Development of Sustainable Polyethylene Formulations with Antioxidant Functionality Using Loquat Byproducts as Additives

Abstract

In this study, biopolyethylene-based formulations were developed using loquat byproducts. Low-density polyethylene (LDPE) derived from renewable resources was employed. The formulations included various loquat byproducts, specifically skin, kernel, and a combination of both. An anhydride maleic copolymer was used as a coupling agent, while glycerol was introduced for the formation of thermoplastic starch (TPS) and, consequently, the development of LDPE/TPS formulations. Loquat exhibits antioxidant activity, a property that is effectively transferred to the manufactured formulations. The antioxidant performance of these materials was assessed through differential scanning calorimetry (DSC), demonstrating an increase in oxidation induction time (OIT) from 1.6 min of neat LDPE up to 31.1 min in the loquat formulations. Also, the onset oxidation temperature (OOT) was extended up 269.7 °C in contrast to 209.7 °C for neat LDPE. These results underscore the potential benefits of incorporating loquat byproducts as functional additives in sustainable polymer formulations. The compatibilization strategies applied enabled the optimization of the mechanical properties of the loquat-based formulations as observed in microscopy. Mechanical properties were enhanced with an elongation at break that reached values of up to 40.0% in the compatibilized systems. Tensile strength also improved, reaching up to 6.3 MPa in the loquat-containing formulations. Additionally, the water uptake capacity of the samples decreased as a result of the compatibilization process. Changes in the samples were assessed through thermomechanical analysis and color variation measurements, while chemical characterization confirmed the presence of structural modifications at the molecular level.