The Natural and Accelerated Evolution of EVA Adhesion Through Intermediate Exposures

Patrick Thornton, Nick Bosco, Reinhold Dauskardt

Research output: Contribution to journalArticlepeer-review

1 Scopus Citations


Ethylene vinyl acetate (EVA) encapsulants comprise the majority of the encapsulants currently in use; much work has been done to understand and model the adhesive characteristics of EVA-encapsulated modules, but limited work has provided reliable insight into adhesion during the intermediate stages of exposure, limiting the ability to validate model predictions in this range. Here we provide the adhesion energy measurements for EVA adhesion after nearly six years of field aging and 10 000 h of accelerated aging. Both field and accelerated aging reveal a distinct plateau that emerges during the intermediate exposure periods (after one year in the field and after 1000 h in a chamber). At 10 000 h, adhesion within accelerated aged minimodules falls to a level generally seen after long-term field exposures (>15 years). Previous modeling predicted that adhesion would steadily decrease over the lifetime of a module, but these current results uncover an intermediate plateauing trend that is important to accurately modeling the evolution of adhesion and predicting adhesive failure. Based on these findings, three key model refinements concerning the rate of UV-radical formation and subsequent ß-scission, the rate and acceleration of hydrolytic depolymerization, and the profile of the plasticity contribution over time are implemented and discussed.

Original languageAmerican English
Pages (from-to)1319-1323
Number of pages5
JournalIEEE Journal of Photovoltaics
Issue number6
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 2011-2012 IEEE.

NREL Publication Number

  • NREL/JA-5K00-81905


  • Adhesion
  • ethylene vinyl acetate (EVA)
  • field/accelerated aging
  • modeling


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