Thermomechanical and transport properties of LLDPE films impregnated with clove essential oil by high-pressure CO2

Abstract

Clove essential oil (CEO) was impregnated in linear low-density polyethylene (LLDPE) films by high-pressure CO2 technique. Impregnations were performed at 150 bar, 25 and 32 °C for 2 h followed by depressurization at 10, 50 and 100 bar min−1. The influence of operational parameters was observed on impregnation, optical, topographic, morphological, thermomechanical and transport properties of films. Higher amounts of CEO were impregnated when reducing depressurization rate and increasing temperature, with a maximum of 26.83 mg CEO/g LLDPE. Diffusion mechanism governed CEO migration from LLDPE in 10% and 95% (v/v) ethanolic solutions. The effective diffusion coefficient of CEO in LLDPE ranged from 5.4 × 10−13 to 1.0 × 10−12 m2 s−1. Operational parameters can be adjusted to enhance CEO incorporation, presenting negligible effect over CEO diffusivity in LLDPE. The results suggest the potential for developing active food packaging materials by green processes, also aggregating value to compounds from natural sources.