Influence of Carbon-Based Fillers on the Electromagnetic Shielding Properties of a Silicone-Potting Compound

• Published in: Materials Vol. 17; no. 2; p. 280
• Main Authors: Seidel, Rafael, Katzer, Konrad, Bieck, Jakob, Langer, Maurice, Hesselbach, Julian, Heilig, Michael
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.01.2024
• Subjects: Additives; Adhesive strength; Analysis; Carbon; Carbon black; Carbon fibers; Carbon nanotubes; carbon-based fillers; Composite materials; conductivity; Dispersion; Electric properties; Electrical resistivity; Electromagnetic interference; Electromagnetic shielding; Electromagnetism; Fillers; Frequencies; Influence; Investigations; Nanocomposites; Nanomaterials; Nanotubes; Polymers; Potting compounds; Radiation; Rheological properties; Rheology; shielding; Silicones; stripline; Viscosity; Germany; United States > US; rheology; carbon nanotubes; conductivity; electromagnetic interference; carbon-based fillers; shielding; stripline
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17020280

The effect of carbon-based additives on adhesives and potting compounds with regard to electrical conductivity and electromagnetic interference (EMI) shielding properties is of great interest. The increasing power of wireless systems and the ever-higher frequency bands place new demands on shielding technology. This publication gives an overview of the effect of carbon-based fillers on electrical conductivity, electromagnetic shielding properties, and the influence of different fillers and filler amounts on rheological behavior. This work focuses on carbon black (CB), recycled carbon fibers (rCF), carbon nanotubes (CNTs), and complex nanomaterials. Therefore, silicon samples with different fillers and filler amounts were prepared using a dual asymmetric centrifuge and a three-roll mill. It has been found that even with small filler amounts, the electromagnetic shielding properties were drastically raised. The filler content as well as the dispersion technique have a significant influence on most of the fillers. It has also been found that the complex viscosity is strongly influenced by the dispersion technique as well as by the choice and amount of filler. In the experiments carried out, shielding values of over 20 dB were achieved with several fillers, whereby even 43 dB were reached with complex, pre-crosslinked fillers. This signal reduction of up to 99.99% enables almost complete shielding of the related frequency.