Document Type : Research Paper
Authors
1
Department of Organic and Polymer Chemistry, Faculty of Chemistry, Kharazmi University, Tehran, Iran.
2
Department of Organic and Polymer Chemistry, Faculty of Chemistry, Kharazmi University, Tehran, Iran
10.22063/jipst.2026.35850.2448
Abstract
Hypothesis: Due to the limited thermal stability of poly(vinyl chloride) (PVC), the development of multifunctional additive systems capable of simultaneously enhancing its thermal stability and mechanical performance has attracted considerable attention. The main hypothesis of this study was that the combination of two components including an organometallic thermal stabilizer with a phosphorus-containing nanostructured flame retardant could synergistically improve the thermal performance of PVC without compromising its mechanical properties.
Methods: Accordingly, a zinc Schiff base complex (ZSC) was synthesized as a thermal stabilizer, while magnesium hydroxide nanoparticles (MDH) modified with a DOPO-based dicarboxylic acid (DMMH) were prepared as a flame retardant. These additives were incorporated individually and in combination into the PVC matrix. PVC nanocomposite films were fabricated by the solution casting method using tetrahydrofuran (THF) as the solvent. The chemical structures and successful synthesis of the additives were confirmed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and elemental analysis. The thermal behavior and flame-retardant performance of the nanocomposites were evaluated using thermogravimetric analysis (TGA) and the limiting oxygen index (LOI) test, while their mechanical properties were assessed by tensile testing.
Findings: The results demonstrated that the simultaneous incorporation of ZSC and DMMH increased the temperature corresponding to 50% weight loss by 7.5%, enhanced the char yield by 50%, and improved the LOI value by 3% compared with neat PVC. Furthermore, the optimum additive formulation increased the tensile strength and Young's modulus by 40% and 47%, respectively, relative to neat PVC. These findings demonstrate that the proposed synergistic additive system provides an effective strategy for producing safer PVC materials with enhanced thermal stability, flame retardancy, and mechanical performance.
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