Cold plasma‐mediated kapok fiber/epoxy composites for printed circuit board applications

Abstract This study investigates the structural, mechanical, viscoelastic, dielectric and impedance properties of raw and RF plasma‐treated kapok fiber/epoxy composites for printed circuit board (PCB) applications, with a focus on fiber‐matrix interface characteristics. Kapok fiber (KF), known for its lightweight, was used as reinforcement in epoxy‐based polymer composites, and RF plasma treatment on KF was employed to enhance interfacial adhesion and composite performance. The flexural strength ( F s ), tensile strength ( T s ), impact strength ( I s ) and storage modulus ( E ′) of the composites increased by 168%, 121%, 151% and 104% respectively, after plasma treatment on KF. Further, the dielectric and impedance analysis demonstrated the impact of interfacial adhesion in reducing electrical losses and enhancing electrical insulation properties in plasma‐treated KF/epoxy composites, with impedance studies highlighting the role of crystalline and amorphous content in AC conductivity. Also, the water absorption percentage of the composites decreased from 8.1% to 4.0% after plasma treatment on KF. The investigation confirms that 30‐Watt and 30‐min plasma‐treated KF/epoxy composites exhibit superior properties compared to raw KF/epoxy composites due to the plasma treatment on KF, making them viable candidates for lightweight, high‐strength and eco‐friendly PCBs in electronic applications. Highlights Plasm treatment enhanced interfacial, chemical, and mechanical bonding. Glass transition temperature increased by 28°C. Electrical insulation properties of composites enhanced with plasma treatment on KF. The water absorption percentage decreased from 8.1% to 4.0%.