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Editorial: Looking forward, looking back, TAPPI Journal January 2022

ABSTRACT: Much like 2020, 2021 was another year of remarkable highs and lows delivered by the COVID-19 pandemic. Vaccines, variants, and infection surges altered the way we behaved personally and professionally last year. As we move into 2022, we are now grappling with health and business concerns from the omicron variant that has overwhelmed hospitals in some areas and contributed to a global supply chain crisis. The ability to adjust has once again become a key skill in adapting to our shifting “new normal.”

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Furnishing autohydrolyzed poplar weakly alkaline P-RC APMP to make lightweight coated base paper, TAPPI Journal February 2022

ABSTRACT: This work investigated the effects of autohydrolysis pretreatment severity on poplar (Populus tomentosa Carr.) woodchips used to make a type of high-yield pulp (HYP) known as preconditioning followed by refiner chemical treatment, alkaline peroxide mechanical pulp (P-RC APMP). It also investigated the ratios for partially replacing sodium hydroxide (NaOH) with magnesium oxide (MgO) in the high-consistency (HC) retention stage of the P-RC APMP process on the obtained HYP’s properties. The results show that the pretreatment severity of autohydrolysis at combined hydrolysis factor (CHF) = 10.77 and the 50 wt% ratio for partially substituting NaOH with MgO were the optimum conditions for making light-weight coated (LWC) base paper. Compared to the conventional P-RC APMP, the optimized P-RC APMP had similar bulk and higher tensile, burst, and tear indices, as well as opacity, but a slightly lower ISO brightness. When the optimized P-RC APMP and commercial softwood bleached sulfate pulp (SBKP) were blended to make LWC base paper, the most favorable pulp furnish was comprised of 50% optimized P-RC APMP and 50% commercial SBKP. The obtained LWC base paper handsheet had better bulk, and its other properties could also meet the require-ments of LWC base paper.

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The Effect of Component Removal Upon the Porous Structure of the Cell Wall of Wood. II. Swelling in Water and the Fiber Saturation Point, TAPPI Journal May 2022

ABSTRACT: The word "swelling" applied to an assemblage of fibers such as wood or wood pul p is very vague.

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Open Access
Editorial: Shaping industry and career success with TAPPI Standards involvement, TAPPI Journal May 2023

ABSTRACT: Within TAPPI, there are many ways to help advance our industry and make sure it thrives for years to come. Writing a research paper for publication or acting as peer reviewer for TAPPI Journal, presenting at a conference or helping to organize one, and becoming involved in the many committees that are part of TAPPI Divisions are just some of the ways. One other very important way to contribute to our industry is through the standards development process.

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Open Access
Monitoring the free lime content in lime mud using zeta potential, TAPPI JOURANL April 2018

Monitoring the free lime content in lime mud using zeta potential, TAPPI JOURANL April 2018

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Rethinking the paper cup — beginning with extrusion process optimization for compostability and recyclability, TAPPI Journal June 2021

