Assessment of moisture protective properties of wood coatings by a portable NMR sensor

Pourmand, Payam; Wang, Lin; Dvinskikh, Sergey V.

doi:10.1007/s11998-011-9348-8

Cited by 18 publications

(7 citation statements)

References 24 publications

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“…Overall, the results, interpretations, and classifications reported in this article facilitate the use of these methods in the characterization of the decomposition process noninvasively in real time. The methods might be used, for example, in the investigation of new kinds of protective agents of wood or in situ detection of decomposition of buildings by portable NMR/MRI devices (Dvinskikh et al 2011a,b;Pourmand et al 2011).…”

Section: Discussionmentioning

confidence: 99%

Characterization of the decay process of Scots pine caused by Coniophora puteana using NMR and MRI

et al. 2020

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Wood decay is an economically significant process, as it is one of the major causes of wood deterioration in buildings. In this study, the decay process of Scots pine (Pinus sylvestris) samples caused by cellar fungus (Coniophora puteana) was followed by nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) methods. Altogether, 30 wood sample pieces were exposed to fungus for 10 weeks. Based on the decrease of the dry mass, the samples were categorized into three classes: decomposed (mass decrease 50–70%), slightly decomposed (10–50%), and nondecomposed (<10%). MRI made it possible to identify the active regions of fungus inside the wood samples based on the signal of free water brought by the fungus and arisen from the decomposition of wood carbohydrates. MRI implies that free water is not only created by the decay process, but fungal hyphae also transports a significant amount of water into the sample. Two-dimensional 1H T1-T2 relaxation correlation NMR measurements provided detailed information about the changes in the microstructure of wood due to fungal decomposition. Overall, this study paves the way for noninvasive NMR and MRI detection of fungal decay at early stages as well as the related structural changes.

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Section: Discussionmentioning

confidence: 99%

Characterization of the decay process of Scots pine caused by Coniophora puteana using NMR and MRI

et al. 2020

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“…Here, the MC of a wood sample is determined on the basis of the mass of the moist wood sample and the amplitude of the free-induction decay (FID) signal. It has also been shown that portable NMR provides a powerful tool for the determination of local MC of wood in situ. − The method can be used in a variety of wood constructions and for both coated and noncoated wood. Anisotropic line shapes can also be associated with the structure of wood .…”

Section: Introductionmentioning

confidence: 99%

Absorption of Water in Thermally Modified Pine Wood As Studied by Nuclear Magnetic Resonance

2014

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Thermal modification is an environmentally friendly method to increase the lifetime and improve the properties of timber. In this work, we investigate absorption of moisture in thermally modified pine wood (Pinus sylvestris) immersed in water using various nuclear magnetic resonance (NMR) methods. Magnetic resonance images (MRI) visualize the spatial distribution of absorbed free water. Spin−echo spectra measured both below and above 0 °C reveal that thermal modification partially blocks the access of water to cell walls; even modification at 180 °C slightly reduces the amount of bound water, and the amount decreases about 80% in the case of the sample modified at 240 °C. The spectra and MRI show that, above the modification temperature of 200 °C, the amount of free water decreases, indicating that high modification temperature tends to close the pits connecting the wood cells. T 2 relaxation time distributions measured using the Carr−PurcellMeiboom−Gill sequence show four components, two associated with bound water and two with free water. NMR cryoporometry measurements indicate that the bound water sites are mostly below 2.5 nm in size. A unique combined NMR cryoporometry and relaxometry analysis showed that the size of cell wall micropores is between 1.5 and 4.5 nm, and thermal modification significantly hinders the access of water to the pores.

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“…The corresponding apparent diffusion coefficients (influenced by the coating, wood and the interfacial layer between coating and wood) are even three orders of magnitude lower. Pourmand et al (2011) measured a similar barrier effect only for an oil-based paint. In contrast, De Meijer and Militz (2000) measured clearly lower differences of the diffusion coefficients (factor C0.086) between coated spruce wood and uncoated samples over a period of 1700 h. Thus, the low diffusion coefficient of coating system 1, which included only the initial phase of the diffusion process, can be explained by the characteristic of water adsorption of coated wood, which is delayed in the initial phase according to Sivertsen and Flaete (2012) and therefore results in a too low apparent diffusion coefficient within this phase.…”

Section: Test 2: Liquid Water Uptakementioning

confidence: 83%

“…The aim of this paper is to investigate the influence of two different coating systems (acrylate/polyurethane and silica based) on the water vapour diffusion behaviour, the water uptake during direct water contact under the coating in the wood and the influence of surface defects. The moisture change within the wood over time was measured with the non-destructive neutron imaging method, which is an approved method in this research field and complements the nuclear magnetic resonance (NMR) technology (Pourmand et al 2011;Van Meel et al 2011), in order to determine the spatial distribution of MC changes (Lanvermann et al 2014;Lehmann et al 2001;Mannes et al 2009;Sedighi-Gilani et al 2012;Sonderegger et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Investigations into the influence of two different wood coatings on water diffusion determined by means of neutron imaging

et al. 2015

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The diffusion of water into spruce wood coated with an acrylate/polyurethane and with a silica-based coating system is investigated by varying the humidity conditions. Thereby, the change of moisture content (MC) is measured and analysed with the non-destructive method of neutron imaging. For the acrylate/polyurethane based coating system, the barrier effect of the coating on wood sorption in direct water contact and the influence of surface defects on this barrier effect are also tested. On changing the humidity conditions, the specimens with silica-based coating initially show a clear deceleration of the sorption process, whereas after 10 days the MC gradient is nearly similar to the uncoated reference specimens. In contrast, the specimens with acrylate/polyurethane based coating show a strong barrier effect against water sorption into wood over the whole measurement period when changing the humidity conditions and in direct water contact. As can be expected, a defect in the coating strongly reduces its barrier effect. Thereby, the kind of defect (saw kerf or blade cut) is rather irrelevant.

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Assessment of moisture protective properties of wood coatings by a portable NMR sensor

Cited by 18 publications

References 24 publications

Characterization of the decay process of Scots pine caused by Coniophora puteana using NMR and MRI

Characterization of the decay process of Scots pine caused by Coniophora puteana using NMR and MRI

Absorption of Water in Thermally Modified Pine Wood As Studied by Nuclear Magnetic Resonance

Investigations into the influence of two different wood coatings on water diffusion determined by means of neutron imaging

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