Molecular relaxation in cross-linked poly(ethylene glycol) and poly(propylene glycol) diacrylate networks by dielectric spectroscopy

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• 作者：Sumod Kalakkunnath ; Douglass S. Kalika ; Haiqing Lin ; Roy D. Raharjo ; Benny D. Freeman
• 关键词：Membranes ; Poly(ethylene oxide) ; Dielectric spectroscopy
• 刊名：Polymer
• 出版年：2007
• 期刊代码：83_00323861
• 类别：ms
• 出版时间：12 January 2007
• 卷：48
• 期：2
• 页码：579-589
• 文件大小：1032 K

摘要

The molecular relaxation characteristics of rubbery amorphous crosslinked networks based on poly(ethylene glycol) diacrylate [PEGDA] and poly(propylene glycol) diacrylate [PPGDA] have been investigated using broadband dielectric spectroscopy. Dielectric spectra measured across the sub-glass transition region indicate the emergence of an intermediate “fast” relaxation in the highly crosslinked networks that appears to correspond to a subset of segmental motions that are more local and less cooperative as compared to those associated with the glass transition. This process, which is similar to a distinct sub-T_g relaxation detected in poly(ethylene oxide) [PEO], may be a general feature in systems with a sufficient level of chemical or physical constraint, as it is observed in the crosslinked networks, crystalline PEO, and PEO-based nanocomposites.