Thermo- and photooxidation of polyisobutylene. I. Evolutions at temperatures above 50°C

✍ Scribed by Richard Pazur; Michel Troquet; Jean-Luc Gardette

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 304 KB
• Volume: 35
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19970715)35:9<1689::aid-pola10>3.0.co;2-1

✦ Synopsis

Polyisobutylene films (PIB) were submitted to a thermal oxidation at 100ЊC and to a photooxidation by exposure to long-wavelength radiations ( l ¢ 300 nm) at 60ЊC. The modifications of the chemical structure resulting from the oxidation were determined by FT-IR analysis of the polymer films, coupled to chemical treatments that converted specifically the oxidation products. Dissolution of oxidized samples permitted analysis of the polymer by 13 C-and 1 H-NMR. The structure of the volatile products was determined by mass spectroscopy analysis of the gas phase. Identification of the numerous products formed permitted the proposal of a scheme that accounts for the oxidation of PIB. When the irradiations are carried out at a temperature above 50ЊC, the depolymerization is favored and the mechanism involves two main routes of oxidation. A direct oxidation starts with the oxidation of radicals obtained by homolysis of the C{C bonds on the main chain, and an induced oxidation involves hydrogen abstraction on the methylene and methyl groups by radicals formed by the direct oxidation of the polymer.