Glassy polymers: historical findings, membrane applications, and unresolved questions regarding physical aging

Melanie M. Merrick, Rahul Sujanani, Benny D. Freeman

Research output: Contribution to journalArticleResearchpeer-review

19 Citations (Scopus)


Polymers below their glass transition temperature (Tg) are non-equilibrium glasses because excess free volume “frozen” between kinetically-restricted polymer chains slowly relaxes over time towards equilibrium via local, segmental chain motion. This process, known as physical aging, is observed through time-dependent decreases in a polymer's specific volume, enthalpy, etc. This article focuses on the history of glassy polymers in membrane separation applications. Open questions regarding the influence of thickness (e.g., membrane geometry) and temperature on physical aging in glassy polymers are highlighted.

Original languageEnglish
Article number123176
Number of pages16
Publication statusPublished - 21 Dec 2020
Externally publishedYes


  • Glass transition
  • Membranes
  • Physical aging
  • Sorption

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