Optimization of percolation limit of carbon black for electromagnetic interference shielding

• Published in: Journal of magnetism and magnetic materials 2023-11, Vol.586, p.171164, Article 171164
• Main Authors: Maryam, Ayesha, Rizwan, Zahid, Nasir, Nadeem, Ahmad, Javeria, Imran khan, Muhammad, Nawab, Yasir, Shehbaz Ahmad, Hafiz
• Format: Article
• Language: English
• Subjects: Carbon Black; EMI Shielding; Percolation limit; Reflection loss; Skin depth
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2023.171164

•The study identifies the critical point, known as the percolation limit, at which the material demonstrates its highest performance. Beyond this loading concentration, the material's properties begin to deteriorate.•The research focuses on calculating the percolation limit of carbon black specifically for its impact on Electromagnetic Interference (EMI) shielding effectiveness.•At the percolation limit of carbon black, a significant breakthrough is observed, with the maximum EMI shielding effectiveness reaching 21 dB, signifying a sudden and substantial increase in shielding performance.•The study goes beyond EMI shielding effectiveness and evaluates a range of material properties, including absorbance, reflectance, transmittance, dielectric conductivity, skin depth, and reflection loss, providing a comprehensive understanding of the material's behaviour. Over the past few decades, the excessive use of electronic paraphernalia has increased the interference of electromagnetic waves, which not only disrupts the functionality of electronic appliances but also enhances environmental pollution. To avoid this destruction, an efficient material is required that can provide shielding from electromagnetic interference. Numerous researchers have made significant efforts to enhance EMI shielding using various types of nanofillers. However, a crucial aspect that has been lacking in these studies is an investigation into the optimal material quantity required for effective activation. Therefore, it becomes imperative to establish the percolation limit of the material, as this knowledge is vital in preventing unnecessary wastage and ensuring efficient utilization. Among polymer nanocomposites, Carbon black is the most demanding material for shielding purposes and is frequently used due to its abundance, superconductivity, and chemical stability. This work aims to identify the percolation limit of carbon black, which indicates the point at which the material becomes activated. To achieve this, different loading concentrations of the material have been tested. The thickness of all the samples was kept the same, at 3 mm. A vector network analyzer is used to analyze the EM shielding effectiveness of the composite material. Moreover, absorbance, reflectance, transmittance, skin depth, AC conductivity, and reflection loss have also been studied within the frequency range of 0.1 GHz to 13.6 GHz.