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Journal articles
Alkyl ketene dimer (AKD) sizing of paper under simplified tr
Alkyl ketene dimer (AKD) sizing of paper under simplified treatment conditions, TAPPI JOURNAL August 2016
Journal articles
Effects of localized environment on eucalyptus clone chemica
Effects of localized environment on eucalyptus clone chemical composition, TAPPI JOURNAL September 2016
Journal articles
Magazine articles
In-process detection of fiber cutting in low consistency ref
In-process detection of fiber cutting in low consistency refining based on measurement of forces on refiner bars, TAPPI JOURNAL April 2017
Journal articles
Magazine articles
Low consistency refining of mechanical pulp — system design
Low consistency refining of mechanical pulp — system design, TAPPI JOURNAL July 2017
Journal articles
Magazine articles
Kinetics of sulfur dioxide-alcohol-water (SAW) pulping of su
Kinetics of sulfur dioxide-alcohol-water (SAW) pulping of sugarcane straw (SCS), TAPPI JOURNAL June 2017
Journal articles
Pre-damping effects on water absorption and drying dynamics in flexographic printing, TAPPI Journal November 2025
ABSTRACT: Optimizing flexographic printability can involve the ink and the substrate, as well as the printing process. It has been widely reported in the literature that controlling topography of the substrate and its porosity are vital for good flexographic printability, especially when using water-based inks. This study focuses on how pre-damping a surface impacts liquid absorption and improves wet trapping (ink on ink with no intermediate drying) in flexographic printing. A Prüfbau universal print tester was adapted to analyze flexographic wet-on-wet ink printing and trapping using yellow and magenta inks for contrast. Slow drying of the first ink layer (yellow) leads to mottle when the second layer (magenta) is applied. The study explores the “wet sponge” hypothesis: a pre-damped surface should absorb liquid faster. The Lucas- Washburn equation describes long-term absorption, but it does not capture short-term uptake, which instead follows a linear dependence on time.
Journal articles
Effects of biopolymer coatings on paper permeability and capillarity for paper-based rapid diagnostic test devices, TAPPI Journal September 2025
ABSTRACT: Rapid diagnostic test (RDT) devices are widely used for diagnostics due to their affordability, portability, and user-friendliness. However, conventional assays typically rely on nitrocellulose membranes and plastic casings. These materials raise environmental concerns due to their non-renewable nature, energy-intensive production methods, and poor biodegradability. This study explores the development of fully bio-based RDT substrates using a sustainable alternative: softwoodderived microfibrillated cellulose (MFC), cellulose nanocrystals (CNC), and chitosan as surface modifiers to improve paper properties and enhance RDT sustainability. Cotton filter paper substrates were coated with different biopolymer formulations using a manual blade coater: bleached MFC (BMFC), lignin-containing MFC (LMFC), BMFC combined with CNC, LMFC combined with CNC, and chitosan. Evaluation of the most relevant physical properties concerning RDT performance was conducted, including wetting, water retention value, air permeability, capillary flow rate, and surface morphology. Results showed that biopolymer- based coatings can effectively modify surface properties by reducing pore size and tuning hydrophilicity, while maintaining the renewable and bio-based characteristics of the substrate. The LMFC-coated paper exhibited the best overall performance among all formulations, reducing flow time by 50% (3.00 mm/s vs. 1.5 mm/s) compared to the uncoated paper, yet preserving high water retention. The BMFC+CNC coating also significantly improved flow rate, showing a 36.7% reduction (2.37 mm/s vs. 1.5 mm/s), and enhanced porosity uniformity. In contrast, the flow rate of chitosan-coated paper decreased by over 5,000% (0.027 mm/s), reflecting its strong barrier properties and hydrophobic surface (highest contact angle: 91.4°). These findings suggest that MFC-based coatings are promising ecofriendly alternatives to nitrocellulose, offering optimized capillary transport and structural adaptability. This paves the way for the development of sustainable, high-performance, rapid diagnostic tests.
