Adaptable bio-based dynamically cross-linked networks via disrupting physical cross-linking and chain entanglement for electromagnetic interference shielding materials

Abstract

AbstractDynamically cross-linked networks combine the uniqueness of thermoplastics and thermosets to allow for reprocessability while being covalently crosslinked, but the lack of functionality seriously limits practical applications. Here, we propose a strategy to develop tung oil based dynamically cross-linked networks (PNMETs) by introducing primary amine to disrupt the physical cross-linking and chain entanglements, and achieved tunable mechanical strength and toughness, chemical stability, self-healing, solid state plasticity, and topological transformation. The constructed PNMETs based on hydrogen bonds and the dynamic imine bond exhibited multiple stimulus responses for light, heat, microwave and infrared radiation, and achieved excellent recycling and self-healing without any catalyst. By doping multiwalled carbon nanotubes (MWCNTs) and nano Fe3O4in PNMETs, the resulted electromagnetic interference (EMI) shielding materials (PNMETs/MWCNT@Fe3O4) were fabricated and realized dual characteristics of dynamically cross-linked networks and EMI shielding material for the first time. PNMETs/MWCNT@Fe3O4composite based on the topological rearrangement of PNMETs showed shape memory behavior, reprocessing, recycling and self-healing property under the conditions of infrared radiation and voltage, as well as exhibited EMI shielding effectiveness of 20–23 dB in the X-band with thickness less than 1 mm, meeting the standards for commercial applications. This work provides a simple but highly practical strategy for the fabrication of functional materials that integrated with dynamically cross-linked polymer and EMI shielding performance suitable for harsh environments.