The increasing usage of petroleum-based compounds has prompted numerous environmental concerns. Consequently, there has been a steady rise in research on the synthesis of useful materials from natural sources. Paper technologists are seeking environmentally acceptable dry end and wet end additives. Among the bio-based resources available, nanocellulose is a popular sustainable nanomaterial additive in the paper industry because of its high strength, high oxygen barrier performance, low density, great mechanical properties, and biocompatibility. NC’s extensive hydroxyl groups provide a unique possibility to dramatically modify the hydrophilicity and charge of the surface in order to improve their potential applications in the paper industry. The current paper reviews two series of surface modifications, each with various subcategories, depending on why modified nanocellulose is added in the paper production: to improve barrier properties or to improve mechanical properties of packaging materials. The methods presented in this study use the minimum amount of chemically hazardous solvents to have the least impact on the environment. This review focuses on modifications of nanocellulose and their subsequent application in the papermaking. The knowledge and the discussion presented in this review will form a literature source for future use by various stakeholders and the sustainable paper manufacturers.

The ability of cationized dialdehyde cellulose to improve the mechanical properties of paper was evaluated. The majority of cationized additives are synthesized by introducing cationic groups through chemical reactions. Here, cationized additives were produced in a more environmentally friendly manner by use of non-toxic and readily biodegradable deep eutectic-like solvent mixtures (DESs). The modified cellulose’s properties were characterized by FTIR, polarized-light optical microscopy, charge titrations, and SEM/EDX. The cationized additives were investigated as strength additives for papermaking. Three different amounts of cationic additive (2%, 5%, and 10%) were added to the pulp, and the properties of handsheets were studied. Because increasing the additive content can affect dewatering of the process, the dewatering capabilities of the pulps with additives were evaluated by Schopper-Riegler (°SR) value, water retention value (WRV), and vacuum dewatering. Finally, the recyclability of the DES was assessed in terms of cationization reaction efficiency and their effect on paper mechanical properties.