Geopolymer as a multifunctional mineral binder to produce laminated veneer lumber: effect of various aluminosilicate powder types on panels and geopolymer binder features

Allahverdipoorazar, Farzaneh; Shalbafan, Ali; Berthold, Dirk

doi:10.1007/s00107-020-01633-7

Cited by 5 publications

(6 citation statements)

References 29 publications

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“…Excess water could also have caused pores and contributed to the observed reduction in strength [ 23 ]. It is also conceivable that the binder with lower solids content (higher W/C molar ratio) penetrated more into the wood cells/cavity structure and resulted in a weak glue joint (starved glue joint) [ 14 , 15 , 29 ]. The highest bond shear strength was observed for samples with M/C and W/C molar ratios of 9 and 15, respectively, with 1.1 MPa for the untreated sample, 0.62 MPa for the water-soaked (24 h) and 0.55 MPa for the water-boiled (6 h) samples.…”

Section: Resultsmentioning

confidence: 99%

“…The higher the W/C molar ratio, the lower the binder strength and the lower the bending properties of the plywood panels. A more dilute binder can penetrate more into the wood structures, resulting in a starved binder line, which in turn has a negative effect on the bending properties [ 14 , 15 , 29 ]. Moreover, the further formation of Mg(OH) 2 in the hardened binder leads to instability and a subsequent decrease in binder performance [ 24 ].…”

Section: Resultsmentioning

confidence: 99%

“…A pressing temperature of 140 °C, a pressing pressure of 1.5 MPa and a pressing factor of 55 s/mm were used for hot pressing, resulting in a pressing time of 495 s for all panels. These parameters were chosen in view of our previous experience with mineral binders as well as the preliminary tests [ 14 , 15 ]. A similar hot-pressing schedule was used for the production of all panels.…”

Section: Methodsmentioning

confidence: 99%

“…The application rate of the dry MOC binder was kept constant at 420 g/m 2 for all plywood panels, while the solid content of the binder varied in the different formulations. The mineral binder has higher density compared to conventional adhesive; hence, a higher amount of binder is needed to meet the full coverage of veneer faces [ 14 ]. The average density of the plywood panels made with MOC binder was about 560 kg/m 3 .…”

Section: Methodsmentioning

confidence: 99%

“…Berzins et al [ 12 ] have shown that geopolymers can be used for the gluing of solid wood. Researchers also successfully demonstrated that the organic binder can be replaced by a mineral binder for the laboratory production of plywood and LVL [ 13 , 14 , 15 ]. In these works, geopolymer was formulated as a mineral binder using aluminosilicate powder and an alkaline activator prepared from a mixture of sodium silicate and potassium hydroxide.…”

Section: Introductionmentioning

confidence: 99%

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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%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

Shalbafan

Thoemen

2023

Polymers

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Development of bentonite-based organo-geopolymer hybrid wood binder

Gonultas

2024

Eur. J. Wood Prod.

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The study addresses concerns associated with formaldehyde-based adhesives in wood panel board production by proposing geopolymer-based wood binders as promising, formaldehyde-free alternatives. Using bentonite, the research delves into the development and performance properties of this geopolymer wood binder. The BET method was employed for the surface characterization of precursor raw materials for binder preparation. Si and Al elements identified through XRF analysis were correlated with characteristic bands in the FTIR spectrum. Alkaline activation solutions, employing sodium silicate and sodium hydroxide with a molar ratio range of 0.5 to 2.5 (SiO2:Na2O), revealed that binders with a molar ratio of 2.5 exhibited lower pH and higher adhesion strength. Different geopolymer formulations at solution to powder ratios (s/p) of 1.33, 3, and 3.5 determined s/p 3.5 as optimal for bentonite-based organo-geopolymer binders. Viscosity, gel time, pH, and solids content were examined, showing the effectiveness of substituting 10% silica fume to enhance the geopolymerization process and improve adhesion. Modifications using citric acid, sucrose, paraffin, pMDI, triacetin, and resorcinol demonstrated wet bonding strength comparable to urea formaldehyde adhesive. Analytical techniques, including FTIR spectroscopy, XRD analysis, and SEM EDX analysis, provided insights into functional groups, crystallographic properties, and microstructural characteristics. The concentration of Si and Al compounds on the bonding line, coupled with Na element diffusion, was observed through these analyses. Light microscopy of lap shear samples revealed a thinner bonding line, affirming effective binder penetration into wood cell lumens in bentonite-based organo-geopolymer binder formulations.

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Improving the performance of geopolymer-based wood adhesives using a green mechanochemical strategy

Lin,

Zheng,

Bian

et al. 2024

International Journal of Adhesion and Adhesives

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Geopolymer as a multifunctional mineral binder to produce laminated veneer lumber: effect of various aluminosilicate powder types on panels and geopolymer binder features

Cited by 5 publications

References 29 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

Development of bentonite-based organo-geopolymer hybrid wood binder

Improving the performance of geopolymer-based wood adhesives using a green mechanochemical strategy

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