Investigation of the void formation mechanism during laser drawing

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K05990
• 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: Kim KyoungHou 信州大学, 学術研究院繊維学系, 教授 (30504550)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 繊維材料 / ボイド繊維 / フィブリル構造

Outline of Final Research Achievements

Ultra-small-angle X-ray scattering images before and after neck deformation of PET and PPS fibers were measured, and structural changes on the scale of tens to hundreds nm were analyzed, and their correspondence with physical properties was also investigated. In the case of PET fiber, the X-shaped scattering observed in PET after neck deformation is considered to reflect the shear band structure formed by shear deformation during neck deformation. On the other hand, as the IV was lower and the feed speed was slower, the void ratio tended to increase. The obtained void ratio was maximum 63%, for the case when the fiber was drawn at a feed speed of 1.0 m/min and a draw ratio of 6.25 times. Also, as a result of X-ray CT measurement of the 800 micrometer section along the fiber axis direction, there are much higher possibility that voids inside the fiber are continuous in the fiber axis direction.

Free Research Field

繊維材料

Academic Significance and Societal Importance of the Research Achievements

合成繊維に嵩高性及びバルキー性を付与するため特殊なノズルを使い中空糸を作る検討が多くなされている。しかし、延伸段階で繊維の断面に中空あるいはボイドを作る研究はない。また、一般的に、繊維の疲労に伴ってフィブリルが形成されるが、このフィブリルの元になる構造（ミクロフィブリル構造）が繊維製造のどの時点で形成されるのかは明らかでは無い。それで、合成繊維にフィブリル構造を基にする階層構造を想定して、フィブリル構造が、繊維の製造時、特にネック延伸時に形成されるとの仮説を立て、その検証に挑んだ。中空およびフィブリル構造の究明は一般的に繊維の疲労破壊メカニズムを知る上でも重要である。