Effect of 9,9′-Bis(aryl)fluorene-modified nanocellulose, bamboo, and bagasse fibers on mechanical properties of various polymer composites

Impact-resistant automotive components were studied by evaluating the effects of single-screw and twin-screw extrusion on the mechanical properties of composites made from fluorene-modified nanocellulose (FCF) or bamboo fibers (30 wt%) combined with various polymers. Natural fiber composites were injection molded, and their mechanical properties were evaluated. Results showed that fluorene-modified nanocellulose exhibited improved dispersion when kneaded with polycarbonate and polyamide 6 using twin-screw extrusion, resulting in increases of over 5000 MPa in flexural modulus and over 40 MPa in maximum flexural stress compared to the base polymer. However, composites made with polyamide 66 and bamboo fibers required high injection molding temperatures exceeding 260 °C, which led to thermal degradation and reduced the fiber reinforcement effect on mechanical properties. The polypropylene showed weak interfacial compatibility with bamboo fibers, resulting in limited reinforcement effects in both single and twin-screw extrusion. The brittleness of the fibers did not significantly influence the elongation of the PP composite. Nonetheless, it exhibited less reduction in elongation compared to composites where bamboo or FCF was added to other polymers. Building on these results, flexural tests were conducted on composites combining high-impact polypropylene with natural fibers, demonstrating the potential for high-impact-resistant composite materials suitable for automotive applications.