title: Preparation of chitosan nanofibers from completely deacetylated chitosan powder by a downsizing process.
abstract: Chitosan nanofibers were easily prepared from fully deacetylated chitosan dry powder using a high-pressure waterjet system. From SEM observation, after 10 cycles of treatment, most of the chitosan had been reduced to homogeneous nanofibers measuring tens of nanometers. On the other hand, further mechanical treatment did not show a significant change. Relative crystallinity of chitosan nanofibers gradually decreased as the number of passes increased since high-pressure waterjet treatment damaged the crystalline region of chitosan nanofibers. The transmittance of the chitosan nanofiber slurry increased steeply, as the number of passes increased, indicating that the chitosan fibers were disintegrated effectively. Viscosity of chitosan nanofiber slurry also showed that the chitosan disintegrated well into nanofibers up to 10 passes. Above 10 passes, disintegration efficiency was saturated. The molecular weights of the nanofibers steeply decreased due to the depolymerization of chitosan by mechanical disintegration. The Young's modulus and tensile strength of chitosan nanofiber sheets were improved as the number of treatments increased, but further treatments deteriorated the tensile strength.
authors.affiliation: Department of Chemistry and Biotechnology, Tottori University, Tottori 680-8552, Japan.
authors.forename: Yihun Fantahun
authors.initials: YF
authors.lastname: Aklog
authors.affiliation: Department of Chemistry and Biotechnology, Tottori University, Tottori 680-8552, Japan.
authors.forename: Ajoy Kumar
authors.initials: AK
authors.lastname: Dutta
authors.affiliation: Department of Chemistry and Biotechnology, Tottori University, Tottori 680-8552, Japan.
authors.forename: Hironori
authors.initials: H
authors.lastname: Izawa
authors.affiliation: Research Center for Bioscience and Technology, Tottori University, Tottori 680-8553, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Morimoto
authors.affiliation: Department of Chemistry and Biotechnology, Tottori University, Tottori 680-8552, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Saimoto
authors.affiliation: Department of Chemistry and Biotechnology, Tottori University, Tottori 680-8552, Japan. Electronic address: sifuku@chem.tottori-u.ac.jp.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Ifuku
mesh_terms: D000107:Acetylation; D048271:Chitosan / Q000737:chemistry*; D003460:Crystallization; D055119:Elastic Modulus; D008027:Light; D008970:Molecular Weight; D057139:Nanofibers / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D011208:Powders; D013535:Suspensions; D013718:Tensile Strength; D014783:Viscosity
chemical_list: D011208:Powders; D013535:Suspensions; D048271:Chitosan
keywords: Chitosan; High-Pressure Waterjet System; Nanofiber