Evaluation of the drainage and the strength of specialty paper made with cellulose nanofibrils originated from cotton fibers

Abstract

In this study, we investigated the effect of cellulose nanofibrils (CNF) made from cotton fibers on the drainage and the strength of specialty papers. The cotton CNFs were made by grinding according to the freeness of the pulp and the micro-grinding pass number. After the cotton CNFs were manufactured, their main properties, including low-shear viscosity, particle size, zeta-potential, and fiber width, were measured. The drainage rate of the cotton CNF slurries and the cotton stock containing the cotton CNFs were determined using a pressure dehydration tester and a dynamic filtration system, respectively. Handsheet samples were prepared with a mixture of cotton stock and cotton CNFs, and the strength properties of the samples were measured. As the freeness decreased and the pass number increased, the viscosity of the CNFs increased and the particle size and fiber width of the CNFs decreased. The drainage rate of the CNF slurries and the cotton stock decreased as a function of the micro-grinding pass number, but no statistically significant difference in the drainage rate of the CNF slurries treated at a freeness value of 132 mLCSF and 78 mLCSF was observed. However, the increased pass number and dosage of the cotton CNFs improved the tensile strength and folding endurance of the handsheets, proportionally. Therefore, the pass number and the dosage of the cotton CNFs should be determined by considering both the paper strength and drainage. ? 2018 Korean Technical Assoc. of the Pulp and Paper Industry. All rights reserved.