A comparative study of the effects of UV- and γ-radiation on copolymers of acrylonitrile/butadiene

✍ Scribed by Cardona, Francisco; Hill, David J T; Pomery, Peter J; Whittaker, Andrew K

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 141 KB
• Volume: 48
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(199910)48:10<985::aid-pi258>3.0.co;2-3

✦ Synopsis

The radiolysis of nitrile rubbers with different acrylonitrile/butadiene composition and the homopolymers, poly(butadiene) (PBD) and poly(acrylonitrile) (PAN) has been investigated and compared with the photolysis of the same polymers. A signi®cantly different mechanism of degradation was found for the two types of radiation. The results obtained by ESR, FTIR and measurements of soluble fractions of irradiated samples, indicated that the acrylonitrile units of the nitrile rubbers are more sensitive units to g-radiation, with the effects of irradiation increasing with the acrylonitrile content. The reactions observed were consumption of double bonds, crosslinking, and cyclization with the formation of conjugated double bonds. No chain-scission reactions were detected. In contrast to g-irradiation, the effects of photolysis were centred at the butadiene units, and increases in the acrylonitrile content resulted in a proportional decrease in the sensitivity of the copolymers. Crosslinking and chain scission were identi®ed as the main effects of photolysis of NBR rubbers.