Bimetallic and Monometallic Chelate Complexes of Salt Tannates With Mg and Zn Ions as Bio‐Friendly Multifunctional Stabilizers in Enhancing Thermal Stability and Mechanical Properties of P‐PVC‐Based Compounds

Achieving a good stabilization effect for polyvinyl chloride during processing remains a challenging issue. In this work, () and complexes were derived from tannic acid (TA) as green thermal stabilizers. Tannic acid was chemically extracted from the pomegranate bark. The effectiveness of these complexes with variable amounts on the thermal stability and mechanical properties of PVC was investigated. PVC compounds were prepared through the melt mixing method. The structure of these complexes was identified through Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy‐dispersive x‐ray (EDX). The dehydrochlorination and thermo‐oxidative degradation behavior of PVC samples was evaluated through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Mechanical properties were considered using a tensile test. The results showed that the efficiency of thermal stabilization of PVC samples is significantly improved in the presence of TA complexes. The onset and peak degradation temperatures, along with the rates observed in TGA and DSC studies, demonstrate that the stabilizing effect of these complexes is comparable to or even superior to that of conventional stabilizers. The enhanced interfacial interaction of TA complexes significantly improved the tensile strength and elongation at break of PVC. Salt tannates containing bimetal and mono‐metal ions were compared and evaluated; the mixed metal tannate showed more efficient thermal stability. This research appears to validate the usefulness of chelate complexes, particularly the bimetallic type, as bio‐based additives that offer multi‐functional effects and cost‐effectiveness for stabilizing PVC, demonstrating clear stabilization effects and good flexibility.