Synthesis and characterization of new fluorescent polyimides bearing 1,2,4-triazole and 1,2-diaryl quinoxaline: Study properties and application to the extraction/elimination of metallic ions from aqueous media

摘要

In this article, synthesis and characterization of triazole-based polyimides for solid-phase extraction of metal cations is described. For this purpose, new aromatic diamines containing 1,2,4-triazole and substituted 1,2-diaryl quinoxaline units were synthesized and used in polycondensation reaction with aromatic dianhydrates to yield poly(triazole-imide)s (PTAI)s. These polymers had inherent viscosities in the range of 0.58-0.62 dL/g and were readily soluble in a variety of organic solvents; they formed low-colored and tough thin films via solution casting. The PTAIs exhibited T_8 between 280 and 338℃, and their 10% weight loss temperatures were in excess of 540℃ with up to 76% char yield at 700℃ in N2. These polymers emitted green or blue fluorescence in dilute NMP solution and in the solid state. The triazole groups in the polymer chain were efficient chelating/host units for heavy metal ions. One of these polymers, PTAI(1b), was investigated for its extraction capability for environmentally deleterious metal ions such as Cr~(Ⅵ), Cr~(Ⅲ), Co~(Ⅱ), Zn~(Ⅱ) Pb~(Ⅱ), Cd~(Ⅱ), Hg~(Ⅱ) and Mn~(Ⅱ) from aqueous solutions either individually or in the mixture and at different pH values.