Analysis and development of hydrophobic and oleophobic fluorine-free modifiers for paper

This research addresses the need for sustainable alternatives to PFAS, a class of highly persistent chemicals widely used in paper packaging for water- and oil-repellent properties but associated with serious environmental and health risks. The study, carried out by the University of Pisa and Fedrigoni Group under the PNRR program, developed fluorine-free coatings for cellulose-based paper that provide barrier properties while remaining biodegradable or recyclable with the paper matrix. Two strategies were investigated. The first involved water-based acrylic polymer latexes synthesized by emulsion polymerization. When applied to paper, these coatings formed thin, uniform layers that filled pores, reduced roughness, and improved smoothness without altering paper texture. They also lowered air permeability, water vapor transmission, and liquid absorption, reducing water uptake by up to 20% and oil uptake by 25%, while increasing hydrophobicity and oleophobicity. The second strategy used Pickering emulsion polymerization with phosphorylated cellulose nanofibers as natural stabilizers, eliminating added surfactants. These hybrid latexes showed excellent colloidal stability and formed cohesive coatings on paper fibers. Coated papers achieved water contact angles up to 101°, over 50% lower water and oil absorption, and up to 70% lower water vapor transmission. Overall, both approaches demonstrate promising PFAS-free solutions for high-performance, sustainable paper coatings.