Integrated manufacturing of REciclable multi-material COmposites for the TRANSport sector

Due to advantages of low cost and intrinsic flame retardancy, urea?formaldehyde (UF) foams with electromagnetic shielding function present a promising application prospect in field of construction, transportation and electronics. In this study, by using carbon nanotubes (CNTs) as conductive filler and thermo?expandable microspheres (EM) as physical foaming agent, a series of UF/CNTs composite foams with perfect and polygonal closed cellular structure were prepared for electromagnetic shielding. By adding 6 wt% EM, the composite foam exhibited uniform cell wall thickness, while the local accumulation of CNTs was inhibited and CNTs distributed evenly within the cell walls. With increasing CNTs content, the dispersion of CNTs transformed from scattered and "island?like" structure to interconnected structure, and for samples with CNTs content higher than 1.34 vol%, a continuous conductive network was constructed within the cell walls, thus significantly improving the electrical conductivity and electromagnetic shielding effectiveness (EMI SE) for foams, which reached 34.5 dB and satisfied the requirement of commercial application. Moreover, the contribution of absorption to the EMI SE was much larger than that of reflection for composite foams, indicating that absorption was the dominant shielding mechanism.This article is protected by copyright. All rights reserved.

» Publication Date: 06/04/2023

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