Waste‐Valorized Straw Charcoal Polypropylene Composites With High Electromagnetic Shielding Effectiveness Through Simplified Manufacturing

ABSTRACT Rapid advancements in electronics have created an urgent demand for efficient EMI shielding materials to address worsening electromagnetic pollution. However, most current research relies on high‐quality biomass as raw materials or employs complex manufacturing processes, thereby substantially increasing production costs and complicating manufacturing procedures. In this study, waste straw charcoal (SC) and discarded polypropylene (PP) plastics were utilized as raw materials to fabricate low‐cost polypropylene/biochar (SC/PP) composites with outstanding EMI shielding performance, using a simple one‐step thermoforming method. At 15% biochar content, the SC/PP composite achieves 63.3 dB EMI shielding effectiveness with low density (0.825 g/cm 3 ), excellent mechanical strength (24.12 MPa tensile, 32.99 MPa flexural), thermal conductivity (0.6708 W/mK), and water resistance (147°WCA, ~0% absorption), while reducing production costs and carbon emissions. With their outstanding overall performance, the SC/PP composites show strong potential to replace conventional EMI shielding materials currently available on the market, characterized by their exceptional overall performance.