Bio-based adaptable dynamically cross-linked networks and their composites: multiple stimulus responses and potential electromagnetic shielding applications

Abstract

Dynamically cross-linked networks combine the characteristics of thermoplastics and thermosets, enabling reprocessability while maintaining covalent cross-linking. However, they still face 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 a 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 to light, heat, microwaves, and infrared radiation and exhibit excellent recycling and self-healing capabilities without catalysts. 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 responses produced via a simple strategy hold significant potential as next generation electromagnetic shielding materials, suitable for industrial scale production.