Tough Polyurethane Elastomer Enabled by Dynamic Hot Pressing Induced Disentanglement and Enhanced Hydrogen Bonding

Polyurethanes (PU) are considered promising candidates for advanced flexible elastomers due to their tunable softness and hardness, making it suitable for applications such as flexible electronic packaging. However, obtaining PU elastomers with excellent softness and toughness at the same time requires extensive and complex molecular chain structure design, which is a significant challenge. To address this challenge, a simple dynamic hot pressing (DHP) strategy is proposed to increase energy injection, molecular disentanglement, and enhance hydrogen bonding. The cyclic interval time in the DHP0 process matches the characteristic relaxation time of the molecular chains, playing a crucial role in enhancing the softness, stretchability, and mobility of the elastomer. Using this straightforward DHP approach, we successfully fabricated a DHP elastomer with a 3.9-fold increase in toughness (32.13 MJ m^-3) compared to the untreated PU elastomer. Notably, this toughness enhancement is accompanied by excellent softness (1.13 MPa of Young's modulus), ultrahigh stretchability (2551.3 %), and effective energy dissipation. This advanced DHP process fills a critical gap in PU final synthesis treatment research and is expected to accelerate the development of the synthesis of highly flexible hydrogen-bonded amorphous polymers for large-scale mass production.