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Proton exchange membranes by radiation grafting of styrene onto fep films. III. Structural investigation
Author(s) -
Gupta Bhuvanesh,
Haas Otto,
Scherer Günther G.
Publication year - 1994
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1994.070540407
Subject(s) - membrane , crystallinity , grafting , glass transition , differential scanning calorimetry , polymer chemistry , amorphous solid , materials science , styrene , polystyrene , crystallite , chemical engineering , copolymer , chemistry , polymer , composite material , organic chemistry , biochemistry , physics , metallurgy , engineering , thermodynamics
Structural investigation on proton‐exchange membranes, obtained by the radiation grafting of styrene onto FEP films and subsequent sulfonation, was carried out by differential scanning calorimetry. The membrane crystallinity was found to show a decreasing trend with increasing degree of grafting. The melting temperature of all the membranes also showed a slight decrease as compared to the ungrafted FEP. The results have been explained in terms of the cumulative effect of the decrease in the crystalline/amorphous ratio by the incorporation of amorphous polystyrene grafts and of disruption of spherulitic crystallites of the FEP component in the membranes. The glass transition temperature of the membranes with different water contents was also evaluated. A correlation of the glass transition temperature with the residual water in dried membranes was established. © 1994 John Wiley & Sons, Inc.