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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. [ABSTRACT FROM AUTHOR]

Die traditionelle chinesische Kunst des Scherenschnitts, Jianzhi, führt zu wunderschönen und komplexen Mustern. In der Zuschrift auf S. 11593 ff. verwenden Q. Zhao, T. Xie et al. die Jianzhi ‐ Technik, um klassische duroplastische Polyurethane mit komplexen dreidimensionalen Formen zu erhalten. Das duroplastische Polymer zeichnet sich durch seine intrinsische Plastizität aus und kann durch eine topologische Netzwerk ‐ Reorganisation, die durch Transcarbamoylierung ausgelöst wird, permanent und wiederholt umgeformt werden. [ABSTRACT FROM AUTHOR]