Stabilization mechanism of antimony mercaptides in poly(vinyl chloride): ab initio theory studies

Abstract

Ab initio quantum theory has been used to study stabilizing mechanism of antimony mercaptides in poly(vinyl chloride) (PVC). Analysis of composition of the frontier orbitals, dipole moment of the systems, charge on Sb and its bonded atoms in antimony mercaptides, indicates that these compounds could absorb the HCl produced during the decomposition of PVC. The mechanism of stabilization is electrophilic followed by a nucleophilic step. Also they could substitute the Cl in PVC to prevent the production of HCl, thus preventing the decomposition of PVC. This mechanism is nucleophilic followed by an electrophilic process. The results from theoretical calculation match well with the test of the stabilizing effect on a PVC product containing these stabilizers. The structures of some organoantimony compounds are also reported.