Thermal stabilization of polyvinyl chloride with traditional and naturally derived antioxidant and thermal stabilizer synthesized from tannins.

The effects of tannin-cadmium complex on the thermal and oxidation stability of PVC were investigated. Tannin-cadmium complex has been successfully synthesized and characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and energy-dispersive X-ray analysis techniques. Thermal degradation and thermal oxidation-degradation behaviors of PVC formulations obtained by thermal mixing method were evaluated by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) under inert and oxidizing atmospheres, respectively. The obtained results such as the onset, maximum and final degradation temperatures as well as the degradation rates from TG and DTG curves revealed that the tannin-cadmium has significant impact on the thermal stability of PVC. The experimental data of PVC thermal degradation obtained by DSC studies also clearly showed that the stabilizing efficiency of tannin-cadmium is superior to that of synthetic thermal stabilizer applied as reference. Due to the HCl scavenging and antioxidation activities of tannin-cadmium, the global thermal and morphological properties of PVC stabilized by this product proved the best in morphology and stabilization properties both against thermal and thermal oxidation-degradations. Graphical abstract: [ABSTRACT FROM AUTHOR]