Mass transfer kinetics and diffusion coefficient estimation of bioinsecticide terpene ketones in LDPE films obtained by supercritical CO₂‐assisted impregnation

Abstract

Release kinetics of thymoquinone and R-(1)-pulegone impregnated in low-density polyethylene (LDPE) films into air and the effect of supercritical CO 2 -assisted impregnation process on the diffusional properties of these films were investigated. The incorporation of both ketones into LDPE films was performed under different conditions (pressure, depressurization rate, time, and initial ketone mole fraction). Release experiments were performed under controlled laboratory conditions (24 8C, 60% relative humidity), and the total release profile was determined gravimetrically, while the individual release of each ketone was quantified by Fourier transformed infrared. The experimental data were used to fit a mass transfer model based on the second Fick's law for unsteady-state diffusion, and the diffusion coefficients of both ketones in LDPE were estimated, ranging from 2.35 3 10 213 to 5.53 3 10 213 m 2 s 21 (thymoquinone) and from 1.24 3 10 213 to 4.52 3 10 213 m 2 s 21 (pulegone). Finally, analysis of variance testing indicated that impregnation pressure and depressurization rate (and their combination) have significant effects on the diffusion coefficient values.

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

“…Experimental characterization of mass transfer in polymers under scCO2 conditions is a difficult task that often requires specific equipment, robust methods, good quality data, and appropriate models. For this reason, the available data in the open literature are limited, compared to the studies concerning the diffusion at ambient J o u r n a l P r e -p r o o f conditions [6,19]. Different methodologies have been applied to the determination of impregnation diffusion coefficients.…”