Thermoset Shape‐Memory Polyurethane with Intrinsic Plasticity Enabled by Transcarbamoylation

Abstract

Thermoset polymers are known for their superior thermomechanical properties, but the chemical crosslinking typically leads to intractability. This is reflected in the great differences between thermoset and thermoplastic shape-memory polymers; the former exhibit a robust shape memory but are not capable of redefining the permanent shape. Contrary to current knowledge, we reveal here that a classical thermoset shape-memory polyurethane is readily capable of permanent reshaping (plasticity) after a topological network rearrangement that is induced by transcarbamoylation. By employing the Jianzhi technique (also known as kirigami), unexpected shape-shifting versatility was observed for this otherwise classical material. As the essential carbamate moiety in polyurethanes is one of the most common polymer building units, we anticipate that our finding will have significant benefits beyond shape shifting.

Ultrafast Digital Printing toward 4D Shape Changing Materials

“…This rapid fabrication of shape memory polymers with complex 3D permanent geometries is highly desirable for device applications of shape memory polymers. [1,6,30] In particular, the low surface energy of the wax-like material along with its shape memory function makes it highly attractive for use as smart molds to make polymer parts. In addition, the material can also be used for lost-wax casting, in which the wax-based material serves as the sacrificial mold (burned out after the process) to make metal parts with intricate 3D shapes (e.g., custom jewelry).…”

Fast-responding bio-based shape memory thermoplastic polyurethanes

“…[10–14] More recently, highly tunable thermoset shape-memory polyurethanes with permanent shape reconfigurability have been synthesized, where the cross-linking density can be adjusted over a wide range. [15, 16] This discovery, in many ways, blurs the traditional definition of thermoplastic and thermoset SMPs.…”

Self‐Healing Polycaprolactone Networks through Thermo‐Induced Reversible Disulfide Bond Formation

“…Shape memory polymers are capable of temporarily adopting programmed shapes and shape upon external stimulation . The shape recovery process of P7000‐20 film is displayed in Figure a.…”