Journal articles: 'Polyimide'

1

Xiao, T. J., S. Q. Gao, A. J. Hu, X. C. Wang, and S. Y. Yang. "Thermosetting Polyimides with Improved Impact Toughness and Excellent Thermal and Thermo-Oxidative Stability." High Performance Polymers 13, no. 4 (December 2001): 287–99. http://dx.doi.org/10.1088/0954-0083/13/4/307.

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Thermoset polyimides were prepared by thermally curing B-staged endcapped polyimide resins that were obtained by thermally baking PMR polyimide matrix resins. The polyimide matrix resins were prepared by incorporating flexible ether-bridged aromatic segments [–Ar–O–Ar–] into PMR polyimide backbone to improve their processability and impact toughness. Experimental results indicated that the B-staged polyimide resins possessed adjustable and easily controllable thermal processability which ensure that thermoset polyimides are produced with improved impact strength and high glass transition temperature compared with PMR-15. Thermal and thermo-oxidative stability as well as hygrothermal resistance of the thermoset polyimides were also systemically investigated.

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2

Yamada, Yasuharu. "Siloxane Modified Polyimides for Microelectronics Coating Applications." High Performance Polymers 10, no. 1 (March 1998): 69–80. http://dx.doi.org/10.1088/0954-0083/10/1/009.

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Two types of siloxane modified polyimide were prepared as coating materials for microelectronics applications and their thermal, mechanical, electrical, adhesive and coating properties were characterized. The coatings prepared were classified as polysiloxane block (type A) polyimides and disiloxane modified (type B) polyimides. All of the polyimides showed excellent thermal, mechanical, electrical, adhesive and coating properties suitable for use in microelectronics coating applications. The type A polyimides have lower dielectric constants and good stress relaxation capability as compared with typical aromatic polyimides. The type B polyimides have excellent adhesive properties to silicon wafers. The polyimide prepared from 2, 2-bis[4-aminophenoxyphenyl]hexafluoropropane exhibited the lowest dielectric constant due to the presence of trifluoromethyl groups in the polymer backbone. Model encapsulated semiconductor devices coated with various polyimides were assembled, and the interface adherence between the polyimide and the encapsulant along with the reliability of the semiconductor devices were examined. Superior interface adherence between the polyimide passivant and the encapsulant was exhibited, resulting in improved reliability of integrated circuit chips. With the incorporation of siloxane moieties into the polyimide backbone these siloxane modified polyimides were shown to be good candidate materials for microelectronics coatings.

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Takeichi, Tsutomu, Kohji Nakajima, Min Zuo, and Rikio Yokota. "Polyimide/Polyimide Molecular Composite Films: Difference between Reactive Oligoimide and Reactive Polyimide as the Matrix Component." High Performance Polymers 10, no. 1 (March 1998): 111–20. http://dx.doi.org/10.1088/0954-0083/10/1/012.

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Polyimide/polyimide molecular composite (MC) films were prepared by blending precursor solutions of a rigid polyimide and a reactive oligoimide or a reactive polyimide that contains acetylene units in the backbone in a 7:3 ratio, followed by casting, drying and thermal imidization at 300 °C. 3, 3′, 4, 4′-Biphenyltetracarboxylic dianhydride (BPDA), pyromellitic dianhydride (PMDA), p-phenylenediamine (PDA), oxydianiline (ODA) and 3, 3′-diaminodiphenylacetylene ( m-intA) were used as acid dianhydride and diamine monomers for the preparation of polyimide. The rigid components were prepared from PMDA or BPDA and PDA. The matrix components were prepared from PMDA or BPDA and ODA or m-intA. The polyimide/polyimide MCs have exotherm on DSC due to the reaction of internal acetylene units, which indicates that the MC films are laminate processable. Tensile measurements revealed that the tensile modulus of the MCs utilizing reactive oligoimides is 20–30% higher than that of the MCs utilizing reactive polyimides. Viscoelastic analyses of the MC films showed that the crosslinking of the acetylene units gave polyimides that have a very high glass transition temperature.

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Araki, Hitoshi, Akira Shimada, Hisashi Ogasawara, Masaya Jukei, Takenori Fujiwara, and Masao Tomikawa. "Low Temperature Curable Low Dk & Df Polyimide for Antenna in Package." International Symposium on Microelectronics 2021, no. 1 (October 1, 2021): 000130–35. http://dx.doi.org/10.4071/1085-8024-2021.1.000130.

