The thermal stabilization behavior and mechanism of a metal organic framework with high thermal stability towards PVC

Abstract

Thermal stabilizers play a crucial role in improving the thermal stability of PVC samples. However, the effect of thermal behavior of the stabilizer itself on PVC samples has been rarely reported. In this work, a metal organic framework Zn–Atz with a spatial three-dimensional structure was prepared and applied for stabilizing PVC. It was found that Zn–Atz displays both initial and long-term thermal stabilization effects on PVC. However, its long-term thermal stabilization effect is unsatisfactory due to the hydrogen chloride and unstable chlorine atom diffusion rate limitation in the pore structure of Zn–Atz. CaSt₂ and triphenyl phosphite (TP) can quickly absorb hydrogen chloride and chlorine free radicals produced in the PVC thermal degradation. When utilized together with Zn–Atz, CaSt₂ and TP can provide longer reaction time for the diffusion of hydrogen chloride and unstable chlorine atoms in the pore structure of Zn–Atz, to significantly improve the long-term thermal stability of PVC. Meanwhile, a possible synergistic stabilization mechanism of Zn–Atz, CaSt₂ and TP was proposed.