A Comprehensive Review of Polypropylene-Based Hybrid Composites: Structure, Properties, and Applications

Abstract - The increasing demand for lightweight, high-strength, and cost-effective materials in engineering and industrial applications has driven the development of reinforced and hybrid polymer composites. This review comprehensively examines the evolution and current advancements in polypropylene (PP)-based composites, particularly focusing on hybrid systems incorporating both short fibers and inorganic fillers such as wollastonite, talc, and glass fibers. The article highlights the mechanical, thermal, morphological, and crystallization behavior of these composites, drawing from both historical and recent studies. Key strategies, such as the use of compatibilizers (e.g., PP-g-MA), nanofiller hybridization, and bio-based reinforcements, are explored for enhancing interfacial adhesion, impact resistance, and thermal stability. The role of wollastonite as a multifunctional filler—improving dimensional stability, heat deflection temperature, and processability—is emphasized. Additionally, the review discusses rheological behavior and processing considerations critical to optimizing composite performance. The findings underscore the potential of PP-based hybrid composites to meet diverse application requirements in automotive, construction, packaging, and electronics industries, while also offering pathways for sustainable and multifunctional material solutions. Key Words: Thermoplastics, Hybrid composites, Mechanical properties, rheological properties