2005 Fiscal Year Final Research Report Summary
High Strength and High Thermal Stability of Polylactide Fibers with Stereocomplex Crystal Obtained by High-Speed Melt Spinning and Subsequent Drawing and Annealing Processes
| Project/Area Number |
15350129
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Polymer/Textile materials
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
KIKUTANI Takeshi Tokyo Institute of Technology, Department of Organic and Polymeric Materials, Professor, 大学院・理工学研究科, 教授 (70153046)
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| Co-Investigator(Kenkyū-buntansha) |
SHIOYA Masatoshi Tokyo Institute of Technology, Department of Organic and Polymeric Materials, Associate Professor, 大学院・理工学研究科, 助教授 (10196363)
ITO Hiroshi Tokyo Institute of Technology, Department of Organic and Polymeric Materials, Assistant professor, 大学院・理工学研究科, 助手 (20259807)
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| Project Period (FY) |
2003 – 2005
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| Keywords | polylactides / streocomplex / high-speed melt spinning / drawing / annealing / birefringence / on-line measurement / wide angle X-ray diffraction |
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| Research Abstract |
To clarify the effect of molecular orientation on crystal structure change of racemate polylactide, structure formation of fibers obtained by high-speed melt spinning was investigated during heating and cooling processes. Changes in crystal structure of racemate polylactide fibers and films were analyzed by in-situ WAXD, DSC, and birefringence measurements during heating and cooling processes. The co-existence of α-form and stereocomplex crystals was observed above the take-up velocity of 4 km/min, and reflection intensity of stereocomplex crystal increased with an increase in the take-up velocity. During heating process, α-form crystals of as-spun fibers started to increase at around 80℃ which was independent of molecular orientation of as-spun fibers. The reflection intensity of stereocomplex crystal of as-spun fibers appeared when α-form crystal started to decrease. Existence of the α-form crystals in these fibers was confirmed even at melting temperature of α-form crystal of 170℃. The development of α-form crystal was also observed in the fibers drawn at 70℃. Birefringence of drawn fibers showed the highest value at 2 km/min, and decreased with increasing take-up velocity. On the other hand, birefringence of drawn decreased by annealing at 190℃ and became close to the birefringence of fibers obtained by directly annealing the high-speed spun fibers at the same temperature.
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