Advancing windmill palm fibers for high-performance composites

In the pursuit of sustainable materials, researchers at Donghua University have turned to windmill palm fibers, an abundant and renewable resource. The team's findings, published in the Journal of Bioresources and Bioproducts, detail a method to refine these fibers through various chemical treatments, significantly improving their mechanical properties.

The researchers began with raw windmill palm fibers (RWPF) and applied three different delignification treatments: sodium chlorite, sodium sulfite, and hydrogen peroxide. These treatments were chosen for their ability to remove lignin, a complex organic polymer that provides rigidity to plant cell walls but can hinder the mechanical performance of fibers.

The sodium chlorite treated fiber (WPFCN) exhibited the highest crystallinity index of 61.3%, indicating a more ordered and potentially stronger material. Meanwhile, the sodium sulfite treated fiber (WPFNN) demonstrated the highest tensile strength of 227.34 ± 52.27 MPa, showcasing its potential in applications requiring high toughness.

The hydrogen peroxide treatment, while effective at removing most of the lignin and hemicellulose, increased the cellulose content to 68.83% ± 0.65%, but resulted in a decrease in thermal properties of the fibers. This trade-off highlights the need for a balance between material properties for specific applications.

The study also scrutinized the fatigue resistance of the fibers, a critical factor for materials expected to endure cyclic loading. The windmill palm fibers showed promising results, with minimal plastic deformation accumulation over cycles.

The research was funded by the special fund support for basic scientific research business expenses of central universities, the basalt fiber and composite key laboratory of Sichuan province, and the Opening Project of National Engineering Laboratory for Modern Silk, Soochow University.