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Abstract In this paper, we developed novel low temperature curable (around 200~250 °C) low Dk (2.7) & Df (0.002) polyimide with high glass transition temperature (170 °C) and elongation (100%). We also developed negative tone photosensitive polyimide with low Dk (3.0) & Df (0.007) by photo initiator and cross linker. Material types of them are liquid or B-stage sheet materials. Patterning methods of the non-photosensitive polyimides were imprint and UV laser ablation. Resolution of those process were 10um via and 30um via respectively. Photosensitive polyimide was patterned by photolithographic tool. We fabricated fine patterned polyimide of photosensitive polyimide by photolithography. We investigated the frequency dependence of the novel low Dk & Df polyimide up to 95 GHz, and confirmed that Df gradually increased from 0.002 to 0.005 as the frequency increased. To confirm effect of the novel polyimide, insertion loss of micro-strip line whose length was 10 mm were measured using the new developed polyimide. Insertion loss (S21 parameter) of the novel polyimide was 0.8 and that was less than half of conventional polyimide. RDL structure was fabricated by novel low Dk and Df polyimide and we tested bump shear strength after thermal cycle test. All shear mode were ductile solder failure without polyimide delamination. Because our novel polyimides show excellent dielectric, thermal and mechanical properties, they are suitable to insulator of RDL for FO-AiP.

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Tomikawa, Masao, Kazuyuki Matsumura, Yu Shoji, Yoshiko Tatsuta, and Ryoji Okuda. "Fine Resolution Photosensitive Polyimide Dry Film with High Resistance to Electromigration under HAST condition." International Symposium on Microelectronics 2017, no. 1 (October 1, 2017): 000029–35. http://dx.doi.org/10.4071/isom-2017-tp15_126.

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Abstract We investigated the effects of photosensitive system (positive and negative) and polymer structures on Cu migration under bias HAST test. The HAST condition is 130C for 85% RH. Bias condition is 2MV/m. We found that there is polyimide structure shows big effect is big effect of no big difference between negative photosensitivity and positive photosensitivity in photo sensensitive polyimides. Polyimide structure effects significant difference on Cu migration under bias HAST condition. Cu migration of soft polyimide seems better than that of rigid polyimide. From these results, we developed good reliable photosensitive polyimide B-sheet having fine pattern capability successfully.

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6

Yuan, Yuan, Bing Xie, and Yu Wang. "An Interesting Result of Dielectric Property for Novel Polyimides with Fluorene Groups." Materials Science Forum 663-665 (November 2010): 511–14. http://dx.doi.org/10.4028/www.scientific.net/msf.663-665.511.

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A series of polyimide thin films were prepared successfully based on bis[3,5-dimethyl-4- (4-aminophenoxy)phenyl]methane （BDAPM）, 9,9-bis（4-（4-aminophenoxy）phenyl）fluorene (BAOFL) and different dianhydrides. And an interesting result of dielectric property for polyimide thin films was found that the polyimide thin film prepared with 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) exhibited high dielectric constants of 5.7 at 1MHz. Conversely, the other polyimides possessing fluorene groups showed low dielectric constants. The structures and the mechanical properties of polyimide films also proved the reason for results of dielectric properties.

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7

Rosolovsky, J., R. K. Boggess, A. F. Rubira, L. T. Taylor, D. M. Stoakley, and A. K. St. Clair. "Supercritical fluid infusion of silver into polyimide films of varying chemical composition." Journal of Materials Research 12, no. 11 (November 1997): 3127–33. http://dx.doi.org/10.1557/jmr.1997.0408.

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Polyimides can be infused with silver complexes by the use of supercritical fluids. Highly reflective polyimide films were formed by infusing (1,5-cyclooctadiene-1,1,1,5,5,5-hexafluoroacetylacetonato)silver(I) [Ag(COD) (HFA)] into a number of polyimides and then thermally curing those films at 300 °C for time intervals between 30 min and 3 h. Reflectivities of the films exhibited strong dependence on the infusion and cure conditions as well as on the type of polyimide used. The highest reflectivity of 67.1% was achieved with a silvered film prepared from 3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride (BTDA) and oxydianiline (ODA) infused at 5000 psi, 100 °C, for 30 min and cured for 1 h at 300 °C. Reflectivities of silvered surfaces of other polyimides investigated varied from 39% to 61%. A strong correlation between the presence of a ketonic group in the polyimide structure and the formation of mirror surfaces was detected.

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8

Vaganov G. V., Didenko A. L., Myagkova L. A., Elohovsky V. Yu., Popova E. N., and Yudin V. Yu. "Viscoelastic properties of carbon plastics based on powdered polyimide binders." Technical Physics Letters 49, no. 5 (2023): 60. http://dx.doi.org/10.21883/tpl.2023.05.56031.19403.

