Effects of cellulosic nanofibrils on papermaking properties of fine papers

Cellulosic nanofibrils (CNF) were produced in a disk refiner, to various fines contents. This material was used as an additive to papermaking furnish at laboratory and pilot scales. Handsheets showed improved strength and surface properties with the addition of CNF. Properties also tended to improve with increasing fines content of CNF. Desired strength properties were achieved using CNF at different fines contents by adjusting the loading levels of CNF. On a pilot scale, CNF allowed an increased ash level while maintaining control properties. Strength and surface properties were generally enhanced with use of CNF, although drainage properties were adversely affected. Machine runnability was good, even at higher CNF dosages and slower drainage. CNF in the sheet appears to increase press solids.