Enhanced Antioxidant and Antibacterial Activity through Esterification of polycaprolactone with Oleic Acid Catalyzed by Maghnite-H +

Abstract

Abstract Biodegradable polymers, such as poly(ε-caprolactone) (PCL), have gained significant attention due to their potential applications in various fields. To enhance the properties of PCL, researchers have focused on developing composites by blending it with other polymers or incorporating bioactive agents. One approach is the synthesis of PCL with oleic acid (OA), a natural fatty acid, resulting in improved mechanical, thermal, and in vitro activities. In this study, the synthesis of PCL modified with oleic acid was investigated using Maghnite-H+ as a sustainable heterogeneous solid catalyst. The Maghnite clay was treated with sulfuric acid to activate its catalytic properties. The impact of various synthesis conditions, such as the temperature and duration of the reaction, as well as the quantity of catalyst used, is evaluated using a response surface technique. This method employs a central composite design with three factors, each having three different levels. The resulting PCL-OA composite showed enhanced properties and in vitro activities, including antioxidant and antibacterial properties. The antioxidant activity was evaluated using the DPPH radical scavenging assay, where PCL-OA exhibited a significant increase in inhibition rate. Ascorbic acid (vitamin C) was used as a standard, demonstrating remarkable scavenging activity. The enhanced scavenging activity of PCL-OA can be attributed to the chemical modifications occurring during the grafting process of PCL with oleic acid. The antimicrobial properties of PCL-OA were investigated against various microorganisms, and the results showed different sensitivities of the strains to the compounds. Combinations of caprolactone, oleic acid, and PCL-OA resulted in increased antimicrobial activity for most of the tested strains, indicating a synergistic effect. Physicochemical characterization techniques, including FTIR and NMR, confirmed the successful synthesis and structural changes of PCL-OA. Thermal stability analysis revealed the decomposition behavior of the composite.