Supercritical CO2 -assisted impregnation kinetics of polyamide fibers with eugenol: experimental data and modeling

JOSE E. MOSQUERA; NICOLÁS GAÑAN; RAQUEL MARTINI; LAURA GOÑI; JOSE E. MOSQUERA; NICOLÁS GAÑAN; RAQUEL MARTINI; LAURA GOÑI

Campinas

Congreso; V Iberoamerican Conference on Supercritical Fluids; 2019

University of Campinas (UNICAMP)

Supercritical fluid technology has been widely used to incorporate active substances into polymeric matrices with different potential applications, principally due to the advantage of obtaining solvent-free products and the enhanced mass transfer rates that can be obtained in CO2-swollen polymers. The present work was aimed to investigate the supercritical CO2-assisted impregnation kinetics of eugenol into polyamide 6 fibers in order to obtain a material potentially applicable as an active dental floss, based on the well known antimicrobial activity of eugenol. Impregnation essays were performed in a high-pressure cell at two temperature levels (40 and 60°C), two pressures levels (10 and 12 MPa) and two depressurization rates (0.5 and 5 MPa min −1), at different contact times (from 15 min to 6 h). Experimental results of eugenol uptake vs. time suggested that the impregnation process follows a ?two-stage? sorption behavior, with sigmoidal uptake curves. The sorption process was modeled by developing an analytical solution of the second Fick?s law of diffusion for cylindrical fibers with a time-dependent surface concentration of eugenol. This kind of behavior has been reported for sorption in glassy polymers when the diffusion and relaxation rates are comparable. The resulting three parameter model was fitted to reproduce the experimental data with a good agreement.