A High Strength but Fast Fracture‐Self‐Healing Thermoplastic Elastomer

Abstract

Herein, a new type of healable thermoplastic poly(urethane-urea) (PUU) elastomer with a unique dual dynamic network structure consisting of multi-strength hydrogen bonds and aromatic disulfide bonds, is designed and synthesized. The resultant PUU elastomer exhibits high tensile strength (41 MPa), great toughness (104 MJ m −3 ), and excellent self-healing capability (completely severes, heals at 60°C for just 1 h, and recovers more than 80% of the original tensile strength). Although the PUU possesses high-density hydrogen bonds, it is completely homogeneous without micro-phase separation. The unique dual dynamic network structure alleviates the adverse effects of strong molecular interactions on self-healing process, simultaneously endowing the polymer with outstanding mechanical properties and excellent self-healing capability at mild temperature. In addition, the underlying mechanism between performance and structure is revealed. The PUU has potential applications in soft robots and wearable electronics.

Bioinspired Thermoplastic Elastomer with Flexible, Self-Healing Capabilities

“…(i) Self-healing performance of scratched HM-PU2-SS. (j) Comparison of our work and previous research studies. ,− …”

Rapid self-healing and tough polyurethane based on the synergy of multi-level hydrogen and disulfide bonds for healing propellant microcracks

“…Compared with the structures of MDI–APDS–MDI and IPDI–APDS–MDI that may exist in PU-B, PU-C, and PU-D, a uniform hard segment structure of PU-A can be formed more thoroughly through microphase separation without interference. 48,49…”

Advances and Challenges of Self-Healing Elastomers: A Mini Review

“…Aromatic disulfide bonds possess rapid reaction kinetics at mild temperature, which promotes the migration of polymer chains, and are widely investigated in the fabrication of fast self-healing elastomers with high tensile strength. Zhang et al [ 75 ] has fabricated mechanically robust self-healing polyurethane with disordered structure through one-step synthesis procedure. The steric hindrance of asymmetric alicyclic structure endows the polymer chains or chain segments with sufficient mobility and retaining of mechanical properties simultaneously, while the soft segments maintain the toughness and supply high-density hydrogen bonds to improve tensile strength simultaneously (see Figure 3 b).…”

“…( b ) Schematic diagrams of ideal elastomer structure and self-healing mechanism. Reproduced with permission [ 74 , 75 ]. Copyright 2018 WILEY-VCH Verlag GmbH & Co. KGaA.…”