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Carbon fiber reinforced plastics based on thermoplastic partially crystalline fusible polyimide R-BAPB and oligoimide IDA (diacetyl imide) have been obtained. The thermal, thermomechanical and mechanical properties of carbon plastics based on polyimides have been studied. It has been shown that carbon plastics based on the used polyimide binders have increased crack resistance, which makes it possible to operate them at temperatures up to ~ 400oC Keywords: carbon fiber reinforced plastic, polyimide binder, electrostatic spraying, interlaminar fracture toughness.

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9

Hsiao, Sheng-Huei, and Ying-Hsiu Hsiao. "Synthesis and electrochemical properties of new redox-active polyimides with (1-piperidinyl)triphenylamine moieties." High Performance Polymers 29, no. 4 (May 8, 2016): 431–40. http://dx.doi.org/10.1177/0954008316648005.

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A series of new electroactive aromatic polyimides with (1-piperidinyl)triphenylamine moieties were prepared from 4,4′-diamino-4″-(1-piperidinyl)triphenylamine and aromatic tetracarboxylic dianhydrides via the conventional two-step polycondensation technique. Flexible and strong polyimide films could be obtained via the thermal curing of their precursor poly(amic acid) films. The polyimides showed high glass transition temperatures between 288°C and 318°C, and they did not show significant decomposition before 500°C in air or nitrogen atmosphere. Cyclic voltammograms of the polyimide films on the indium–tin oxide-coated glass substrate exhibited a pair of reversible oxidation waves with low onset oxidation potentials of 0.45–0.49 V (vs. silver/silver chloride) in acetonitrile solution. Upon oxidation, the color of the polyimide films changes from pale yellow to yellowish green and finally to blue.

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10

Zhang, Yixiang, Masahiko Miyauchi, and Steven Nutt. "Structure and properties of a phenylethynyl-terminated PMDA-type asymmetric polyimide." High Performance Polymers 31, no. 3 (March 12, 2018): 261–72. http://dx.doi.org/10.1177/0954008318762592.

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A new polymerized monomeric reactant (PMR)-type polyimide, designated TriA X, was investigated to determine polymer structure, processability, thermal, and mechanical properties and establish the relationship between the molecular structure and those properties. TriA X is a PMR-type polyimide with an asymmetric, irregular, and nonplanar backbone. Both the imide oligomers and the cross-linked polyimides of TriA X exhibited loose-packed amorphous structures, independent of thermal processing. The peculiar structures were attributed to the asymmetric backbone, which effectively prevented the formation of closed-packed chain stacking typically observed in polyimides. The imide oligomers exhibited a lower melt viscosity than a control imide oligomer (symmetric and semi-crystalline), indicating a higher chain mobility above the glass transition temperature ( Tg). The cured polyimide exhibited a Tg = 362°C and a decomposition temperature = 550°C. The cross-linked TriA X exhibited exceptional toughness and ductility (e.g. 15.1% at 23°C) for a polyimide, which was attributed to the high-molecular-weight oligomer and loose-packed amorphous structure. The thermal and mechanical properties of TriA X surpass those of PMR-15 and AFR-PE-4.

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11

Akinyi, Caroline, Jimmy Longun, Siqi Chen, and Jude O. Iroh. "Decomposition and Flammability of Polyimide Graphene Composites." Minerals 11, no. 2 (February 5, 2021): 168. http://dx.doi.org/10.3390/min11020168.

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Polyimide-graphene composites were synthesized by in-situ condensation polymerization and the thermal stability and decomposition behavior of the composites were studied. Polyimides, because of their aromatic backbone, are a class of fire-retardant polymers. Their high char retention ≥50% at testing temperatures ≥600 °C makes them thermally stable polymers. The effect of nanographene sheets on the decomposition behavior of polyimide is presented in this paper. It is shown that the reinforcement of polyimide with nanographene sheets significantly decreased the rate of decomposition of polyimide and increased the char retention of the composite. Thermogravimetric analysis data were used to assess the thermal stability, rate of mass loss and predicted limiting oxygen index of the neat polyimide and composites. Results obtained showed around a 43% decrease in the rate of polyimide degradation at 50 wt.% graphene loading. The limiting oxygen index of the polyimide nanocomposite was calculated by using the char retention, and it was found to increase by up to 24% at 50 wt.% graphene loading over that for the neat matrix.

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12

Xu, Qinging, Yunhui Li, Fanming Zeng, Yifan Zhang, Pengyang Deng, and Zhongmin Su. "Improved ablation resistance and thermal insulation performances of polyimide composites by introducing albite/glass powder composition." Polymers and Polymer Composites 30 (January 2022): 096739112210878. http://dx.doi.org/10.1177/09673911221087806.

