2D patterning and 3D hierarchical recovery of waste carbon fiber reinforced polymers via programmable laser strategy

The environmental concerns associated with the disposal of waste carbon fiber reinforced polymer have escalated due to its rapid accumulation. Many countries have outlawed its burning and landfilling, promoting recovery and reuse methods instead. However, these methods are generally inefficient, require stringent conditions, and can cause secondary pollution. This study introduces a novel programmable laser recovery (PLR) strategy that requires no pretreatment, chemical reagents, or high temperature and pressure environments. Separation and oxidative cleaning of CFRP were achieved based on the synergistic principles of photothermal and photomechanical effects utilizing a 1064 nm laser. For the first time, it enables 2D patterning and 3D hierarchical recovery of waste CFRP. At a scanning velocity of 3000 mm/s, the entire recovery process can be completed in just 310 s. The research comprehensively examines how laser parameters and the recovery environment affect the physicochemical properties of the recovered carbon fiber (rCF). In both nitrogen and air environments, employing laser energy densities of 500 J/cm2 and 334 J/cm2, respectively, can effectively prevent laser-induced damage to rCF, while preserving the fiber's original size and woven structure. The strength and modulus retention rates can reach 89.06 % and 105.01 %. The PLR strategy offers high spatial controllability, enabling full-scale and in-situ recovery of waste CFRP (305 x 132 mm2) and composite sandwich structures layer-by-layer. It efficiently recovers carbon fiber fabric and honeycomb or foam cores without the need for cutting, separating, sieving, or cleaning. This method shows great promise for use in recycling components like wind turbine blades and aircraft fuselages.