Influence of Wet and Dry Cycle on Properties of Magnesia-Bonded Wood-Wool Panel

Bin, Na; Wang, Haiqing; Ding, Tao; Lu, Xiaoling

doi:10.37763/wr.1336-4561/65.2.271282

Cited by 3 publications

(2 citation statements)

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“…This is an important result, showing the potential of MOC-bonded plywood also for exterior applications. Studies have shown that free/released MgCl 2 in hot water can generate and precipitate Mg(OH)Cl, which effectively improves the hygroscopic properties of MOC [ 34 ]. In particular, the bio-based adhesives based on tannin, soy, chitosan, etc., developed for EWP production showed very low water resistance (see Table 5 ), especially to boiling water, making their final application a major challenge [ 1 , 2 ].…”

Section: Resultsmentioning

confidence: 99%

Development of Mineral-Bonded Plywood with Magnesium Oxychloride as a Binder Using the Hot-Pressing Process

Shalbafan

Thoemen

2023

Polymers

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Environmentally friendly plywood panels were produced by a hot-pressing process using magnesium oxychloride cement (MOC) as a no-added formaldehyde adhesive. Magnesium oxychloride cement binders were prepared with different molar ratios of MgO:MgCl2 (M/C) and H2O:MgCl2 (W/C) ranging from 6 to 12 and 15 to 21, respectively, for plywood production. The binder properties measured were gel time, differential scanning calorimetry (DSC) and Fourier transom infrared spectroscopy (FTIR). The quality of the plywood panels was analyzed based on their mechanical (shear and bending) and physical (thickness swelling and water absorption) properties. A positive effect on the properties of the MOC binder as well as on the properties of the plywood was observed by increasing the molar ratio M/C up to a value of 9. The shear and flexural properties of the plywood specimens were negatively affected by further increasing the molar ratio M/C to 12 and the molar ratio W/C from 15 to 21. Differential scanning calorimetry analysis showed a peak temperature of less than 100 °C for MOC curing, which meets the requirements of hot press technology. No delamination of the plywood specimens was observed after 24 h immersion in tap water or 6 h immersion in boiling water and after a cyclic delamination test. In general, mineral-bonded plywood with magnesium oxychloride shows promising properties for indoor and outdoor use, although the binder quality should still be improved.

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Section: Resultsmentioning

confidence: 99%

Development of Mineral-Bonded Plywood with Magnesium Oxychloride as a Binder Using the Hot-Pressing Process

Shalbafan

Thoemen

2023

Polymers

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“…The major hemicellulose in spruce is galactoglucomannan, which consists of a backbone of randomly distributed (1→4)-linked mannose and glucose units with side groups of (1→6)-linked galactose units attached to mannose (Azhar 2015, Sjöström 1993, Timell 1967). Not all types of sugar have the same inhibitory effect (Na et al 2014). Glucose and sucrose were determined as the main inhibitory components for the hardening of cement matrixes (Yasuda et al 2002).…”

Section: Sugars and Ph Analysingmentioning

confidence: 98%

Spruce chips stabilization in wood-cement materials: Effect of matrix composition

Melichar,

Bydzovsky,

Meszarosova

et al. 2023

Maderas-Cienc Tecnol

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The problem of the presented research is stabilization of spruce chips in modified cement matrix of wood-cement composites and analysing the effect of the stabilisation on selected parameters of these composite materials. The matrix has an impact on the stabilization of the spruce wood content. Silicate matrix based on Portland and blended cement was modified by finely ground thermal power plant slag (TPPS) and limestone (LS). Four types of wood-cement composite were subjected to water immersion tests for 28 days. During water immersion, both swelling in thickness and mass changes were analysed. The amount of sugars and pH in leachate were determined after 7 day intervals. Mechanical properties and microstructures were analysed before and after water immersion. Different behaviour with regard to spruce chips stabilization was proved in dependence of wood-cement matrix modification. Differences in thickness, swelling and sugar leach indirectly indicate the influence of the wood-cement composites matrix composition on the stabilization of spruce chips contained in this matrix. Boards with the matrix modified with thermal power plant slag showed the highest thickness swelling (%) and sugar leaching (0,042 %). Therefore, in the presence of thermal power plant slag modified matrix, spruce chips are more susceptible to sugar leach. The results of strength characteristics confirmed that sugars leached during hydration and after longer contact of wood-cement composites with water have no negative influence in their final properties in the case of all materials tested (reference and modified).

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The Effect of Wet and Dry Cycles on the Strength and the Surface Characteristics of Coromandel Lacquer Coatings

Liu,

Zhu,

Varodi

et al. 2024

Forests

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Research on the degradation mechanism of coating materials is crucial for the preservation of cultural heritage. The purpose of this study was to evaluate the protective effect of Coromandel coatings on wooden substrates by analyzing their dimensions, weight, adhesion strength, hydrophobicity, and glossiness. The results indicate that after five cycles, the radial moisture expansion rate of the wood specimen is 0.332%, while that of the lacquer specimen is 0.079%, representing 23.8% of the radial moisture expansion rate of untreated wood specimens. This performance is superior to that of the ash and pigment specimens. Across different experimental conditions, the change in the mass of the Coromandel specimens aligns with the trend in their dimensional changes, indicating that moisture absorption and desorption are the primary reasons for dimensional changes. The influence of temperature on mass and dimensional stability is significant only in terms of dry shrinkage rate. After wet and dry cycles at 40 °C, the adhesion strength of the Coromandel specimens decreases the most, with the ash specimens decreasing by 7.2%, the lacquer specimens by 3.2%, and the pigment specimens by 4.5%. Following wet and dry cycles at three different temperatures, the contact angle of the lacquer layers changes by less than 5%, with their contact angle values exceeding 120°. These data indicate that among the Coromandel coatings, the lacquer layer provides the best protection for the wooden substrate, while the ash coating is the most fragile. The degradation rate of the Coromandel specimens increases with rising temperatures. These findings emphasize the critical roles of humidity and temperature in protecting wooden coatings and aim to provide theoretical insights and practical significance for the preservation of wooden artifacts and the assessment of coating performance.

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Influence of Wet and Dry Cycle on Properties of Magnesia-Bonded Wood-Wool Panel

Cited by 3 publications

References 0 publications

Development of Mineral-Bonded Plywood with Magnesium Oxychloride as a Binder Using the Hot-Pressing Process

Development of Mineral-Bonded Plywood with Magnesium Oxychloride as a Binder Using the Hot-Pressing Process

Spruce chips stabilization in wood-cement materials: Effect of matrix composition

The Effect of Wet and Dry Cycles on the Strength and the Surface Characteristics of Coromandel Lacquer Coatings

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