Glassy polymers: Historical findings, membrane applications, and unresolved questions regarding physical aging
Glassy polymers: Historical findings, membrane applications, and unresolved questions regarding physical aging
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DOI：
10.1016/j.polymer.2020.123176
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发表时间：
2020-12-21
期刊：
影响因子：
4.6
通讯作者：
Freeman, Benny D.
中科院分区：
文献类型：
--
作者：
Merrick, Melanie M.;Sujanani, Rahul;Freeman, Benny D.
低于其玻璃化转变温度（Tg）的聚合物是非平衡玻璃，因为在动力学限制的聚合物链之间“冻结”的过量自由体积随着时间的推移经由局部链段运动缓慢地松弛朝向平衡。这个过程，被称为物理老化，是通过观察聚合物的比容，焓等随时间变化的减少本文重点介绍了玻璃态聚合物在膜分离应用的历史。关于厚度影响的悬而未决的问题（例如，膜几何形状）和温度对玻璃态聚合物物理老化的影响。
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.