Nanofibrillated cellulose applied as reinforcement for short-fiber paper

In this work we studied the influence on the mechanical and physical properties of paper made from short-fiber pulp by adding different percentages of nanofibrillated cellulose. Bleached Eucalyptus sp. Kraft pulp was submitted to three different grinding regimes to obtain the nanofibrillated cellulose of 2, 10 and 20 passes through the grinder. Paper was produced by incorporating nanofibrillated cellulose in the proportions of 3, 6 and 9 wt%. The results showed that the addition of nanofibrillated cellulose increased the following mechanical properties: tensile index, tear index, and burst index. The porosity and the apparent density decreased. The addition of 9% of nanofibrillated cellulose obtained from 2 grinding passes provided the best results with improvements in tensile, burst and tear resistance of 111, 114 and 70 %, respectively, in comparison to normal paper. The improvement in the mechanical properties of paper is related to the very dense network of hydrogen bonds, resulting in greater surface area obtained after defibrillation. Nanofibrillated cellulose can be applied to improve paper quality and for reinforcing composites.