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Wet-laying is a mature technology that is applied in large scale for the manufacture of nonwovens, including paper products. However, it usually uses large volumes of water and is energy-intensive. Here we used foam-laying to substantially diminish the volume of water consumed in the formation of fiber networks (5-fold reduction) and to reduce the water content of the nonwovens produced before drying, achieving a reduced energy demand. The prospects of foam-laying were evaluated by comparing foam-laid and wet-laid webs of two types of wood fibers: stiff (lignin-containing) or flexible (lignin-free). Also, the effect of foaming agent type (anionic, cationic, nonionic, and amphoteric) was elucidated. Reference webs were produced by conventional wet-laying, with or without surfactants. Foam-laying was effective in producing a more uniform areal mass distribution (better formation) after wet-pressing. This effect was more evident for the webs synthesized with the flexible fibers. Unlike the layered network structures that were obtained by wet-laying, foam-laid webs exhibited a more felted network, with fibers positioned in the out-of-plane direction. As a result, higher air permeability, web porosity, and light scattering coefficients were measured for the foam-laid webs. The enhanced porosity (lower density) was related to the effect of bubbles during foam-laying and the reduction in surface tension of the foamed-fiber dispersion. The resistance to delamination of low-density webs obtained by foam-laying in the out-of-plane direction was preserved. However, the reduction in tensile strength and modulus of foam-laid webs were determined, owing to the reduced density of the formed structures. Notably, the type of foaming agent used played a minor role as far as the resultant properties of the webs, making the process flexible in terms of the selection of environmentally friendly alternatives. Overall, we compared the physico-mechanical properties of fiber networks formed by web- and foam-laying, depending on fiber type and foaming agent, yielding a property space that is useful in the design of lightweight structures (nonwovens, including paper). The prospects of water and energy savings by foam-laying are the major benefits in the sustainable use of fibers for the assembly of porous materials, such as lightweight nonwoven and paper products.
|Journal||ACS Sustainable Chemistry and Engineering|
|Publication status||Published - 23 Sep 2018|
|MoE publication type||A1 Journal article-refereed|
- Felted structure
- Lignocellulosic fibers
- Out-of-plane strength
FingerprintDive into the research topics of 'Foam Processing of Fibers As a Sustainable Alternative to Wet-Laying : Fiber Web Properties and Cause-Effect Relations'. Together they form a unique fingerprint.
Rojas Gaona, O., Abidnejad, R., Ajdary, R., Bhattarai, M., Zhu, Y., Zhao, B., Robertson, D., Reyes Torres, G., Johansson, L., Garcia Greca, L., Klockars, K., Kämäräinen, T., Majoinen, J., Tardy, B., Dufau Mattos, B. & Ressouche, E.
30/07/2018 → 31/07/2023
Project: EU: ERC grants
Halonen, K., Saarinen, V., Pulkkinen, M., Moayer, M. M., Haapala, T. & Salomaa, J.
01/01/2017 → 31/12/2018
Project: Business Finland: Other research funding
SIRAF / Rojas
Tardy, B., Rojas Gaona, O., Ishfaq, A., Lehtonen, J., Johansson, L., Beaumont, M., Klockars, K., Zhu, Y., Dufau Mattos, B., Borghei, M. & Xiang, W.
01/09/2016 → 31/08/2020
Project: Academy of Finland: Other research funding
Bioeconomy Research Infrastructure
Jukka Seppälä (Manager)School of Chemical Engineering
Anna Rissanen (Manager)Aalto University
OtaNano - Nanomicroscopy Center
Jani Seitsonen (Manager)OtaNano