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Abstract This study reports on the effect of organic polyvinyl alcohol (PVA) and silica matrix on the properties of cellulose-based nanocomposites. Nanofibrillated cellulose was isolated from kraft pulp and treated with Pulpzyme HC 2500 enzyme prior to high-pressure homogenization in order to lower energy consumption. Three nanocomposite films were fabricated via the casting process: nanofibrillated cellulose, nanocellulose-PVA (NC-PVA) and nanocellulose-silica (NC-Si). Chemical characterization and crystallization were determined with FTIR. Thermal stability was investigated with thermogravimetric analysis. Morphological alterations were monitored with scanning electron microscopy. A universal testing machine and dynamic mechanical thermal analysis were used for determination of Young’s and storage moduli. The real and imaginary parts of permittivity and electric modulus were evaluated using an impedance analyzer. Considerable alterations were seen under FTIR. Thermal stability was lower in NC-Si than in NC-PVA due to lower crystallinity. Higher Young’s modulus and storage moduli were observed in NC-PVA than in NC-Si. NC-PVA exhibited a singular relaxation process, while a double relaxation process was seen in NC-Si. Consequently, the nanocomposite film prepared from the organic matrix (NC-PVA) had a mechanical advantage for industrial applications. However, neat NC composite revealed the highest storage modulus and thermal stability.

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Industrial applications of microfibrillated cellulose (MFC) and nanofibrillated cellulose (NFC) have been in use for some time; however, there is a need to improve the production steps and at the same time to obtain better quality products. NFC and MFC were generated from NaBH 4-modified kraft pulp, produced from a red gum tree plant (Eucalyptus camaldulensis). The generated NFC and MFC were characterized by high-performance liquid chromatography, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and 13 C-nuclear magnetic resonance (NMR). Morphological and viscoelastic properties were investigated by scanning electron microscopy and rheometry, respectively. The storage moduli of biofilms produced from NFC and MFC were investigated by dynamic mechanical thermal analysis (DMTA). Both exhibited mostly identical FTIR spectra. When the spectra were compared with those of NaBH 4-modified kraft pulp, minor shifts were observed due to crystallinity. In NMR spectra, disordered cellulose structures were observed for both NFC and MFC, and these findings were also confirmed by differential scanning calorimetry. Rheology studies revealed that the lowest viscosity was observed with MFC. TGA results showed that NFC degraded earlier compared with NaBH 4-modified kraft pulp. DMTA exhibited that NFC films had about six times higher storage modulus compared with MFC.