Bio-based Adaptable Dynamically Cross-linked Networks and Their Composites: Multiple Stimulus Response and Potential Electromagnetic Shielding Applications

Dynamically cross-linked networks combine the characteristics of thermoplastics and thermosets, enabling reprocessability while maintaining covalent cross-linking. However,it still faces multiple challenges in practical applications. Here, we present a strategy for the development of tung oil-based dynamically cross-linked networks (PNMETs) through the introduction of primary amine to disrupt the physical cross-linking and chain entanglements. This approach allows for the achievement of tunable mechanical strength and toughness, self-healing, solid-state plasticity, and topological transformation. The resulting PNMETs demonstrate multiple stimulus responses in light, heat, microwave, and infrared radiation, and exhibit excellent recycling and self-healing capabilities without catalyst. Furthermore, the incorporation of multiwalled carbon nanotubes (MWCNTs) and nano Fe3O4 into PNMETs leads to the fabrication of electromagnetic interference (EMI) shielding materials that possess dual characteristics of dynamically cross-linked networks and EMI shielding performance. The resulting PNMETs/MWCNT@Fe3O4 composite, utilizing the topological network rearrangement of PNMETs, demonstrates shape memory behavior, recycling and self-healing properties under infrared radiation and voltage application conditions, while also exhibiting an EMI shielding effectiveness of 20-35 dB with a thickness of less than 1 mm, meeting the standards for commercial and civilian applications. The bio-based adaptable dynamically cross-linked networks and their composites with multiple stimulus response produced via a simple strategy hold significant potential for next generation electromagnetic shielding materials, suitable for industrial scale production.