Sustainable Polypropylene Composites with Rod-Like Calcium Carbonate Particles Derived from Ocean-Mineralization-Based Carbon Capture

Abstract Efficiently utilizing captured carbon as high-value materials is a cornerstone of achieving global carbon neutrality. In this study, we present a sustainable approach to upcycle calcium carbonate (CaCO3) microparticles, synthesized via ocean-mineralization-based carbon capture, into functional fillers to enhance the performance of polypropylene (PP) composites. The unique morphology of mineralized rod-like CaCO3 (MRC) influenced the mechanical and rheological properties of PP composites compared with commercial rhombohedral CaCO3 (CRC). The MRC particles, characterized by a high aspect ratio and narrow size distribution, significantly enhanced both Young’s modulus and storage modulus of the PP composites. To improve interfacial adhesion, surface modification with stearic acid (SA) was employed, which effectively promoted ductile fracture and energy dissipation. Consequently, the PP composite reinforced with 30 wt % of surface-treated MRC exhibited a simultaneous 2.3-fold increase in tensile toughness and a 1.2-fold increase in Young’s modulus compared with neat PP. In addition to mechanical reinforcement, the PP composite films showed high solar reflectance and mid-infrared emissivity, demonstrating their potential for radiative cooling applications. Life-cycle and techno-economic assessments further showed that the incorporation of MRC-SA reduced the carbon footprint and estimated production cost of the composites by up to 35% and 26% compared with neat PP, respectively.