Enhancing the inter-fiber bonding properties of cellulosic fibers by increasing different fiber charges

A novel approach to determining the contribution of the fiber and fines fraction to the water retention value (WRV) of chemical and mechanical pulps

“…The swelling behavior influenced by the pulping process and yield (Andreasson et al 2003;Forsstrom et al 2005;Stone and Scallan 1967), by drying and rewetting (Stone et al 1968;Wang 2006) and by refining (Bäckström and Haimnar 2010;Laivins and Scallan 1996) have been documented. Further, swelling is influenced by enzymatic treatment (Gil et al 2009;Stock et al 1995), by chemical modification (Chen et al 2013;Racz and Borsa 1997;Scallan 1983;Zhao et al 2016) or by addition of cationic polymers (Aarne et al 2012;Strom and Kunnas 1991). Swelling depends to a certain extent, also, on charge density.…”

Estimating the Inter-fiber Bonding Capacities of High-yield Pulp (HYP) Fibers by Analyzing the Fiber Surface Lignin and Surface Charge

“…The characterization of fiber charge was obtained following the method of Zhao et al (2016), which is depending on the poly-DADMAC accessibility to cellulose fibers. The determination of the fiber charge has four steps: 1) protonated form of the fibers (or removing the metal ions in the fibers) was prepared by soaking the fibers with overdosed 0.01 M HCL, then the fibers were filtered by using Büchner funnel and washed several times with deionized water until the conductivity of filtrate was below 5 μS/cm; 2) sodium form of the fibers was prepared by soaking the fibers in 10 -3 M NaHCO3 solution, then the fibers were filtered and washed as same as step 1; 3) the fibers in its sodium form were dispersed in two kinds of excess 10 -3 N poly-DADMAC solutions respectively (the poly-DADMAC with Mw of 11 kDa and charge density of 6.05 meq/g was used for the determination of total charge, while the poly-DADMAC with Mw of 260 kDa and charge density of 6.10 meq/g was used for the determination of fiber surface charge); 4) the fibers were filtered and the filtrate was titrated in a MÜTEK particle charge detector (PCD-03, Germany) and 10 -3 N PVSK solution was used for the polyelectrolyte titration.…”

“…The blank values were determined by titrating the same volume of 10 -3 N poly-DADMAC solutions; 5) the total and surface charge of the fibers was calculated following the Eq. 1 (Zhao et al 2016),…”

“…Compared with bleached chemical pulps, HYPs have a high bulk, opacity, and light scattering coefficient, but their main drawback is their weak inter-fiber bonding strength, which limits the application of HYPs in value-added products (Li et al 2014(Li et al , 2015. In the past decade, a kind of HYPs, P-RC APMP has achieved widespread application in many paper and paper-based products in worldwide, especially in China (Li et al 2014;Zhao et al 2016).…”

“…), chemical content (i.e., the ratio of cellulose, hemicellulose, lignin, and extractives), and the fiber charge (Zhao et al 2016). Fiber morphology is the basic characteristic of lignocellulosic fibers.…”