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Polyimide is a class of resins with high heat resistance, and their composites have a wide range of applications in military and civilian. However, the application of polyimides as an ablation and thermal insulation material has always been a challenge due to their low char yield during ablation in the air. Herein, we described the first application of polyimide composites—albite/glass powder doped polyimide hybrid materials - as an ablation and thermal insulation material. The key to the success of this case is that the process of the ceramization of albite/glass powder can greatly reduce the carbon loss of polyimide during the ablation process in the air. Moreover, the mechanical properties, thermal stability, ablation and thermal insulation properties of these polyimide hybrid materials have been studied systematically. This work not only opens up a new application for polyimide, but also provides a new idea for the design of novel ablation and thermal insulation material.

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13

Hsiao, Sheng-Huei, and Kai-Han Lin. "Synthesis and properties of electroactive aromatic polyimides with methyl- or trifluoromethyl-protecting triphenylamine units." High Performance Polymers 29, no. 5 (June 16, 2016): 544–55. http://dx.doi.org/10.1177/0954008316653456.

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Two series of new redox-active aromatic polyimides with methyl- (–CH3) or trifluoromethyl (–CF3)-protecting triphenylamine moieties were prepared from 4,4′-diamino-4″-methyltriphenylamine and 4,4′-diamino-4″-(trifluoromethyl)triphenylamine with aromatic tetracarboxylic dianhydrides via the conventional two-step polycondensation technique. Flexible and strong polyimide films could be obtained via the thermal curing of their precursor poly(amic acid) films or direct solution cast from some organosoluble polyimides. The polyimides showed high glass-transition temperatures between 269°C and 312°C, and they did not show significant decomposition before 500°C in air or under nitrogen atmosphere. Cyclic voltammograms of the polyimide films on the indium–tin oxide-coated glass substrate exhibited a pair of reversible redox waves with half-wave oxidation potentials of 1.08–1.10 V (for the –CH3 series) and 1.23–1.26 V (vs. silver/silver chloride; for the –CF3 series) in acetonitrile solution. The polyimide films showed anodic electrochromism from pale yellow neutral state to purplish blue (for the –CH3 series) and chrome yellow (for the –CF3 series) when oxidized.

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14

Saeed, Malik Adnan, Zulfiqar H. Lodhi, Aziz Ullah Khan, and Wasim Asghar. "Synthesis and Characterization of Processable Polyimide Titania Nanohybrids." Advanced Materials Research 326 (September 2011): 88–96. http://dx.doi.org/10.4028/www.scientific.net/amr.326.88.

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A new aromatic diamine monomer {4-amino [4-(diphenylamino) phenyl] anilino} phenyl amine (DPA -4) were synthesized in high yield and purity. {4-amino [4-(diphenylamino) phenyl] anilino} phenyl amine (DPA -4) monomer were reacted with Tetra carboxylic dianhydride (BT) leading to the formation of polyamic acid, followed by the preparation of polyimide/Titania hybrid films through non-hydrolytic sol-gel method. The synthesized polyimide were considered as blank & compared with the nano-hybrids derived from polyimides/Titania blends of different TiO2content. Synthesized polyimide showed excellent solubility in aprotic solvents like DMF, DMSO, NMP, and DMAC proving best processibility in various applications. Polyimide exhibited excellent thermal stability and its glass transition temperature was 450°C & 5% weight loss is in the range of 500°C~600°C. The thermal stability of Polyimide/Titania composites decreased slightly with increase of TiO2content. Result show decrease in thermal stability of nano-hybrids caused by the decomposition of catalytic activity of Titania & incomplete imidizations of polyamic acid. The absorption band of PI-O-Ti bonds in FTIR spectra of hybrids films revealed the formation of hybrid inorganic network between polyimide and TiO2.Scanning electron microscopy results indicated that the nanometer-scaled inorganic domains were homogeneously dispersed in polyimides matrix due to the introduction of TiO2.The studies on the optical properties of hybrids films indicated the red-shift to the absorption band increased with increasing TiO2content, while all the hybrids films maintained their transparencies. This kind of hybrid materials has potential commercial application in the field of opto-electronics appliances.

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Choi, Ju-Young, Seung-Won Jin, Dong-Min Kim, In-Ho Song, Kyeong-Nam Nam, Hyeong-Joo Park, and Chan-Moon Chung. "Enhancement of the Mechanical Properties of Polyimide Film by Microwave Irradiation." Polymers 11, no. 3 (March 12, 2019): 477. http://dx.doi.org/10.3390/polym11030477.

