Designing Biomimetic Microphase‐Separated Motifs to Construct Mechanically Robust Plant Protein Resin with Improved Water‐Resistant Performance

Abstract

AbstractPlant protein, as a sustainable alternative to petroleum‐derived resin, has exhibited notable potential for engineering wood products without formaldehyde emission, while the poor mechanical and water‐resistant performances limit its practical applications. Inspired by mussel chemistry and structure, a dopamine‐functionalized polyurethane (D‐PU) elastomer is synthesized in this work acting as a bio‐inspired crosslinking unit to improve the properties of soy protein (SP) resin. It is found that the catechol groups of the incorporated D‐PU not only triggers polyurethane to interact with SP matrix giving rise to a stable crosslinking network with excellent load‐bearing capacity, but also serves as a water‐resistant barrier to reduce the water erosion effect on resin. Moreover, a desired microphase‐separated morphology is observed within the continuous protein phase after introducing D‐PU. The microphase‐separated structure simultaneously strengthens and toughens SP adhesive layer, thus achieving high‐efficiency stress transfer and energy dissipation as well as accelerating SP to further permeate into the substrate forming more mechanical adhesion nails. As a result, the modified SP‐D‐PU resin presents an impressive improvement in dry and wet adhesion strength up to 70.5% and 133.9% compared to the pristine SP resin, respectively. The proposed biomimetic design may offer a workable strategy for preparing of high‐performance bio‐based composites.