Stora Enso (Finland)

Abstract The adoption of timber, specifically cross-laminated timber (CLT), as a primary construction material is gaining traction due to its carbon sequestration capabilities, environmental advantages, and potential for precision manufacturing. However, the combustibility of wood raises legitimate concerns about fire safety in timber-based residential buildings. This paper investigates the fire performance of timber in a residential context, attempting to fill knowledge gaps and outline strategies for improving fire robustness in timber-built dwellings. Through comprehensive experimental studies on residential-type enclosures constructed with CLT panels, this research explores different configurations and the effects of varying degrees of non-combustible protective lining. The findings underscore the significance of considering timber surface exposure and adopting effective encapsulation strategies in CLT buildings. It has been estimated that the exposure of timber walls leads to a proportional increase in heat release rate, corresponding to the area of exposed timber surfaces and their charring rates. Consequently, the external flame has a larger projection, resulting in a much greater heat flux to the façade. Furthermore, threshold conditions for initial flaming self-extinguishment of timber defined in literature of 44.5 ± 1.2 kW/m2 have been found to be applicable to the experiments conducted in this research. Finally, it has been observed that partial encapsulation, where the protective lining will likely fall off during a fire, may hinder rather than increase the likelihood of self-extinguishment. This work contributes towards a nuanced understanding of fire dynamics in timber structures, offering insights for safer and more effective design strategies for CLT-based construction.

Four major toners are used in the printing industry, cyan, magenta, yellow and black (Key) for making color images on paper. Paper brands suitable for printing have thin mineral/latex coatings, and toners are applied on top of the coating in the printing process. Chemical compositions from toner to toner, as well as from coating to coating, vary according to the needs of the end user. Interactions between the toner and the coating define the final color formation of the images in printing. Hence, it is important to study characteristics and dynamics of toners on coated papers. In this paper, we have used laser-induced plasma spectroscopy (LIBS) to provide information on elemental distributions of the toner and the coating layers on three coated papers and the base paper at a sub-micrometer resolution. Ablation crater depth profiles in the three different material layers were converted into metric scale by combining elemental information from the LIBS measurements and optical profilometry. Ablation efficiencies for a toner of 150 nm/pulse, for a coating of approximately 350 nm/pulse and for a base paper of approximately 1 μm at a fluence of 0.6 J/cm2 of an ArF excimer laser were determined. Using these results, the average layer thicknesses of the toner and the coating layers were evaluated. The detailed analysis of the elemental profiles of the two cyan toners studied revealed strong accumulation of silicon and titanium compounds of the toner on the toner–air interface but also on the toner–coating interface, but to a much smaller extent. The observation reveals the significance of toner component diffusion due to substrate–machine interaction in the printing process. Such diffusion processes must have an important role in final color formation of the images in printing. The method developed provides a unique and accurate means to study toner diffusion processes in coated papers under printing conditions.

This paper provides further understanding of the fire performance of exposed cross-laminated timber (CLT) in large enclosures. An office-type configuration has been represented by a 3.75 by 7.6 by 2.4 m high enclosure constructed of non-combustible blockwork walls, with a large opening on one long face. Two experiments are described in which propane-fuelled burners created a line fire that impinged on CLT ceilings. The first experiment had a smooth CLT soffit, with the CLT formed from 160 mm thick panels (40-20-40-20-40 mm). The second experiment adopted the same CLT but included a 400 mm deep, 200 mm wide glulam beam half-way along the length of the enclosure. In both experiments, the lamella of each CLT were bonded using a standard polyurethane adhesive. The facing lamella of the CLT was not edge bonded. The results indicate the importance of consideration of the impact of ceiling protrusions, such as down-stand beams, with differences in both radiative heat flux to the ceiling and floor observed between the two cases. Considering large contemporary open plan office enclosures, this would likely translate to differences in spread rate within an enclosure and time to auto-extinction of flaming combustion which should be addressed by designers.

