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Journal articles
Water-based adhesive penetration into paperboard and coated paperboard, TAPPI Journal January 2025
The setting of water-based adhesives in contact with paperboard is important in the production of boxes and other packaging, but the topic has received little attention in the literature. The penetration of the adhesive into the paper surface is important to get good bond strength through mechanical interlocking. The influence of the process conditions and the paper properties on this penetration is lacking. A water-based adhesive was applied to an uncoated and coated paperboard. The coating layer had two latex levels. Samples were characterized in terms of air permeability, void fraction, average pore size, and coat weight. The adhesive was applied to the samples in a mechanical press, squeezing a drop between two samples. The penetration of the adhesive was characterized with a silicone oil absorption method that measured the decrease in pore volume after the adhesive had been applied to approximate the pore volume taken up by the adhesive. The bond strength was measured with a peeling test. The penetration depth into uncoated paper did not depend on the application method parameters such as pressing time, pressure, or initial solids of the adhesive. The penetration depth ranged from 35•40 mm. The penetration into 10 pph latex content coated paper was similar to the uncoated samples, but reduced penetration was observed into the 40 pph latex content coatings. The results were compared to the limiting amount of adhesive that was obtained from the weight gain of the samples and to a simple model that is based on flow in porous media. Peel tests revealed that good penetration was needed, as well as a strong coating layer to obtain high peel forces.
Journal articles
Comparison of the application of polysaccharide-based barrier coatings on paper using film press and spray coating, TAPPI Journal January 2025
The growing demand for sustainable packaging has spurred research into biopolymer-based solutions and their application to paper substrates. This study compares the application of low solids, high viscous aqueous solutions of alginate and chitosan on two different paper substrates using a laboratory film press coater and a purpose-built spray coating unit, with a focus on barrier performance and practical industry considerations. Key parameters investigated are air flow rate, water vapor transmission rate, and grease resistance. Results showed that due to the low solids content of the applied biopolymer solutions, film press coating required a double-layer application for coat weights exceeding 4 g/m², making it less viable for industrial application. In contrast, spray coating allowed for higher application weights in a single step. The barrier properties of spray coated samples, compared to film press coatings, varied with the paper substrate: spray coating performed better on one substrate and worse on the other. Contact angle measurement of the substrates suggested that spray coating is more suitable for a more hydrophilic substrate because of improved surface wetting. The study also identified issues with drying conditions and pinholes affecting the quality of spray coated samples, indicating a need for further research to optimize these parameters.
Journal articles
Filtration performance of face masks and facepiece respirators used during COVID-19 pandemic, TAPPI Journal February 2025
ABSTRACT: The rapid spread of SARS-CoV-2 has created challenges for societies, healthcare settings, businesses, and institutions. To curb virus transmission, various measures like lockdown, social distancing, hand hygiene, and using appropriate personal protective equipment (PPEs), including face masks, have been recommended. Face masks and facepiece respirators are considered to act as barriers against microbial transmission from person to person. In this study, we selected barrier materials used during the COVID-19 pandemic that included four non-medical face masks and three facepiece respirators. Facepiece respirators were distributed by the U.S. Administration through pharmacy outlets. Results showed that facepiece respirator R95 has the highest filtration efficiency (above 99%), which remains more or less the same over different particle sizes. The N95 respirator’s filtration efficiency was lower than that of R95, but its barrier resistance was lower than that of the R95, indicating that it can be comfortably used over longer duration. Face masks were evaluated using ASTM F 3502-24 for their barrier performance. At 0.1 and 0.3 ìm particle size, domestically manufactured masks met the standard for higher performance. Interestingly, the results indicate that quality of raw materials and manufacturing standards play important roles, as is evident in domestically manufactured face mask and facepiece respirators.
Journal articles
Effects of different parameters on the morphology of electrospun cellulose acetate/polyaniline nanocomposite, TAPPI Journal February 2025
ABSTRACT: Cellulose is the most abundant naturally occurring polysaccharide. Its inherent mechanical stability, biocompatibility, biodegradability, and abundant hydroxyl groups available for derivatization provide benefits in the production of fiber-based materials such as conductive fibers. Cellulose derivatives, including cellulose esters such as cellulose acetate (CA), are readily generated in the fiber form following dissolution using a variety of solvents. Electrospinning is one of the emerging technologies with an outstanding ability to regenerate fibers in the nanoscale range. Polyaniline (PANI) is a conductive polymer that is popular for its high chemical stability, nontoxicity, good processability, and stable intrinsic redox state. This study explored the fabrication of a conductive PANI/CA nanocomposite through electrospinning. Working conditions, electrospinning variables, and solution parameters were established to produce coherent PANI/CA nanofibers. The effects of varying CA concentration, amount of PANI, molecular weight of CA, and feed flowrate on the morphology of the nanofibers were investigated.
Journal articles
Application of AI-based approach to control the papermaking process, TAPPI Journal March 2025
ABSTRACT: This paper explores AI’s role in revolutionizing the pulp and paper industry, and specifically in predicting wet tensile strength (WTS) for specialty-grade papers. Leveraging eLIXA technology, a 90-day study achieved a 15% reduction in chemical dosage and an 80% decrease in wet tensile standard deviation. The real-time dosage prediction led to optimizing the wet strength resin (WSR) consumption and improved process reliability. The self-learning models exhibited adaptability to changing variables, ensuring their robustness. Overall, this study highlights AI’s transformative impact on efficiency, cost savings, and product quality within the dynamic landscape of papermaking. The approach used for wet strength optimization has been used to optimize other aspects of pulp and paper production.
