Lignocellulose nanofibrils (LCNFs) are nano-objects produced in aqueous suspension by industrially adaptable methods, with a high yield, low production cost and the potential to replace or complement delignified cellulose nanofibrils in their current applications. To this end, it is necessary to understand how their constituents affect the production and characteristics of the final product. This review explores the most recent results on the effect of the residual amount of lignin and hemicelluloses on the properties of LCNF suspensions. In the current literature, there is a consensus on hemicelluloses, a larger amount of which favors the mechanical fibrillation process, with mannans providing the greatest benefits. Meanwhile, there is no consensus on the effect of residual lignin on mechanical fibrillation, since it can act as an antioxidant, which promotes fibrillation, or as a cementing agent, which hinders fibrillation and, therefore, the production of LCNFs.

This article presents new research on producing lignin nanoparticles (LNPs) using the antisolvent nanoprecipitation method. Acetone (90%) served as the lignin solvent and water (100%) as the antisolvent, using five types of lignins from various sources. Comprehensive characterization techniques, including NMR, GPC, FTIR, TEM, and DLS, were employed to assess both lignin and LNP properties. The antioxidant activity of the LNPs was evaluated as well. The results demonstrated the successful formation of spherical nanoparticles below 100 nm with initial lignin concentrations of 1 and 2%^w/_v. The study highlighted the crucial role of lignin purity in LNP formation and colloidal stability, noting that residual carbohydrates adversely affect efficiency. This method offers a straightforward, environmentally friendly approach using cost-effective solvents, applicable to diverse lignin sources. The innovation of this study lies in its demonstration of a cost-effective and eco-friendly method to produce stable, nanometric-sized spherical LNPs. These LNPs have significant potential as reinforcement materials due to their reinforcing capability, hydrophilicity, and UV absorption. This work underscores the importance of starting material purity for optimizing the process and achieving the desired nanometric dimensions, marking a pioneering advancement in lignin-based nanomaterials.