Interaction between microfibrillar cellulose fines and fibers: influence on pulp qualities and paper sheet properties

Abstract

Due to the high potential of cellulose nanoparticles in composite materials and for both fundamental and technological considerations, we investigated the interaction between microfibrillar cellulose and fibers. The contribution to the paper properties of fines added to a pulp suspension was determined. The impact of various proportions of fines added to a softwood kraft pulp on the paper strength and how they affected porosity and density was evaluated. The respective effects of dried fines (dead fines), originating from paper or board degradation, and the newly formed secondary fines (fresh fines) generated during refining were examined. The nature of the bonding between the fines and the fibers versus physical retention was characterized in the pulp suspension. For the first time the respective parts in the interaction of hydrogen bonds and mechanical associations were demonstrated and quantified. The amount of H-bonded fresh fines exceeded that of dead fines by more than 30 %. The results revealed that, for both types, the amount of H-bonded fines reached a threshold, independently of the proportion of fines added to the fibers. Addition of fines significantly affected the porosity of papers, fresh fines decreasing porosity more readily than dead fines. All the results are convergent to indicate that fresh fines penetrate more evenly and more deeply into the fiber network and induce better bonding that produces a closure of the fiber mat structure. They also demonstrate that incorporating an optimal proportion of fresh cellulose fines in fiber networks can bring significant improvement to the final composite material.

Utilization of Cellulose Nanofibrils as a Binder for Particleboard Manufacture

“…If wood particles are present in the system, the CNF particles can encompass particles mixed with them and hold them together upon water removal. Considering the exceptionally high mechanical properties of cellulose nanoparticles (Reising et al 2013) and excellent hydrogen bonding between cellulose nanoparticles and other types of cellulosic materials (Joseleau et al 2012), cellulose nanofibrils can bond wood particles to form a strongly bonded composite system. Figure 12a depicts a wet mat formed by mixing CNF suspension and wood particles.…”

Prospects for Maintaining Strength of Paper and Paperboard Products While Using Less Forest Resources: A Review

“…To make matters yet more challenging, if a relatively high level of refining has been applied during the initial cycle of papermaking, then one can expect there to be less possibility to restore bonding within the pulp during subsequent cycles of papermaking (McKee 1971). Cellulosic fines obtained from recovered paper are sometimes considered "dead fines" due to their reduced contribution to inter-fiber bonding Scallan 1993, 1995;Joseleau et al 2012). Some authors have even suggested removing some fines and discarding them as a solution to this dilemma (Cardwell and Alexander 1977;Doshi 1998).…”

“…Related work was reported more recently by Joseleau et al (2012), who compared the effects of once-dried cellulosic fines (i.e. "dead fines") in comparison to what they called microfibrillar cellulose, freshly created by refining.…”

“…In addition, the recent advances in technologies related to nanocellulose, as mentioned earlier in this article Ramires and Dufresne 2011;Chauhan and Chakrabarti 2012), can contribute either together with or as an alternative to the use of freshly-prepared cellulosic fines. Promising results, in term of dry strength, have been reported, especially when adding microfibrillated cellulose -a class of nanocellulose that retains high flexibility due to its content of amorphous cellulose (Ahola et al 2008;Eriksen et al 2008;Guimond et al 2010;Joseleau et al 2012;González et al 2012).…”

Effect of Cationic Hemicellulosic Fractions from Corncob Obtained by Graded Ethanol Precipitation on Recycled Paper Strength

“…It should be noted that among all the derivatized hemicellulosic fractions tested that CH30% addition slightly enhanced the tear strength of the handsheets made in the absence and presence of fines. Obviously, the addition of small amounts of paper machine white water fines can improve the mechanical strength of handsheets, which might be attributed to fines enhancing the interaction among the pulp fibers (Bäckström et al 2008;Joseleau et al 2012;Chen et al 2013). Although the addition of these cationic hemicellulosic fractions can improve some of the physical strength properties of the handsheets, the inclusion of fines had a negative influence on the amount of strength developed.…”