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Polyimide films have conventionally been prepared by thermal imidization of poly(amic acid)s (PAAs). Here we report that the improvement of tensile strength while increasing (or maintaining) film flexibility of polyimide films was accomplished by simple microwave (MW) irradiation of the PAAs. This improvement in mechanical properties can be attributed to the increase in molecular weight of the polyimides by MW irradiation. Our results show that the mechanical properties of polyimide films can be improved by MW irradiation, which is a green approach that requires relatively low MW power, very short irradiation time, and no incorporation of any additional inorganic substance.

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16

Zhang, Qing Xin, Kimiyoshi Naito, and Yutaka Kagawa. "Synthesis and Mechanical Properties of Advanced Polyimide/Silicon Dioxide Nanocomposites." Materials Science Forum 561-565 (October 2007): 709–12. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.709.

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Hybrid inorganic-organic materials based on a polyimide (PI) and silicon dioxide (SiO2) were prepared previously only via sol-gel approach. However, sol-gel processes have some critical limitations. The primary drawback is that the resultant gel is extremely fragile and sol-gel process is complicated and costly. In this study, using SiO2 nanoparticles polyimide/SiO2 nanocomposites were synthesized from 4,4'-diaminodiphenyl ether (ODA) and 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA). A coupling agent, 3-glycidyloxyporpl trimethoxysilane (GTMOS), was used to functionalize the SiO2 nanoparticles which enhanced the compatibility between polyimide and SiO2 nanoparticles. The microstructures of polyimide/SiO2 nanocomposites were characterized by Fourier transform infrared spectroscopy (FT-IR) and wide angle X-ray diffraction (WAXD). All the polyimides show typical noncrystalline X-ray diffraction. The frequent occurrence of particular interatomic distances (R) denoted by the noncrystalline WAXD maxima were determined. All the modulus, strength and fracture strain of polyimide were improved with 5 wt% SiO2 modified with the coupling agent.

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17

Ваганов, Г. В., А. Л. Диденко, Л. А. Мягкова, В. Ю. Елоховский, Е. Н. Попова, and В. Ю. Юдин. "Вязкоупругие свойства углепластиков на основе порошковых полиимидных связующих." Письма в журнал технической физики 49, no. 10 (2023): 21. http://dx.doi.org/10.21883/pjtf.2023.10.55429.19403.

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Carbon fiber reinforced plastics based on thermoplastic partially crystalline fusible polyimide R-BAPB and oligoimide IDA (diacetyl imide) have been obtained. The thermal, thermomechanical and mechanical properties of carbon plastics based on polyimides have been studied. It has been shown that carbon plastics based on the used polyimide binders have increased crack resistance, which makes it possible to operate them at temperatures up to ~400oC.

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18

Akimoto, Satoshi, Daisuke Kato, Mitsutoshi Jikei, and Masa-aki Kakimoto. "Polyimide Containing an Acetal Structure with a Photoacid Generator: A Novel Positive Polyimide Photoresist." High Performance Polymers 12, no. 1 (March 2000): 185–95. http://dx.doi.org/10.1088/0954-0083/12/1/315.

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A main-chain degradable photosensitive polyimide containing an acetal structure which degrades by the action of acid coming from a photoacid generator has been developed. Polyimides 4 were prepared by the reaction of bis(4-aminophenoxy)methane 1 and various tetracarboxylic anhydrides 2, followed by thermal treatment. In the resulting polyimides 4, 4f filmderivedfrom 4,4′-hexafluoroisopropylidenebis(phthalicanhydride)(6FDA)and 1 showedgood solubility in organic solvents and transparency to UV light. The acid-catalysed degradation reaction was confirmed by the model imide compound in the presence of p-toluenesulfonic acid. The system of the polyimide 4f containing 30 wt% of diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate (DIAS), which is a photoacid generator (PAG) showed a sensitivity of 150 mJ cm−2 with 436 nm light, when it was post-exposure baked at 140°C for 30 min, followed by development with 5% tetramethylammonium hydroxide solution at 45°C.

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19

Li, Jiang, Wenhua Zhao, Chenchen Zhao, Tongqing Qi, Pengchang Ma, De Ning, Chunlei Yang, and Weimin Li. "A comparison study of high thermal stable and resistant polyimides." AIP Advances 12, no. 9 (September 1, 2022): 095301. http://dx.doi.org/10.1063/5.0101600.

