High pressure carbon dioxide for impregnation of clove essential oil in LLDPE films

- High pressure CO2 impregnation is suitable to incorporate CEO in LLDPE films.
- CEO is successfully impregnated throughout the polymer matrix.
- CEO acts as plasticizer agent of LLDPE films.

High-pressure carbon dioxide (CO2) impregnation is a promising technology in the development of active packaging films. Clove essential oil (CEO), a multicomponent active agent naturally rich in eugenol, was incorporated in linear low density polyethylene (LLDPE) films by using high pressure CO2 impregnation. The parameters of temperature (25, 35 and 45 °C), pressure (150 and 250 bar) and CEO:CO2 mass ratio (2 and 10%) were screened using a variable-volume view cell for 4 h to determine the best impregnation conditions. Kinetic assays of CEO impregnation were also performed. The highest amount of CEO (40.2 mg g− 1 of LLDPE) impregnated was obtained at 10% CEO:CO2 mass ratio, 45 °C and 150 bar. The impregnation at 2 h showed advantage in reducing processing time. A preferential eugenol impregnation was observed due to thermodynamic interactions and mass transfer phenomena. Thermal and mechanical properties of LLDPE films remained stable after high pressure processing.Industrial relevanceThe development of innovative technologies for active packaging systems has attracted the interest of food, pharmaceutical, and chemical industries. The consumer's demand for products with low healthy risk makes the CEO an advantageous active agent for packaging development purposes, besides possessing strong antimicrobial and antioxidant activities. The employment of high pressure CO2 allowed a homogeneous CEO impregnation in LLDPE films without damaging mechanical and thermal properties of the polymer matrix, which is important for industrial applications. The CEO-impregnated LLDPE films have potential use in antimicrobial and antioxidant packaging systems.