Characterization of 4D printed shape memory and conventional polymer blends for thermal responsive applications

Thermal-responsive polymers have applications in smart devices, packaging materials, sensing structures, and smart grippers. On the other side, 3D printing of smart materials (4D printing) enables printing complex structures for specific applications. Low strength and high cost are two major problems with shape memory polymers. In the present study, shape-memory polyurethane (SMPU) and polylactic acid (PLA) blends were obtained, mechanical and shape recovery characteristics were obtained experimentally. 3D printable filaments of SMPU, PLA and SMPU/PLA blend were obtained from a twin-screw extruder, and required test specimens were printed and characterized. Flexural tests of SMPU/PLA blends were compared with pure SMPU for repetitive cycles. The present study shows improved results in mechanical properties with a limited loss in shape recovery by blending SMPU with PLA. Further, the present study gives a feasible future path to work on shape memory and conventional polymer blends.