ABSTRACT: More than 50 billion disposable paper cups used for cold and hot beverages are sold within the United States each year. Most of the cups are coated with a thin layer of plastic — low density polyethylene (LDPE) — to prevent leaking and staining. While the paper in these cups is both recyclable and compostable, the LDPE coat-ing is neither. In recycling a paper cup, the paper is separated from the plastic lining. The paper is sent to be recycled and the plastic lining is typically sent to landfill. In an industrial composting environment, the paper and lining can be composted together if the lining is made from compostable materials. Coating paper cups with a compostable performance material uniquely allows for used cups to be processed by either recycling or composting, thus creating multiple pathways for these products to flow through a circular economy.A segment of the paper converting industry frequently uses an extrusion grade of polylactic acid (PLA) for zero-waste venues and for municipalities with ordinances for local composting and food service items. The results among these early adopters reveal process inefficiencies that elevate manufacturing costs while increasing scrap and generally lowering output when using PLA for extrusion coating. NatureWorks and Sung An Machinery (SAM) North America researched the extrusion coating process utilizing the incumbent polymer (LDPE) and PLA. The trademarked Ingeo 1102 is a new, compostable, and bio-based PLA grade that is specifically designed for the extrusion coating process. The research team identified the optimum process parameters for new, dedicated PLA extrusion coating lines. The team also identified changes to existing LDPE extrusion lines that processors can make today to improve output.The key finding is that LDPE and PLA are significantly different polymers and that processing them on the same equipment without modification of systems and/or setpoints can be the root cause of inefficiencies. These polymers each have unique processing requirements with inverse responses. Fine tuning existing systems may improve over-all output for the biopolymer without capital investment, and this study showed an increase in line speed of 130% by making these adjustments. However, the researchers found that highest productivity can be achieved by specifying new systems for PLA. A line speed increase to more than 180% and a reduction in coat weight to 8.6 µm (10.6 g/m2 or 6.5 lb/3000 ft2) was achieved in this study. These results show that Ingeo 1102 could be used as a paper coating beyond cups.

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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.

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Convolutional neural networks enhance pyrolysis gas chromatography mass spectrometry identification of coated papers, TAPPI Journal August 2024

ABSTRACT: In the evolving paper industry, accurate identification of coated paper components is essential for sustainability and recycling efforts. This study employed pyrolysis-gas chromatography mass spectrometry (Py-GCMS) to examine six types of coated paper. A key finding was the minimal interference of the paper substrate with the pyrolysis products of the coatings, ensuring reliable analysis. A one-dimensional convolutional neural network (1D-CNN) was employed to process the extracted ion chromatograms directly, simplifying the workflow and achieving a predictive accuracy of 95.2% in identifying different coating compositions. Additionally, the study high-lighted the importance of selecting an optimal pyrolysis temperature for effective feature extraction in machine learning models. Specific markers for coated papers, including polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene succinate (PBS), polylactic acid (PLA), and waterborne polyacrylates (WP), were identified. This research demonstrates a novel approach to coated paper identification by combining Py-GCMS with machine learning, offering a foundation for further studies in product quality and environmental impact.

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Compression refining: the future of refining? Application to Nordic bleached softwood kraft pulp, TAPPI Journal August 2024

ABSTRACT: A new compression refining technology based on the kneading of high consistency pulp has been selected and tested in various conditions with a model Nordic bleached softwood kraft (NBSK) pulp. The method uses a kneader mixer referred to as the ultra continuous mixer (UCM) to condition the pulp. Its performance levels were also compared with those obtained with traditional low consistency (LC) refining of the same pulp.Compression refining of the NBSK pulp with the UCM led to a much better °SR/strength compromise than conventional LC refining. High strength properties can also be achieved by compression refining, in a range similar to/or better than LC refining. The higher the strength required, the greater the advantages of this technology: for a given strength, a difference of up to 10°SR can be obtained as compared to LC refined pulp. Moreover, a higher tear index can be obtained with compression refining, since fiber cutting is greatly reduced.The lower °SR is due to the release of fewer cellulosic fines, which also results in the manufacturing of new papers combining a high strength and a high permeability that cannot be obtained with traditional LC refining. Indeed, with LC refining, a high strength is generally associated with a low permeability. Upscaling this technology seems to be possible since large production devices are already on the market for applications other than paper/pulp. With this new pulp behavior, papermakers will have to learn to think differently, as paper strength and °SR can now be decorrelated.

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Editorial: Concentrated content: TAPPI Journal special issues create research visibility, TAPPI Journal September 2024

You may have noticed that TAPPI Journal often brings readers special focused issues from time to time. Over the years, these issues have covered a range of topics, including wet-end technology, recovery cycle, foam forming, coating, additives, biorefinery, nanotechnology, lignin, pulping, recycling, university research, and more.