Ultrarobust, Self-Healing Poly(urethane-urea) Elastomer with Superior Tensile Strength and Intrinsic Flame Retardancy Enabled by Coordination Cross-Linking
Yuxin Luo, Meiyan Tan, Jae Man Shin, Cheng Zhang, Shiyuan Yang, Ningning Song, Wenchao Zhang, Yunhong Jiao, Jixing Xie, Zhishuai Geng, Jiyu He, Min Xia, Jianzhong Xu, Rongjie Yang
Abstract
Poly(urethane-urea) elastomers (PUUEs) have gained significant attention recently due to their growing demand in electronic skin, wearable electronic devices, and aerospace applications. The practical implementation of these elastomers necessitates many exceptional properties to ensure robust and safe utilization. However, achieving an optimal balance between high mechanical strength, good self-healing at moderate temperatures, and efficient flame retardancy for poly(urethane-urea) elastomers remains a formidable challenge. In this study, we incorporated metal coordination bonds and flame-retarding phosphinate groups into the design of poly(urethane-urea) simultaneously, resulting in a high-strength, self-healing, and flame-retardant elastomer, termed PNPU-2%Zn. Additional supramolecular cross-links and plasticizing effects of phosphinate-endowed PUUEs with relatively remarkable tensile strength (20.9 MPa), high elastic modulus (10.8 MPa), and exceptional self-healing efficiency (above 97%). Besides, PNPU-2%Zn possessed self-extinguishing characteristics with a limiting oxygen index (LOI) of 26.5%. Such an elastomer with superior properties can resist both mechanical fracture and fire hazards, providing insights into the development of robust and high-performance components for applications in wearable electronic devices.