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Abstract
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To improve the solubility, thermal properties and processability of polyxanthones, a new class of polyxanthones, poly(xanthone-imide)s (PXIs), with a high yield was prepared using a two-step chemical imidation of 2,7-diaminoxanthone with pyromellitic dianhydride (PMDA), 3,3’,4,4’-benzophenone tetracarboxylic dianhydride (BTDA) and 2,2’-bis-(3,4-dicarbo- xyphenyl) hexafluoropropane dianhydride (6-FDA)). These PXIs were characterized with FT-IR and 1 H NMR spectroscopies.They presented a good solubility in aprotic polar solvents such as N,N-dimethyl acetamide (DMAc), N,N-dimethyl formamide (DMF), N-methyl pyrrolidone (NMP) and dimethyl sulfoxide (DMSO), and showed inherent viscosities in a range of 0.34–0.58 dL/g. These PXIs exhibited lower glass-transition temperatures than the original polyxanthones and a high thermal stability. The obtained results of the UV-vis absorption and photoluminescence indicated that the maximum absorption and fluorescence emission of PXIs were in the range of 300–304 nm and 432–510 nm, respectively. The antioxidant activity of PXIs was evaluated with a DPPH assay. The antioxidant values for PXIs were greater than for the parent xanthone (X). The polyimides were investigated for the extraction of environmentally noxious metal ions such as Cr (VI), Co (II), Ni (II), Cu (II), Pb (II) and Cd (II) from aqueous solutions.
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