Interfacial Transcrystallization and Mechanical Performance of 3D-Printed Fully Recyclable Continuous Fiber Self-Reinforced Composites

To fully exploit the preponderance of three-dimensional (3D)-printed, continuous, fiber-reinforced, thermoplastic composites (CFRTPCs) and self-reinforced composites (which exhibit excellent interfacial affinity and are fully recyclable), an approach in which continuous fiber self-reinforced composites (CFSRCs) can be fabricated by 3D printing is proposed. The influence of 3D-printing temperature on the mechanical performance of 3D-printed CFSRCs based on homogeneous, continuous, ultra-high-molecular-weight polyethylene (UHMWPE) fibers and high-density polyethylene (HDPE) filament, utilized as a reinforcing phase and matrix, respectively, was studied. Experimental results showed a qualitative relationship between the printing temperature and the mechanical properties. The ultimate tensile strength, as well as Young's modulus, were 300.2 MPa and 8.2 GPa, respectively. Furthermore, transcrystallization that occurred in the process of 3D printing resulted in an interface between fibers and the matrix. Finally, the recyclability of 3D-printed CFSRCs has also been demonstrated in this research for potential applications of green composites.