Dewatering of foam-laid and water-laid structures and the formed web properties

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dc.contributorAalto-yliopistofi
dc.contributorAalto Universityen
dc.contributor.authorLehmonen, Janien_US
dc.contributor.authorRetulainen, Eliasen_US
dc.contributor.authorPaltakari, Jounien_US
dc.contributor.authorKinnunen-Raudaskoski, Karitaen_US
dc.contributor.authorKoponen, Anttien_US
dc.contributor.departmentDepartment of Bioproducts and Biosystemsen
dc.contributor.groupauthorPaper Converting and Packagingen
dc.contributor.organizationVTT Technical Research Centre of Finlanden_US
dc.contributor.organizationPaptic Ltden_US
dc.date.accessioned2020-06-25T08:42:51Z
dc.date.available2020-06-25T08:42:51Z
dc.date.issued2020-02-01en_US
dc.description.abstractThe use of aqueous foams as a carrier fluid for pulp fibers instead of water has re-emerged in the paper and board industry in recent years. In foam forming, a surfactant is needed to reduce the surface tension of the carrier liquid and to create foam as a process fluid and flowing medium. This presents the following questions: (1) How do the water forming and foam forming processes differ? (2) How do the obtained wet/dry fibre sheets differ after forming and after wet pressing? (3) Which differences in the process behavior and sheet properties are due to the surfactant, and which are due to the presence of air bubbles in the flowing medium? The answers to these questions were sought by using an experimental academic approach and by applying a special dynamic vacuum assisted sheet former. Although foams are much more viscous than water, dewatering times were found to be approximately equal in water and foam forming at higher vacuum levels. The hydrodynamic resistance of sheet was approximately constant during water forming, while in foam forming resistance was initially even smaller than in water forming but it increased with time, being substantially higher at the end of the forming process. In certain cases, surfactant alone was found to have a similar, albeit often lower, effect on the sheet properties of foam. Surfactant improved sheet dryness (both after forming and wet pressing), lowered density, and lowered strength properties also in water forming. Foam, on the other hand, had a crucial effect particularly on certain structural properties such as formation and porosity. The difference between water and foam-laid sheets typically reduced in line with higher wet pressing pressure. This suggests that the role of surface tension and foam bubbles in controlling interfiber contact is overridden by wet pressing pressure. Thus applying foam as a carrier fluid has characteristic effects both on the papermaking process and the end product properties. The main features of foam forming can be explained by the chemical effects caused by the surfactant, and the structural effects caused by the foam bubbles. Graphic abstracten
dc.description.versionPeer revieweden
dc.format.extent1127–1146
dc.format.mimetypeapplication/pdfen_US
dc.identifier.citationLehmonen, J, Retulainen, E, Paltakari, J, Kinnunen-Raudaskoski, K & Koponen, A 2020, ' Dewatering of foam-laid and water-laid structures and the formed web properties ', Cellulose, vol. 27, no. 3, pp. 1127–1146 . https://doi.org/10.1007/s10570-019-02842-xen
dc.identifier.doi10.1007/s10570-019-02842-xen_US
dc.identifier.issn0969-0239
dc.identifier.issn1572-882X
dc.identifier.otherPURE UUID: d2849bff-5f88-4bda-a632-8ae615641842en_US
dc.identifier.otherPURE ITEMURL: https://research.aalto.fi/en/publications/d2849bff-5f88-4bda-a632-8ae615641842en_US
dc.identifier.otherPURE LINK: http://www.scopus.com/inward/record.url?scp=85075458627&partnerID=8YFLogxKen_US
dc.identifier.otherPURE FILEURL: https://research.aalto.fi/files/43341305/CHEM_Lehmonen_et_al_2020_Dewatering_Cellulose.pdfen_US
dc.identifier.urihttps://aaltodoc.aalto.fi/handle/123456789/45220
dc.identifier.urnURN:NBN:fi:aalto-202006254177
dc.language.isoenen
dc.publisherSPRINGER
dc.relation.ispartofseriesCelluloseen
dc.relation.ispartofseriesVolume 27en
dc.rightsopenAccessen
dc.subject.keywordDewateringen_US
dc.subject.keywordFoam formingen_US
dc.subject.keywordIn-plane strength propertiesen_US
dc.subject.keywordInterfiber contacten_US
dc.subject.keywordStructural propertiesen_US
dc.subject.keywordWater formingen_US
dc.subject.keywordz-strengthen_US
dc.titleDewatering of foam-laid and water-laid structures and the formed web propertiesen
dc.typeA2 Katsausartikkeli tieteellisessä aikakauslehdessäfi
dc.type.versionpublishedVersion
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[article-cris] Kemian tekniikan korkeakoulu / CHEM