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Journal articles
Editor's Notes: Ready for a Test Drive, TAPPI JOURNAL, Novem
Editor's Notes: Ready for a Test Drive, TAPPI JOURNAL, November, 2006
Journal articles
Evaluation of Various Mechanical Pulping Processes for Mature and Juvenile Loblolly Pine in Lightweight Coated Paper, TAPPI JOURNAL March 2009
Evaluation of Various Mechanical Pulping Processes for Mature and Juvenile Loblolly Pine in Lightweight Coated Paper, TAPPI JOURNAL March 2009
Journal articles
Prediction of the Solubility of Recovery Boiler Precipitator Ash, TAPPI JOURNAL May 2009
Prediction of the Solubility of Recovery Boiler Precipitator Ash, TAPPI JOURNAL May 2009
Journal articles
Magazine articles
Lignin-based resins for kraft paper applications, TAPPI Journal November 2019
ABSTRACT: We investigated miscanthus (MS) and willow (W) lignin-furfural based resins as potential reinforce-ment agents on softwood and hardwood kraft paper. These resins might be sustainable alternatives to the commercial phenolformaldehyde (PF) resins. Phenol is a petrochemical product and formaldehyde has been classified as a carcinogen by the U.S. Environmental Protection Agency. The lignin used in this study was derived from hot water extraction (160ºC, 2 h) of MS and W biomass, and may be considered sulfur-free. These biorefinery lignins were characterized for their chemical composition and inherent properties via wet chemistry and instrumental techniques. The resin blends (MS-resin and W-resin) were characterized for their molecular weight, thermal behavior, and mechanical properties. Mechanical properties were measured by the resin’s ability to reinforce softwood and hard-wood kraft papers. The effect of adding hexamethylenetetramine (HMTA), a curing agent, to the resin was also examined. Mixtures of PF and lignin-based resins were investigated to further explore ways to reduce use of non-renewables, phenol, and carcinogenic formaldehyde. The results show that lignin-based resins have the potential to replace PF resins in kraft paper applications. For softwood paper, the highest strength was achieved using W-resin, without HMTA (2.5 times greater than PF with HMTA). For hardwood paper, MS-resin with HMTA gave the highest strength (2.3 times higher than PF with HMTA). The lignin-based resins, without HMTA, also yielded mechanical properties comparable to PF with HMTA.
Journal articles
Magazine articles
Application of ATR-IR measurements to predict the deinking efficiency of UV-cured inks, TAPPI Journal January 2022
ABSTRACT: In recent years, ultraviolet (UV)-curable ink has been developed and widely used in various printing applications. However, using UV-printed products (UV prints) in recovered paper recycling causes end-product dirt specks and quality issues. A new method was developed that can distinguish UV prints from other prints by means of attenuated total reflectance infrared (ATR-IR) spectroscopy. Application of this method could allow more efficient use of UV prints as raw materials for paper recycling.First, a mill trial was performed using UV prints alone as raw materials in a deinked pulp (DIP) process. Second, test prints were made with four types of UV inks: a conventional UV ink and three different highly-sensitive UV inks. Each print sample had four levels of four-color ink coverage patterns (100%, 75%, 50%, and 25%). Next, deinkability of all prints was evaluated by laboratory experiments. Finally, each print was measured using the ATR-IR method, and the relationship between the IR spectra and deinkability was investigated. Mill trial results showed that UV prints caused more than 20 times as many dirt specks as those printed with conventional oil-based ink. There were variations in recycling performance among UV prints taken from bales used for the mill trial. Lab tests clearly revealed that not all UV-printed products lead to dirt specks. In order to clarify the factors that affected deinkability of UV prints, the print samples were investigated by lab experiments. Key findings from lab experiments include: œ The number of dirt specks larger than 250 µm in diameter increased as the ink coverage increased. œ Higher ink coverage area showed stronger intensity of ATR-IR spectral bands associated with inks. These results indicate that deinkability of UV prints could be predicted by analysis of ATR-IR spectra. œ Finally, the method was applied for assessment of recovered paper from commercial printing presses. It was confirmed that this method made it possible to distinguish easily deinkable UV prints from other UV prints. Based on these findings, we concluded that the ATR-IR method is applicable for inspection of incoming recovered paper.
Journal articles
Magazine articles
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.
