Spinning of High-strength Fibers consisting of only nanocellulose crystals

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K05991
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Polymer/Textile materials
• Research Institution: Shinshu University
• Principal Investigator: Araki Jun 信州大学, 学術研究院繊維学系, 准教授 (10467201)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: セルロース / ナノウィスカー / 繊維 / 湿式紡糸 / ヤング率 / 破断強度 / 配向度 / 化学架橋

Outline of Final Research Achievements

Fibers consisting of only cellulose nanowhiskers (CNWs) could be obtained by wet spinning of aqueous CNW suspensions. Spinning under various conditions, including different organic solvents for coagulation baths, different types and amounts of electrolytes in coagulation baths, and solid content of spinning dope suspensions, were examined to obtain fibers with best mechanical properties and CNW orientation. Young's modulus of the fibers were found to be dependent on CNW orientation, whereas break at strength were not. Washing the fibers with water and subsequent air-drying markedly enhanced the mechanical properties of the CNW fibers. Elemental analyses suggested ionic cross-linking of CNWs with Ca2+ cations, which were added in the coagulation solvents. Chemical cross-linking of the CNWs rendered fibers with improved elongation at break, even with decreased stress at break.

Free Research Field

セルロース化学、高分子化学、超分子科学

Academic Significance and Societal Importance of the Research Achievements

繊維の力学物性は用いる高分子の結晶化度に大きく依存する。非晶を加水分解して結晶のみを残したセルロースナノウィスカーのみから繊維が形成できたことは100%結晶からなる繊維の調製を意味し、また微結晶の集合体であることによりしなやかさも備えている。100%結晶からなる繊維はこれまでに実現されたことがなく画期的であり、軽さの割に鉄やガラス並の強度を持つセルロース結晶の利点を生かした材料創成の先駆けとなる。