Cellulose nanocrystals (NCC) and cellulose nanofibrils (CNF) were obtained by a single step process, with synergy between 64% sulfuric acid hydrolysis and high shear from ultra-turrax stirring, which is an advantageou...Cellulose nanocrystals (NCC) and cellulose nanofibrils (CNF) were obtained by a single step process, with synergy between 64% sulfuric acid hydrolysis and high shear from ultra-turrax stirring, which is an advantageous process for disintegrating cellulose microcrystalline and also may improve the hydrolysis process. The surface modification on the cellulose was performed by the sol-gel process, in which the sulfate groups from hydrolysis were replaced by nanoparticles of zinc oxide, which led to the increase of up to 54°C Tonset, according to thermogravimetric analysis (TGA) results. The morphology and crystallinity degree were characterized by Helium Ion Microscopy (HIM), atomic force microscopy (AFM) and X-ray diffraction. In addition, the ZnO band was observed in Fourier transform infrared spectroscopy, furthermore, the change in the zeta potential confirmed the cellulose modification. The changes in the values of proton spin-spin relaxation time for the systems showing the confined hydrogen in the rigid domains, confirmed the results observed with the aforementioned techniques, for both cellulose after hydrolysis and ZnO modified cellulose, suggesting that ZnO disrupted crystal formation in cellulose.展开更多
基金financially supported by CAPES code 001 and CNPQ.
文摘Cellulose nanocrystals (NCC) and cellulose nanofibrils (CNF) were obtained by a single step process, with synergy between 64% sulfuric acid hydrolysis and high shear from ultra-turrax stirring, which is an advantageous process for disintegrating cellulose microcrystalline and also may improve the hydrolysis process. The surface modification on the cellulose was performed by the sol-gel process, in which the sulfate groups from hydrolysis were replaced by nanoparticles of zinc oxide, which led to the increase of up to 54°C Tonset, according to thermogravimetric analysis (TGA) results. The morphology and crystallinity degree were characterized by Helium Ion Microscopy (HIM), atomic force microscopy (AFM) and X-ray diffraction. In addition, the ZnO band was observed in Fourier transform infrared spectroscopy, furthermore, the change in the zeta potential confirmed the cellulose modification. The changes in the values of proton spin-spin relaxation time for the systems showing the confined hydrogen in the rigid domains, confirmed the results observed with the aforementioned techniques, for both cellulose after hydrolysis and ZnO modified cellulose, suggesting that ZnO disrupted crystal formation in cellulose.
