Search
Use the search bar or filters below to find any TAPPI product or publication.
Filters
Publications
Level of Knowledge
Collections
Journal articles
Magazine articles
Probing the molecular weights of sweetgum and pine kraft lignin fractions, TAPPI Journal June 2021
ABSTRACT: The present investigation undertook a systematic investigation of the molecular weight (MW) of kraft lignins throughout the pulping process to establish a correlation between MW and lignin recovery at different extents of the kraft pulping process. The evaluation of MW is crucial for lignin characterization and utilization, since it is known to influence the kinetics of lignin reactivity and its resultant physico-chemical properties. Sweetgum and pine lignins precipitated from black liquor at different pHs (9.5 and 2.5) and different extents of kraft pulping (30–150 min) were the subject of this effort. Gel permeation chromatography (GPC) was used to determine the number average molecular weight (Mn), mass average molecular weight (Mw), and polydispersity of the lignin samples. It was shown that the MW of lignins from both feedstocks follow gel degradation theory; that is, at the onset of the kraft pulping process low molecular weight-lignins were obtained, and as pulping progressed, the molecular weight peaked and subsequently decreased. An important finding was that acetobromination was shown to be a more effective derivatization technique for carbohydrates containing lignins than acetylation, the technique typically used for derivatization of lignin.
Journal articles
Magazine articles
Characterization and evaluation of antioxidation of lignin from bamboo powder using a formic acid-catalyzed ethanol organosolv process, TAPPI JOURNAL January 2019
Characterization and evaluation of antioxidation of lignin from bamboo powder using a formic acid-catalyzed ethanol organosolv process, TAPPI JOURNAL January 2019
Journal articles
Magazine articles
Nano-magnesium oxide as hard template synthesis of lignin carbon-based solid acids and its application for cellulose hyrdrolysis, TAPPI JOURNAL January 2019
Nano-magnesium oxide as hard template synthesis of lignin carbon-based solid acids and its application for cellulose hyrdrolysis, TAPPI JOURNAL January 2019
Journal articles
Magazine articles
Slot die coating of nanocellulose on paperboard, TAPPI Journal January 2018
Slot die coating of nanocellulose on paperboard, TAPPI Journal January 2018
Journal articles
Magazine articles
Discrete element method to predict coating failure mechanisms, TAPPI JOURNAL January 2018
Discrete element method to predict coating failure mechanisms, TAPPI JOURNAL January 2018
Journal articles
Magazine articles
Adsorption performance of magnetic aminated lignin for the removal of Cu(II) and Cd(II), TAPPI Journal January 2019
Adsorption performance of magnetic aminated lignin for the removal of Cu(II) and Cd(II), TAPPI Journal January 2019
Journal articles
Magazine articles
Factors affecting particulate removal efficiency of kraft recovery boiler electrostatic precipitators: a technical review, TAPPI JOURNAL May 2018
Factors affecting particulate removal efficiency of kraft recovery boiler electrostatic precipitators: a technical review, TAPPI JOURNAL May 2018
Journal articles
Magazine articles
Dry chip feedrate control using online chip moisture, TAPPI JOURNAL May 2018
Dry chip feedrate control using online chip moisture, TAPPI JOURNAL May 2018
Journal articles
Magazine articles
In-process detection of fiber cutting in low consistency ref
In-process detection of fiber cutting in low consistency refining based on measurement of forces on refiner bars, TAPPI JOURNAL April 2017
Journal articles
Magazine articles
A novel predictive method for filler coflocculation with cellulose microfibrils, TAPPI Journal November 2019
ABSTRACT: Different strategies aimed at reducing the negative impact of fillers on paper strength have been the objective of many studies during the past few decades. Some new strategies have even been patented or commercialized, yet a complete study on the behavior of the filler flocs and their effect on retention, drainage, and formation has not been found in literature. This type of research on fillers is often limited by difficulties in simulating high levels of shear at laboratory scale similar to those at mill scale. To address this challenge, a combination of techniques was used to compare preflocculation (i.e., filler is flocculated before addition to the pulp) with coflocculation strategies (i.e., filler is mixed with a binder and flocculated before addition to the pulp). The effect on filler and fiber flocs size was studied in a pilot flow loop using focal beam reflectance measurement (FBRM) and image analysis. Flocs obtained with cationic polyacrylamide (CPAM) and benonite were shown to have similar shear resistance with both strategies, whereas cationic starch (CS) was clearly more advantageous when coflocculation strategy was used. The effect of flocculation strategy on drainage rate, STFI formation, ash retention, and standard strength properties was measured. Coflocculation of filler with CPAM plus bentonite or CS showed promising results and produced sheets with high strength but had a negative impact on wire dewatering, opening a door for further optimization.