Spontaneous Molecular Orientation of Polyimides Induced by Thermal Imidization. 3. Component Chain Orientation in Binary Polyimide Blends

1997 ◽  
Vol 30 (19) ◽  
pp. 5745-5752 ◽  
Author(s):  
Masatoshi Hasegawa ◽  
Kenji Okuda ◽  
Masato Horimoto ◽  
Yoichi Shindo ◽  
Rikio Yokota ◽  
...  
Keyword(s):  
Molecular Orientation ◽  
Chain Orientation ◽  
Thermal Imidization

Charge Transport Anisotropy due to Interfacial Molecular Orientation in Polymeric Transistors with Controlled In-Plane Chain Orientation

2012 ◽  
Vol 5 (2) ◽  
pp. 021602 ◽  
Author(s):  
Shun-ichiro Watanabe ◽  
Hisaaki Tanaka ◽  
Shin-ichi Kuroda ◽  
Akio Toda ◽  
Haruki Tomikawa ◽  
...  
Keyword(s):  
Charge Transport ◽  
Molecular Orientation ◽  
Chain Orientation

Spontaneous molecular orientation of polyimides induced by thermal imidization (6). Mechanism of negative in-plane CTE generation in non-stretched polyimide films

2010 ◽  
Vol 46 (4) ◽  
pp. 681-693 ◽  
Author(s):  
Junichi Ishii ◽  
Aya Takata ◽  
Yoko Oami ◽  
Rikio Yokota ◽  
Leonid Vladimirov ◽  
...  
Keyword(s):  
Molecular Orientation ◽  
Polyimide Films ◽  
Thermal Imidization

Spontaneous Molecular Orientation of Polyimides Induced by Thermal Imidization. 2. In-Plane Orientation

1996 ◽  
Vol 29 (24) ◽  
pp. 7897-7909 ◽  
Author(s):  
Masatoshi Hasegawa ◽  
Takafumi Matano ◽  
Yoichi Shindo ◽  
Tokuko Sugimura
Keyword(s):  
Molecular Orientation ◽  
Plane Orientation ◽  
Thermal Imidization

Spontaneous molecular orientation of polyimides induced by thermal imidization. I. Uniaxial stretching of polyamic acid film

1994 ◽  
Vol 32 (7) ◽  
pp. 1299-1303 ◽  
Author(s):  
Masatoshi Hasegawa ◽  
Yoichi Shindo ◽  
Tokuko Sugimura ◽  
Rikio Yokota ◽  
Masakatsu Kochi ◽  
...  
Keyword(s):  
Molecular Orientation ◽  
Polyamic Acid ◽  
Uniaxial Stretching ◽  
Thermal Imidization

Spontaneous molecular orientation of polyimides induced by thermal imidization (4): Casting- and melt-induced in-plane orientation

2010 ◽  
Vol 46 (1) ◽  
pp. 69-80 ◽  
Author(s):  
Junichi Ishii ◽  
Naoko Shimizu ◽  
Nobuaki Ishihara ◽  
Yasutaka Ikeda ◽  
Nobuyuki Sensui ◽  
...  
Keyword(s):  
Molecular Orientation ◽  
Plane Orientation ◽  
Thermal Imidization

Polarized microbeam FT-IR analysis of single fibers

1996 ◽  
Vol 54 ◽  
pp. 206-207
Author(s):  
Liling Cho ◽  
David L. Wetzel
Keyword(s):  
Molecular Orientation ◽  
Transition Point ◽  
Polymer Fibers ◽  
Single Fiber ◽  
Wire Grid ◽  
Polyester Fibers ◽  
Ft Ir ◽  
Ir Analysis ◽  
The Relationship ◽  
Wire Grid Polarizer

Polarized infrared microscopy has been used for forensic purposes to differentiate among polymer fibers. Dichroism can be used to compare and discriminate between different polyester fibers, including those composed of polyethylene terephthalate that are frequently encountered during criminal casework. In the fiber manufacturering process, fibers are drawn to develop molecular orientation and crystallinity. Macromolecular chains are oriented with respect to the long axis of the fiber. It is desirable to determine the relationship between the molecular orientation and stretching properties. This is particularly useful on a single fiber basis. Polarized spectroscopic differences observed from a single fiber are proposed to reveal the extent of molecular orientation within that single fiber. In the work presented, we compared the dichroic ratio between unstretched and stretched polyester fibers, and the transition point between the two forms of the same fiber. These techniques were applied to different polyester fibers. A fiber stretching device was fabricated for use on the instrument (IRμs, Spectra-Tech) stage. Tension was applied with a micrometer screw until a “neck” was produced in the stretched fiber. Spectra were obtained from an area of 24×48 μm. A wire-grid polarizer was used between the source and the sample.

Observing the relaxation of molecular orientation in sheared liquid crystalline polymer solutions

1990 ◽  
Vol 48 (4) ◽  
pp. 1092-1093
Author(s):  
Wendy Putnam ◽  
Christopher Viney
Keyword(s):  
Molecular Orientation ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Polymer Processing ◽  
Molecular Alignment ◽  
Global Alignment ◽  
Shear Direction ◽  
Axial Strength ◽  
Strength And Stiffness

Liquid crystalline polymers (solutions or melts) can be spun into fibers and films that have a higher axial strength and stiffness than conventionally processed polymers. These superior properties are due to the spontaneous molecular extension and alignment that is characteristic of liquid crystalline phases. Much of the effort in processing conventional polymers goes into extending and aligning the chains, while, in liquid crystalline polymer processing, the primary microstructural rearrangement involves converting local molecular alignment into global molecular alignment. Unfortunately, the global alignment introduced by processing relaxes quickly upon cessation of shear, and the molecular orientation develops a periodic misalignment relative to the shear direction. The axial strength and stiffness are reduced by this relaxation.Clearly there is a need to solidify the liquid crystalline state (i.e. remove heat or solvent) before significant relaxation occurs. Several researchers have observed this relaxation, mainly in solutions of hydroxypropyl cellulose (HPC) because they are lyotropic under ambient conditions.

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