TY - JOUR
T1 - Structure-property correlations of sulfonated polyimides. II. Effect of substituent groups on membrane properties
AU - Lee, Choonkeun
AU - Sundar, Saimani
AU - Kwon, Jinuk
AU - Han, Haksoo
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2004/7/15
Y1 - 2004/7/15
N2 - A series of sulfonated polyimides with increasing alkyl substituents in the o-position to diamine were synthesized from 4,4′-methylene dianiline, 4,4′-diamine-3,3′-dimethyl-diphenylmethane, and 4,4′-diamine- 3,5,3′,5′-tetraethyl-diphenylmeth-ane using 1,4,5,8- naphthalenetetracarboxylic dianhydride and perylenetetracarboxylic dianhydride by chemical imidization method. 4,4′-Diaminobiphenyl 2,2′-disulfonic acid was used as sulfonated diamine. The variation in the membrane properties with increase in substitution was analyzed. Solubility increased with substitution whereas the thermal stability decreased with increase in substitution. Ion exchange capacity and water uptake reduced with increase in substitution because of the low sulfonic acid content at a particular weight due to the increased molecular weight of the repeating unit. The conductivity of the substituted diamines was higher than the unsubstituted diamines at higher temperature regardless of low ion exchange capacity and water uptake. The increase in conductivity with increase in temperature was more rapid in polyimides than in Nafion®115. Hydrolytic stability of the polyimides with substitution is more than the unsubstituted diamines.
AB - A series of sulfonated polyimides with increasing alkyl substituents in the o-position to diamine were synthesized from 4,4′-methylene dianiline, 4,4′-diamine-3,3′-dimethyl-diphenylmethane, and 4,4′-diamine- 3,5,3′,5′-tetraethyl-diphenylmeth-ane using 1,4,5,8- naphthalenetetracarboxylic dianhydride and perylenetetracarboxylic dianhydride by chemical imidization method. 4,4′-Diaminobiphenyl 2,2′-disulfonic acid was used as sulfonated diamine. The variation in the membrane properties with increase in substitution was analyzed. Solubility increased with substitution whereas the thermal stability decreased with increase in substitution. Ion exchange capacity and water uptake reduced with increase in substitution because of the low sulfonic acid content at a particular weight due to the increased molecular weight of the repeating unit. The conductivity of the substituted diamines was higher than the unsubstituted diamines at higher temperature regardless of low ion exchange capacity and water uptake. The increase in conductivity with increase in temperature was more rapid in polyimides than in Nafion®115. Hydrolytic stability of the polyimides with substitution is more than the unsubstituted diamines.
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U2 - 10.1002/pola.20215
DO - 10.1002/pola.20215
M3 - Article
AN - SCOPUS:3142577381
VL - 42
SP - 3621
EP - 3630
JO - Journal of Polymer Science, Part A: Polymer Chemistry
JF - Journal of Polymer Science, Part A: Polymer Chemistry
SN - 0887-624X
IS - 14
ER -