Tannin-based wood adhesive with good water resistance crosslinked by hexanediamine

Xu, Gaoxiang; Zhang, Qianyu; Xi, Xuedong; Lei, Hong; Cao, Ming; Du, Guanben; Wu, Zhigang

doi:10.1016/j.ijbiomac.2023.123644

Cited by 19 publications

(8 citation statements)

References 35 publications

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“…The appearance of these two absorption peaks showed that, first, model compound UF2 was hydrolyzed in the solution system and produced free formaldehyde, as shown in Formula (6); second, resorcinol experienced hydroxymethylation with formaldehyde, and protonated formaldehyde was formed under acidic conditions, as shown in Formulas (7) and (8). Moreover, resorcinol benzene ring anions were formed under alkaline conditions, as shown in Formulas ( 17) and (18); third, the self-polycondensation structure of resorcinol could be formed under both acidic and alkaline conditions. The acidic active intermediates came from hydroxymethyl resorcinol carbocation, as shown in Formulas ( 9)-( 12), and the active intermediate under alkaline conditions was resorcinol benzene ring anion, which reacted with the resorcinol benzoquinone structure, as displayed in Formulas ( 19) and (20).…”

Section: The Polycondensation Law Of Model Compounds Resorcinol and D...mentioning

confidence: 96%

“…Tannin adhesives can be prepared with high-tannin-content plants as the main Forests 2024, 15, 98 2 of 18 raw materials [10][11][12][13][14], showing broad application prospects. According to the chemical composition and structure, condensed tannins account for 90% of the world tannin yield, with economic development value in the production of adhesives and resins [15][16][17][18]. In addition, condensed tannins are composed of flavonoid monomers differing in degree of condensation in a fixed structural mode, and their basic structural units are displayed in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

“…As a result, the final bonding strength of TF resin is not ideal. Meanwhile, it shows poorer water resistance and higher brittleness than traditional adhesives [18,[27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

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Crosslinking Mechanism of Tannin-Based Adhesives Based on Model Compounds: Copolycondensation of Resorcinol with Dimethylol Urea

Liang,

Li,

Zhong

et al. 2024

Forests

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This study focuses on the competition reaction rules of a system containing resorcinol (as a tannin model compound) and dimethylol urea (as a urea–formaldehyde resin model compound) under various alkaline and acidic environments. The aim is to investigate the crosslinked modification mechanism of urea–formaldehyde resin with tannin adhesive. The study delves into the competitive relationship between self-condensation polymerization reactions and co-condensation polymerization reactions. It specifically highlights the conditions for the copolycondensation reaction of dimethylolurea and resorcinol and validates its rationality through an examination of the resorcinol–urea–formaldehyde system’s reaction rules. The results show that (1) under strongly acidic conditions, the activity of carbocation intermediates produced by hydroxymethyl resorcinol for the resorcinol phenol ring is higher than the electrophilic reactivity of nitrogen atoms on hydroxymethyl urea, which is more beneficial for the resorcinol–formaldehyde self-polycondensation reaction, and the co-polycondensation structures do not play a dominant role. (2) Under weakly acidic conditions, the co-polycondensation structures are evidently advantageous over self-polycondensation structures, and the degree of the co-polycondensation reaction is positively correlated with pH below the neutral point of resorcinol. (3) Under alkaline conditions, the self-polycondensation between resorcinol and formaldehyde is dominant in the system. (4) The concentration of hydroxymethyl urea carbocation is the key factor to determine the degree of the co-polycondensation reaction.

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Section: The Polycondensation Law Of Model Compounds Resorcinol and D...mentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Crosslinking Mechanism of Tannin-Based Adhesives Based on Model Compounds: Copolycondensation of Resorcinol with Dimethylol Urea

Liang,

Li,

Zhong

et al. 2024

Forests

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“…With the increasing shortage of nonrenewable resources and the recent growing concerns about environmental protection (Xiao et al, 2023), the need to replace conventional petroleum-based adhesives, which have proved to have a signi cant impact on the environment as well as on human health, has been pushing towards the abandon of synthetic resins (Tene Tayo et al, 2022), and the development bio-based adhesives have become an important goal for the wood-based panel industry (Guigo et al, 2010;Arbenz and Avérous, 2015;Xu et al, 2020;Hussin et al, 2022). In recent decades, extensive research has been done on bio-based adhesives, with focus on protein adhesives (Li et al, 2022a(Li et al, , 2022bChen et al, 2023),tannin adhesives (Gholami et al, 2021;Xu et al, 2023), lignin adhesives (Gonçalves et al, 2021;Siahkamari et al, 2022;Peng et al, 2023), and starch adhesives (Din et al, 2020;Maulana et al, 2022;Watcharakitti et al, 2022). Although soy has received extensive attention and has been so far one the most promising protein source for the development of bio adhesive, concerns raised about the competition between bio-based products and human food and animal feed (Li et al, 2012a) somehow shows the limitation of soy as alternative for replacing formaldehyde-containing adhesives.…”

Section: Introductionmentioning

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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“…The idea of using tannin as a phenolic counterpart is intriguing because of the properties of these bio-based adhesives, which are also water-resistant when crosslinked [ 27 , 28 ].…”

Section: Introductionmentioning

confidence: 99%

Optimization of Starch–Tannin Adhesives for Solid Wood Gluing

Magnabosco,

Kulyk,

Avancini

et al. 2024

Polymers

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Bio-based solutions for solid timber gluing have always been a very sensitive topic in wood technology. In this work, we optimize the gluing conditions of a starch–tannin formulation, which allows high performance in dry conditions and resistance to water dipping for 3 h, allowing for the D2 classification to be reached according to EN 204. It was observed that the starch–tannin formulations enhanced their performance by increasing the heating temperature, achieving satisfactory results at 140 °C for 13 min. The proportion of polyphenols in the mixture enhances the water resistance but is only tolerated until 20–30%. In particular, the addition of 10% tannin–hexamine enhances the water-resistant properties of starch for both quebracho and chestnut extract. The application of the jet of cold atmospheric plasma allows for good results with more viscous formulations, increasing their penetration in wood. Solid-state 13C-NMR analysis was also performed, and the spectroscopic information suggests establishing a coordination complex between starch and tannin.

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Tannin-based wood adhesive with good water resistance crosslinked by hexanediamine

Cited by 19 publications

References 35 publications

Crosslinking Mechanism of Tannin-Based Adhesives Based on Model Compounds: Copolycondensation of Resorcinol with Dimethylol Urea

Crosslinking Mechanism of Tannin-Based Adhesives Based on Model Compounds: Copolycondensation of Resorcinol with Dimethylol Urea

Canola Protein Wood Adhesive with Improved Bonding properties

Optimization of Starch–Tannin Adhesives for Solid Wood Gluing

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