Antioxidant action of organic sulphites III. Antioxidative effect of esters of sulphurous acid in hydrocarbons and polypropylene

• Published in: Polymer degradation and stability Vol. 64; no. 1; pp. 115 - 126
• Main Authors: Günther, A., König, T., Habicher, W.D., Schwetlick, K.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-01-1999; Elsevier Science
• Subjects: Applied sciences; Compounding ingredients; Exact sciences and technology; Polymer industry, paints, wood; Stabilizers (antioxydants, antiozonants, etc.); Technology of polymers; Performance evaluation; Oxygen sulfur heterocycle; Structure effect; Hydrocarbon; Propylene polymer; Thermooxidative degradation; Antioxidant; Experimental study; Autoxidation; Additive; Stabilizer agent; Model compound; Light stabiliser; Kinetic parameter; Mechanism of action; Organic sulfite
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/S0141-3910(98)00184-0

The influence of aliphatic, aromatic, cyclic and acyclic esters of sulphurous acid on the AIBN initiated oxidation of the hydrocarbons cumene and tetraline at 65°C as well as of polypropylene at 180°C was examined. AIBN initiated oxidation of cumene and tetraline in presence of alkyl sulphites took place without an induction period, but the reaction rate was reduced. Aromatic sulphites caused occurrence of induction periods and considerably reduced oxygen uptake rates. The thermooxidative decomposition of hydrocarbons and polymers was retarded. The rate constants of the reaction of organic sulphites with peroxyl radicals were determined and compared with those of the appropriate phenols. During thermooxidation of polypropylene films and the processing of polypropylene, the stabilizing effect of sterically hindered aromatic sulphites was similar to those of the commercially produced antioxidant BHT. They acted also as lightstabilizers and reduced the UV ageing of polypropylene.