Circular Carbon Nanotube Production for Advanced Structural Fiber Applications

Plastic waste accumulation remains a global challenge, with only a small fraction currently being recycled. Upcycling postconsumer plastics into value-added materials offers a sustainable solution for waste reduction and advanced manufacturing. In this study, we demonstrate a cost-effective method for synthesizing multiwalled carbon nanotubes (MWCNTs) from postconsumer plastics via catalytic chemical vapor deposition. The waste-derived MWCNTs were incorporated into polyacrylonitrile (PAN) through wet spinning to fabricate high-performance composite fibers. Compared to conventional PAN-based fibers that use commercially sourced CNTs, which often contain residual catalysts that weaken performance, the synthesized MWCNTs exhibit lower metal content and enhanced crystallinity (66%), reducing defects and improving composite integrity. The resulting PAN-MWCNT fibers achieved a Young's modulus of 13.4 GPa and tensile strength of 941 MPa. This work provides a dual benefit: mitigating plastic waste while producing high-value carbon nanomaterials, offering a sustainable route to manufacture lightweight, high-performance fibers applicable in aerospace, automotive, and energy sectors.