4D Printing‐Encapsulated Polycaprolactone–Thermoplastic Polyurethane with High Shape Memory Performances

There are a few shape memory polymers (SMPs) like polylactic acid (PLA) and polyurethane (PU) that 4D printable, other SMPs must be synthesized with complicated chemical lab effort. Herein, considering dual-material extrusion printing microscopic mechanism behind effect (SME), bilayer-encapsulated polycaprolactone (PCL)–thermoplastic (TPU) composite structures printed for the first time. The SME performance is investigated by assessing fixity, recovery, stress relaxation under bending compression loading modes. PCL, TPU, melting temperature of PCL play role switching phase, net point, transition temperature, respectively. Due to destruction dripping molten in contact water, encapsulated TPU. Encapsulation successfully solves challenge bonding/interface between layers, results show higher than bilayer PCL–TPU one's. Experiments reveal maximum recovery 4D-printed composites remains constant over This great achievement compared previous extrusion-based SMP have weakness due weak low crystalline fractions unraveling molecular entanglements semicrystalline amorphous thermoplastic SMPs,