Synergism of pentaerythritol-zinc with β-diketone and calcium stearate in poly(vinyl chloride) thermal stability

Abstract

Pentaerythritol-zinc (called Penzinc), which is a novel thermal stabilizer for PVC, was synthesized, and its performance was characterized during the thermal processing of PVC. The stabilization effects of this new stabilizer combined with calcium stearate (CaSt2) and stearoyl benzoyl methane (β-diketone) were investigated using conductivity tests, thermal aging tests, and torque rheometry tests. The results revealed that the addition of Penzinc can improve the color and thermal stability of PVC in both static and dynamic tests. There are no obvious synergistic effects between Penzinc and CaSt2. However, the synergistic action between Penzinc and β-diketone is excellent. The thermal stability mechanisms of Penzinc and β-diketone are also discussed with the help of quantum chemical calculations. Pentaerythritol-zinc (Penzinc) has been synthesized and its thermal stability, especially its synergism with β-diketone and calcium stearate, was characterized. Experimental results show that PVC stabilized with complex of Penzinc and β-diketone has an excellent initial color and long-term thermal stability. Moreover, the thermal stability mechanism of Penzinc and β-diketone are also discussed with the help of quantum chemical calculations. Results indicate that both α-H atom of β-diketone and zinc atom of Penzinc, having low electron density, can easily react with labile chloride atom of PVC, which has high electron density.