Production and comparative characterization of (ligno)cellulose micro/nanofibers and micro/nanopapers from date palm...

In this study, lignocellulose and cellulose microfibers (LCMFs and CMFs) and nanofibers (LCNFs and CNFs) were produced from three types of date palm wastes: leaflet (L), rachis (R), and empty fruit bunch (E). Subsequently, micropapers (MPs) and nanopapers (NPs) were prepared from the micro/nanofibers. Different date palm wastes (E, R, and L) had significant differences in anatomy, morphology, and chemical composition of fibers compared to each other and other sources of cellulose. Bleaching increased the crystallinity index, while mechanical downsizing reduced it. The highest (9.03 g/cm³) and lowest (5.27 g/cm³) densities were observed in LCNF-E-NP and CMF-L-MP, respectively. CNF-L-NP had the highest burst strength (12.86 kPa·m²/g), and LCNF-R-NP the lowest (4.12 kPa·m²/g). In tear index, LCMF-L-MP showed the highest (7.43 mN·m²/g), and LCNF-L-NP the lowest (4.93 mN·m²/g). Regarding tensile strength, LCNF-E-NP exhibited the highest value (121.66 MPa), while LCMF-L-MP showed the lowest (33.39 MPa). This study demonstrated that date palm wastes, particularly empty fruit bunches, were promising renewable resources for the sustainable production of high-performance bio-based micro/nanofibers. The type of waste significantly affected the mechanical, physical, and functional properties of the resulting fibers and papers. Micro/nanopapers derived from empty fruit bunches exhibited the highest technical performance.