Inverse effect in simultaneous thermal and radiation aging of EVA insulation
2015 (English)In: eXPRESS Polymer Letters, ISSN 1788-618X, Vol. 9, no 4, 384-393 p.Article in journal (Refereed) Published
Poly(ethylene-co-vinyl acetate) (EVA) insulation of the cable applied in nuclear power plants was accelerated aged by gamma-rays at two various temperatures, namely 55 and 85 degrees C. Radiation degradation in the dose range of 01500 kGy was monitored using a Differential Scanning Calorimetry method by measuring oxidative induction temperature (OITp), gel fraction, mechanical and electrical tests. It was confirmed that a dose rate effect in the range of 420-1500 Gy/h was negligible whereas progress of degradation with increasing dose was strongly temperature dependent. For the insulation accelerated aged at 85 degrees C the OITp and permittivity measurements confirmed lower degradation than for the specimens radiation treated at 55 degrees C at the same dose rates. It was postulated that an inverse thermal effect resulted from radiation induced cross-linking facilitated by melting of EVA crystallites at 85 degrees C.
Place, publisher, year, edition, pages
2015. Vol. 9, no 4, 384-393 p.
material testing, radiation degradation, thermal degradation, inverse thermal effect, poly(ethylene-co-vinyl acetate)
IdentifiersURN: urn:nbn:se:kth:diva-161596DOI: 10.3144/expresspolymlett.2015.36ISI: 000349450100007ScopusID: 2-s2.0-84922014897OAI: oai:DiVA.org:kth-161596DiVA: diva2:798013
QC 201503252015-03-252015-03-132015-03-25Bibliographically approved