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Cellulose microfibers surface treated with imidazole as new proton conductors
Ist Teil von
Materials chemistry and physics, 2020-01, Vol.239, p.122056, Article 122056
Ort / Verlag
Lausanne: Elsevier B.V
Erscheinungsjahr
2020
Quelle
Access via ScienceDirect (Elsevier)
Beschreibungen/Notizen
A newly synthesized polymeric proton-conductive composite (3.5CMF-Im), based on pure cellulose microfibers (CMF) functionalized with imidazole molecules (Im) on their surface, was comprehensively studied in terms of structural, thermal, and electrical properties. According to elemental analysis of 3.5CMF-Im composite contains on average one imidazole molecule per 3.5 glucose units. Fourier transform infrared spectroscopy (FTIR) was used to identify the crystalline structure and hydrogen bond network. Thermogravimetric analysis (TGA + DTG) and differential scanning calorimetry (DSC) tests were carried out to examine the stability and thermal decomposition of studied materials. In order to determine temperature dependences of electrical conductivity, the impedance spectroscopy was used. For the first time, evidence of imidazole dissociative mechanism in this type of material using FTIR was obtained. Imidazole may dissociate into an imidazolium cation and an imidazole anion, and this mechanism may contribute to the proton conductivity of cellulose-imidazole composites. The new material exhibits a maximum conductivity of 2.7 × 10−4 S m−1 at 150 °C, which is four orders of magnitude higher than that of pure cellulose microfibers. The composite is environmentally friendly solid polymer electrolyte operating in the temperature range above the water boiling point.
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•Cellulose microfibers (CMF) are functionalized with imidazole molecules.•Structural, thermal and electrical properties of the new material are determined.•Imidazole cations and anions are present in the material at room temperature.•The highest proton conductivity is measured at 150 °C.•The composite shows four orders of magnitude higher conductivity value than CMF.