Preparation and applications of cellulose nanofibrils with different chemical composition using various pretreatments

다국어 초록 (Multilingual Abstract)

Cellulose nanofibrils (CNF) can be divided into lignocellulose nanofibrils (LCNF), holocellulose nanofibrils (HCNF), and pure cellulose nanofibrils (PCNF), dependent upon their chemical compositions. The chemical composition can be adjusted by various chemical treatments such as acid treatment, sodium chlorite-acetic acid treatment, alkaline-peroxide treatment, alkaline treatment, hydrothermal treatment, which affects properties of CNF and CNF reinforced nanocomposites as well as defibrillation efficiency. In this study, the effect of chemical composition on properties of CNF and CNF/thermoplastic starch plastic (TPS) composite was investigated. The contents of lignin and hemicellulose in lignocellulose were adjusted by sodium chlorite-acetic acid treatment and NaOH treatment, respectively, and then defibrillated using a wet-disk mill. As the content of lignin and hemicellulose was decreased, the defibillation efficiency was improved, resulting a decrease in the average diameter and an increase in the specific surface area of CNFs. As the hydrophobic lignin was removed, the hydrophilicity of CNF　was increased, resulting in improved tensile properties of nanopapers and CNF/TPS composite. The presence of hemicellulose in HCNF without lignin can enhance the tensile properties of nanopaper and CNF/TPS composite due to the high hydrophilic property of hemicellulose, which can act as an adhesive between hydrophilic polymers.