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Understanding extensibility of paper: Role of fiber elongation and fiber bonding, TAPPI Journal March 2020

ABSTRACT: The tensile tests of individual bleached softwood kraft pulp fibers and sheets, as well as the micro-mechanical simulation of the fiber network, suggest that only a part of the elongation potential of individual fibers is utilized in the elongation of the sheet. The stress-strain curves of two actual individual pulp fibers and one mimicked classic stress-strain behavior of fiber were applied to a micromechanical simulation of random fiber networks. Both the experimental results and the micromechanical simulations indicated that fiber bonding has an important role not only in determining the strength but also the elongation of fiber networks. Additionally, the results indicate that the shape of the stress-strain curve of individual pulp fibers may have a significant influence on the shape of the stress-strain curve of a paper sheet. A large increase in elongation and strength of paper can be reached only by strengthening fiber-fiber bonding, as demonstrated by the experimental handsheets containing starch and cellulose microfibrils and by the micromechanical simulations. The key conclusion related to this investigation was that simulated uniform inter-fiber bond strength does not influence the shape of the stress-strain curve of the fiber network until the bonds fail, whereas the number of bonds has an influence on the activation of the fiber network and on the shape of the whole stress-strain curve.

Effects of different soda loss measurement techniques on brownstock quality, TAPPI Journal July 2024

ABSTRACT: The efficiency of the kraft recovery plant, bleaching process, and paper machine are affected when black liquor carryover from the brownstock washers is not controlled well. Measuring soda loss within a mill can vary from using conductivity, either in-situ or with a lab sample of black liquor filtrate squeezed from the last stage washer, to measuring absolute sodium content with a lab sodium specific ion probe or spectrophotometer. While measuring conductivity has value in tracking trends in black liquor losses, it is not an acceptable method in reporting losses in absolute units, typically in lb/ton of pulp. This is further complicated when trying to benchmark soda loss performance across a fleet of mills with multiple washer lines. Not only do the testing methods vary, but the amount of bound soda on high kappa pulps can be significant. This variability creates inconsistent results, and studies are needed to understand the effect of different testing methods on the pulp quality. In this study, soda loss is expressed as sodium sulfate (Na2SO4). Four different methods to measure soda content in pulp off commercial brownstock washers were studied: full digestion (FD), washing soaking overnight and washing (WSW), soaking in boiling water and stirring 10-min (SW-10), and squeeze-no wash (Sq). Total, washable, and bound sodium sulfate calculations were determined for each soda content measuring technique using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Results showed bound and washable sodium sulfate amounts significantly depend on which soda measurement technique was used. In addition, the soda results were correlated with the pulp kappa numbers. As the kappa number increases, bound soda increases, regardless of the soda measurement method used. Impacts of high sodium sulfate in brownstock are also discussed.

A Novel One Step Method to Prepare Carboxycellulose Nanofibe

A Novel One Step Method to Prepare Carboxycellulose Nanofibers from Raw Biomass and their Applications to Remediation for Heavy Metal Ions. 2017PEERS

Developing LignoBoost for the end user lignin quality requir

Developing LignoBoost for the end user lignin quality requirements, 2017PEERS

Kinetics of Deacetylation of Northeast Hardwood, 2017PEERS

Kinetics of Deacetylation of Northeast Hardwood, 2017PEERS

Using online bubble size and total dissolved solids (TDS) me

Using online bubble size and total dissolved solids (TDS) measurements to investigate the performance of oxygen delignification, 2017PEERS

Evaluation of Acid Stage and of Hydrogen Peroxide on Alkalin

Evaluation of Acid Stage and of Hydrogen Peroxide on Alkaline Extraction of Eucalyptus Kraft Pulp, 2017PEERS

Decreased Water Usage in a Softwood ECF Bleaching Sequence •

Decreased Water Usage in a Softwood ECF Bleaching Sequence • Full Mill Simulations, 2017PEERS

Woodchipper Process Optimization, TAPPICon26

Optimizing Refining Energy and Freeness: An AI-Driven Approach to Efficient Papermaking, Advanced Coating Symposium (TAPPICon26)