Study on the mechanical properties of ramie fiber/polypropylene composites prepared by hot pressing after the carding machine mixing

Abstract A growing variety of composites utilize natural plant fibers with naturally occurring veins structured hierarchically in an effort to reduce dependence on petroleum‐based materials. In this article, ramie fibers were extracted by alkaline delignification. Then, ramie fibers and PP matrix, were prepared in filament form and an amino‐silane coupling agent KH550, and maleic anhydride grafted polypropylene were added to improve interfacial compatibility. Ramie fiber/polypropylene fiber‐reinforced polymer composites (FRC) were prepared by hot pressing after using a carding machine. This method preserves the structure and length of ramie fibers to a large extent, thus greatly improving the mechanical properties of the material. After optimization, the FRC prepared from plant fibers of 2 cm length and 60% content had a density of 0.95 g/cm³, showed an increase in tensile and flexural strength of 276% and 339%, respectively, compared to the pure PP matrix. The specific strength of the FRC in the work was higher than galore FRC prepared from talc, carbon fiber, other plant fibers, and so forth. The FRC has a wide range of potential applications due to its own low‐cost, lightweight, and high‐performance, and is highly feasible in replacing the current polymers in the preparation of numerous everyday items. Highlights The preparation method of FRC resulted in a more complete fiber length and structure. The mechanism to improve the interfacial compatibility of RF and PP is discussed. The effect of varying fiber length on the FRC mechanical properties was investigated.