FDM 3D printed MXene/Recycled carbon fibre reinforced polylactic acid composites: Interface optimization, toughening and enhanced electromagnetic shielding performance

Polylactic acid (PLA), a rapidly emerging bio-based plastic, faces challenges in reinforcement due to its weak mechanical properties and poor interface adhesion with carbon fibre surfaces. This study introduces an MXene/recycled carbon fibre (rCF) reinforced PLA 3D printing material, prepared through electrostatic self-assembly of MXene and recycled carbon fibre. MXene addition significantly enhances the fibre-substrate interface bonding in fibre-reinforced PLA filaments. This results in the printed parts displaying enhanced toughness, the flexural strength achieved of 105.45 MPa, modules of 5.98Gpa, and notched impact strength of 7.12 kJ/m 2 , realizing 15.6 %, 112.1 %, and 31.8 % improvements, respectively in comparison to pure PLA. Additionally, the modified PLA demonstrates absorption-dominated superior electromagnetic shielding performance. This research offers a viable approach for enhancing recycled carbon fibre-reinforced thermoplastic PLA and insights into designing sustainable, structurally, and functionally integrated composites.