Comparison of structural, thermal and proton conductivity properties of micro- and nanocelluloses

Our search for a cellulose-based proton conducting material is continued. This paper presents selected physicochemical properties of cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) together with cellulose microcrystals (CMCs) and cellulose microfibrils (CMFs), determined by X-ray diffraction (XRD), thermogravimetric analysis (TGA+DTA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), and electrical impedance spectroscopy (EIS). The CNCs and CNFs were studied in the forms of powder and film. They were produced in the process of transition metal catalyzed oxidative process or by TEMPO-mediated oxidation. It has been shown that regardless of the production method and the form of the sample the celluloses retained the cellulose I beta crystalline structure, the cellulose films showed similar thermal properties in the relevant temperature range from room temperature to about 200 degrees C, and the TEMPO-oxidized CNF film showed the highest proton conductivity when compared with those of the other samples studied.