Sustainable Hybrid Latexes Derived from Starch Bioparticles and Biobased Monomers

Starch is a widely available biopolymer with the potential to replace petroleum-based acrylic monomers in coating binders, but its hydrophilicity and water sensitivity limit its incorporation. This study enhances biobased content in hybrid latexes by simultaneously incorporating starch/zein bioparticles (BPs), produced via nanoprecipitation, and commercial biobased monomers including 2-octyl acrylate, 2-octyl methacrylate, and isobornyl methacrylate. Waterborne hybrid dispersions were synthesized through semibatch emulsion polymerization, using BPs as seeds with variable biobased formulations. The influence of solids content, increased from 20% to 32%, was also examined. The resulting hybrid latexes achieved biobased contents exceeding 70% and demonstrated excellent film-forming properties. When applied in paint formulations, they yielded stable coatings with high surface hydrophobicity (contact angle of 98°) and good coverage. These findings demonstrate the potential of combining starch-based bioparticles with bioderived monomers to create sustainable waterborne coatings with high biobased content and competitive performance.