High-Intensity Ultrasonication (HIU) Effect on Sunn Hemp Fiber-Reinforced Epoxy Composite: A Physicochemical Treatment Toward Fiber

Abstract

The present study aims to disintegrate fibrils from sunn hemp (Crotalaria juncea) cellulosic fiber by using a treatment method where a fusion of chemical as well as physical technique is involved. Before fabricating the composite, sunn hemp fiber was treated with a combination of alkali and high-intensity ultrasonication (HIU) that induces cavitation by means of the shock wave with high pressure and temperature. Sunn hemp fibers were subjected to 5% alkali (NaOH) solution and then were exposed under HIU vibration for 60, 90, and 180 min. The impact of treatment was researched on cellulose crystallinity, morphology, functional groups of fiber, and mechanical properties of their strengthened epoxy composites. Cellulose crystallinity was increased by increasing the exposure time of ultrasonication toward chemical impregnation. Morphology of sunn hemp fiber showed an irregular and hew surface that confirmed the removal of noncellulosic components that were well agreed by the change in functional groups. Mechanical properties of treated and untreated sunn hemp reinforced composite were likewise expanded with expanding introduction time and the best outcome was seen in the mix of 5%NaOH+180-min treated fibers. Therefore induced cavitation by the shock wave generated 194with HIU plays a very essential role in strengthening the mechanical properties of composites.