The preparation and antioxidant activity of BHA bonded to porous glass

During ageing and oxidative degradation of stabilized polymers, transformations of antioxidants take place as a result of reactions with radicals Ro· and Roo·, alkyl hydroperoxides and/or oxygen. Knowledge of these processes as well as of the properties of products thus forrned is necessary for a complex evaluation of antioxidants. Data are given dealing with typical products of oxidative transforrnations of phenolic antioxidants prepared by independent syntheses, with model transformations under conditions simulating interactions in a stabilized organic substrate, with products identified under real conditions of oxidation of a stabi1ized substrate, and with influence of sorne transformation products on the course of oxidation of tetralin and polypropylene.The oxidative radical degradation of polymers which takes place under most varied accompanying conditions during the atmospheric ageing or processing of polymers is limited by stabilization. The importance of the stabilization process and the theoretical interest devoted to it are an unequivocal consequence of the technical and commercial interests. The majority of the antioxidants technically used have an empirical basis. Complex requirements dealing with the properties of the stabilization systems have been gradually formulated. The data acquired so far about the stabilization processes and the chemical structure of the stabilizers have been summarized in a nurober ofmonographs 1 -7 • Every year suggestionsarealso made concerning the use of new stabilization systems.When choosing the antioxidants, one concentrates on attaining the maximum activity while preserving at the sametime the optimum technical properties of the polymer. In the initiationstage of the degradation process, free radicals are formed from the oxidized polymer, RHAccording to the generally accepted scheme of autoxidation, alkyl peroxyls and alkyl hydroperoxides are formed in the propagation step ofthe reaction; they are a source of further radicals which play their role in the degradation process

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The preparation and antioxidant activity of BHA bonded to porous glass

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References 11 publications

Functionalized oligomers and polymers as stabilizers for conventional polymers

Functionalized oligomers and polymers as stabilizers for conventional polymers

Transformations of phenolic antioxidants during the inhibited oxidation of polymers

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