✦ LIBER ✦

Initiation processes in the photodegradation of high impact polystyrene—I Effects of prior thermal oxidation

✍ Scribed by A. Ghaffar; A. Scott; G. Scott

Publisher: Elsevier Science
Year: 1976
Tongue: English
Weight: 362 KB
Volume: 12
Category: Article
ISSN: 0014-3057
DOI: 10.1016/0014-3057(76)90026-4

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✦ Synopsis

The processes of thermal and photo-oxidation of high impact polystyrene have been shown to be closely related. Thermally produced hydroperoxides are directly responsible for subsequent oxidative reactions which occur during u.v. irradiation. Olefinic unsaturation associated with the polybutadiene phase is depleted rapidly on u.v. irradiation in air during which time the rate of oxidation and the hydroperoxide concentration rise to a maximum and then decrease. The rubber phase is shown to behave as a photo-pro-oxidant for polystyrene and photo-initiation by carbonyl compounds does not appear to be important under conditions encountered in industrial fabrication operations.

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Initiation processes in the photodegradation of high impact polystyrene—II. Effects of prior exposure to sensitizing environments

✍ A. Ghaffar; A. Scott; G. Scott 📂 Article 📅 1977 🏛 Elsevier Science 🌐 English ⚖ 405 KB

It is shown that processes leading to the introduction of peroxide groups into polybutadiene also lead to photo-sensitization of polybutadiene modified polystyrene (HIPS). Four such processes were compared, viz. prior thermal oxidation, ozonization, direct photolysis and photosensitization b.x added