Mass transfer kinetics and diffusion coefficient estimation of bioinsecticide terpene ketones in LDPE films obtained by supercritical CO 2 -assisted impregnation

GOÑI, MARÍA LAURA; GAÑÁN, NICOLÁS ALBERTO; MARTINI, RAQUEL EVANGELINA; STRUMIA, MIRIAM CRISTINA

JOURNAL OF APPLIED POLYMER SCIENCE

JOHN WILEY & SONS INC

Año: 2017 vol. 134

0021-8995

Release kinetics of thymoquinone and R-(+)-pulegone impregnated in LDPE films into air and the effect of supercritical CO2-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°C, 60%RH), and the total release profile was determined gravimetrically, while the individual release of each ketone was quantified by FTIR. The experimental data was 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 2.35×10-13 to 5.53×10-13 m2 s-1 (thymoquinone) and from 1.24×10-13 to 4.52×10-13 m2 s-1 (pulegone). Finally, ANOVA testing indicated that impregnation pressure and depressurization rate (and their combination) have significant effects on the diffusion coefficient values.