Influence of treatment temperature on wettability of Norway spruce thermally modified in vacuum

Kutnar, Andreja; Kričej, Borut; Pavlič, Matjaž; Petrič, Marko

doi:10.1080/01694243.2012.727168

Cited by 19 publications

(13 citation statements)

References 32 publications

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“…Other studies of UW components from spruce showed similar results to this study; 42 mJ/m 2 (Wålinder and Gardner 2000;Peterlin et al 2010) and 41 mJ/m 2 (Cordeiro et al 2012). In previous studies of the surface energy of TMW from spruce determined by contact angle measurement, the dispersive part of the surface energy was increased, whereas the polar part was decreased with thermal modification temperature (Kutnar et al 2013;Altgen et al 2016a). Similar results were obtained for TMW pine (Gérardin et al 2007), and aspen (Populus tremula) and grey alder (Alnus incana) (Sansonetti et al 2013).…”

Section: Surface Propertiessupporting

confidence: 85%

Sorption and Surface Energy Properties of Thermally Modified Spruce Wood Components

Källbom

Altgen

Militz

et al. 2018

W&FS

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The objective of this work is to study the water vapor sorption and surface energy properties of thermally modified wood (TMW) components, ie wood processing residuals in the form of sawdust. The thermal modification was performed on spruce wood components using a steam-pressurized laboratoryscale reactor at two different temperature (T ) and relative humidity (RH) conditions, T ¼ 150°C and RH ¼ 100% (TMW150), and T ¼ 180°C and RH ¼ 46% (TMW180). A dynamic vapor sorption (DVS) technique was used to determine water vapor sorption isotherms of the samples for three adsorption-desorption cycles at varying RH between 0% and 95%. Inverse gas chromatography (IGC) was used to study the surface energy properties of the samples, including dispersive and polar characteristics. The DVS results showed that the EMC was reduced by 30-50% for the TMW samples compared with control samples of unmodified wood (UW) components. A lower reduction was, however, observed for the second and third adsorption cycles compared with that of the first cycle. Ratios between EMC of TMW and that of UW samples were lower for the TMW180 compared with the TMW150 samples, and an overall decrease in such EMC ratios was observed at higher RH for both TMW samples. The IGC results showed that the dispersive contribution * Corresponding author † SWST member to the surface energy was higher at lower surface coverages, ie representing the higher energy sites, for the TMW compared with the UW samples. In addition, an analysis of the acid-base properties indicated a higher K B than K A number, ie a higher basic than acidic contribution to the surface energy, for all the samples. A higher K B number was also observed for the TMW compared with the UW samples, suggested to relate to the presence of ether bonds from increased lignin and/or extractives content at the surface. The K B was lower for TMW180 compared with TMW150, as a result of higher modification temperature of the first, leading to cleavage of these ether bonds.

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Section: Surface Propertiessupporting

confidence: 85%

Sorption and Surface Energy Properties of Thermally Modified Spruce Wood Components

Källbom

Altgen

Militz

et al. 2018

W&FS

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“…Moderate heat treatment of beech increases its free energy, while severe thermal modification decreases free energy in spruce (Kutnar et al 2013). At the beginning of thermal modification, lignin starts to degrade, but at a slower rate than polysaccharides (Windeisen et al 2007;Esteves et al 2008;Esteves and Pereira 2009), which contributes to a more hydrophilic surface, particularly with spruce, which was modified at higher temperatures than beech.…”

Section: Determination Of Contact Anglesmentioning

confidence: 99%

Influence of Artificial and Natural Weathering on the Hydrophobicity and Surface Properties of Wood

Žlahtič¹,

Humar²

2016

BioResources

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The use of wood in outdoor, above-ground applications is increasing in Europe. To further increase wood usage, more information related to service life and maintenance costs must be provided. Water exclusion efficacy (WEE) is one of the most important factors influencing service life and strongly correlates to wood moisture dynamics, surface properties, and hydrophobicity (WEE as a whole). WEE can be improved with modifications and hydrophobic treatments. The aim of this study was to elucidate which wood surface properties affect WEE and to note changes over time caused by artificial or natural aging. Wood samples of oak (Quercus), sweet chestnut (Castanea sativa), European larch (Larix decidua), Scots pine heartwood and sapwood (Pinus sylvestris), Norway spruce (Picea abies), and beech (Fagus sylvatica) were used to investigate this phenomenon. The moisture performance of the wood samples was improved with thermal modification, wax, oil, and biocide treatment. In total, 17 materials were prepared. After treatment, four different aging procedures were applied. Before and after aging, Fourier transform infrared spectra, colour, and contact angle were determined. The analysis of untreated wood based materials indicated that durability and hydrophobicity are related. Of all the treatments, wax performed the best and retained high hydrophobicity even after the most severe aging method (outdoor exposure).

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“…Treatment of wood samples at high temperatures under vacuum caused a slight change in samples weight, as it is reflected by Δw before leaching ( Table 1). The low Δw of wood samples due to vacuum-heat treatment was reported previously (Allegretti et al 2012, Kutnar et al 2013, which is mainly due to the removal of volatile compounds (Pockrandt et al 2018). Combined treatment of wood samples with glycerol pretreatment and vacuum-heat treatment caused a significant change in Δw values.…”

Section: Resultsmentioning

confidence: 51%

Vacuum-heat treatment of Scots pine (Pinus sylvestrisL.) wood pretreated with propanetriol

Sivrikaya

Hosseinpourpia

Ahmed

et al. 2020

Wood Material Science & Engineering

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Influence of treatment temperature on wettability of Norway spruce thermally modified in vacuum

Cited by 19 publications

References 32 publications

Sorption and Surface Energy Properties of Thermally Modified Spruce Wood Components

Sorption and Surface Energy Properties of Thermally Modified Spruce Wood Components

Influence of Artificial and Natural Weathering on the Hydrophobicity and Surface Properties of Wood

Vacuum-heat treatment of Scots pine (Pinus sylvestrisL.) wood pretreated with propanetriol

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