Exploring the development and applications of sustainable natural fiber composites: A review from a nanoscale perspective

As a result of global sustainable development, natural fiber composites (NFCs) have become increasingly attractive due to their remarkable performance, novel functionality, and eco-friendliness. Natural fibers are biodegradable, affordable, and low-density, which makes them potential materials for use in developing alternatives to traditional petroleum-based synthetic fiber composites. However, challenges such as inadequate compatibility between natural fibers and matrix limit the further development of NFCs. Studies have shown that molecular dynamics (MD) simulations can offer valuable insights into the fundamental properties and deformation mechanisms governing the macroscopic performances of NFCs, including mechanical properties, thermal stability, and interfacial interactions. Based on the underlying understanding of the nanostructure of natural fibers, these fibers can be modified at nanoscale to improve the performance of NFCs. This paper first reviews the hierarchical structures of natural fibers, mainly wood and bamboo fibers, highlighting their relationship with mechanical and thermal properties. Treatments to improve natural fiber-matrix compatibilities are then presented. The fundamental factors behind the functionalized properties of modified NFCs are emphasized from the nanoscale. Additionally, applications of NFCs as structural and functional materials in the construction, automotive, and aerospace industries are reviewed. Finally, this paper identifies the growing use of machine learning-assisted MD simulation techniques to facilitate the design of NFCs. Literature and data sources for this study were obtained through a combination of online academic databases, citation chaining, government databases, and industry reports.