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Polyimide thin films with high thermal stability and resistance will contribute to the development of flexible energy devices, which could be compatible with their high temperature fabrication process. Thus, we have prepared poly(amic acid) solutions with bisbenzimidazole and bisbenzoxazole based diamines and finally fabricated polyimide thin films. After comparing with commercial type polyimides, the polyimides containing bisbenzimidazole and bisbenzoxazole segments showed excellent thermal decomposition temperatures (of 581 and 584 °C, respectively), outstanding mechanical properties (with a tensile strength of 218 and 192 MPa, respectively), and relatively low water absorption percentages (of 0.68% and 0.63%, respectively). The superior properties should be ascribed to the rigid molecular chain skeleton, strong inter- and intra-molecular-chain forces, and hydrogen bonds.

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Bes, L., A. Rousseau, B. Boutevin, R. Mercier, B. Sillion, and E. Toussaere. "Synthesis and Characterization of Aromatic Polyimides Bearing Nonlinear Optical Chromophores." High Performance Polymers 12, no. 1 (March 2000): 169–76. http://dx.doi.org/10.1088/0954-0083/12/1/313.

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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.

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Wang, Kun Li, Jian Wei Lee, I. Hao Shih, Yi Liang Liu, and En Tang Kang. "Resistive Polymer Memory Materials Containing Electron Donor and Acceptor Moieties." Advanced Materials Research 488-489 (March 2012): 3–7. http://dx.doi.org/10.4028/www.scientific.net/amr.488-489.3.

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Two series of polymers including polyimides and poly(aryl ether)s were prepared and used as active layers of polymer memories. The poly(aryl ether)-based polymers showed flash behaviors and polyimide-based polymers showed WORM behaviors. The poly(aryl ether)s flash memories can be negatively switched on and positively switched off, and the switching voltages are relative to the chemical structure of bisphenol moiety. On the other hand, the polyimide-based polymer devices can be bidirectionally switched on with comparable positive and negative switching threshold voltages, but cannot be switched off. The polyimides showed write-once-and-read- many-times (WORM) memory behavior. The poly(aryl ether) (AZTA-PAEb) showed very different memory behavior from polyimides (AZTA-PI and AZTA-PEI) although they contain the similar chemical structure (electron-donor triphenylamine and electron-acceptor triazine moieties). The imide structure in the polyimides plays a great role in the memory effects.

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Lu, Yun Hua, Peng Pan, Bing Wang, Hong Bin Zhao, and Zhi Zhi Hu. "Synthesis and Properties of Polyimides Containing Tert-Buty Group." Applied Mechanics and Materials 275-277 (January 2013): 1636–39. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.1636.

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Two diamine monomers 2-tert-butyl-1,4-bis(4-nitro-2-trifluoromethylphenoxy)benzene and 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene were reacted with the alicyclic dianhydride monomers 1,2,3,4-cyclobutanetetracarboxylic dianhydride to synthesize the poly(amic acid)s, and then obtain the corresponding polyimide films through thermal imidization. The structure and properties were characterized by fourier transform infrared spectroscopy (FT-IR), ultraviolet visible spectroscopy (UV-vis), thermogravimetic analysis (TGA), solubility test and so on. The effect of introduction of bulky tert-butyl and trifluoromethyl to the polyimide backbone on the properties of polyimide films was investigated. The experimental results showed that polyimides with tert-buty group exhibit excellent solubility, but their thermal and optical properties decreased slightly.

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23

Tsuda, Yusuke, Yuki Matsuda, and Takaaki Matsuda. "Soluble Polyimides Bearing Long-Chain Alkyl Groups on Their Side ChainviaPolymer Reaction." International Journal of Polymer Science 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/972541.

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Novel soluble polyimides having long-chain alkyl groups on their side chain were synthesizedviapolymer reaction with the polyimides having phenolic OH groups and 3,4,5-tris(dodecyloxy)benzoic acid (12GA) using N,N′-dicyclohexylcarbodiimide (DCC) as a dehydration reagent. The polyimides having phenolic OH groups were synthesized from the tetracarboxylic dianhydrides such as 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (cyclohexene-DA), 4,4′-hexafluoroisopropylidendi(phthalic anhydride) (6FDA), and 3,3′,4,4′-diphenylsulfone tetracarboxylic dianhydride (DSDA) and aromatic diamines such as 4,4′-diamino-3,3′-dihydroxybiphenyl (HAB). The polymer reactions were carried out in NMP and the progresses of polymer reactions were quantitatively monitored by1H NMR measurements (conversion; 12.2–98.7%). The obtained polyimides bearing long-chain alkyl groups have enough molecular weights, good film-forming ability, good solubility for various organic solvents, and enough thermal stability. The water contact angles of the polyimide films were investigated, and it is noted that the introduction of long-chain alkyl groups increases the hydrophobicity of polyimide surface. These polyimides are expected to be applicable as the functional materials for microelectronics such as the alignment layers of LCDs.

