Improved fracture toughness of glass fibers reinforced polypropylene composites through hybridization with polyolefin elastomers and polymeric fibers for automotive applications

Polypropylene-reinforced composites mostly exhibit a trade-off between stiffness and toughness. In this study, the impact of incorporating polyolefin elastomer (POE) and Polyvinyl Alcohol (PVA) fibers as individual and hybrid reinforcement to glass fiber-reinforced polypropylene composite in the presence of a compatibilizer was explored. The main focus was on achieving an optimal stiffness/toughness balance. Several ternary and quaternary hybrid composite systems were developed and analyzed. All components were melt-blended using a twin-screw extruder and then injection molded for subsequent mechanical and morphological analysis. A significant stiffness of approximately 2.4 GPa Young's modulus, and notched izod impact strength ranges between 250 and 400 J/m can be attained with the quaternary hybrid system, PP/GF/POE/PVA fibers. Its performance can be controlled by altering the POE/PVA fibers ratio to achieve the targeted stiffness/toughness balance. These values represent a remarkable increase, with Young's modulus being 120% higher and the izod impact strength surpassing that of the control sample by over 800%. The achieved results aligned with the requirements of the automotive industry, so the developed composites could have a high potential for automotive parts. Highlights: Ternary and quaternary hybrid systems were fabricated by a twin-screw extruder. An improvement of 120% in stiffness and 800% in toughness was observed. Distinct micromechanical deformation mechanisms were identified. Remarkable stiffness-toughness balance was achieved. Reduction in weight makes the system suitable for automotive applications.