Kinetics of Cross-Linking Softwood Kraft Pulp with 1,2,3,4-Butanetetracarboxylic Acid

Cross-linked fluff pulp fibers for use in, for example, acquisition layers in absorption products can be found in the patent literature. Cross-linking improves properties such as the wet resilience of fluff pulp fiber networks. Among the more commonly seen cross-linkers are polycarboxylic acids, such as 1,2,3,4-butanetetracarboxylic acid (BTCA). These acids form ester bonds with the hydroxyl groups in the fiber wall. In this study, softwood kraft pulp fibers were cross-linked with BTCA. The swelling behavior of the fibers and properties related to acquisition in absorption products were studied. It was found that the water retention value (WRV) decreased as a consequence of the introduced cross-linker. After deprotonization of a large part of the introduced carboxylic acids, the WRV increased, but the cross-linker was still able to limit significant swelling of the fiber wall. The wet bulk under load of fiber networks, composed of cross-linked fibers, generally increased with a decrease in WRV. Furthermore, it was found that the property development obtained after a cross-linking reaction with BTCA may be predicted by introducing a relative reaction intensity, RIrel, that takes into account both time and temperature in the curing step. This shows that the time and temperature in the curing step are interchangeable.

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Modeling of alkaline extraction chemistry and kinetics of softwood kraft pulp

Holzforschung ◽

10.1515/hf-2013-0225 ◽

2014 ◽

Vol 68 (7) ◽

pp. 733-746 ◽

Cited By ~ 1

Author(s):

Susanna Kuitunen ◽

Ville Tarvo ◽

Tiina Liitiä ◽

Stella Rovio ◽

Tapani Vuorinen ◽

...

Keyword(s):

Chlorine Dioxide ◽

Kraft Pulp ◽

Oxygen Demand ◽

Alkaline Extraction ◽

Fiber Wall ◽

Transfer Equations ◽

Softwood Kraft Pulp ◽

Engineering Parameters ◽

Liquid Mass Transfer ◽

Kinetics Of

Abstract A comprehensive model for alkaline extraction (E) of chlorine dioxide delignified (D0) softwood kraft pulp (KP) is presented. The dynamics of the process is modeled by taking into account both irreversible and reversible chemical reactions and gas-liquid and liquid-liquid mass transfer. Equations linking molecular-scale composition (amounts of monomeric lignin and carbohydrate structures) and general engineering parameters [κ number (KN), brightness, intrinsic viscosity, total organic carbon (TOC), chemical oxygen demand (COD), etc.] are presented. The model is capable of reproducing the development of KN and brightness from the molecular-level kinetics. Reactions responsible for the darkening of chlorine dioxide bleached (D0) pulp in alkali, brightening of pulp due to the action of hydrogen peroxide and oxygen, and reduction in KN were identified. The model predicts the chemical composition of both fiber wall and filtrate. This feature enables studies concerning the interaction of the AE chemistry with upstream (D0 washing) and downstream (D1 stage) processes. Quantitative physicochemical modeling approach also points out shortcoming in the present knowledge.

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Optimization of elemental chlorine-free bleaching for a softwood kraft pulp • part 2: economic analysis of chemical and steam consumption

TAPPI Journal ◽

10.32964/tj9.9.47 ◽

2010 ◽

Vol 9 (9) ◽

pp. 47-53 ◽

Cited By ~ 2

Author(s):

BRIAN N. BROGDON

Keyword(s):

Chlorine Dioxide ◽

Previous Investigation ◽

Kraft Pulp ◽

Energy Costs ◽

Alkaline Extraction ◽

Stage Versus ◽

Kraft Pulps ◽

Steam Consumption ◽

Elemental Chlorine ◽

Softwood Kraft Pulp

Our previous investigation [1] re-analyzed the data from Basta and co-workers (1992 TAPPI Pulping Conference) to demonstrate how oxidative alkaline extraction can be augmented and how these changes affect chlorine dioxide consumption with elemental chlorine-free (ECF) sequences. The current study manipulates extraction delignification variables to curtail bleaching costs with a conventional U.S. Southern softwood kraft pulp. The economic advantages of ~0.35% to 0.65% H2O2 peroxide reinforcement in a 70°C (EOP)-stage versus 90°C (EO)-stage are predisposed to the brightness targets, to short or long bleach sequences, and to mill energy costs. Minimized bleaching costs are generally realized when a 90°C (EO) is employed in D0(EO)D1 bleaching, whereas a 70°C (EOP) is economically advantageous for D0(EOP)D1E2D2 bleaching. The findings we disclose here help to clarify previous ECF optimization studies of conventional softwood kraft pulps.

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An effective method for determining the retention and distribution of cellulose nanofibrils in paper handsheets by dye labeling

TAPPI Journal ◽

10.32964/tj17.03.157 ◽

2018 ◽

Vol 17 (03) ◽

pp. 157-164 ◽

Cited By ~ 3

Author(s):

Shengdan Wang ◽

Wenhua Gao ◽

Kefu Chen ◽

Jinsong Zeng ◽

Jun Xu ◽

...

Keyword(s):

Correlation Coefficient ◽

Congo Red ◽

Kraft Pulp ◽

Cellulose Nanofibrils ◽

Standard Curve ◽

Congo Red Dye ◽

Mechanical Disintegration ◽

Softwood Kraft Pulp ◽

White Water ◽

Red Dye

Cellulose nanofibrils (CNF) were prepared by cellulase in conjunction with mechanical disintegration from the bleached softwood kraft pulp and labelled by Congo red dye. The labelled CNF were used to investigate the retention and distribution of CNF in paper handsheets. The retention of the labelled CNF was obtained by measuring the absorbance of white water using an ultraviolet-visible spectrophotometer. The results showed that this method for measuring the retention was rapid, feasible, and sensitive, owing to the high correlation coefficient R2 (0.9993) of the standard curve. The labelled CNF showed even distribution in paper handsheets. The colorimetric values of paper handsheets were explored with a residual ink analyzer.

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