Journal articles
Editorial: Fundamental understanding enables new coating opportunities, TAPPI Journal January 2025
TAPPI's Coating, Printing, and Surface Enhancement (CPSE) Division pursues open exchange of technical information related to materials, equipment, and processes for the manufacture, quality control, and use of coated papers, paperboard, and other substrates. Much of this technical information is presented at sponsored conferences, including TAPPICon and the Advanced Coating Symposium. Based on feedback from these events, TAPPI Journal peer reviews the research from these events that adds significant value to the scientific community. In last year's November issue, we presented five peer-reviewed manuscripts based on presentations given at TAPPICon 2024.
Journal articles
Editorial: TAPPI’s ongoing efforts in standards development for the pulp, paper, and related industries, TAPPI Journal February 2025
ABSTRACT: TAPPI has been involved in developing standards for the pulp and paper industry since the 1920s, and those efforts are still going on today with the help of volunteers who propose new standards and review existing ones. Just last year, 30 standards were either reviewed or reaffirmed, and one new standard was developed. There are currently 235 TAPPI Standard Test Methods and nearly 400 volunteers who work on them. These standards are used around the world in laboratories and production situations. Many are used by TAPPI Journal authors to support research efforts and assess results from their experiments, playing an important role in advancing science.
Journal articles
Reducing aox by increasing oxidation potential in the first caustic extraction stage, TAPPI Journal December 2024
Authors: Peter W. Hart and Jeffrey S. Hsieh | Tappi J. 74(11): 117(1991) - ABSTRACT: An increase in the standard oxidation potential of the reinforcing agent in the first caustic extraction stage will reduce the amount of AOX in the stage's effluent. A chlorinated broumstock pulp was treated alternatively in a basic caustic extraction (E) stage, an oxygen-reinforced caustic extraction (EO) stage, and an extraction stage reinforced with oxygen and peroxide (EOP). An AOX reduction of up to 30% was obtained in the effluent from the peroxide-reinforced extraction stage. In addition to the brownstock work, using two different model lignin compounds, we ran tests using oxyen, potassium permanganate, hydrogen peroxide with oxygen, and ozone with oxygen-reinforced caustic stages. In all cases, increasing the oxidation potential of the reinforcing agent decreased the amount of AOX detected in the effluent.
Journal articles
Magazine articles
Numerical analysis of the impact of rotor and screen hole plate design on the performance of a vertical pulper, TAPPI Journal April 2025
ABSTRACT: The dissolving of mechanical pulp is one of the most important process steps in stock preparation, since pulping occurs at the very beginning of the papermaking process. Efficient mixing of the pulp in a short amount of time is essential to achieve high furnish volume flow rates. The design of the rotor, as well as the pulper vat and inserts, significantly affects the overall performance of the pulper, such as mixing efficiency and power demand. Using advanced numerical methods such as computational fluid dynamics (CFD) can accelerate the development process. The CFD simulations allow for detailed analysis of flow phenomena, making it possible to study a real-size machine numerically. This approach is particularly advantageous because it can reduce the need for timeconsuming and costly experiments associated with scaling up test rigs. In this study, we compared two different rotor designs utilized in a vertical pulper and evaluated the numerical results with experimental data. Rotor A is designed for low turbulence and low power demand, while rotor B is designed for high turbulence with high power demand. The CFD results showed good agreement with the experimental measurements. We investigated how the rotor design influences the free fluid surface and the mixing efficiency. Our study also highlights the differences in results depending on whether water or furnish is simulated, which exhibit Newtonian or, respectively, non-Newtonian fluid behavior. Additionally, a detailed numerical investigation of various screen hole plate designs revealed that the newly developed hole design significantly reduces pressure loss compared to a standard drilled hole. This outcome was consistent for both types of fluids investigated: water and furnish.
Journal articles
Effect of xylan on the mechanical performance of softwood kraft pulp 2D papers and 3D foams, TAPPI Journal March 2025
ABSTRACT: Pulp fibers are paramount in paper products and have lately seen emerging use in fiber foams. Xylan, an integral component in pulp fibers, is known to contribute to paper strength, but its effect on the strength of pulp fiber foams remains less explored. In this study, we investigate the role of xylan in both 2D handsheets and 3D foams. For a softwood kraft pulp, we enzymatically removed 1% from pulp fibers and added 3% xylan to them by adsorption, corresponding to approximately a decrease of a tenth and an increase of a third of the total xylan content. The mechanical properties of 2D fiber networks, i.e., handsheets, made using the xylan-enriched pulp improved, particularly regarding tensile strength and Young’s modulus; however, the decrease in mechanical properties of handsheets made from enzymatically- treated xylan-depleted pulp was more pronounced. In 3D networks • pulp fiber foams, much less fiber-fiber contacts formed, and thus the mechanical properties were not as much influenced by removal of xylan. Furthermore, the presence of the required surfactant on the fibers, acting as debonding agent, overshadows any positive effect xylan might have on fiber-fiber bonding. We propose that the improved mechanical properties for the sheets result from a combination of an increased number of fiber-fiber bonds and higher sheet density, while the deterioration in mechanical properties of handsheets comprising enzymatically-treated fibers is caused by the opposite effect.