Water-based polymerization methods, such as emulsion polymerization, offer improved sustainability by reducing or eliminating volatile organic compound use.1 The US paints and coatings market has exhibited a yearly increase in demand, with the waterborne segment leading the largest market share. The demand for eco-friendly products is expected to positively impact market growth in the coming years.2 Both academia and industry have shown interest in cellulose nanocrystals (CNC), derived from biological sources, typically using sulfuric acid hydrolysis. One of the recent technologies considered simple and “greener” than acid hydrolysis is oxidation with hydrogen peroxide.3 The peroxide treatment yields a CNC surface with carboxylic acid groups rather than sulfate half-esters.
Carboxylated CNC (cCNC) has previously been added into pressure-sensitive adhesive formulations and appears to exhibit improvements in adhesive properties.4 Despite these findings, the enhancement effects in high-performance latex-based coatings have not been studied. This study focuses on enhancing the properties of a high solids polymer content commercial-level performance coating formulation through the incorporation of cCNCs via in situ seeded semi-batch emulsion polymerization. The work investigates the effects of CNCs with different surface chemistry through rheological, water whitening and water absorption characterizations. The superior results obtained from the coatings based on cCNC latex nanocomposites broaden their potential industrial applications.
This work aligns with the principles of green chemistry, as water-based polymerization methods provide a more sustainable alternative to traditional solvent-based coatings. Furthermore, cCNC serves as an eco-friendly substitute for petroleum-derived fillers. This project integrates the principles of safer solvents and auxiliaries, with water as the continuous phase, and the use of renewable feedstocks.
- Lovell, P. A.; El-Aasser, M. S. Emulsion Polymerization and Emulsion Polymers; John Wiley & Sons: Chichester, 1997.
- Grand View Research. Global Paints & Coatings Market Size Report, 2020-2027; 2020.
- Grand View Research. Global Waterborne Coatings Market Size & Share Report, 2023-2030; 2023.
- Andrews, M. P.; Morse, T. Method for Producing Functionalized Nanocrystalline Cellulose and Functionalized Nanocrystalline Cellulose Thereby Produced. 10,968,283, April 6, 2021.
- Gabriel, V. A.; Tousignant, M. N.; Wilson, S. M. W.; Faure, M. D. M.; Cranston, E. D.; Cunningham, M. F.; Lessard, B. H.; Dubé, M. A. Improving Latex‐Based Pressure‐Sensitive Adhesive Properties Using Carboxylated Cellulose Nanocrystals. Macromol React Eng 2022, 16 (3), 1–11.