Recent advances in PVC stability with metal and organic compounds

Abstract

The functions of the combinations of Zn—Ca and Cd—Ba soaps as primary stabilisers and various organic compounds as secondary stabilisers (epoxidised soya bean oil, phosphites, a—phenylindole, —aminocrotonate esters, ft-diketone and po— lyols) in the thermal stabilisation of the polyvinylchloride are reviewed through the mechanisms established previously. The use of chlorohexene isomers as models of allylic chlorine atoms located at the end of a growing polyene chain in the po lymer has elucidated the basic chemistry of the reactions of stabilisation. Coulo— metric titration of metal chlorides accumulation in the polymer matrix has proved to be a powerful tool in the study of stabilisers transformation and in the true explanation of the synergistic action of the secondary stabilisers.