Green Wood Adhesives from One-Pot Coacervation of Folic Acid and Branched Poly(ethylene imine)

Abstract

Adhesives are extensively used in furniture manufacture, and most currently utilized furniture glues are formaldehyde-based chemicals, which emit formaldehyde throughout the entire life of the furniture. With increasing concerns about formaldehyde emission effects on human health, formaldehyde-free and environmentally friendly wood adhesives from bio-based resources are highly desired. In this study, we developed an eco-friendly, high-strength, and water-based wood adhesive from one-pot coacervation of the hierarchical self-assembly of folic acid (FA, a biomolecule, vitamin B9) with a commercially available biocompatible polymerbranched poly­(ethylene imine) (b-PEI). The coacervation is caused by multiple hydrogen bonds between b-PEI and the stacks of FA quartets, which demonstrates a continuous robust 3D network, thus realizing adhesion and cohesion behaviors. This coacervate has the strongest adhesion toward wood compared with other substrates. The long-lasting shear bonding strength is up to 3.68 MPa, which is much higher than that of commercial super glue, but without releasing any toxic components. Since all the fabrication and application processes are under ambient conditions without any heating and high-pressure procedures, this work provides a facile yet powerful strategy to develop formaldehyde-free, eco-friendly, and high-performance bio-based waterborne adhesives for wood bonding.

Unprecedented Nonflammable Organic Adhesives Leading to Fireproof Wood Products

“…Additionally, the wood surface is coarse, which allows the formation of mechanical interlocking in the presence of viscous PA/b-PEI, as evidenced by the SEM measurement (Figure S7). This mechanical interlocking between the two wood strips also improved the interfacial interactions, thus leading to excellent bonding performance, − as illustrated in Figure S8.…”

Engineering cohesion and adhesion through dynamic bonds for advanced adhesive materials

“…Gao and colleagues designed a green wood adhesive based on the coacervation of folic acid and poly(ethylene imine). [ 76 ] The aromatic ring‐rich folic acid was stacked into quartets via π–π stacking to serve as physical cross‐links to provide internal cohesion. The adhesion on wood achieved 3.68 MPa, higher than that of commercially available wood glues.…”

Reversible Anisotropic Wet Adhesion Enabled by Rigid Amphiphiles

“…7,8 Usually, the quali ed adhesion strength should be in the order of MPa, which is especially true in the adhesion of metal, glass, wood and other inorganic materials 9 . So far strong adhesion to various surfaces like wood 10,11 and glass 12 can be easily achieved since there are abundant binding sites with adhesives, and strong adhesion in the order of MPa for low polarity surfaces, such as polytetra uoroethylene(PTFE) and polyethylene (PE), has also been achieved 13,14 .…”