preparation of cellulose nanofiber by mechanochemical methods

• Main Author: Kodchakorn Vongjitpimol
• Other Authors: Masaki Ujihara
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/8kccx9

碩士 === 國立臺灣科技大學 === 應用科技研究所 === 106 === The cellulose nanofiber was prepared from a bleached chemical wood pulp by three methods i.e. I) Mechanical process using a high-speed blender, II) Chemical process using NaOH pre-treatment and III) Mechanochemical (Mechanical + Chemical) process using ultrasonication in the presence of NaOH. The characterization of nanofiber was carried out by the sedimentation test and the scanning electron microscopy (SEM). After mechanical process, the pulp became a floc, and the production of nanofibers with several tens nanometer in diameter was confirmed by the SEM observation. In the chemical process, the crystallinity of cellulose was analyzed. The swelling and the crystalline transformation were observed after the NaOH treatment at low temperature. However, the chemical process and the mechanochemical process resulted in the swelling of cellulose fibrils to the sum-micrometer structures, and did not effectively provide the cellulose nanofiber. To compare the swelling property with the bleached chemical wood pulp, the microcrystalline cellulose from cotton linters was also examined by the chemical process using NaOH and NaOH/urea aqueous solutions. The microcrystalline cellulose exhibited the transparent gel formation at low temperature. The regenerated cellulose from the gel was the cellulose II. The difference in swelling/gelation properties of the wood pulp and the microcrystalline cellulose could be due to their purity and their higher-order structures.