Physicochemical properties of "green" nanocrystalline cellulose isolated from recycled newspaper

Abstract

Green”nanocrystalline cellulose (NCC) was isolated through an acid hydrolysis process from recyclednewspapers and preparedviatreatment with NaOH and NaClO2. Morphological characterization andphysicochemical property measurements were executed using scanning electron microscopy (SEM),atomic force microscopy (AFM), transmission electron microscopy (TEM), Fourier transform infrared(FTIR) spectroscopy, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). FTIR and chemicalcomposition analysis demonstrated that lignin and hemicellulose structures were removed usingdifferent pretreatment steps with NaOH and NaClO2. From the SEM results, it was discovered that thesize of purified cellulosefibrils reduced to a great extent, and the structure of cellulose microfibersbecame smoother and cleaner due to the removal of lignin with other extracts. The XRD analysis resultsrevealed that NCC exhibits the highest crystallinity index after acid hydrolysis of bleached cellulosemicrofibers. TEM and AFM analysis revealed that the rod-like structure of NCC was obtained with size5.78±2.14 nm wide and 121.42±32.51 nm long. The TGA results suggested that the thermal stability ofthe NCC was affected mainly by the dehydration reaction caused by sulphate groups. The isolatednanocrystalline cellulose attracts great interest as an inexpensive bio-basedfiller in polymernanocomposites.