1994 Fiscal Year Final Research Report Summary
Creation of High Young Modulus Aromatic Copolyester by Heat-treatment in a Magnetic Field
| Project/Area Number |
05650680
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Structural/Functional materials
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| Research Institution | Tokyo Metropolitan University |
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Principal Investigator |
ITO Eiko Tokyo Metropolitan University, Faculty of Engineering, Professor, 工学部, 教授 (20087307)
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| Co-Investigator(Kenkyū-buntansha) |
YAMATO Masafumi Tokyo Metropolitan University, Faculty of Engineering, Instructor, 工学部, 助手 (40244420)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Liquid crystalline polymer / Orientation / Magnetic field / Young's modulus |
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| Research Abstract |
Thermotropic liquid crystalline polymers (LCP) having moduli of elasticity are known. The moduls much depends on the degree of molecular chain alignment. Application of a magnetic field is effective to orient the LCP chains. The purpose of this study is as follows : (1) to orient the molecular chains of a liquid crystalline copolyester in the magnetic field, (2) to clarify the structure of the oriented LCP and (3) to measure tensile strength for the oriented LCP.
The copolyester used in this contains p-hydroxybenzoic acid (PHB) and poly (ethylene terephthalate) (PET) ; the ratio of PHB/PET being 0.6 : 0.4. Copolymer samples taken from pressed film were heat-treated in a magnetic field (6 tesla) at temperatures ranging between 190ﾟC and 250ﾟC for 10 minutes-24 hours in nitrogen atmosphere.
The degree of molecular chains orientation was calculated by measurements of wide angle X-ray sacttering.
Young's modulus was obtained by measurements of tensile strength.
The diffraction patterns of the
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sample heat-treated at 225ﾟC in a magnetic field became more sharp in time, but any peak attributed to the crystallization was not observed. It suggests that the crystallization was not allowed to occur though the molecular chains were oriented. The degree of orientation increased rapidly at about 225ﾟC.The molecular orientation at 225 and 230ﾟC set in within a few minutes. At 220ﾟC,it took longer time to obtain the sample degree of orientation as those at 225 and 230ﾟC.
As it is generally known that the softening point of this copolyster is about 190ﾟC and the phase transition temperature (from random to the nematic phase) is about 230ﾟC,it is considered that the molecular orientation occurred instantly at the phase transition temperature and slowly at the softening point temperature.
Young's modulus for the oriented samples in a magnetic field was obtained by measurements of tensile strength. Young's modulus increaased with the increase of degree of orientation. The elongation at the braek down point decreased with the increase of degree of orientation. Less
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Research Products
(2 results)
