Effect of Polymer Melt Memory as Studied by Nuclear Magnetic Resonance

2002 Fiscal Year Final Research Report Summary

• Project/Area Number: 13650956
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 高分子構造・物性(含繊維)
• Research Institution: Tokyo Metropolitan University
• Principal Investigator: KIMURA Tsunehisa Graduate School of Engineering, Tokyo Metropolitan University, Professor, 大学院・工学研究科, 教授 (40264593)
• Co-Investigator(Kenkyū-buntansha): YAMATO Masafumi Graduate School of Engineering, Tokyo Metropolitan University, Assistant, 大学院・工学研究科, 助手 (40244420)
• Project Period (FY): 2001 – 2002
• Keywords: NMR / Magnetic Alignment / Polymer / Molecular Weight Dependence / Structure Formation

Research Abstract

A high-temperature NMR probe became repaired this year and the in-situ NMR measurements for poly(ethylene oxide) (PEO) and paraffin were carried out during the heating and cooling processes. The PEO sample of Mn=4,600 did not show any difference between the starting powder pattern and the spectrum obtained after heating followed by cooling, indicating no alignment. But the sample of Mn=2,000 exhibited the difference, indicating magnetic alignment.
The spectrum of paraffin starts with a powder pattern typical of a σ_<11>, σ_<22>, σ_<33> system, then changed to σ_<11> = σ_<22> type pattern upon heating. This is due to the phase change to the hexagonal phase. Upon melting, the broad peak changed to a narrow one. During the cooling process, the melt passes through a hexagonal phase at which the magnetic alignment was indicated by the reduction of the high-field σ_<33> component. This means that the chain (33 direction) aligned perpendicular to the magnetic field. This is consistent with the previous results by X-ray.