Effect of the Pretreatment on the Properties of Cellulose Nanofibril Derived from Recycled Pulp

Although wood pulp is the main raw material for the production of cellulose nanofibrils (CNF), seaweed, agricultural waste, and recycled pulp can also be used as raw materials.Despite requiring thorough cleaning, recycled pulp offers a cost-effective alternative for CNF production.This study aims to explore the feasibility of utilizing CNF derived from pretreated recycled pulp by comparing its quality to CNF derived from bleached kraft virgin pulp.The performance of CNF derived from chemically treated recycled pulp was evaluated by fabricating it into a sheet form.The results showed that the reduction of the inorganic content resulted in approximately 40% and 50% increase in light transmittance and dry tensile strength, respectively.In particular, carboxymethylation pretreatment enabled the fabrication of CNF sheets with over 90% light transmittance, while cationization pretreatment allowed for the development of CNF sheets with dry tensile strength exceeding 150 MPa.It was found that the reduction in ash content of recycled pulp is very important to improve the properties of CNF.Consequently, chemical pretreatment can be employed to use recycled pulp as the raw material for CNF.