Enhancing the Energy Absorption Performance of 3D-Printed CF/TPU Composite Materials by Introducing a "Rigid-Elastic" Structure Through Multi-Scale Synergies.

Thermoplastic polyurethane (TPU) combines elastomeric and thermoplastic properties but suffers from insufficient rigidity and strength for structural applications. Herein, we developed novel carbon fiber-reinforced TPU (CF/TPU) composites filaments and utilize melt extrusion for 3D printing to maintain elasticity, while achieving enhanced stiffness and strength through multi scale-the control of fiber content and optimization of printing parameters, reaching a rigid-elastic balance. A systematic evaluation of CF content (0-25%) and printing parameters revealed optimal performance to be at 220-230 °C and 40 mm/s for ensuring proper flow to wet fibers without polymer degradation. Compared with TPU, 20% CF/TPU exhibited 63.65%, 105.51%, and 93.69% improvements in tensile, compressive, and impact strength, respectively, alongside 70.88% and 72.92% enhancements in compression and impact energy absorption. This work establishes a fundamental framework for developing rigid-elastic hybrid materials with tailored energy absorption capabilities through rational material design and optimized additive manufacturing processes.