UA was successfully grafted onto soy protein through the reaction between COOH and NH2 under facile conditions, as confirmed by the disappearance of carbonyl peak at 1706cm−1 in FTIR spectra and decreased amino group concentration tested through ninhydrin reagent. The reduced thermal stability after UA modification was detected via denature and degradation peak changes in DSC and TGA curves. Increased viscoelastic properties demonstrated the unfolding of protein during reaction. AFM images and particle size distribution verified the dissociation and less protein-to-protein cross-linkage after UA grafting, and AFM phase contrast information also validated changed viscoelastic properties in UA-modified samples. UA modification significantly improved wet shear adhesion strength by 35–62%. The non-water-soluble nature
and long hydrophobic alkyl chains of UA prevented water penetration, which contributed to significant improvement in water
resistance