Synthesis of nickel and copper metal complexes for blending in PVC to enhance UV absorption and stability

Abstract Three new copper and nickel complexes were synthesized using N-alkylated imidazole as a ligand, characterized by NMR, FTIR, and UV analysis, and subsequently assessed as UV absorbers to enhance the stability of polyvinyl chloride (PVC). PVC is widely used due to its cost-effectiveness, resistance to alkali and acid corrosion, and ease of molding. However, its susceptibility to degradation under prolonged UV exposure poses a significant challenge to its durability. To address this, the study focuses on the effect of these synthesized complexes on the stabilization of PVC films subjected to 500 h of UV irradiation at 25 °C. Analytical techniques, including IR spectroscopy, UV-visible spectroscopy, weight loss analysis, and SEM with EDX, were employed to evaluate the degradation of the PVC films. The results demonstrated that the C1 complex provided superior protection against UV-induced damage, significantly reducing decomposition, and minimizing surface roughness, cracks, and overall deterioration compared to C2 and C3 complexes, and a blank sample. C1 exhibited the highest efficiency, with a 91% reduction in degradation. Response Surface Methodology (RSM) was utilized to optimize the experimental results, further confirming the outstanding performance of C1 in stabilizing PVC against UV exposure. GRAPHICAL ABSTRACT HIGHLIGHTS Three new metal complexes (C1–C3) have been synthesized with good yield. FT-IR and FT-NMR were used to characterize the synthesized complexes. Complexes were incorporated into PVC to examine their efficiency as photo-stabilizers. Response Surface Methodology (RSM) was used to optimize the efficiency of complexes. C1 was found to be the best photo stabilizer with 91% efficiency.