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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
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Multiple recycling of paperboard: Paperboard characteristics and maximum number of recycling cycles— Part I: Multiple recycling of corrugated base paper, TAPPI Journal November 2019
ABSTRACT: Paper for recycling is an important fiber source for the production of corrugated base paper. The change in production capacity toward more and more packaging papers affects the composition of paper for recy-cling and influences the paper quality. This research project investigated the influence of the multiple recycling of five different corrugated base papers (kraftliner, neutral sulfite semichemical [NSSC] fluting, corrugating medium, testliner 2, and testliner 3) on suspen-sion and strength properties under laboratory conditions. The corrugated board base papers were repulped in a low consistency pulper and processed into Rapid-Köthen laboratory sheets. The sheets were then recycled up to 15 times in the same process. In each cycle, the suspension and the paper properties were recorded. In particular, the focus was on corrugated board-specific parameters, such as short-span compression test, ring crush test, corrugat-ing medium test, and burst. The study results indicate how multiple recycling under laboratory conditions affects fiber and paper properties.
Journal articles
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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
Where RCM Fits in the Maintenance Program, Paper360º May/June 2018
Where RCM Fits in the Maintenance Program, Paper360º May/June 2018
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Magazine articles
SetPoint: Ladies and Gentlemen, The Year You’ve Been Waiting For, Paper360º January/February 2021
SetPoint: Ladies and Gentlemen, The Year You’ve Been Waiting For, Paper360º January/February 2021
Journal articles
Magazine articles
Quantification of vegetable oil in recycled paper, TAPPI JOURNAL September 2020
ABSTRACT: Vegetable soybean oil is commonly used in cooking foods that are packaged in takeaway paper-board containers. Vegetable oil is hydrophobic, and in sufficiently high concentration, could interfere with interfiber bonding and result in paper strength loss. In order to quantify the effect of oil on the resulting paperboard strength, it is necessary to quantify the oil content in paper. A lab method was evaluated to determine the soybean oil content in paper. Handsheets were made with pulps previously treated with different proportions of vegetable oil. Pyrolysis gas chromatography-mass spectrometry (pyGCMS) was used to quantify the amount of oil left in the handsheets. The results revealed a strong correlation between the amount of oil applied to the initial pulp and the amount of oil left in the handsheets.In addition, the effect of vegetable oils on paper strength may be affected by the cooking process. Vegetable oil is known to degrade over time in the presence of oxygen, light, and temperature. The vegetable oil was put in an oven to imitate the oil lifecycle during a typical pizza cooking process. The cooked oil was then left at room temperature and not protected from air (oxygen) or from normal daylight. The heated, then cooled, oil was stored over a period of 13 weeks. During this time, samples of the aged oil were tested as part of a time-based degradation study of the cooked and cooled oil.
Journal articles
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Celupaper Puts Its Trust in Toscotec, Tissue360º Spring/Summer 2020
Celupaper Puts Its Trust in Toscotec, Tissue360º Spring/Summer 2020
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Recycling performance of softwood and hardwood unbleached kraft pulps for packaging papers, TAPPI Journal February 2023
ABSTRACT: The scope of this work is to evaluate the recyclability potential of hardwood and softwood unbleached kraft pulps, leading to a sound basis for comparison and even to support a decision about fibers accord-ing to the performance achieved. The influence of successive recycling cycles (up to 10 cycles) on the fiber morphol-ogy, pulp suspension drainability, water retention capacity, and handsheet mechanical properties were studied for Eucalyptus globulus and Pinus sylvestris unbleached kraft pulps. The performance of these pulps as linerboard and corrugating medium for packaging was also evaluated. The requirements for brown kraftliner and for high perfor-mance recycled fluting grades is preserved for E. globulus pulp during all 10 recycling cycles, evidenced by the mod-erate decrease of burst index and crush resistance index and by the short-span compression index, whereas the P. sylvestris pulp loses this rating after the second cycle. These results strongly support the higher performance of E. globulus pulp for recycling as compared with softwood kraft pulp from the perspective of packaging papers.
Journal articles
Magazine articles
Chemical addition to wet webs using foam application, TAPPI Journal January 2023
ABSTRACT: In papermaking, the conventional way to add chemicals to the web is to dose them into the fiber stock and form the paper afterwards. However, in many cases, adding chemicals directly to the stock is challenging. For example, strength aids tend to increase flocculation in the stock, which limits the addition amounts of those aids. The need for better performance of paper (and paperboard) products has given rise to the need for functionalization of paper. Adding such functional chemicals to the stock is usually rather inefficient. Hence, novel methods are needed to add chemicals to the paper bulk. One such method is dosing chemicals to the wet web via foam application. In this study, we built a laboratory-scale sheetfed dynamic foam application device and utilized it to study addition of starch to wet bleached chemithermomechanical pulp (BCTMP) paper handsheets. The impact of parameters such as vacuum level, the amount of added chemical, and the viscosity of the foaming liquid on the penetration of starch into the wet web was explored. Starch penetration into wet webs was measured via iodine-potassium iodide staining, followed by image analysis. According to our results, controlling the viscosity of the foaming liquid gives the best possibility to control the penetration.
Journal articles
Magazine articles
Dielectric spectroscopic studies of biological material evolution and application to paper, TAPPI JOURNAL September 2018
Dielectric spectroscopic studies of biological material evolution and application to paper, TAPPI JOURNAL September 2018