Design and fabrication of polyurethane-modified epoxy duroplastic TPMS lattice structures via laser powder bed fusion additive manufacturing

Innovative material design is crucial to the advancement of additive manufacturing (AM) technologies, particularly for producing lightweight high-performance components. This work presents a novel epoxy–polyurethane hybrid material system engineered for laser powder bed fusion (L-PBF) to fabricate and evaluate complex triply periodic minimal surface (TPMS) lattice structures. By integrating high stiffness and thermal resistance of epoxies with toughness and elasticity of polyurethanes, the hybrid material system achieves an optimal balance of rigidity, energy absorption, and durability, critical for lightweight structural applications with tunable mechanical properties. In this study, three type of TPMS lattice architectures, including gyroid, diamond, and Schwarz-P, were fabricated using novel duroplastic formulations of Epoxy-amine (EP) modified with varied weight proportions of thermoplastic polyurethane (TPU) (20 to 60 wt%) and their mechanical performances such as strength, stiffness, and energy absorption capability were experimentally characterized under quasi-static compression. Results highlight the strong dependence of mechanical performance on both, material composition and lattice architectures. Diamond lattices exhibited the highest compressive strength, stiffness, and energy absorption fabricated with 30/70 TPU/EP formulation. All the fabricated duroplastic TPMS lattices achieved more than 60% weight reduction while retaining high compressive strength and recoverability, surpassing the performance of conventional thermoplastics with comparable designs. These findings underscore the potential of TPU/EP hybrid systems in driving the next generation of lightweight structurally efficient and sustainable lattice architectures for high-performance aerospace, automotive, biomedical, and advanced engineering applications.