Mechanisms of antioxidant action: Tellurium dithiocarbamates as antioxidants for polypropylene

The tetrakis (dialkyldithiocarbamato)tellurium(IV) complexes are highly effective thermal antioxidants and melt stabilizers for polypropylene and the evidence suggests that they are converted to the bis(dialkyldithiocarbamato)tellurium(II) complexes and the corresponding dithiocarbamoyl disulfides during processing. The Te(IV) complexes are also effective photoantioxidants and their activity increases with increasing processing time. The bischelates are in general less effective when used alone.