Fenglong Li,Xiaolin Wang,Jiyang Zuo,Chao Chen,Jing Chen,Jin Zhu,Wu Bin Ying
3D printing has emerged as a highly accurate, highly customizable, and low-cost fabrication method to realize structures with designed geometry. However, the integral printing of complex structures, such as suspended structures, still poses significant challenges in the most commonly used 3D printing technology-fused filament fabrication (FFF). Therefore, designing a self-healing material, segmenting the printing of complex structures, and finally assembling them into a whole by the self-healing capability are expected to resolve this issue. In this research, we successfully synthesized a self-healing polyurethane (LNPU-3) with the introduction of dynamic oxime-urethane bonds. Specifically, we employed polycaprolactone diol as the soft segment, 2,4-pentanedione dioxime as the chain extender, and 4,4′-methylenebis(phenyl isocyanate) as the hard segment. LNPU-3 exhibited outstanding mechanical properties, with a tensile stress of 8.5 MPa and a fracture toughness of 20.1 MJ/m3. Even after cyclic stretching five times at a strain of 30%, the specimen could still recover 95% of its original value. Furthermore, LNPU-3 could be fully self-healed at room temperature (25 °C) within 8 h, with a healing efficiency of 92.9%. Finally, LNPU-3 was successfully printed by using FFF and the self-healing capability of the printed samples was tested. The printing components were then assembled into a complex structure that was difficult to print as a whole. In summary, LNPU-3 is an ideal self-healing 3D printing material, demonstrating significant potential for the application of self-healing materials and the advancement of 3D printing technology.
Ze Xu,Dan Shou,Wenrong Cai,Junyao Li,Datong Wu,Tao Jiang,Yong Kong
6-Deoxy-6-arginine grafted chitosan (DAC) is cross-linked with dibenzaldehyde-functionalized polyethylene glycol (DF-PEG) via the acylhydrazone (–N=CH–) bonds, which can be utilized for the encapsulation of metformin (MET). The resultant injectable DAC/DF-PEG/MET (DDM) hydrogels highlight well-behaved antibacterial and anti-inflammatory activity as well as self-healing capability. More interestingly, the DDM hydrogels exhibit appealing dynamic self-degradability. The electrostatic attraction between DAC and DF-PEG is significantly weakened at slightly alkaline surface (pH 7.0–8.0) that is the characteristic of skin wounds, resulting in the swelling of the hydrogels and the release of MET. As the wounds gradually get healed, the skin tissue turns to be weakly acidic (pH 4.0–6.0), leading to the hydrolysis of the –N=CH– bonds between DAC and DF-PEG. Therefore, the DDM hydrogels can be dynamically self-degraded during the wound healing process. Owing to the injectability and self-healing properties, the DDM hydrogels are suitable for use as the wound dressing for the wounds in any shape. The developed DDM hydrogels also display excellent hemocompatibility and cytocompatibility, indicating that they might be a potential wound dressing for skin wounds.
危险品化学品经营许可证（带存储）