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Gas permeation and positron annihilation lifetime spectroscopy of poly(ether imide)s with varying ether
Author(s) -
Pethrick R. A.,
SantamariaMendia F.
Publication year - 2016
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.24268
Subject(s) - ether , imide , materials science , positron annihilation , permeation , positron annihilation spectroscopy , positron , annihilation , spectroscopy , polymer chemistry , analytical chemistry (journal) , nuclear physics , organic chemistry , physics , membrane , chemistry , biochemistry , quantum mechanics , electron
A series of poly(ether imide)s are investigated using positron annihilation lifetime spectra [PALS] and gas permeation measurements. The glass transition temperature T g, determined by differential scanning calorimetry, does not correlate with the void sizes calculated from density or determined by PALS, implying that in these materials polymer−polymer chain interactions and not free volume has a dominant role in determining the overall chain dynamics. Significant differences observed in the permeability process with respect to carbon dioxide and nitrogen, highlight the role of polar interactions between the diffusing gas molecule and the polymer matrix on the transport processes. Diffusion coefficients do not change in a simple manner with void size. The solubility parameters vary across the series of materials and produce a small variation in the solubility coefficients for nitrogen and argon, but significantly differences were observed for carbon dioxide, reflecting the influence of polar interactions plasticizing the matrix. This study indicates that whilst the void structure is important in influencing gas transport, chain–chain interactions are controlling many of the higher temperature physical properties of these polymers. High values of selectivity between carbon dioxide and nitrogen were observed indicating that these materials have potential applications as gas separation membranes. POLYM. ENG. SCI., 56:427–434, 2016. © 2016 Society of Plastics Engineers