Journal articles
Local delamination in pharmaceutical blister packages • A thermomechanical theory on buckling of heat-sealed composite laminates in flexible packaging, TAPPI Journal July 2025
ABSTRACT: Pharmaceutical blister packages consist of cavities made from a thick polymeric form foil and a thin aluminum lid foil. Heat-sealing technology is usually used to bond the lid foil to the form foil. Occasionally, the sealed area shows buckling defects of the lid foil, which allow contamination to enter into the cavity. A contaminated product is a worst-case scenario for pharmaceutical production and must be avoided. We discuss a thermomechanical theory on buckling defects in blister packages and derive strategies to avoid these. The theory is based on the assumption that the seal of a blister packaging behaves like a laminate of thin composite layers under compressive load. Literature research on buckling of thin laminated films, thermal behavior of polymers, and seal strength of heat-sealed polymers provides the technical and physical background to elaborate the theory. The theory comprises three elements: an initial condition regarding thermal load and precedent defects; a buckling condition; and a crack propagation condition. The plausibility of the theory is verified using model calculations and heat-seal tests. The paper concludes with strategies against buckling of heat-sealed lid foils and an outlook on other applications in laminating and coating of polymer films.
Journal articles
Pilot-made, highly extensible paper for dry 3D forming, TAPPI Journal May 2025
Cellulose fiber-based packaging materials must perform well in demanding three dimensional (3D) forming process conditions. On the other hand, the development of manufacturing concepts is required for improved competitiveness of bio-based materials. This study covers some key factors that influence the extensibility of cellulose fiber-based structures and presents a pilot-scale development study of a 3D formable material concept. Bleached softwood kraft (BSK) pulp from a Nordic pulp mill was used in the pilot trials. Cellulose-based webs were formed using water-laid and foam-laid web forming using a pilot paper machine. For the water-laid forming, the BSK pulp was refined by applying a high consistency (HC) phase at over 40% consistency, followed by a low consistency (LC) refining at 4% consistency. The BSK pulp was refined for the foam-laid forming by only applying lowconsistency refining. In the foam-laid web forming, anionic sodium dodecyl sulfate (SDS), two foamable latexes, and polyvinyl alcohol (PVA) were used as foaming agents. The pilot rolls were dried at a separate steam cylinder dryer pilot and compacted in-plane in the machine direction (MD) at a separate pilot machine. Tensile properties of the treated paper webs were measured and evaluated with respect to achieved web shrinkage. The same dimensional contraction brought by shrinkage was almost strained out in tensile testing. The results indicated that the shrinkage that occurred by drying and in-plane compaction depended on the pulp furnish. The water-laid material achieved about 30% elongation, whereas the foam-laid material achieved significantly above 50% elongation. The 3D forming performance of the dry materials was tested using fixed and sliding blank methods. The dry paper sheets performed well enough in 3D forming for application to many consumer package applications according to their extensibility.
Journal articles
Magazine articles
Peracetate/singlet oxygen chemistry used in post-bleaching of kraft pulp as a practical oxidant for paper machines, TAPPI Journal May 2021
ABSTRACT: The use of a novel sodium peracetate/singlet oxygen chemistry for brightening bleached kraft pulp shows exciting potential for technical performance, supply logistics, safety, and cost reduction. Potential chemical carryover to the paper machine raises questions about whether peracetate will impact paper machine performance, such as metal corrosion, useful press felt life, and interference with existing biocide programs or paper machine chemistry. Sodium peracetate/singlet oxygen chemistry can be used in high-density storage chests for brightening/whitening and to increase color stability. Any oxidant used directly before the paper machine has the possibility of impacting paper machine operations. Traditional oxidants used in bleaching, such as chlorine dioxide and hydrogen peroxide, are known to cause corrosion on machinery metals and press felts. Hydrogen peroxide residuals can interfere with common biocide programs. Traditional oxidants used in biocide treatments themselves significantly degrade press felt life when the rule-of-thumb concentration thresholds are exceeded. Sodium peracetate is evaluated in this paper for its impact on nylon press felt fiber degradation, metal corrosion, and interference with typical biocide programs.Laboratory results indicate that sodium peracetate/singlet oxygen chemistry is less corrosive than chlorine, bromine, and hydrogen peroxide on press felt nylon fiber and can therefore be used at higher levels than those chemistries to increase brightness without increasing negative downstream impact. Sodium peracetate can also be used with current biocide programs without negative impacts such as consumptive degradation. Higher residuals of peracetate going to the paper machine may be useful as a biocide itself and can complement existing programs, allowing those programs to stay within their safe operating levels and thereby extend press felt useful life.