polypropylene (PP) is reinforced with 30 wt.% short hemp fibers (HF). The composites were produced via melt compounding using a twin-screw extruder, followed by injection molding. To improve adhesion between hydrophilic hemp fibers and the non-polar PP matrix, polypropylene-graft-maleic anhydride (PP-g-MA) was used as a coupling agent. Structural and mechanical properties were assessed using SEM, FTIR, tensile, and scratch tests. Results revealed a significant improvement in fiber-matrix adhesion with the use of PP-g-MA, demonstrating enhanced interfacial bonding. The hemp fibers were uniformly dispersed within the PP matrix, resulting in a dense and homogeneous composite structure. Mechanically, the addition of 30 wt.% HF markedly increased the stiffness and tensile properties of the composites. The Young’s modulus and tensile strength of the HPP composites reached 3804 MPa and 28.07 MPa, respectively, compared to 1523 MPa and 22.98 MPa for neat PP. Scratch testing further supported these findings, showing a notable reduction in penetration depth upon the inclusion of hemp fibers. This study highlights the potential of hemp-reinforced polypropylene composites as a sustainable alternative in applications requiring enhanced mechanical performance.