The development of dynamic bonds-based nanocomposites with excellent mechanical properties and multi-stimulated self-healing capabilities is critical for the design of high-performance self-healing materials. In this study, dynamic nanocomposites based on carboxyl-functionalized multiwalled carbon nanotube (CNT -COOH ) fillers and a crosslinked polyurea (CPU) matrix were prepared through a facile two-step method involving in situ photo-induced polymerization and hot compression. Herein, the effect of CNT -COOH concentration on the properties of the resulting CPU@CNT nanocomposites was studied. The proposed novel method promoted the formation of a strong interfacial bond between the CNT -COOH and CPU. The dynamic nanocomposites exhibited excellent and rapid photo-induced self-healing abilities and regained their mechanical properties after damage. This can be attributed to the synergistic effect of the dynamic exchange reactions in the CPU matrix and the efficient photo-thermal effect of the fillers. The nanocomposite prepared using 1% CNT -COOH exhibited excellent toughness (up to 36.57 ± 1.28 MJ m −3 ), high stretchability (ca. 607 ± 50%), high tensile strength (7.36 ± 0.51 MPa), efficient photo-thermal shape memory effect , and good recyclability . Therefore, the facile method demonstrated in this study paves a way for the design of high-performance nanocomposites with rapid self-healing properties for sensing and flexible electronic applications.
Jiao Liu,Shuhan Xu,Xukang Han,Mingliang Ma,Xiyao Wang,Wenjuan Ren,Jinhu Hu,Haoyan Duan,Ye-Tang Pan
Effective mitigation of electromagnetic microwave (EMW) pollution requires the development of lightweight, broadband, and high-performance microwave absorbing materials. In this work, a novel Fe 3 SnC/Sn/CNF composite is synthesized via a combination of hydrothermal synthesis, electrospinning, and high-temperature carbonization. The optimal sample (FSC3) achieved a minimum reflection loss ( RL min ) of −28.33 dB and an effective absorption bandwidth ( EAB ) of 6.40 GHz at a thickness of 2.50 mm. To enhance environmental durability and broaden application potential, FSC3 is incorporated into a polyurea (PUA) matrix to fabricate a composite coating. The resulting material exhibited significantly improved microwave absorption, with an RL min of −65.78 dB and an EAB of 6.68 GHz at only 2.17 mm thickness. This enhancement is attributed to increased interfacial and dipolar polarization, as well as improved impedance matching due to the synergy between the filler and the elastomer matrix. Computer Simulation Technology (CST) simulations confirmed excellent Radar Cross Section (RCS) reduction performance, validating its stealth potential. Furthermore, the composite coating displayed enhanced mechanical strength and a hydrophilic surface, broadening its application prospects in harsh environments. This work presents a scalable and versatile strategy for designing multifunctional microwave absorbing coatings with outstanding performance.
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