Synergistic Enhancement of Electrical, Thermal, and Mechanical Properties in Lossy Dielectric Polymer Composites for High‐Frequency EMI Shielding Applications

ABSTRACT With wireless communication, electronic downsizing, and ubiquitous connectivity, Electromagnetic Interference (EMI) presents an ever‐growing threat in our environment. Flexible polymers have emerged as a promising alternative for metals in EMI shielding applications because of their lightweight and inherent flexibility. Natural rubber (NR) is a highly versatile material that can play a significant role in green engineering and sustainable practices. Its electromagnetic shielding capability is limited because of poor intrinsic electrical conductivity. To improve electrical conductivity, acetylene black (AB) is used to reinforce NR, and its cure characteristics, mechanical, thermal, dielectric, and EMI shielding properties were evaluated. Stress–strain analysis reveals that corresponding to 20 phr of AB, tensile strength is improved from 22.10 to 27.96 MPa by 26.5%. Transmission Electron Microscopy (TEM) reveals that AB 20 composites exhibit uniform dispersion of filler particles. Thermogravimetric analysis (TGA) reveals that the incorporation of AB can improve onset degradation temperature by 6°C for AB 30 composites. Kinetics involved in TGA have been analyzed through Kissinger–Akahira–Sunose (KAS) modeling, and activation energy required for degradation has been evaluated. An increase in AB content led to improved AC conductivity, dielectric constant, and EMI shielding. A shielding efficiency of 20 dB was reported, corresponding to AB 30 composites, which can attenuate almost 99% of electromagnetic waves. With an affordable filler in a biodegradable matrix and streamlined, sustainable techniques, this study creates a new paradigm for developing materials with improved mechanical strength, dielectric properties, and EMI‐shielding capabilities.