Ramie fiber and its composites: A review

Abstract

Nowadays, natural fibers are in greater demand as compared to synthetic fibers because of their various benefits, such as affordability, lightweight, biodegradability, and environmental friendliness. Ramie is one such natural fiber that is gaining importance owing to its outstanding mechanical properties. This article examines the literature on ramie fibers as a reinforcing material, with the main emphasis on the recent decade (2013–2023). Various studies on surface treatments to improve the bonding and properties of ramie fiber-reinforced composites (RFRCs) are discussed. The tribological and mechanical properties of several RFRCs are explored. The applications of ramie-based composites in several industrial areas are also highlighted. The findings of this review indicate that a combination of alkali and silane surface treatment greatly improves the mechanical and thermal behavior of RFRCs, whereas treating ramie fibers with ammonium polyphosphate enhances their flame retardant properties. Furthermore, the lack of literature on the characterization of RFRCs with different filler materials, such as rice husk, eggshell powder, waste tire particles, and fishbone powder needs to be studied. The insufficient studies on the tribological behavior of RFRCs, particularly in thermoplastic polymers, highlight research gaps that demand attention from researchers to understand their potential for wear-resistant applications. Highlights: Surface treatments enhance ramie fiber-polymer bonding. Alkali + silane treatment boosts composite rigidity. Ammonium polyphosphate improves flame retardancy. Hybrid ramie/epoxy with synthetic fibers shows strong mechanical properties. Research needed on RFRCs with LDPE, PC, and various filler materials.