Microwave‐Irradiated Luffa Fiber‐Reinforced Epoxy Composites for Electrical Insulation Applications

ABSTRACT Luffa fiber (LF), a lignocellulosic plant fiber, has recently garnered global attention in composite materials due to its eco‐friendly characteristics, including biodegradability, renewability, low density, and low energy consumption during processing. The present study aims to develop LF‐reinforced epoxy composites with enhanced fiber‐matrix interfacial bonding through an effective fiber pretreatment strategy. The pretreatment involved a dewaxing process followed by microwave irradiation of LF at exposure times ranging from 5 to 20 min (at 5‐min intervals) under a constant power of 480 W. Fourier transform infrared spectroscopy analysis confirmed chemical modifications in the functional groups of LF after treatment, indicating improved interfacial bonding potential. Subsequently, the pretreated LF‐reinforced epoxy composites were fabricated, and their electromechanical properties were systematically evaluated. The results demonstrated that the flexural, tensile, and impact strengths increased by 50.1%, 105.7%, and 39.5%, respectively, compared to untreated composites. Furthermore, the proposed composite exhibited a minimum dielectric constant of 17 at 100 Hz frequency and ambient temperature conditions, which falls within the acceptable range for electrical insulation, highlighting its potential for use in electrical and electronic applications.