Synthesis and properties of poly(amic acid)s and polyimides based on 2,2′,6,6′-biphenyltetracarboxylic dianhydride

2006 ◽  
Vol 44 (21) ◽  
pp. 6385-6393 ◽  
Author(s):  
Katsuya Sakayori ◽  
Yuji Shibasaki ◽  
Mitsuru Ueda
Keyword(s):  
Amic Acid ◽  
Biphenyltetracarboxylic Dianhydride

Synthesis and properties of low coefficient of thermal expansion copolyimides derived from biphenyltetracarboxylic dianhydride with p-phenylenediamine and 4,4′-oxydialinine

e-Polymers ◽  
2016 ◽  
Vol 16 (4) ◽  
pp. 295-302 ◽  
Author(s):  
Yonglin Lei ◽  
Yuanjie Shu ◽  
Jinhua Peng ◽  
Yongjian Tang ◽  
Jichuan Huo
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Thermomechanical Analysis ◽  
Amic Acid ◽  
Molar Ratio ◽  
Structure And Property ◽  
Property Relations ◽  
Ft Ir ◽  
Biphenyltetracarboxylic Dianhydride

AbstractA series of copolyimides were prepared by thermal imidization of poly(amic acid)s (PAAs) derived from 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3′,3,4′-biphenyltetracarboxylic dianhydride (a-BPDA), p-phenylenediamine (PDA) and 4,4′-oxydialinine (4,4′-ODA) commonly used for the production of commercial polyimides. The flexible copolyimide films were obtained from that the molar ratio of s-BPDA, a-BPDA, PDA and 4,4′-ODA was 9:1:8:2 (Co-PIs-3), 8:2:9:1 (Co-PIs-5) and 8:2:8:2 (Co-PIs-6). These obtained copolyimide films were characterized by Fourier transform-infrared spectroscopy(FT-IR), wide angle X-ray (WAXD), Thermogravimetric (TG), dynamic mechanical thermal analysis (DMA), thermomechanical analysis (TMA), field-emission scanning electron microscopy (FE-SEM) and mechanical properties measurement. The results showed that three copolyimides remained semi-crystalline and exhibited high glass transition temperature (Tg), high thermal stability, great ultimate tensile strength and low coefficient of thermal expansion (CTE). The Co-PIs-5 had lower crystallinity, lower CTE, greater elongation at break, higher Tg and thermal stability and the greater dense extent, compared with Co-PIs-3 and Co-PIs-6. Structure and property relations of the prepared polyimides were also briefly discussed. The results revealed that the copolymerization of s-BPDA/PDA with a small number of 4,4′-ODA/a-BPDA was a useful means for enhancing flexibility without sacrificing low CTE.

scholarly journals Poly(ester imide)s Possessing Low Coefficients of Thermal Expansion and Low Water Absorption (V). Effects of Ester-linked Diamines with Different Lengths and Substituents

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 859 ◽  
Author(s):  
Masatoshi Hasegawa ◽  
Tomoaki Hishiki
Keyword(s):  
Thermal Expansion ◽  
High Performance ◽  
Printed Circuit Boards ◽  
Dielectric Substrate ◽  
Amic Acid ◽  
Substrate Material ◽  
Polymerization Process ◽  
Molecular Weights ◽  
Flexible Printed Circuit ◽  
Biphenyltetracarboxylic Dianhydride