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Song, Ningning, Tianjiao Wang, Hongyan Yao, Tengning Ma, Kaixiang Shi, Ye Tian, Yongcun Zou, Shiyang Zhu, Yunhe Zhang, and Shaowei Guan. "Construction and carbon dioxide capture of microporous polymer networks with high surface area based on cross-linkable linear polyimides." Polymer Chemistry 10, no. 33 (2019): 4611–20. http://dx.doi.org/10.1039/c9py00100j.

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Microporous polyimide networks with high surface area and excellent CO₂ adsorption performance have been constructed based on cross-linkable linear polyimides through crosslinking reaction.

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Wu, Ziyu, Jianjun He, Haixia Yang, and Shiyong Yang. "Progress in Aromatic Polyimide Films for Electronic Applications: Preparation, Structure and Properties." Polymers 14, no. 6 (March 21, 2022): 1269. http://dx.doi.org/10.3390/polym14061269.

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Aromatic polyimides have excellent thermal stability, mechanical strength and toughness, high electric insulating properties, low dielectric constants and dissipation factors, and high radiation and wear resistance, among other properties, and can be processed into a variety of materials, including films, fibers, carbon fiber composites, engineering plastics, foams, porous membranes, coatings, etc. Aromatic polyimide materials have found widespread use in a variety of high-tech domains, including electric insulating, microelectronics and optoelectronics, aerospace and aviation industries, and so on, due to their superior combination characteristics and variable processability. In recent years, there have been many publications on aromatic polyimide materials, including several books available to readers. In this review, the representative progress in aromatic polyimide films for electronic applications, especially in our laboratory, will be described.

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Li, Zhirui, Yong Hou, Pengchang Ma, and Wenhua Zhao. "Preparation and Characterization of High Temperature Resistant Polyimide Films." MATEC Web of Conferences 358 (2022): 01046. http://dx.doi.org/10.1051/matecconf/202235801046.

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To prepare high temperature resistant polyimide thin films, we have discussed the synthesis of high-purity diamine precursors in this study. We have prepared polyamide acid solutions first via two-step solution-based polymerization of heat-resisting diamine and dianhydride, and then obtain polyimides after dehydration during a high temperature curing process. The thermal, mechanical and hygroscopic properties of four polyimides thin films were tested and compared.

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Soldatova, Anastasiia E., Regina N. Shamsutdinova, Tatiana V. Plisko, Katsiaryna S. Burts, Anna Yu Tsegelskaya, Dmitry A. Khanin, Kristina Z. Monakhova, Tikhon S. Kurkin, Alexandr V. Bildyukevich, and Alexander A. Kuznetsov. "Synthesis of Aromatic Polyimides Based on 3,4′-Oxydianiline by One-Pot Polycondensation in Molten Benzoic Acid and Their Application as Membrane Materials for Pervaporation." Materials 15, no. 19 (October 2, 2022): 6845. http://dx.doi.org/10.3390/ma15196845.

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A series of aromatic polyimides based on the asymmetrical diamine 3,4ʹ-oxydianiline and various tetracarboxylic acid dianhydrides, both “rigid” and “flexible” structure, have been synthesized using the original method of one-pot high-temperature catalytic polycondensation in molten benzoic acid. The synthesized polyimides were investigated using fourier-transform infrared (FTIR) and 1H NMR spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), thermomechanical analysis (TMA) and wide-angle X-ray scattering (WAXS). It was found that the synthesized polyimides, depending on the used dianhydride, are characterized by different solubility in organic solvent and molten benzoic acid, molecular weight, glass transition temperature (Tg) from 198 to 270 °C, an amorphous or semi crystalline structure with the degree of crystallinity from 41 to 52%. The influence of the method of synthesis on the formation of the crystalline phase of polyimides was studied, and the obtained results were compared with the literature data. The effect of dianhydride chemical structure on the performance of polyimide in pervaporation more specifically, dehydratation of azeotropic isopropanol solution was investigated and compared with the commercially available polyetherimide Ultem 1000™. Membrane structure was studied using scanning electron microscopy. It was found that polyimide PI-DA is the most effective for separation of 88 wt.% isopropanol/12 wt.% water mixture compared to the polyimide PI-6FDA and commercial polyetherimide Ultem 1000™ demonstrating normalized permeation flux of 2.77 kg µm m−2 h−1 and separation factor of 264 (water content in permeate 97 wt.%).