Abstract There is currently a great demand for sustainable and bio-derived coatings for fiber-based packaging materials, which are technically implementable with a high performance. The aim of this work was to investigate the grease resistance of coatings prepared from methyl nanocellulose when applied on paperboard. Co-additives selected from native microfibrillated cellulose (MFC) and hydrophobically modified ethyl(hydroxyethyl)cellulose (EHEC) were used in order to determine their impact on film formation and crack resistance for folds. Small and moderate coat weights were applied in order to determine the critical coat weight for the barrier properties. It was found that high grease resistance can be achieved with methyl nanocellulose and a combination of methyl nanocellulose and MFC coatings. Contact angle determinations for water on uncoated and coated materials showed that EHEC-MFC films have a very high contact angle which is due to both the surface chemistry and roughness. This indicates and confirms that EHEC may facilitate the wetting of oil and greases. Methyl nanocellulose mixed with hydrophobically modified EHEC significantly changed the barrier properties indicating a change in the film formation.

The aim of this study was to determine hydrothermally induced changes in the physico-chemical properties of a fine microfibrillated cellulose (MFC). The MFC was prepared from a monocomponent endoglucanase-treated never-dried birch kraft pulp which had been run several times through a microfluidizer in order to obtain a sample substantially free from fibers or fiber fragments. The fine MFC was subjected to hydrothermal treatment at 150,^{circ }hbox {C} for 0.5, 2.5, 4.5, 8.5 and 20.5 h, after which the viscosity, water-retention capacity, surface charge, discoloration and formation of hydrolysis products were determined. The viscosity, surface charge and water-retention capacity of MFC decreased as a result of the treatment but in oscillatory measurements the storage and loss moduli increased. Hydrothermal treatment also caused discoloration of the sample which could not be fully washed away with water. Surface analysis with XPS revealed no significant changes in the surface structure of the dried MFC cakes but the filtrates after the hydrothermal treatment were complex mixtures of sugars, organic acids and furans. The main degradation products detected were xylose and xylobiose, but isomerization products of sugars (xylulose, fructose) were also found in the filtrates. In addition numerous organic acids, including formic, glycolic, lactic and xylonic acid, were identified in the filtrates, showing that both acid and alkaline catalyzed reactions occur due to dissociation of water into hbox {H}^{+} and hbox {OH}^{-}.

The number of polymers successfully electrospun is increasing, and methods are needed predict the electrospinnability of polymers. With such methods, researchers should consider the polymer solution parameters and perform measurements in conditions that mimic the electrospinning process. A novel test method based on the electromechanical simulation of the fiber formation was developed. We formed fibers by mechanically dragging a conductive ball from the solution at an applied voltage and measuring the electrical current. The changes in the time of the electrical current (the ball current) reflect the fiber‐formation process, which depended on certain polymer solution properties (e.g., viscosity, surface tension, liquid flow) and on the influence of charges on the fiber surface. The data obtained with the proposed method was compared with experimental data from electrospinning trials with the spinneret and bubble electrospinning. The results demonstrate that the ball‐current method made it possible to predict the polymer solution behavior in the electrospinning process. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41091.

During carbon steel manufacture, slag residues are generated to remove material impurities from liquid metal and thus control the quality of carbon steel. As the utilization of secondary metallurgical slags is not as efficient as those of primary slags, a comprehensive characterization of steel ladle slag was performed. Pseudo-total concentrations of a wide range of elements were determined during a 6-week sampling period with relevant physical and chemical properties, sequential extraction of trace elements, and parallel mineralogical characterization of extraction residues from a representative combined sample. According to the results, only Cr and V occurred in elevated concentrations with respective 6-week mean values of 198 and 310 mg kg−1 (d.w.). The residual standard deviation of the weekly pseudo-total concentration values of the aforementioned elements (24 and 31 %, respectively) indicated that significant variation in the concentration of trace elements can occur due to fluctuation in process conditions and/or slag characteristics. The sequential extraction procedure suggested potential phytoavailability of V (123 mg kg−1, d.w., amounting to 41 % of the respective pseudo-total concentration) through, e.g., changes in prevailing redox conditions. Although the analytical approach was validated by the analysis of a certified reference material and the calculation of extraction recoveries, the mineralogical characterization of parallel extraction residues indicated non-selectivity of the procedure coupled with potential redistribution phenomena during extraction with hydrogen peroxide and ammonium acetate.