Citric Acid and Dimer Diol-Based Polyester Films for Food Packaging Applications

This study investigates the properties and potential advantages of citric acid and dimer diol-based polyester films for flexible food packaging applications. Sebacic acid and Neopentyl glycol are used to enhance tensile strength and improve thermal stability. Our objective was to develop bio-based polyesters, focusing on improving barrier properties, compatibility with food constituents, resistance to liquid water, and water vapor permeability. To achieve this, citric acid and dimer diol were employed, with varying ratios of dimer diol tested in four different formulations. The use of dimer diol, derived from vegetable oil, is known for its ability to reduce water absorption in polymers. Comprehensive characterization of the polyester films was performed using techniques such as scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), contact angle, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and oxygen transmission rate (OTR). We also evaluated the biodegradability of the prepared films via the soil burial test. The study yielded valuable insights into the impact of different formulations on the thermal characteristics of the resulting polyesters, providing essential information for the development of improved packaging materials for extending the shelf life of packaged foods.