Mechanochemical conversion of cellulose acetate from residues to cellulosic nanospheres for emulsion application

Abstract

Cellulose acetate is a common industrial polymer found in several residues, with no defined recycling route. Here we propose a route for its recovery and reuse through simple mechanochemical activation in a solid basic medium to simultaneously reduce particle size and potentially hydrolyze acetate groups, followed by treatment with citric acid and H2O2. The cellulosic nanoparticles were submitted to mechanical activation in the presence of Ca(OH)2 or CaCO3. The results show that the process with Ca(OH)2 was enough for the hydrolysis of acetate groups, while the treatment with CaCO3 reduced the particle size, keeping the acetate functional groups. In both cases, the cellulosic nanoparticles presented spherical shapes with an average diameter of 18.6 ± 3.4 nm. The nanoparticles were successfully applied in Pickering emulsions, with subtle differences in droplet sizes probably related to the differences between the functional groups of these particles.