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Editorial: Ravi Challa brings tissue, nonwovens, and operational expertise to TJ Editorial Board, TAPPI Journal September 2022

ABSTRACT: TAPPI and the TAPPI JOURNAL (TJ) editorial staff would like to welcome a new member to the TJ Editorial Board, Ravi Challa, Ph.D., who is Research & Development (R&D) manager for Suominen Corporation at the company’s Bethune, SC, facility. There, his primary focus is new product development on wetlaid nonwovens paper machines, from maintaining mature technologies and innovation to discovering patterns in paper machine shutdowns and executing nonwovens product development trials.

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Development of reinforced paper and mitigation of the challenges of raw material availability by utilizing Areca nut leaf, TAPPI Journal September 2022

ABSTRACT: Paper industries are facing a raw material crisis and searching for alternate raw materials that may be able to help mitigate the issue. Many industries use agro-waste as a raw material, irrespective of it having low bleachability and poor mechanical strength. Areca nut leaf (ANL) is a nonwood-based material that may be acceptable as an alternate source of raw material that contains 61.5% holocellulose and 13.6% lignin, which is comparable to other agro-wastes and hardwood pulps. Kraft anthraquinone pulping with 20% active alkali as sodium oxide (Na2O), 25% sulfidity, and 0.05% anthraquinone produced 15 kappa pulps with about 38.5% pulping yield. The bleachability of ANL pulp was good, and 83.5% ISO brightness could be achieved using the D0(EOP)D1 bleaching sequence. The ANL fiber has 33.8% better tensile, 54.5% better tear, and 15.2% better burst index than hardwood fiber. Similarly, 60.4% better tensile, 56.5% better tear, and 21.7% better burst index were observed in ANL than in wheat straw. Thus, the study revealed that Areca nut leaf can be used as an alternative raw material for papermaking, as well as to improve the physical property of paper products by blending it with inferior quality pulp.

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Open Access
Economic and competitive potential of lignin-based thermoplastics using a multicriteria decision-making method, TAPPI Journal September 2022

ABSTRACT: As a result of new lignin extraction plants hatching and increasing volumes of technical lignin becoming available, a variety of lignin derivatives, including phenolic resins and polyurethane (PU) foams, are reaching the marketplace or being used as intermediate products in many industrial applications. In the spectrum of possible lignin derivatives, thermoplastics appear particularly attractive due to a symbiosis of market, policy, and technology drivers. To assess the preferredness for lignin-based thermoplastics, this paper adapted a risk-oriented methodology formerly applied to assess lignin usage in various applications (phenol-formaldehyde [PF] resins, PU foams, and carbon fiber applications) to the case of lignin-based thermoplastics using hydroxypropylated lignin (HPL) and miscible blends of lignin and polyethylene oxide (PEO). The HPL is considered for garbage bags and agricultural films applications, while lignin-PEO blends are used as replacement for acrylonitrile butadiene styrene (ABS) in applications such as automotive parts. In the methodology, two phased-implementation strategies were defined for each thermoplastic derivative, considering perspectives for profit maximization (90 metric tons/day integrated units) and revenue growth (350 metric tons/day overall capacity), which were considered for implementation within a softwood kraft pulping mill. A set of six criteria representative of the main economic and market competitiveness issues were employed, and their respective importance weights were obtained in a multicriteria decision-making (MCDM) panel.Early-stage techno-economic estimates were done as a basis for the calculation of decision criteria. Compared to product derivatives previously assessed, capital investment for thermoplastic strategies appeared marginally higher due to the required lignin modification steps (on average 30% higher at similar capacity, and 6% for higher-scale revenue diversification strategies). Higher operating costs were also observed due to increased chemical expenses for all thermoplastic strategies, which are ultimately balanced by revenues associated with targeted thermoplastic products, leading to greater annual margins and cash flow generation over the project lifetime for thermoplastic strategies compared to other product applications (58% to 66% higher on average, at similar scale). Benefits of improved economics were reflected in economic criteria, internal rate of return (IRR), and cash flow on capital employed (CFCE), as well as in the price competitiveness criterion, CPC. Overall, the combination of relatively high lignin content in the plastic formulation and the less costly modification method contributed to lignin-PEO strategies, gaining the top two rankings. Based on their overall scores, both strategies defined for HPL would also integrate the group of “preferred” strategies, but are outranked by strategies that consider lignin positioning on PU foam applications.

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Fiber-based characterization of pulp refining, TAPPI Journal September 2022

ABSTRACT: Fiber development in pulp refining can be characterized by three parameters: number of impacts on pulp, N; energy per impact, I, and bar force on fibers, F. These parameters enable comparisons of radically different refining conditions; determination of intensity for hardwoods and softwoods; assessment of effect of bar width on fiber shortening; and predictions of tensile strength increases.

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Open Access
Guest Editorial: TAPPI Journal names two Best Research Paper Award winners for 2020, TAPPI Journal April 2021

For the first time since the annual award was introduced back in 2006, TAPPI Journal's editoria board elected two scientific papers to receive the TAPPI Journal Best Research Paper Award for 2020.

