Mass transfer kinetics of CO2 and eugenol in the supercritical impregnation of polyamide fibers: Experimental data and modeling

Abstract

In this work, mass transfer kinetics of CO2 and eugenol into polyamide 6 (PA6) fibers under supercritical conditions were investigated in the context of the development of a functional dental floss for dental care applications using scCO2-assisted impregnation. The sorption kinetics was evaluated at different temperature (40 and 60 °C) and pressure conditions (10 and 12 MPa), measuring the total amount of CO2 and eugenol incorporated in PA6 fibers after certain time intervals (from 30 min to 4 h). Equilibrium sorption was determined for all operation conditions, obtaining the highest values at low CO2 density. Diffusion coefficients of CO2 and eugenol under different process conditions were estimated fitting the experimental data with analytical solutions of the second Fick's law. In addition, thermal behavior of eugenol-loaded PA6 fibers impregnated at different time intervals was evaluated by differential scanning calorimetry (DSC), observing only small changes in the polymer crystallinity during the high-pressure process.