Polyphenylenes chemical modification

In the search for the gas separation membrane materials of improved permeability and selectivity, various chemical modifications of PPO have been investigated - e.g. carboxylation [4, 5], fluorination [6], nitration [7] bromination [8-10] and sulfonation [11]. In this chapter though we shall focus on the investigations of gas transport through the membranes of unmodified 2,6-substituted polyphenylene ethers - both homo- and copolymers - with the repeat unit represented by the formula (1). In this formula, R stands for methyl, phenyl or allyl group. 

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