Thermoset Shape-Memory Polyurethane with Intrinsic Plasticity Enabled by Transcarbamoylation.

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.

[1]  R. Vaia,et al.  Shape‐Reprogrammable Polymers: Encoding, Erasing, and Re‐Encoding , 2014, Advanced materials.

[2]  Tao Xie,et al.  Shape memory polymer network with thermally distinct elasticity and plasticity , 2016, Science Advances.

[3]  A. Lendlein,et al.  Multifunctional Shape‐Memory Polymers , 2010, Advanced materials.

[4]  W. Huang,et al.  Polyurethane Shape Memory Polymers , 2011 .

[5]  Ludwik Leibler,et al.  Making insoluble polymer networks malleable via olefin metathesis. , 2012, Journal of the American Chemical Society.

[6]  Wei Zhang,et al.  Heat‐ or Water‐Driven Malleability in a Highly Recyclable Covalent Network Polymer , 2014, Advanced materials.

[7]  M. Dickey,et al.  Self-folding of polymer sheets using local light absorption , 2012 .

[8]  Yi Wang,et al.  Angiopep-conjugated electro-responsive hydrogel nanoparticles: therapeutic potential for epilepsy. , 2014, Angewandte Chemie.

[9]  H. Qi,et al.  Recent progress in shape memory polymer: New behavior, enabling materials, and mechanistic understanding , 2015 .

[10]  C. Bowman,et al.  Photoinduced Plasticity in Cross-Linked Polymers , 2005, Science.

[11]  T. Xie.  Tunable polymer multi-shape memory effect , 2010, Nature.

[12]  A. Lendlein,et al.  Reversible Bidirectional Shape‐Memory Polymers , 2013, Advanced materials.

[13]  Yen Wei,et al.  Mouldable liquid-crystalline elastomer actuators with exchangeable covalent bonds. , 2014, Nature materials.

[14]  Andrey V. Dobrynin,et al.  Shapeshifting: Reversible Shape Memory in Semicrystalline Elastomers , 2014 .

[15]  P. Damasceno,et al.  A kirigami approach to engineering elasticity in nanocomposites through patterned defects. , 2015, Nature materials.

[16]  Christopher J. Cramer,et al.  Mechanically activated, catalyst-free polyhydroxyurethane vitrimers. , 2015, Journal of the American Chemical Society.

[17]  Ludwik Leibler,et al.  Catalytic Control of the Vitrimer Glass Transition. , 2012, ACS macro letters.

[18]  Zhibin Guan,et al.  Malleable and Self-Healing Covalent Polymer Networks through Tunable Dynamic Boronic Ester Bonds. , 2015, Journal of the American Chemical Society.

[19]  T. J. McCarthy,et al.  A surprise from 1954: siloxane equilibration is a simple, robust, and obvious polymer self-healing mechanism. , 2012, Journal of the American Chemical Society.

[20]  Stuart J. Rowan,et al.  Inherently Photohealable and Thermal Shape-Memory Polydisulfide Networks. , 2013, ACS macro letters.

[21]  Yen Wei,et al.  Regional Shape Control of Strategically Assembled Multishape Memory Vitrimers , 2016, Advanced materials.

[22]  P. Mather,et al.  Shape Memory Polymer Research , 2009 .

[23]  S. Rowan,et al.  Using the dynamic bond to access macroscopically responsive structurally dynamic polymers. , 2011, Nature materials.

[24]  Stephen R. Forrest,et al.  Dynamic kirigami structures for integrated solar tracking , 2015, Nature Communications.

[25]  Jianjun Cheng,et al.  Dynamic urea bond for the design of reversible and self-healing polymers , 2014, Nature Communications.

[26]  Guohua Deng,et al.  Covalent cross-linked polymer gels with reversible sol-gel transition and self-healing properties , 2010 .

[27]  Jinlian Hu,et al.  Effect of MDI–BDO hard segment on pyridine-containing shape memory polyurethanes , 2011 .

[28]  Ludwik Leibler,et al.  Silica-Like Malleable Materials from Permanent Organic Networks , 2011, Science.