Study on the fiber property revelation by the in-situ observation of structure development

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05597
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 35020:Polymer materials-related
• Research Institution: Shinshu University
• Principal Investigator: Ohkoshi Yutaka 信州大学, 学術研究院繊維学系, 教授 (40185236)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: Fiber Property / Structure Development / ポリエチレンテレフタレート / X-ray diffraction / SPring-8 / Fiber Strength

Outline of Final Research Achievements

Fiber properties as like tensile strength and thermal shrinkage are strongly affected by the fibrillar structure formed in the fiber by orientation-induced crystallization. Development of the fibrillar structure after instantaneous stretching of fiber was observed in this study with 100 micro-seconds time-resolution in-situ measurement using ultra-high luminant X-ray source of SPring-8. As the results, lamellae crystal was revealed to be developed together with the smectic, which thought to be an embryo of microfibril structure, for the low molecular weight poly(ethylene terephthalate), while the development of the smectic was dominant for the high molecular weight one. The apparent modulus obtained by the d-apacing of smectic revealed that the tensile strength of fiber was decided by only 5% of inter-microfibrillar tie-chain.

Free Research Field

繊維材料学

Academic Significance and Societal Importance of the Research Achievements

強度など繊維の諸物性は配向結晶化によって形成されるフィブリル状構造の影響を強く受ける。本研究では、繊維を瞬間的に伸長した後のフィブリル状構造の形成過程を、SPring-8の超高輝度X線を使い、時間分解能100マイクロ秒でその場測定した。この結果、ポリエチレンテレフタレートでは、分子量が小さいとフィブリル構造の母体となるsmectic相が形成されるのと同時にラメラ状結晶が成長するのに対し、分子量が大きいとsmectic相の形成が支配的になるなど、原料や製造条件と繊維物性との定量的な関係を明らかにできた。この成果は繊維の物性設計のみならず、新たな機能発現へのBreak Throughになり得る。