Novel Natural Cellulosic Fiber from Lotus Stem: Structure and Performance Characterization

The systematic exploration of the application prospects of lotus stem fibers (LSFs) in natural composites is significantly important for the development of green, lightweight, functional biomass materials and products. In this study, the physical and chemical properties, micro/nano structures, micromechanical characteristics, cellulose crystallinity, and thermal stability of LSFs were systematically explored. The density, microstructure, and nanoindentation analyses revealed that the LSF is a lightweight natural fiber with a high modulus (11.2–11.7 GPa) and a good hardness (0.41–0.57 GPa). The transmission electron microscopy analysis indicated the existence of four types of sclerenchyma cells in a gradient distribution in the epidermis and exodermis of the LS. The chemical analysis, X-ray diffraction, and Fourier transform infrared spectroscopy indicated that the outer-layer LSFs have a high cellulose content (44.73%), high relative crystallinity index (49.2%) of cellulose, and small cellulose crystallite size (2.2 nm). As a result, these LSFs possess good mechanical properties.