Other synthetic routes to polyimides

Takekoshi, T.

doi:10.1007/978-94-010-9661-4_2

Cited by 28 publications

(33 citation statements)

References 33 publications

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“…The cross-linked portion usually shows a deep yellow color because unsaturated double bonds are left after the reaction. Takekoshi 25 pointed out that the formation of an imino group may take place between the carbonyl group in benzophenone moiety and the amino group at the end of the polymer chain. Aromatic imines are usually intense yellow.…”

Section: Color Intensity Of Polyimides and Electron-accepting Propertmentioning

confidence: 99%

Coloration of Aromatic Polyimides and Electronic Properties of Their Source Materials

Ando

Matsuura

Sasaki

1997

Polym J

270

209

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ABSTRACT:The relationships between the color intensities of polyimide films and the electronic properties of their source materials-aromatic diamines and aromatic tetracarboxylic dianhydrides-are discussed. The arrangement of the diamine moieties in order of color intensity of polyimides shows fairly good agreement with the order of the electron-donating properties of the diamines estimated from 15 N NMR chemical shifts (bN). On the other hand, the arrangement of the dianhydrides moieties in order of color intensity of polyimides agrees with the order of the electron-accepting properties of the dianhydrides estimated from experimental and calculated electron affinity (EA) although systematic inconsistencies are observed for the dianhydrides having-CF 3 groups and a benzophenone carbonyl group. These results are consistent with the formation of charge transfer complex (CTC) and indicate that the electron-donating properties of diamines and electron-accepting properties of dianhydrides are retained to a significant extent even in polyimide molecular chains. KEY WORDSPolyimide / Coloration / Charge Transfer Complex / Dianhydride / Diamine / Nuclear Megnetic Resonance Chemical Shift / MNDO-PM3 / Optical transparency of polyimide films is of special importance in some applications such as flexible solar radiation protectors, 1 orientation films in liquid crystal display devices, 2 optical waveguides for communication interconnects, 3 and optical half-waveplates for planar lightwave circuits. 4 However, most of the conventional polyimide films always show considerable coloration ranging from pale yellow to deep brown. Rogers 5 first reported that optically transparent and colorless polyimides can be synthesized from a dianhydride and a diamine that have hexafluoroisopropyridene (-C(CF 3 ) 2-) groups. We have reported that the fluorinated polyimides derived from 2,2' -bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFDB) exhibit excellent properties needed for optical applications. 6 In particular, the polyimide derived from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and TFDB show no color, high transparency in the visible region, and low optical transmission losses in the near-infrared region as well as low dielectric constants, low refractive indices, and low water absorption. The idea that fluorination of dianhydride and diamine moieties give colorless polyimides are widely accepted. On the other hand, we have recently reported the first synthesis of perfluorinated polyimides that have very high optical transparency over the entire range of optical communication wavelengths (1.0--1.7 µm) and high glass transition temperatures over 300°C. 7 • 8 Despite the high fluorination of the diamine and dianhydride, the perfluorinated polyimides show considerable coloration ranging from orange to brown. This fact indicates that the fluorination of source materials does not necessarily lead to colorless polyimides. If the coloration of polyimide films can be predicted from the properties of their source materia...

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Section: Color Intensity Of Polyimides and Electron-accepting Propertmentioning

confidence: 99%

Coloration of Aromatic Polyimides and Electronic Properties of Their Source Materials

Ando

Matsuura

Sasaki

1997

Polym J

270

209

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“…This observation supports the aforementioned speculation that a three-dimensional SiÀ ÀOÀ ÀSi network has formed in the hybrid films. [33][34][35] On the other hand, the presence of dimethylsiloxane (Si-(CH 3 ) 2 ) blocks was evidenced by the CÀ ÀH absorption at 2960 cm À1 . The presence of the dimethylsiloxane blocks is supposed to be beneficial, in terms of better processibility and modulation of the stiffness of the copolymer.…”

Section: Ftir Analysismentioning

confidence: 98%

Preparation and properties of poly(imide siloxane) segmented copolymer/silica hybrid nanocomposites

Liaw

Chen

2007

J of Applied Polymer Sci

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A series of Poly(imide siloxane) (PIS)/silica (SiO2) hybrid nanocomposites with C‐Si covalent bonding between the homogeneous PIS copolymer and SiO2 have been successfully synthesized. The PIS copolymer synthesized in this study is characterized by the coexistence of two segments: the polyimide segment and polydimethyldiphenylsiloxane segment, and the latter are specially featured with the introduction of a diphenyl group for improved homogeneity. The PIS/SiO2 hybrid nanocomposites were prepared from 3,3′,4,4′‐bezonphenone tetracarboxylic dianhydride (BTDA), 2‐2′‐bis[4(3‐aminophenoxy)phenyl] sulfone (m‐BAPS), and vinyl‐containing α,ω‐bis‐(aminopropyl)polydimethyldiphenyl siloxane (APPPVS) oligomer to form vinyl siloxane‐containing poly(amic acid) (PAAVS). This copolymer was further reacted with trimethoxyvinylsilane (TMVS), 2,2′‐azobis‐isobutyronitrile (AIBN), and tetraethoxysilane (TEOS). The PIS/SiO2 hybrid nanocomposites exhibited a series of properties unlike traditional composites, and the nano sized inorganic particles have resulted in a transparent hybrid when the SiO2 content was less than 12 wt %. The Young's modulus and tensile strength of the PIS/SiO2 hybrid nanocomposites increased with increasing SiO2 content, whereas, the elongation at break was only slightly affected. The structure of the hybrids was characterized by FTIR, 29Si‐NMR, 1H‐NMR, and 13C‐NMR, as well as SEM and TEM. The thermal properties of the PIS/SiO2 hybrid nanocomposites were investigated with DSC, TGA, and DMA studies. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

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“…At the same time, this solvent is known for its catalytic effect among other nucleophilic reactions in acidic conditions [16,22,23]. In addition, there is a direct correlation between the basicity and the nucleophilicity: increase of the basicity increases the nucleophilicity [24] and, accordingly, the reaction rate [10,25]. Taking into account the fact that MI has a higher pH value than NMP (pH NMP = 7.7-8; pH MI = 9.5-10.5) [26,27] it can be supposed that MI could bring more benefits as media for the PAI reaction than NMP.…”

Section: Activation Energy Of Polymerizationmentioning

confidence: 99%

Effect of the solvent type and polymerization conditions on the curing kinetics, thermal and viscoelastic performance of poly(amide-imide) resins

Rasheva¹,

Sorochynska²,

Grishchuk³

et al. 2015

Express Polym. Lett.

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Other synthetic routes to polyimides

Cited by 28 publications

References 33 publications

Coloration of Aromatic Polyimides and Electronic Properties of Their Source Materials

Coloration of Aromatic Polyimides and Electronic Properties of Their Source Materials

Preparation and properties of poly(imide siloxane) segmented copolymer/silica hybrid nanocomposites

Effect of the solvent type and polymerization conditions on the curing kinetics, thermal and viscoelastic performance of poly(amide-imide) resins

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