Supercritical CO2 Impregnation of Thymol in Thermoplastic Starch-Based Blends: Chemico-Physical Properties and Release Kinetics

Abstract

The aim of the present study was to investigate starch-based materials, prepared in an environmentally friendly way and from renewable resources, suitable for the development of biodegradable active food packaging. For this purpose, a bioactive compound (thymol) was incorporated into thermoplastic starch (TPS) and a TPS blend with poly (ε-caprolactone) (TPS–PCL) by the supercritical CO2 (scCO2) impregnation process. Impregnation experiments with scCO2 were carried out at a pressure of 30 MPa and temperatures in the range of 40–100 °C during 1 to 20 h. The structural, morphological, and thermal properties of the obtained materials were comprehensively evaluated. Bioactive component release kinetic studies were performed in water at 6 °C and 25 °C. It was shown that the scCO2 impregnation process could be successfully employed for thymol loading into TPS and TPS–PCL. The process was significantly influenced by the operating temperature and time as well as content of PCL. The samples showed a controlled release of thymol within seven days with a higher amount of released thymol from the TPS–PCL blend. The obtained materials are solvent-free and release the bioactive component in a controlled manner.

Influence of Glycerol and SISAL Microfiber Contents on the Thermal and Tensile Properties of Thermoplastic Starch Composites

“…In Figure 2, bands were also observed in the region 1630-1650 cm −1 . These findings were attributed to the absorbed water in the TPS films [47]. The vibrational modes observed at 999 cm −1 are associated with the stretching of the C-O bond, which is present in the glucose ring [48,49].…”

Proof-of-Concept Study on the Feasibility of Supercritical Carbon Dioxide-Assisted Consolidation Treatment for a Pair of Goalkeeper Gloves on Synthetic Latex-Based Foam Mock-Ups

“…Examples of scCO 2 -assisted impregnation include the impregnation process for the dyeing of synthetic and natural textiles [28,29], preparation of drug-eluting implants [30][31][32][33][34][35][36][37], softwood processing [38][39][40][41][42][43], the preparation of hybrid silk material [44] or for food packaging applications [45,46]. In the conservation field, supercritical CO 2 technology is still niche, with a few examples of application such as the cleaning of textiles [47][48][49][50][51], deacidification of paper [52][53][54][55][56] and the removal of pesticides from objects in ethnographic collections [57][58][59].…”