Synthetic Adhesives for Wood Fibers and Composites: Chemistry and Technology

Pizzi, A.

doi:10.1002/9781118773727.ch9

Cited by 6 publications

(5 citation statements)

References 97 publications

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“…In relevant literature, the pH of spruce wood for cold water is 4.9 and for hot water 4.6 [ 15 ], so basically in a similar range but with a tendency to a more acidic range. The pH is not suspected to influence the performance of pMDI curing reaction [ 42 ]. Herzog [ 43 ] found a comparable amount of 4.46% for cold water extraction when investigating the same fiber mix (another batch).…”

Section: Resultsmentioning

confidence: 99%

On the Feasibility of a pMDI-Reduced Production of Wood Fiber Insulation Boards by Means of Kraft Lignin and Ligneous Canola Hulls

et al. 2021

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The thermal insulation of buildings using wood fiber insulation boards (WFIBs) constitutes a positive contribution towards climate change. Thereby, the bonding of wood fibers using mainly petrochemical-based resins such as polymeric diphenylmethane diisocyanate (pMDI) is an important measure to meet required board properties. Still there is a need to reduce or partial substitute the amount of these kinds of resins in favor of a greener product. This study therefore focusses on the feasibility of reducing the amount of pMDI by 50% through the addition of 1% BioPiva 395 or Indulin as two types of softwood Kraft-Lignin and lignin rich canola hulls together with propylene carbonate as a diluent. A panel density of 160 kg/m3 and a thickness of 40 mm was aimed. The curing of these modified pMDI was investigated by using two types of techniques: hot-steam (HS) and innovative hot-air/hot-steam-process (HA/HS). The WFIBs were then tested on their physical-mechanical properties. The equilibrium moisture content (EMC) was determined at two different climates. An exemplary investigation of thermal conductivity was conducted as well. The WFIBs did undergo a further chemically based analysis towards extractives content and elemental (C, N) composition. The results show that it is feasible to produce WFIBs with lower quantities of pMDI resin and added lignin with enhanced physical-mechanical board properties, which were lacking no disadvantages towards thermal conductivity or behavior towards moisture, especially when cured via HA/HS-process.

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Section: Resultsmentioning

confidence: 99%

On the Feasibility of a pMDI-Reduced Production of Wood Fiber Insulation Boards by Means of Kraft Lignin and Ligneous Canola Hulls

et al. 2021

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“…By increasing the molar ratio of formaldehyde to melamine urea, more di hydroxymethylureas and trihydroxymethylureas are produced in the MUF resin and it causes the molecular weight to be higher with longer chains resulting from methylene and methylene ether bonds and more branched chains [43]. On the other hand, by using NH 4 Cl, the coagulation speed and temperature can be reduced as a result of the release of hydrochloric acid, so that the higher the molar ratio of formaldehyde, the higher the coagulation speed of MUF [44]. But due to the non-use of NH 4 Cl, which was due to the possibility of determining the effect of hydrolyzed protein on the coagulation speed of MUF resin, increasing the temperature has completed the polycondensation reaction.…”

Section: Resultsmentioning

confidence: 99%

Application of the Artificial Neural Network to Predict the Bending Strength of the Engineered Laminated Wood Produced Using the Hydrolyzed Soy Protein-Melamine Urea Formaldehyde Copolymer Adhesive

2023

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The artificial neural network (ANN) was used to predict the modulus of rupture (MOR) of the laminated wood products adhered by melamine/urea formaldehyde (MUF) resin with different formaldehyde to melamine/urea molar ratios combined with different weight ratios of the protein adhesive resulting from the alkaline treatment (NaOH) of the soybean oil meal to MUF resin pressed at different temperatures according to the central composite design (CCD). After making the boards and performing the mechanical test to measure the MOR, based on experimental data, different statistics such as determination coefficient (R2), root mean square error (RMSE), mean absolute error (MAE) and sum of squares error (SSE) were determined, and then the suitable algorithm was selected to determine the estimated values. After comparing estimated values with the experimental values, the direct and interactive effects of the independent variables on MOR were determined. The results indicated that using suitable algorithms to train the ANN well, a very good estimate of the bending strength of the laminated wood products can be offered with the least error. In addition, based on the estimated and measured strengths and FTIR and TGA diagnostic analyses, it was found that the replacement of the MUF resin by the protein bio-based adhesive when using low F to M/U molar ratios, the MOR is maximized if a high range of temperature is used during the press.

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“…Knowing that the pH of the binders was around 11, these pH values show a good buffering capacity of the wood chips used, proving that using a binder with high pH value poses no issue for the wood product, as far as the raw wood material has a good ability of neutralizing the effect. This has been proven with synthetic binders such as phenol formaldehyde (Zhang et al, 2010) or pMDI (Pizzi, 2016) which have a pH from low (6-8 for pMDI) to high (about 13 for PF resin) alkaline. The amount of cold-water extractive had the same pattern like the pH, with the highest amount obtained with the S. bisul te variant (6.41%) followed by S. nitrite and S. bisulfate (5.91% and 5.56% respectively).…”

Section: Cold-water Extractives and Phmentioning

confidence: 99%

Canola Protein Wood Adhesive with Improved Bonding properties

Tayo,

Cárdenas-Oscanova,

Beulshausen

et al. 2024

Preprint

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The importance of creating eco-friendly and health-conscious materials has become paramount in striving to attain long term development gaols. For the past decades, constant efforts have been made to tackle the issue of formaldehyde release from wood-based panels which, to date, are still mainly produced using unsustainable synthetic adhesives. In the pursuit of sustainable and environmentally responsible adhesive solutions for the wood industry, sodium bisulfate, sodium bisulfite, and sodium nitrite were used as crosslinkers for canola protein-based bio-adhesive formulations with superior binding properties for the production of particleboards. The developed adhesive formulations showed outstanding mechanical properties, with a viscosity below 4000 mPa/s despite the relatively high solid content, as well as excellent bonding performances. The one-layer particleboards bonded with the canola-based adhesive exhibited excellent mechanical properties, with values of the internal bonding and the bending strength above 0.60 N/mm2 and 10 N/mm2 respectively of the sodium nitrite-treated variants being significantly greater than that of the UF-bonded control boards. the SEM analysis revealed a good crystallisation of the adhesive in the wood-binder matrix. The results of this research showcase not only the possibility of developing a plant protein-based wood adhesive with high solid content, but also the potential superiority of canola protein-based wood adhesives when compared to conventional, synthetic counterparts. This study is a milestone in the field of eco-friendly adhesive technologies, opening new horizons for sustainable wood-based materials.

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Synthetic Adhesives for Wood Fibers and Composites: Chemistry and Technology

Cited by 6 publications

References 97 publications

On the Feasibility of a pMDI-Reduced Production of Wood Fiber Insulation Boards by Means of Kraft Lignin and Ligneous Canola Hulls

On the Feasibility of a pMDI-Reduced Production of Wood Fiber Insulation Boards by Means of Kraft Lignin and Ligneous Canola Hulls

Application of the Artificial Neural Network to Predict the Bending Strength of the Engineered Laminated Wood Produced Using the Hydrolyzed Soy Protein-Melamine Urea Formaldehyde Copolymer Adhesive

Canola Protein Wood Adhesive with Improved Bonding properties

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