Enhancing the Properties of Latex-Based Coatings with Carboxylated Cellulose Nanocrystals

Latex-based nanocomposites containing carboxylated cellulose nanocrystals (cCNCs) were synthesized via in situ seeded semibatch emulsion polymerization. Inspired by nature's use of CNCs to enhance rigidity and mechanical strength in cellulosic materials, we explored similar principles to improve the properties of acrylate water-based coatings. The cCNCs, loaded at 0.3-1.0 wt %, were added 1 h after pre-emulsion feeding began, addressing sensitivity to ionic strength and enabling stable final latexes. Careful control of the polymerization process maintained consistent particle sizes across formulations, allowing for mechanical property comparisons. Films from these latexes were evaluated through rheological and water sensitivity tests. With 1.0 wt % cCNC, significant increases in viscosity, shear-thinning behavior, stiffness, and elastic modulus were observed. Additionally, cCNCs reduced water and moisture absorption without affecting the whitening resistance. These findings demonstrate the enhanced properties of in situ cCNC latex nanocomposites, broadening their potential for industrial applications.