Hydrophobisation of lignocellulosic materials part I: physical modification
2022 (English)In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 29, no 10, p. 5375-5393Article in journal (Refereed) Published
Abstract [en]
This review is the first part of a comprehensive review of hydrophobisation of lignocellulosic materials. The purpose of this review has been to compare physical hydrophobisation methods of lignocellulosic materials. We have compared molecular physical adsorption with plasma etching and grafting. Adsorption methods are facile and rely upon the simple mixing or coating of the substrate with the hydrophobing agent. However, none of the surfactant-based methods reviewed here reach contact angles above 90°, making them unsuitable for applications where a high degree of hydrophobisation is required. Nevertheless, surfactant based methods are well suited for compatibilising the lignocellulosic material with a hydrophobic matrix/polymer in cases where only a slight decrease in the hydrophilicity of the lignocellulosic substrate is required. On the other hand, wax- and lignin-based coatings can provide high hydrophobicity to the substrates. Plasma etching requires a more complex set-up but is relatively cheap. By physically etching the surface with or without the deposition of a hydrophobic coating, the material is rendered hydrophobic, reaching contact angles well above 120°. A major drawback of this method is the need for a plasma etching set-up, and some researchers co-deposit fluorine-based layers, which have a negative environmental impact. An alternative is plasma grafting, where single molecules are grafted on, initiated by radicals formed in the plasma. This method also requires a plasma set-up, but the vast majority of hydrophobic species can be grafted on. Examples include fatty acids, silanes and alkanes. Contact angles well above 110° are achieved by this method, and both fluorine and non-toxic species may be used for grafting. Graphical abstract: [Figure not available: see fulltext.]. © 2022, The Author(s).
Place, publisher, year, edition, pages
Springer Science and Business Media B.V. , 2022. Vol. 29, no 10, p. 5375-5393
Keywords [en]
Adsorption, Cellulose, Hydrophobisation, Plasma etching, Plasma grafting, Coatings, Contact angle, Environmental impact, Fatty acids, Fluorine, Grafting (chemical), Hydrophilicity, Hydrophobicity, Substrates, Surface active agents, Adsorption method, Hydrophobic matrix, Hydrophobizations, Lignocellulosic material, Lignocellulosic substrates, Matrix polymers, Physical adsorption, Physical modifications, Simple++, Copolymerization, Water, Wettability
National Category
Physical Chemistry
Identifiers
URN: urn:nbn:se:ri:diva-60012DOI: 10.1007/s10570-022-04620-8Scopus ID: 2-s2.0-85130756941OAI: oai:DiVA.org:ri-60012DiVA, id: diva2:1701818
Note
Funding details: Norges Forskningsråd, 274975; Funding text 1: The authors would like to acknowledge the Research Council of Norway and its funding of the NanoPlasma project (274975).
2022-10-072022-10-072023-05-25Bibliographically approved