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Mechanical modification of softwood pulp fibers using a novel lightweight vertical bar plate, TAPPI Journal April 2021

ABSTRACT: Refiner plates made using sand casting have a draft angle, which results in a trapezoidal bar shape. These trapezoidal bar plates have a limited throughput compared to the vertical bar plates, and eventually the edges of the bars become dull, resulting in longer time to reach the target freeness and shorter service life. The new light-weight refiner plate with a bar insertion method into a plate base was developed by selecting an aluminium-based alloy as the plate base material and a stainless steel alloy with high wear resistance as the bar material. The light-weight plate with sharp bar edges was very effective in reducing refining energy by reaching the target freeness faster than the sand-cast bar plate. Finally, the lightweight sharp bar plate, which weighed only about half the weight of the cast bar plate, was expected to significantly contribute to easy replacement, improved paper quality, and larger throughput without excessive loss of fiber length.

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A case study review of wood ash land application programs in North America, TAPPI Journal February 2021

ABSTRACT: Several regulatory agencies and universities have published guidelines addressing the use of wood ash as liming material for agricultural land and as a soil amendment and fertilizer. This paper summarizes the experiences collected from several forest products facility-sponsored agricultural application programs across North America. These case studies are characterized in terms of the quality of the wood ash involved in the agricultural application, approval requirements, recommended management practices, agricultural benefits of wood ash, and challenges confronted by ash generators and farmers during storage, handling, and land application of wood ash.Reported benefits associated with land-applying wood ash include increasing the pH of acidic soils, improving soil quality, and increasing crop yields. Farmers apply wood ash on their land because in addition to its liming value, it has been shown to effectively fertilize the soil while maintaining soil pH at a level that is optimal for plant growth. Given the content of calcium, potassium, and magnesium that wood ash supplies to the soil, wood ash also improves soil tilth. Wood ash has also proven to be a cost-effective alternative to agricultural lime, especially in rural areas where access to commercial agricultural lime is limited. Some of the challenges identified in the review of case studies include lengthy application approvals in some jurisdictions; weather-related issues associated with delivery, storage, and application of wood ash; maintaining consistent ash quality; inaccurate assessment of required ash testing; potential increased equipment maintenance; and misconceptions on the part of some farmers and government agencies regarding the effect and efficacy of wood ash on soil quality and crop productivity.

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Continuous tannin extraction by use of screw reactor, TAPPI Journal February 2021

ABSTRACT: A pilot-size screw reactor (extraction unit) was used for tannin extraction of spruce. Yield of the same magnitude or better was obtained when comparing a screw reactor with batch reactors. A longer presoaking time in water seemed to be better than a short one for obtaining higher yield. A higher yield is obtained with lower dry-water ratio, which suggests that the internal diffusion in bark does not determine mass transfer as much as is the case without presoaking of bark. The higher dry-water ratio decreased the yield. The prior soaking of the bark also minimized the mechanical reactor feeding problems (clogging). The benefits of a screw reactor likely are that run time changes for different process conditions are flexible; it simplifies design and construction of an industrial unit for tannin production; and it saves space because of the need for fewer and smaller intermediate storage tanks.

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Key material properties in crease cracking of kraft paper, TAPPI Journal February 2021

ABSTRACT: Crease cracking of paperboard is important to control for the appearance and structural integrity of packages. Crease cracking is affected by creasing operation variables, as well as the physical properties of the paperboard. However, the effects of the physical properties are not clearly known. The objectives of this work were to identify the key material properties that affect crease cracking and to clarify the effects of fiber composition and starch. Laboratory sheets were produced from bleached and refined softwood and hardwood commercial pulp at grammage and thicknesses that match a typical paperboard. To mimic papermaking operations, surface starch was applied via a bench-top size press. The sheets were creased in the lab over a range of penetration depths, and reverse-side cracking was measured. The results showed that less reverse-side cracking was correlated with higher tensile post-peak energy, a lower bending stress, and a lower z-direction (ZD) stiffness. The tensile post-peak energy is a measure of the resistance to crack growth via fiber-bridging. The bending force and the ZD stiffness influence the forces that create cracks. It was observed that decreasing the ratio of hard-wood-to-softwood content and reducing the amount of starch would both decrease crease cracking.

Journal articles
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Open Access
An evaluation of household tissue softness, TAPPI Journal February 2021

ABSTRACT: This study extends our 2019 paper, a study of the softness of household tissues using a tissue softness analyzer (TSA) and hand-felt panels. It revisits the softness theory of Holger Hollmark by applying a reciprocal matrix approach to measure sheet bulk softness and surface softness, and then make comparisons with the results obtained using a TSA instrument. We ascertained that there was a high correlation of R=0.904 between panel-corrected hand-felt (CHF) softness and TSA softness (TSA-HF); and a low correlation of R=-0.678 between panel-corrected hand-felt surface softness (CHSS) and TSA smoothness (TS-750). Three hunches about TSA measurements were confirmed: 1) Hollmark’s theory was confirmed by a high correlation coefficient (R=0.895) between CHF and CHSS softness, indicating that the two parameters are mutually dependent; 2) TS-750 differs from CHSS and has partial influence on TSA-HF results with a correlation of R = -0.510; and 3) although TS-750 has only limited influences on TSA-HF, further opportunities for their application can be provided using pertinent regression equations.