4D printing of biobased shape memory sandwich structures

Lightweight sandwich structures already have many applications in the aerospace, automotive, and construction sectors due to their high strength-to-weight ratio, enhanced stiffness and rigidity, and high energy and shock absorption capabilities. Additive manufacturing (AM) can provide great freedom and flexibility in the fabrication of complex sandwich structures that cannot be made by other conventional processes. The application of smart materials, like shape memory polymers (SMP), can offer the capability of dynamic transformation so that the deformed structure can recover its original shape using external stimuli, such as temperature. This study exploits the potential of this technology in the design and manufacturing of biobased smart sandwich structures with energy absorption capability and shape recovery performance. For that, a combination of recycled poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) biopolymers are developed as printing filaments with shape memory properties. The designed sandwich samples are fabricated by Fused Filament Fabrication (FFF) technology. The mechanical and functional properties of the printed samples are also evaluated. The results show PLA/PBS filaments have good printability and the fabricated parts have acceptable dimensional accuracy, mechanical strength, and functional performance.