Microwave-Induced Surface Activation of Aramid Waste for Additively Manufactured Composite Architectures of PETG

Abstract

Recycling of para-aramid fiber waste remains a formidable challenge owing to its exceptional crystallinity and chemical inertness. In this study, a rapid and energy-efficient microwave-assisted acid activation route was developed to functionalize waste Kevlar fibers, imparting nanoscale surface roughness and introducing polar hydroxyl and carboxyl groups that significantly enhance fiber–matrix interfacial coupling. The modified fibers were incorporated into polyethylene terephthalate glycol (PETG) composites fabricated through a hybrid additive manufacturing route integrating Direct Ink Writing (DIW) and Fused Deposition Modeling (FDM). Comprehensive surface analyses confirmed improved wettability and chemical reactivity, while mechanical evaluations demonstrated pronounced enhancement in tensile strength, interlaminar shear resistance, fracture toughness, and cyclic fatigue endurance. The process operates under short irradiation cycles and moderate energy input, ensuring industrial scalability and environmental viability. This integrated microwave-assisted modification and hybrid fabrication framework provides a sustainable pathway for valorizing aramid waste into structurally robust, high-performance composites for advanced engineering and defense applications.