IIT Mandi Researchers Developed Eco-Friendly Electromagnetic Interference Shielding Solution

Researchers have developed an eco-friendly composite blend of kenaf fibre and HDPE, with added carbon nanotubes, exhibiting superior EMI shielding properties, in addition to being recyclable.

(L to R) Dr. Sunny Zafar, Mr. Aditya Pratap Singh, and Dr. Himanshu Pathak, at IIT Mandi.

Mandi: The Indian Institute of Technology Mandi researchers have produced biodegradable natural fibre-containing composites tailored for various applications, particularly in Electromagnetic Interference (EMI) shielding. Composite materials, blending two or more substances, have been utilized since ancient times. Clay and straw, among other materials, were historically combined to create composite bricks for construction. Today, natural fibre-reinforced composites, such as Jute and Hemp, are making a comeback due to environmental concerns, finding diverse applications in different sectors.

One area where composites are increasingly used is Electromagnetic Interference (EMI) shielding. The proliferation of electronic devices in recent years has led to a new form of pollution known as Electromagnetic Interference. Such interferences can affect the functions of electronic systems across industries such as radar systems, military controls, and networking infrastructure. EMI shielding materials are essential to protect electronic devices and systems from EMI interference.

A team of researchers from IIT Mandi and VTTT Finland, led by Dr. Himanshu Pathak, Associate Professor, and Dr. Sunny Zafar, Associate Professor of the School of Mechanical and Materials Engineering, alongside their research scholar, Mr. Aditya Pratap Singh at IIT Mandi, and Dr. Siddharth Suman, Research Scientist at VTT Technical Research Centre of Finland, have initiated a mission to develop a composite material. This material aims to provide robust EMI shielding while adhering to eco-friendly principles.

The team has developed a distinctive mixture comprising kenaf fiber (known as Deccan Hemp/Ambari in local languages) and High-Density Polyethylene (HDPE). Kenaf, recognized for its strength and low density as a natural fiber, acts as an optimal reinforcement material, augmenting the mechanical properties of the composite while diminishing its environmental impact. Additionally, HDPE, a commonly utilized recyclable plastic, adds to the composite's eco-friendly characteristics.

For EMI shielding, the composite must be an electrical conductor. The researchers incorporated carbon nanotubes (CNTs) to confer electrical conductivity to their composite. A blend of 16% kenaf fibre and 5% CNTs was found to exhibit superior EMI shielding, surpassing 30 dB, and exceptional mechanical strength.

Speaking about the developed composite, Dr. Himanshu Pathak, Associate Professor, School of Mechanical and Materials Engineering, IIT Mandi, said, "Cultivating a sustainable future demands innovation that enhances performance while minimizing environmental impact. Our work in developing eco-friendly EMI shielding materials combines technological advancement with ecological responsibility."

In the past, EMI shielding relied on metals but suffered from drawbacks such as limited flexibility, high weight, and susceptibility to corrosion. In recent decades, researchers have shifted focus to plastic-composite materials due to their inherent flexibility, lightweight nature, ease of processing, chemical resistance, and scalability to address these shortcomings in metal-based shielding materials.

The application potential of this innovative composite material is vast, spanning from electronic equipment casing to overhead bins and unmanned aerial vehicles (UAVs).

Speaking about the applications of the developed composite, Dr. Sunny Zafar, Associate Professor, School of Mechanical and Materials Engineering, IIT Mandi, said, “The developed composite holds immense promise for real-world applications, ranging from electronic equipment casing to overhead bins and unmanned aerial vehicles (UAVs). The composite’s versatility and sustainability make it an asset in addressing contemporary challenges while promoting environmental responsibility.”