Effect of radiochemical ageing on the tensile properties of high density polyethylene

✍ Scribed by L. Audouin-Jirackova; G. Papet; J. Verdu

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 416 KB
• Volume: 25
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(89)90072-4

✦ Synopsis

Samples of high density polyethylene of 4 mm thickness were 7-irradiated in air at 0.69, 0.41 and 0.19 Gy sec ~ and in vacuum at 0.69 Gy.sec t dose rate. Spectrophotometric and sol-gel measurements showed that, for a given dose, the conversions of oxidative degradation in the skin zone and crosstinking in the core zone were nearly independent of the dose rate which controls essentially the depth of the oxidized zone. Tensile measurements showed that the mechanical properties are practically unaffected in the elastic and upper yield regions. The ultimate (true) stress can be considered practically constant. In constrast, the rate of ultimate elongation change is a decreasing function of the dose rate, i.e. an increasing function of the depth of the oxidized zone. The observed variations can be qualitatively explained by fracture mechanics considerations.