The hydrophobicity of lignocellulosic fiber network can be enhanced with suberin fatty acids

Risto I. Korpinen, Petri Kilpeläinen, Tytti Sarjala, Maristiina Nurmi, Pauliina Saloranta, Thomas Holmbom, Hanna Koivula, Kirsi S. Mikkonen, Stefan Willför, Pekka T. Saranpää

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)

Abstract

Suberin fatty acids were extracted from outer bark of Silver birch (Betula pendula Roth.) using an isopropanolic sodium hydroxide solution. Laboratory sheets composed of lignocellulosic fiber networks were prepared from unbleached and unrefined softwood kraft pulp and further impregnated with suberin fatty acid monomers and cured with maleic anhydride in ethanol solution. The treatment resulted in hydrophobic surfaces, in which the contact angles remained over 120 degrees during the entire measurement. The fiber network also retained its water vapor permeability and enhanced fiber–fiber bonding resulted in improved tensile strength of the sheets. Scanning electron microscopy (SEM) images revealed that the curing agent, together with suberin fatty acids, was evenly distributed on the fiber surfaces and smoothing occurred over the wrinkled microfibrillar structure. High concentrations of the curing agent resulted in globular structures containing betulinol derivates as revealed with time-of-flight secondary ion mass spectrometry (ToF-SIMS). Also, the larger amount of suberin fatty acid monomers slightly impaired the optical properties of sheets.

Original languageUndefined/Unknown
Pages (from-to)
JournalMolecules
Volume24
Issue number23
DOIs
Publication statusPublished - 2019
MoE publication typeA1 Journal article-refereed

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