A series of ester-linked diamines, with different lengths and substituents, was synthesized to obtain poly(ester imide)s (PEsIs) having improved properties. A substituent-free ester-linked diamine (AB-HQ) was poorly soluble in N-methyl-2-pyrrolidone at room temperature, which forced the need for polyaddition by adding tetracarboxylic dianhydride solid into a hot diamine solution. This procedure enabled the smooth progress of polymerization, however, accompanied by a significant decrease in the molecular weights of poly(amic acid)s (PAAs), particularly when using hydrolytically less stable pyromellitic dianhydride. On the other hand, the incorporation of various substituents (–CH3, –OCH3, and phenyl groups) to AB-HQ was highly effective in improving diamine solubility, which enabled the application of the simple polymerization process without the initial heating of the diamine solutions, and led to PAAs with sufficiently high molecular weights. The introduction of bulkier phenyl substituent tends to increase the coefficients of thermal expansion (CTE) of the PEsI films, in contrast to that of the small substituents (–CH3, –OCH3). The effects of ester-linked diamines, consisting of longitudinally further extended structures, were also investigated. However, this approach was unsuccessful due to the solubility problems of these diamines. Consequently, the CTE values of the PEsIs, obtained using longitudinally further extended diamines, were not as low as we had expected initially. The effects of substituent bulkiness on the target properties, and the dominant factors for water uptake (WA) and the coefficients of hygroscopic expansion (CHE), are also discussed in this study. The PEsI derived from methoxy-sustituted AB-HQ analog and 3,3′,4,4′-biphenyltetracarboxylic dianhydride achieved well-balanced properties, i.e., a very high Tg (424 °C), a very low CTE (5.6 ppm K−1), a low WA (0.41%), a very low CHE value (3.1 ppm/RH%), and sufficient ductility, although the 26 μm-thick film narrowly missed certification of the V-0 standard in the UL-94V test. This PEsI film also displayed a moderate εr (3.18) and a low tan δ (3.14 × 10−3) at 10 GHz under 50% RH and at 23 °C. Thus, this PEsI system is a promising candidate as a novel dielectric substrate material for use in the next generation of high-performance flexible printed circuit boards operating at higher frequencies (≥10 GHz).

CT Fluorescence And Molecular Aggregation Of A Polyimide As Function Of Imidization Condition.

1991 ◽  
Vol 227 ◽  
Author(s):  
M. Hasegawa ◽  
H. Arai ◽  
K. Horie ◽  
R. Yokota ◽  
I. Mita
Keyword(s):  
Fluorescence Spectra ◽  
Intramolecular Charge Transfer ◽  
Amic Acid ◽  
Polymer Chains ◽  
Molecular Aggregation ◽  
Absorption And Fluorescence Spectra ◽  
Model Compounds ◽  
Higher Temperature ◽  
Biphenyltetracarboxylic Dianhydride ◽  
Monomer Fluorescence

ABSTRACTThe emission mechanisms of solid PI(BPDA/PDA) derived from biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PDA) were examined with the absorption and fluorescence. spectra of model compounds (denoted by M). M(BPDA/CHA) (CHA: cyclohexyl amine) fluoresces at ca. 430 nm in hexafluoro-2-propanol(HFP) solution, while M(BPDA/AN) (AN: aniline) does not. PI(BPDA/PDA) film does not show the monomer fluorescence of biphenyldiimide unit, but shows only intermolecular CT fluorescence peaking at 530–540 nm. This suggests that for PI(BPDA/PDA) film and PI(BPDA/AN) in solution the local excited state of biphenyldiimide units is deactivated owing to intramolecular charge-transfer(CT).The intermolecular CT fluorescence reflecting sensitively molecular packing of PI chains was used to monitor isothermal imidization process of poly(amic acid)(PAA) of BPDA/PDA. The fluorescence of PAA(BPDA/PDA) peaking at 490 nm decreases rapidly and disappears at 30–40% conversion, then the fluorescence of PI(BPDA/PDA) peaking at 540 nm increases gradually during isothermal imidization. The fluorescence intensity at 540 nm increases rapidly as imidization proceeds when imidized at higher temperature. A kinetic study on isothermal imidization shows that the vitrification is strongly related to the reorientation of polymer chains and the final PI structures.

Microporous Membranes from an Insoluble Polyimide

1995 ◽  
Vol 60 (10) ◽  
pp. 1741-1746
Author(s):  
Jan Schauer ◽  
Miroslav Marek
Keyword(s):  
Acetic Anhydride ◽  
Phase Inversion ◽  
Amic Acid ◽  
Microporous Membranes ◽  
Inversion Process ◽  
Phase Inversion Process ◽  
Ultrafiltration Process

Poly(amic acid) prepared from 3,3',4,4'-benzophenonetetracarboxylic dianhydride and bis(4-aminophenyl) ether was used for preparation of microporous membranes by the phase inversion process. Membranes coagulated in acetic anhydride were brittle but usable for ultrafiltration. Coagulation of the poly(amic acid) in water or lower alcohols and subsequent thermal cyclocondensation led to extremely brittle polyimides, which limits their use for ultrafiltration process.

