RESUMEN
Composite polymer materials featured superior thermal conductivity, flame retardancy, and electromagnetic shielding performance are increasingly in demand due to the rapid development of highly miniaturized, portable, and flexible electronic devices. Herein, a facile and green ball milling shear method is utilized for generating MXene@Boron nitride (MXene@BN). The multi-functional fillers (MXene@BN) are constructed and incorporated into polydimethylsiloxane (PDMS) to prepare a multifunctional composite (PDMS/MXene@BN) for achieving improved electromagnetic interference (EMI) shielding performance and thermal conductivity as well as flame retardancy simultaneously. When the PDMS/MXene@BN composite has a MXene@BN loading of 2.4 wt.%, it exhibits a high thermal conductivity of 0.59 W m-1K-1, which is 210% higher than that of the pure PDMS matrix. This is attributed to its unique chestnut-like double-layer structure. With a smoke production rate (SPR) of 0.04 m2 s-1 and total smoke production (TSP) of 3.51 m2, PDMS/MXene@BN 2.4 composite exhibits superb smoke suppression properties. These SPR and TSP values are 63.20% and 63.50% lower than the corresponding values of pure PDMS. Moreover, the EMI SE of the PDMS/MXene@BN 2.4 can reach 26.3 dB at 8.5 GHz. The work reported herein provides valuable insight into developing composites with multiple functions, which show strong potential for application in advanced packaging materials.
RESUMEN
Flexible electromagnetic shielding composites have a great potential for wide range applications. In this study, two flexible composites were produced by plating Ni nanoparticles on carbon nanotubes (CNTs) or infiltrating carbon nanofibers/polydimethylsiloxane (CNF/PDMS) polymer into CNT/sodium alginate (CNT/SA) sponge skeleton (CNT/SA/CNF/PDMS composites). The composites are tested under the X band in the frequency range of 8.2 - 12.4 GHz, the electromagnetic interference shielding effectiveness (EMI-SE) values of the above two composites are almost as twice as that of CNT/SA/PDMS composite at a same CNT loading. Introducing nano-sized Ni particles on CNT improved the microwave absorption capacity of the composite, while adding CNF on the PDMS matrix enhanced the conductivity of these composites. Under 10% strain, both flexible composites show stable conductivity. Simulation and calculation results shown that increasing the cladding rate of Ni nanoparticles on the surface of CNT, reducing the average size of Ni particles, and increasing the loading of CNF in PDMS matrix can significantly improve conductivity and then EMI performance of the materials. All of these could benefit for the design of flexible electromagnetic shielding composites.