Studies of the degradation of organotin stabilizers in poly(vinyl chloride) during gamma irradiation

Organotin stabilizers of the type Bu₂SnX₂ (X = SCH₂CO₂C₈H₁₇ or O₂CCH?CHCO₂C₈H₁₇) present in poly(vinyl chloride) (PVC) and subjected to varying doses of gamma irradiation in the range 1–200 kGy (0.1–20 Mrad) are shown to suffer degradation with dealkylation to form monobutyltin trichloride and tin(IV) chloride, which have been characterized by a subsequent alkylation procedure followed by gas chromatographic analysis. The extent of degradation of the stabilizers on prolonged gamma irradiation is much more severe than during thermal degradation leading to comparable blackening of the polymer.