A new theory of “two-step stabilization mechanism” for triazole-based zinc-containing complex as thermal stabilizer for poly(vinyl chloride)

A totally new theory of “two-step stabilization mechanism” for triazole-based zinc-containing complex (abbreviated as [Zn(ttr)(OAc)]) was proposed through several designed experiments. [Zn(ttr)(OAc)] strongly absorbed HCl at the beginning, and then broke down into 3-amino-1,2,4-triazole which could further stabilized PVC . The structure of [Zn(ttr)(OAc)] was characterized by FTIR spectroscopy , elemental analysis and SEM. Then, Congo red tests and discoloration tests verified [Zn(ttr)(OAc)] could absorb HCl effectively, but PVC showed poor initial whiteness, which further proved above-mentioned stabilization mechanism. Moreover, [Zn(ttr)(OAc)] combined with ZnSt 2 and dibenzoyl methane (DBM) effectively improved the initial color of PVC samples and provided PVC with shorter plasticizing time and longer dynamic thermal stability time than commercial stabilizer 1086F, confirmed by discoloration tests and dynamic thermal stability analysis. We believe [Zn(ttr)(OAc)]/ZnSt 2 /DBM stabilizer system can be used as a commercial stabilizer and the stabilization mechanism of [Zn(ttr)(OAc)] may provide a new way to stabilize PVC.