Journal articles
Magazine articles
Characterizing rheological behavior and fluidization of highly refined furnishes, TAPPI Journal April 2024
ABSTRACT: In this work, highly refined softwood bleached kraft pulp (SWBKP) furnishes, referred to here as XFC, were studied from the perspective of fiber suspension handling in processing. The rheology of the furnishes was studied with a rotational rheometer using a non-standard flow geometry to understand the viscosity development at different consistencies and the impact of temperature. For fluidization analysis during pipe flow, two optical methods were implemented; namely, optical coherence tomography (OCT) and high-speed video (HSV) imaging. The OCT was used to determine the small-scale floc structures near the pipe wall where the shear stress is highest, and the HSV imaging was applied for observing flow instabilities and XFC suspension uniformity at the pipe scale. All these issues can be significant in deciding the minimum flow rate required for a process pipe to get sufficient fluidization of XFC suspensions.
Journal articles
Magazine articles
Dynamic out-of-plane compression of paperboard — Influence of impact velocity on the surface, TAPPI Journal February 2024
ABSTRACT: Processes that convert paperboard into finished products include, for example, printing, where the paperboard is subjected to rapid Z-directional (ZD) compression in the print nip. However, measuring and evaluating the relevant properties in the thickness direction of paperboard are not necessarily straightforward or easy. Measuring at relevant, millisecond deformation rates further complicates the problem. The aim of the present work is to elucidate some of the influences on the compressive stiffness. Both the initial material response and the overall compressibility of the paperboard is studied. In this project, the effect on the material response from the surface structure and the millisecond timescale recovery is explored.The method utilized is a machine called the Rapid ZD-tester. The device drops a probe in freefall on the substrate and records the probe position, thus acquiring the deformation of the substrate. The probe is also allowed to bounce several times on the surface for consecutive impacts before being lifted for the next drop. To investigate the time dependent stiffness behavior, the probe is dropped several times at the same XY position on the paperboard from different heights, thus achieving different impact velocities. The material response from drops and bounces combined allows study of the short-term recovery of the material. The material in the study is commercial paperboard. The paperboard samples are compared to material where the surface has been smoothed by grinding it. Our study shows that there is a non-permanent reduction in thickness and a stiffening per bounce of the probe, indicating a compaction that has not recovered in the millisecond timescale. Additionally, a higher impact velocity has an initial stiffening effect on the paperboard, and this is reduced by smoothing the surface.
Journal articles
Magazine articles
Editorial: TAPPI Journal Best Research Paper for 2023 focuses on black liquor concentration using graphene oxide membranes, TAPPI Journal February 2024
ABSTRACT: TAPPI and the TAPPI Journal (TJ) Editorial Board would like congratulate the authors of the 2023 TAPPI Journal Best Research Paper Award and Honghi Tran Prize: Sam Rae, Ella V. Richards, Max Kleiman-Lynch, Brent D. Keller, and Brandon I. Macdonald. Their paper, “Pilot scale black liquor concentration using pressure driven membrane separation,” appeared on p. 223 of the April 2023 issue. This kraft recovery cycle research was recognized by the TAPPI Journal Editorial Board for its innovation, creativity, scientific merit, and clear expression of ideas.
Journal articles
Magazine articles
Effects of tissue additives on copy paper forming and properties, TAPPI Journal February 2024
ABSTRACT: Laboratory tests were conducted in an effort to determine the effects on paper machine process attributes and the properties of paper made from recycled copy paper furnish upon the addition of chemical agents that are commonly used in the production of hygiene tissue products. Due to continuing growth in tissue and towel grades of paper, such agents are experiencing greater usage. Charge titration test results revealed that certain dry strength agents associated with tissue manufacturing have the potential to shift the balance of charge in papermaking furnish to less negative or even positive values. Creping adhesive was found to contribute to fine particle retention, especially when present at relatively high levels. Release aid and a polyacrylate dispersant had the opposite effect. Low addition levels of both a creping adhesive and a debonding agent surprisingly increased a wide range of strength attributes of paper handsheets in comparison to sheets prepared from unaltered recycled copy paper furnish. The debonding agent decreased paper strength at higher levels of addition. Such effects appear to depend not only on the expected effects of agents themselves, but also on how they affect the charge balance of the wet-end system.