Exploring natural palm fiber's mechanical performance using multi-scale fractal structure simulation

Abstract

Palm fiber, a type of natural multicellular fiber, exhibits distinct mechanical properties, such as excellent elasticity, higher fracture energy, and desirable stretch ability. To reveal the structure-property relationship, a multi-scale layered fractal theoretical model was introduced to investigate the tensile behavior of palm fibers at different scales. A three-circle model was established and used to simulate the hierarchical organization of palm fibers. The palm fibers consisted of cellulose molecular chains, fibril filaments, microfibrils, and cells. Moreover, the characteristics of stress, fracture energy, and Young's modulus on different scales were calculated and verified by tensile testing and atomic force microscopy (AFM). The results revealed that the fractal model effectively decoupled the contributions of different scales to the tensile properties. In particular, the microfibril mainly influenced the stiffness, whereas the cell determined the toughness of palm fibers. The findings of the current study can be utilized to improve the design and preparation of fiber-based nanomaterials.