Abstract Palm trees generate vast amounts of agricultural residue annually, yet only a tiny fraction is used. This work aims at analyzing the use of palm leaflet fibers as potential reinforcement in composite materials. The leaflets fibers are extracted from the date palm (DPLF) and from the Washingtonia palm (WPLF), which are abundant in all regions of Algeria. The morphology of the two types of leaflet fibers was examined by SEM and by FTIR, TGA, DSC, and XRD. Static tensile tests have shown a strong variation of the mechanical response along the length of the types of leaflets. For this reason, leaflets were then separated into distinct top, middle, and bottom parts. The more significant mechanical response was obtained for the top part of the leaflets. Date palm leaflet fibers exhibit 162% higher stress, 44% greater strain, and 81% higher Young’s modulus compared to Washingtonia palm leaflet fibers. Given the substantial variability in the results, multiple statistical methods were applied. The three-parameter Weibull distribution proved to be the best fit for the experimental data.

Abstract Development of all-cellulose composites is a promising approach to fabricate functional textiles. Our research presents a proof of concept to incorporate modified cellulose nanofibrils (CNFs) into a regenerated cellulose textile fibers. In this work, CNFs are modified with a thiol-containing silane coupling agent, available to undergo a “click” reaction with additives possessing a terminal alkene or alkyne. Resulting mercapto-CNF (mCNF) was dissolved in ionic liquid along with the dissolving pulp to attain a controlled concentration of the functional groups. Cellulose-mCNF fibers were spun using Ioncell® technology, resulting in fiber that contains a high percentage of regenerated CNF. During this process, the incorporated silane coupling agents did not withstand the dissolution and were not found in the resultant fiber, likely being discarded with the spin bath.

Abstract In this study, the effects of different raster angles (0°, 45°, 90°, and 0/90/0°) on the mechanical, fracture, and tribological performances of polycarbonate (PC) samples fabricated using fused-filament fabrication were experimentally investigated. The fracture behavior was evaluated using the essential work of fracture (EWF) method, and the results were interpreted along with tensile, dynamic mechanical (DMA), and tribological analyses to provide a comprehensive assessment. The 90° orientation exhibited brittle fracture behavior with a negatively sloped regression line, indicating the limited applicability of the EWF approach under this condition, whereas the 0/90/0° configuration exhibited the highest fracture toughness. Tensile tests revealed that the 0/90/0° specimen had the highest tensile strength, whereas the lowest value was recorded for the 90° orientation. These results highlight the strong influence of filament orientation on the load transfer behavior. The DMA results showed that the storage modulus of the 0/90/0° sample remained more stable across a range of temperatures, indicating improved thermomechanical stability compared to other configurations. In the adhesive wear test, the 0/90/0° orientation exhibited the lowest coefficient of friction (COF) and minimum surface deformation, whereas the 90° orientation exhibited the highest COF and weakest wear resistance with irregular wear patterns. Overall, the findings demonstrate that multidirectional raster configurations, particularly 0/90/0°, provide a more balanced performance across the mechanical, fracture, and tribological properties. Consequently, filament orientation is a critical factor in the performance of PC-based 3D-printed parts and can be considered as a design parameter for optimizing functional performance in engineering applications. Graphic abstract