PAPER making! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® Volume 8, Number 3, 2022
“Relative permeability of barrier dispersion coatings applied on paper-based materials; mathematical modeling and experimental validation”, Gonzalo A. Martinez-Hermosilla, Beko Mesic & John E. Bronlund, Journal of Coatings Technology and Research , Vol.19, 543-558 (2022). Barrier dispersion coatings have been used to improve barrier properties of paper-based materials. Like other technologies such as thermoplastic composites, dispersion coatings include fillers to create obstacles that complicate the pathways for permeants through coatings. The development of these technologies has received significant attention where even predictive barrier performance models have been created. However, to the best of our knowledge, none of them are applicable to barrier dispersion coatings. This research proposed a mathematical model to predict the relative permeability of barrier dispersion coatings applied on paper-based materials based on Fick’s law. The uncertainty of the barrier properties due to variation in filler orientation and spatial location was included through Monte Carlo simulation. Model validation against four models previously published by other authors, and water vapor transmission rate measured on three coating formations and two coating thicknesses was also conducted. The model predictions and experimental results showed that the increase in the amount of fillers reduces the relative permeability, and this reduction can be higher if the size of the fillers is larger. The predictions agreed with experimental results particularly at volume fractions below 10%. In most of the cases, the proposed model achieved better prediction in comparison with those already published. The model is useful to predict relative barrier performance of different coating formulations and can be used as a tool for future developments. “Relating papermaking process parameters to properties of paperboard with special attention to through-thickness design”, Mikael Nygards, MRS Advances , online, (2022). A biaxial stress state has been proposed to formulate a failure criterion for paperboard during bending. About 100 paperboards have been splitted, such that top, middle, and bottom plies have been free-laid and tested in the machine direction, cross- machine direction as well as in out-of-plane direction (ZD). The purpose was to determine the failure stresses and its dependency of papermaking parameters: density, degree of orientation, and fiber length for each layer. A linear model to predict the geometrical strength of a plies was suggested. Analytically simulations of different paperboard structures behavior during bending were performed. The density of the middle ply affected the location of the failure position in ZD, as well as the maximum bending moment. The impact of orientation and degree of anisotropy was simulated, which can be used to optimize the ZD property gradient by tweaking the properties, and hence optimize paperboard performance. TISSUE “Developing Alternative, High-Absorbency Brown Fibers: Tissue Paper from Upcycled Corrugated Packaging Waste to Meet New Consumer Trends”, Franklin Zambrano, Ronald Marquez, Ramon Vera, Hasan Jameel, Richard Venditti, and Ronalds Gonzalez, ACS Sustainable Chemistry & Engineering, 10, 40, 13343-13356 (2022). Consumers’ rising interest in brown tissue papers, perceived as sustainable, has increased the market share and selling prices of such products despite their limited performance. Meanwhile, the current excess of packaging waste in the US has created an opportunity for using old corrugated containerboard (OCC) as an alternative source of brown pulp, despite its inferior tissue-making characteristics relative to bleached fibers. Strength, water absorption capacity, and absorption rate are among the crucial properties of absorbent tissue products. Herein, we studied the feasibility of total chlorine-free treatments, namely, oxygen delignification, alkaline hydrogen peroxide, and ozonation, to
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Technical Abstracts
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