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

Abstract

Four fiber fractions from poplar alkaline peroxide mechanical pulping, performed with refiner-chemical preconditioning (P-RC APMP), were used to estimate inter-fiber bonding capacity. The relationship between fiber characteristics and inter-fiber bonding capacities was investigated. The surface lignin content of the long fiber fraction was slightly lower than that of the short fiber fraction. Atomic force microscopy (AFM) images showed that the fiber surfaces were heterogeneous (i.e., different cell wall layers were exposed along the fiber surface). The fiber fractions that had lower surface lignin content had higher bonding capacities. Furthermore, modified PFI beating was used to peel the surface of the fibers. After the peeling treatment, the fiber surface charge increased remarkably, while the surface lignin concentration decreased considerably. The lignin and charge on the fiber surface are the two key factors for estimating the interfiber bonding capacities.

Determination of Interfiber Bonded Area Based on the Confocal Laser Scanning Microscopy Technique

“…Then, both the fiber fractions of R30 and P30/R50 were used for the optically bonded area measurements. The total lignin contents (sum of Klason lignin and the acid soluble lignin) are 21.09% and 22.46% for the R30 fraction and the P30/R50 fraction, respectively, while the fiber surface lignin contents of the two fiber fractions determined by the X-ray photoelectron spectroscopy (XPS) technique are 72.43% and 72.19%, respectively . Acridine orange (AO, C 17 H 19 N 3 ·HCl·0.5 ZnCl, the molecular weight of 438.12 g/mol), a fluorescent dye (analytical grade) which can label the lignin in the fibers, , was purchased from Sino Pharm Chemical Reagent Co., Ltd.…”

“…In fact, the optically bonded area between the interfiber bonded model will be the overlapped area excluding (1) the unbonded edging area of the two fibers and (2) noncontacted areas inside the overlapped area. Here, we made an assumption that the optically bonded area in the constructed fiber models can only be in one 2D slide, because the step size of the optical sectioning is 0.8 ± 0.06 μm, which is much higher than the fiber surface roughness (0.02–0.3 μm, the image height of the topography images of the fiber surface obtained by the AFM technique for the R30 and P30/R50 fractions is in the range of 0.02–0.3 μm).…”

Preparation of performance of nanosilica-loaded fluorescent yellowing inhibitor in paper made from high-yield pulp

“…Furthermore, APMP pulping greatly simplifies the traditional pulping process, and can also save a lot of costs, which has a good development prospect. Therefore, HYP is widely used in paper industry to address the shortages of wood resource, alleviate environment deterioration, and reduce production waste (Liu et al 2012;Wang et al 2013;Liu et al 2016;Li et al 2017). However, the unseparated lignin in HYP can easily lead to yellow reversion with ambient light irradiation, and this restricts the application of HYP in high-quality paper (Cannell and Cockram 2000;Rundlöf et al 2002;Manda et al 2012;Vänskä et al 2016).…”