Enhanced dielectric properties and thermostability in polyimide composites with core-shell structured polyimide@BaTiO3 nanoparticles

2021 ◽  
pp. 095400832199352
Author(s):  
Wei Deng ◽  
Guanguan Ren ◽  
Wenqi Wang ◽  
Weiwei Cui ◽  
Wenjun Luo
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Energy Density ◽  
Breakdown Strength ◽  
In Situ Polymerization ◽  
Dielectric Materials ◽  
High Energy ◽  
Amic Acid ◽  
High Energy Density ◽  
Core Shell

Polymer composites with high dielectric constant and thermal stability have shown great potential applications in the fields relating to the energy storage. Herein, core-shell structured polyimide@BaTiO3 (PI@BT) nanoparticles were fabricated via in-situ polymerization of poly(amic acid) (PAA) and the following thermal imidization, then utilized as fillers to prepare PI composites. Increased dielectric constant with suppressed dielectric loss, and enhanced energy density as well as heat resistance were simultaneously realized due to the presence of PI shell between BT nanoparticles and PI matrix. The dielectric constant of PI@BT/PI composites with 55 wt% fillers increased to 15.0 at 100 Hz, while the dielectric loss kept at low value of 0.0034, companied by a high energy density of 1.32 J·cm−3, which was 2.09 times higher than the pristine PI. Moreover, the temperature at 10 wt% weight loss reached 619°C, demonstrating the excellent thermostability of PI@BT/PI composites. In addition, PI@BT/PI composites exhibited improved breakdown strength and toughness as compared with the BT/PI composites due to the well dispersion of PI@BT nanofillers and the improved interfacial interactions between nanofillers and polymer matrix. These results provide useful information for the structural design of high-temperature dielectric materials.

Realization of electromagnetic shielding performance for polyimide-matrix composite by self-metallization

2021 ◽  
pp. 002199832110316
Author(s):  
Jiayang Zhang ◽  
Hongjiang Ni ◽  
Ming Gong ◽  
Jun Li ◽  
Daijun Zhang ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Matrix Composite ◽  
Electromagnetic Interference ◽  
Interfacial Strength ◽  
Amic Acid ◽  
Thermal Reduction ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Heat Condition ◽  
Electromagnetic Interference Shielding Effectiveness

Electromagnetic shielding performance has been achieved for a polyimide (PI)-matrix composite by the strategy of self-metallization of its thermosetting PI matrix. Self-metallization of the thermosetting PI was realized by silver ion/poly(amic acid) (PAA) precursor ion exchange and thermal reduction. The factors influencing the self-metallization were investigated. The electrical conductivity and integrity for the surface of the PI were achieved by optimization of ion exchange/thermal reduction parameters. The fabricated PI-matrix composite exhibits a maximum electromagnetic interference shielding effectiveness value of 81 dB. Importantly, the electromagnetic shielding performance can be maintained even after heat condition of 300°C. Meanwhile, the surface-metallized PI composite exhibits mechanical property equivalent to the pristine composite, and an Ag/matrix interfacial strength higher than 19.6 MPa. Besides, self-metallization mechanism of the thermosetting PI was investigated.

Gas permeability and permselectivity in polyimides based on 3,3',4,4'-biphenyltetracarboxylic dianhydride

1989 ◽  
Vol 47 (1-2) ◽  
pp. 203-215 ◽  
Author(s):  
K. Tanaka ◽  
H. Kita ◽  
K. Okamoto ◽  
A. Nakamura ◽  
Y. Kusuki
Keyword(s):  
Gas Permeability ◽  
Biphenyltetracarboxylic Dianhydride

Characterization and Studies of Designed Photodefinable CoPoly(amic Acid) Ionic Salt Solutions

2004 ◽  
Vol 9 (1-3) ◽  
pp. 177-196 ◽  
Author(s):  
Rohitkumar H. Vora ◽  
P. Santhana Gopala Krishnan ◽  
S. Veeramani
Keyword(s):  
Amic Acid ◽  
Salt Solutions ◽  
Ionic Salt
Sign in / Sign up

Export Citation Format

Share Document