Spontaneous Chain Orientation of Aromatic Polyimides Evolved during Thermal Imidization from Shear-Oriented Glassy Liquid Crystalline Precursors

2019 ◽  
Vol 52 (13) ◽  
pp. 5054-5066 ◽  
Author(s):  
Kazuyuki Tanaka ◽  
Shinji Ando ◽  
Ryohei Ishige
Keyword(s):  
Liquid Crystalline ◽  
Chain Orientation ◽  
Aromatic Polyimides ◽  
Thermal Imidization

Synthesis and Characterization of Aromatic Polyimides Bearing Nonlinear Optical Chromophores

2000 ◽  
Vol 12 (1) ◽  
pp. 169-176 ◽  
Author(s):  
L Bes ◽  
A Rousseau ◽  
B Boutevin ◽  
R Mercier ◽  
B Sillion ◽  
...  
Keyword(s):  
Nonlinear Optical ◽  
Second Harmonic ◽  
Uv Spectroscopy ◽  
Harmonic Coefficient ◽  
Aromatic Polyimides ◽  
Relaxation Temperature ◽  
Thermal Imidization ◽  
Nonlinear Optical Chromophores ◽  
Hydroxy Groups ◽  
Optical Chromophores

The syntheses and characterizations of two aromatic polyimides with nonlinear optical (NLO) chromophore side chains were investigated through a two-step synthetic route. These two polymers were prepared by polycondensation of 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) with 4-(4-amino, 2-hydroxy) phenoxyaniline (HODA) and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP), respectively. First the poly(hydroxy)imides were prepared by direct thermal imidization. The resulting polyimides bearing hydroxy groups were found to react easily with the terminal hydroxy group of the chromophore (Disperse Red1 (DR1)) via the Mitsunobu reaction. The high content of chromophore for the polyimide with 6FAP diamine was confirmed by UV spectroscopy and ellipsometry spectroscopy measures. The resulting NLO polyimides possess high glass transition temperatures ( Tg > 185°C), excellent solubilities and processabilities even though the extent of chromophore grafting is up to 95 mol%. The second harmonic coefficient ( d33) at the wavelength of 1320 nm is close to 30 pm V−1. The thermal and temporal stabilities of the NLO properties were investigated. The relaxation temperature of the SHG signal measured at the 50% decay of the initial SHG signal ( I 2ω/2 at 2°C min−1) was 168°C for the polyimide based on HODA and 157°C for the polyimide based on 6FAP.

Chain Conformations Of Aromatic Polvimides And Their Ordering In Thin Films.

1991 ◽  
Vol 227 ◽  
Author(s):  
D. Y. Yoon ◽  
W. Parrish ◽  
L. E. Depero ◽  
M. Ree
Keyword(s):  
Thin Films ◽  
Molecular Modeling ◽  
Film Plane ◽  
Pyromellitic Dianhydride ◽  
X Ray Diffraction ◽  
Ordered Structures ◽  
X Ray ◽  
Aromatic Polyimides ◽  
Thermal Imidization ◽  
Chain Conformations

ABSTRACTWe have investigated the conformation – order relationships of four aromatic polyimides prepared by thermal imidization of the precursor poly(amic acids) in thin films. They are: (i) PMDA-4,4′-ODA polyimide from pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA) monomers; (ii) PMDA-PDA polyimide from PMDA andp-phenylene diamine (PDA); (iii) PMDA-Benzidine polyimide from PMDA and benzidine and (iv) BPDA-PDA polyirnide from biphenylene tetracarboxylicdianhydride (BPDA) and PDA. X-ray diffraction results and their analyses by molecular modeling show that all the four polyimides exhibit extended chain conformations in various smectic-type ordered structures that form monomer repeat layers but differ in the details of interchain packing. Furthermore, the polyimide chains are highly aligned along the film plane.

Thermal Imidization of the Precursor of a Liquid Crystalline Polyimide

2002 ◽  
Vol 287 (12) ◽  
pp. 931-937 ◽  
Author(s):  
Kumari P. Pramoda ◽  
Songlin Liu ◽  
Tai-Shung Chung
Keyword(s):  
Liquid Crystalline ◽  
Thermal Imidization

Synthesis and Properties of Organosoluble and Transparent Fluorinated Aromatic Polyimides

2011 ◽  
Vol 391-392 ◽  
pp. 888-893
Author(s):  
Yun Hua Lu ◽  
Zhi Zhi Hu ◽  
Yong Fei Wang ◽  
Qing Xu Fang
Keyword(s):  
Molecular Structure ◽  
Thermal Properties ◽  
Organic Solvents ◽  
Aromatic Polyimides ◽  
Fluorinated Polyimides ◽  
Thermal Imidization

In this paper, we mainly investigated the properties of fluorinated polyimides film materials. Two aromatic dianhydrides, PMDA and ODPA were poly-condensed with four fluorinated diamines to prepare fluorinated polyimides by the two-step thermal imidization process. The properties of these polyimides were characterized by IR, TGA and UV-vis instrument. The organosolublility of these polyimides was tested in various organic solvents, such as NMP, DMF, DMAc. In addition, the effect of monomers’ molecular structure on the optical, soluble and thermal properties of these polyimides was also studied.

Structure and Chain Orientation in Thin Films of Side-Chain Liquid Crystalline Polymers

Langmuir ◽  
2003 ◽  
Vol 19 (17) ◽  
pp. 7021-7025 ◽  
Author(s):  
Kilwon Cho ◽  
Jeong Ho Cho ◽  
Jong-Chan Lee ◽  
Se-Hui Han ◽  
Ki-Bong Lee ◽  
...  
Keyword(s):  
Thin Films ◽  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Side Chain ◽  
Chain Orientation ◽  
Crystalline Polymers

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
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