Developing High-Performance Cellulose-Based Wood Adhesive with a Cross-Linked Network

Abstract

Green, environment friendly, and sustainable biomass-based adhesive has been considered as an optimum alternative of petroleum-derived adhesive, yet poor water resistance restricts their advancement and popularization to a large extent. Herein, a hyperbranched cross-linking cellulose-based adhesive with a synergistic effect of covalent bonds and secondary bonds (mainly include hydrogen bond and hydrophobic effect) is synthesized based on the Maillard reaction between dialdehyde cellulose (DAC) and polyamines. The active aldehyde sites on the DAC skeleton anchor the amino group to form covalent bonds consuming a large number of hydrophilic groups, the remaining aliphatic segments of polyamines criss-cross to knit a hydrophobic network and endow the adhesive the ability to resist water erosion; integrant-exposed hydrophilic groups form intermolecular hydrogen bonds preferentially after curing and clustering due to the agglomeration effect of cellulose, which reduces the opportunity of forming hydrogen bonds with water molecules. The outstanding water resistance is manifested in two aspects: (1) the dry lap shear strength of modified adhesive increased from 1.47 to 3.29 MPa, making increments of 123.8% compared with the original DAC adhesive, the re-dry strength after 3 h of immersion in water of 63 °C or boiling achieved a breakthrough from 0 to 2.27 and 2.36 MPa; (2) the modified adhesive has a higher residual rate (above 77%) and a lower moisture absorption value (less than 22.2%) compared with the neat DAC adhesive (49 and 26.6%). The work provides an underlying approach to prepare wood adhesive with excellent bonding performance and eminent water resistance based on green and cheap raw materials and simple cooking chemistry.

Dynamic reversible adhesives based on crosslinking network via Schiff base and Michael addition

“…4d) has two peaks at 531.1 eV and 532.3 eV, attributed to the C]O and C-O groups, respectively. 39 It can be found that the C]N group can be observed in the C 1s spectrum, and the C]N group can be observed in the N 1s spectrum. The results indicate that the Schiff base reaction occurred with the smooth formation of imine bonds between FPA and branched polyamines.…”

“…Meanwhile, the modification of adhesive polymers by the introduction of hyperbranched polymers 39–41 has recently become a new research hotspot due to the excellent properties of hyperbranched polymers. Hyperbranched polymers are very different from linear polymers in terms of physicochemical properties.…”

Adhesive Interfaces toward a Zero-Waste Industry

“…As for starch, the hydroxyl group of cellulose can be modified to improve its solubility and decrease its crystallinity, which limits its use in adhesive formulations . Microcrystalline cellulose (MCC) was oxidized selectively using sodium periodate to form dialdehyde cellulose (DAC) . DAC was then further processed with three different polyamines (PA 4N , PA 5N , and PA 6N ) to form a covalently cross-linked hyperbranched polymer network.…”

“… 43 Microcrystalline cellulose (MCC) was oxidized selectively using sodium periodate to form dialdehyde cellulose (DAC). 48 DAC was then further processed with three different polyamines (PA 4N , PA 5N , and PA 6N ) to form a covalently cross-linked hyperbranched polymer network. The resulting adhesives were water-resistant with enhanced lap shear strengths.…”

Tannin as a renewable raw material for adhesive applications: a review

“…To further mitigate the usage of petrochemical-based adhesives, bio-materials incorporating wood adhesives have gained significant attention in recent years. The world's most prevalent biopolymers have been explored for their use in wood adhesives, including cellulose 8,9 derived as a residue or in several other forms such as carboxymethyl cellulose (CMC), 10,11 microfibrilated cellulose, 12 chemically modified nanocellulose, 13 cellulose nanofibrils, 14 or microcrystalline cellulose; 15 starch 16–18 or blends prepared in various ratios using starch and co-ingredients such as polyvinyl alcohol, 19,20 silica nanoparticles, 21 silane coupling agent, 22 or sodium dodecyl sulphate; 23 lignin 24,25 or tailor-made resins like lignin-epoxy from biomass 26 and lignin–polyurethane 27 in an attempt to give an alternative to formaldehyde; similarly, soy proteins 28 or their chemical modifications 29 for enhanced end properties and thus performance. With increasingly acknowledged credibility of these naturally available polymers in terms of abundant supply, cost, and ease of functionalization, 30,31 lately the research focus has shifted from finding suitable raw-materials to developing competent bio-derived adhesives compared to their hydrocarbon-based counterparts.…”