Enabling zero added-coalescent waterborne acrylic coatings with cellulose nanocrystals

Waterborne acrylic coatings contain volatile and non-volatile coalescents. Volatile organic compound (VOC) coalescents enable film formation of hard polymers at ambient temperature, but their evaporation results in air pollution health concerns. Non-volatile alternatives are available, they remain the coating long-term as a result films often tacky lack adequate hardness. Reinforcing mineral fillers associated with sustainability challenges inherent to mining. An alternative approach demonstrated here utilizes renewably-sourced, plant-based hardening filler dispersed water phase, soft polymer latexes that don’t require VOCs for formation. We reinforced coalescent-free film-forming butyl acrylate/methyl methacrylate/methacrylic acid cellulose nanocrystals (CNCs) by post-synthesis blending approach. CNCs possess high elastic modulus tensile strength, making them promising candidates improve mechanical performance latexes. form aggregates within interstices between latex particles dries, however coalescence is not compromised. Films 15 wt% CNC showed almost 230 % improvement Koenig hardness 10x nanoindentation compared neat films, achieving properties similar VOC-containing binders zero-added VOC formulation.