Degradation of polymer mixtures. V. Blends of poly(vinyl chloride) with chlorinated rubber

Blends of PVC with purified commercial chlorinated rubber are substantially less stable than would be predicted from a comparison of the degradations of the constituent polymers. Hydrogen chloride is the sole volatile product in the temperature range of the main degradation reaction. By the use of PVC labeled with 36 Cl together with inactive chlorinated rubber, it has proved possible to distinguish the production of hydrogen chloride from the PVC from that from the other polymer. In this way it has been established that it is the PVC component which is responsible for the greatly increased production of hydrogen chloride. Explanations are advanced for the effect of chlorinated rubber in destabilizing the PVC.