Preparation and characterization of biodegradable cellulose acetate-based films with novel plasticizer obtained by polyethylene terephthalate glycolysis intended for active packaging

An active packaging based on the composite film was developed by incorporation of oregano oil as an antimicrobial agent into a cellulose acetate/polycaprolactone diol blend (CA/PCL-diol). A novel plasticizer based on polyethylene terephthalate (PET) glycolysis product (bis(hydroxyethyl terephthalate)) and tartaric acid was synthesized and its influence on the structural, surface, mechanical, barrier, and thermal properties were investigated. The obtained results have shown that plasticizer also has a compatibilizing effect, improving the miscibility of polymers in a blend. A sample with the optimal amount of plasticizer (30 wt%), as well as the best mechanical and barrier properties, was used for the preparation of series with different amounts of oregano oil (3, 6, and 9 wt%). The synthesized azo dye—5-(4-bromo-phenyl azo)-3-amido-6-hydroxy-4-methyl-2-pyridone, soluble in acetone, as well as a blend and plasticizer, has been shown as an adequate one for this composition, due to its ability to achieve a good pigmentation in a low amount (0.3 wt% per polymer blend weight), to absorb UV light, and decrease the aging of the material. Contemporary lifestyle has imposed a need for ready-to-eat (RTE) meals which saves consumers time. RTE food packaging should meet certain requirements such as the ability to prolong shelf-life and preserve the freshness of the food product, and at the same time to make a minimal amount of waste after usage, considering the fact that it is mostly single-use plastic food packaging. Optimal mechanical properties, biodegradability, and additional functions make these films suitable for the packaging of ready-to-eat (RTE) food such as fresh salad.