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SYSEL, PETR, ROMAN HOLAKOVSKÝ, ŠTĚPÁN HOVORKA, JAROSLAV Ž ÁDNÝ, and PAVEL IZÁK. "Preparation of Optically Active Polyimides Based on 2,2´-diamino-1,1´-binaphthalene." JOURNAL OF POLYMER MATERIALS 39, no. 3-4 (May 1, 2023): 325–35. http://dx.doi.org/10.32381/jpm.2022.39.3-4.10.

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Linear polyimides based on both of the 2,2´-diamino-1,1´-binaphthalene enantiomers and their racemic mixture were synthesized and characterized. A two-step synthetic route, consisting of the preparation of the polyimide precursor followed by its thermal imidization at temperatures not exceeding 200°C, was employed. The products were analyzed by FTIR and 1H NMR spectroscopy. All of the tested materials were nearly fully imidized after 25 h. The final polyimides possess high glass transition temperatures, are thermo-oxidatively stable and are soluble in common organic solvents as 1-methyl-2-pyrrolidone, tetrahydrofuran and chloroform; additionally, those prepared from the enantiomers show optical activity. The values of specific optical rotations for the polymers were higher than those for the corresponding monomers. However, the directions of their optical rotations were identical. Due to their rather low molar masses, the final polyimides form brittle self-standing films. Thin layers of these products on porous polyimide substrates were made under forming composite membranes.

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Borshchov, V. M., O. M. Listratenko, M. A. Protsenko, I. T. Tymchuk, O. V. Kravchenko, O. V. Syddia, M. I. Slipchenko, and B. M. Chichkov. "High-thermally conductive composite polyimide materials." Radiotekhnika, no. 210 (September 28, 2022): 150–59. http://dx.doi.org/10.30837/rt.2022.3.210.12.

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This review is devoted to analysis of works in the field of creating electrically insulating heat-conducting polyimide composite films based on powders of micro-, submicro- or nano-sized fillers with high dielectric and heat-conducting properties for use as effective thermal interface materials in various electronic devices in instrument making. Particular attention is paid to studies on the influence of the size of nano- and microparticles of inorganic fillers on the heat-nducting, dielectric, and physical-mechanical properties of nanocomposite polyimide materials. The analysis of the results of work on the study of the dependence of thermal conductivity on the ratios of micron and nanosized particles in mixtures and their number in polyimides and on the conditions of their polymerization was carried out to confirm the possibility of increasing the thermal conductivity values of promising polyimide materials from 0.12 W/(m•K) up to 5¸10 W/ (m•K). It is noted that the highest thermal conductivity of industrially produced modern polyimide films on market does not exceed 0.75¸0.8 W/(m•K). The task of creating inexpensive, but high-quality heat-conductive polyimide composite materials with sufficiently high thermal conductivity without deteriorating their strength and ductility characteristics is currently relevant and technically in demand.

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Zhang, Kan, Jia Liu, and Hatsuo Ishida. "High performance crosslinked polyimide based on main-chain type polybenzoxazine." RSC Adv. 4, no. 107 (2014): 62550–56. http://dx.doi.org/10.1039/c4ra12015a.

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A novel approach has been developed to prepare thermosetting polyimides by incorporating benzoxazine structure as a repeating unit in the main chain. This method allows the crosslinked polyimide with excellent thermal and mechanical properties.

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Yang, Yooseong, Youngsuk Jung, Myung Dong Cho, Seung Geol Lee, and Soonchul Kwon. "Transient color changes in oxidative-stable fluorinated polyimide film for flexible display substrates." RSC Advances 5, no. 71 (2015): 57339–45. http://dx.doi.org/10.1039/c5ra06066d.

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Stable optical properties of high transmittance and low yellow index, which are required for a polyimide film as a flexible display substrate could be affected by thermal imidization even in oxidative-stable fluorinated polyimides.

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Meng, Ying, Runhua Gao, Xinhua Wang, Sen Huang, Ke Wei, Dahai Wang, Fengwen Mu, and Xinyu Liu. "Direct Bonding Method for Completely Cured Polyimide by Surface Activation and Wetting." Materials 15, no. 7 (March 30, 2022): 2529. http://dx.doi.org/10.3390/ma15072529.

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Polymer adhesives have emerged as a promising dielectric passivation layer in hybrid bonding for 3D integration, but they raise misalignment problems during curing. In this work, the synergistic effect of oxygen plasma surface activation and wetting is utilized to achieve bonding between completed cured polyimides. The optimized process achieves a void-less bonding with a maximum shear strength of 35.3 MPa at a low temperature of 250 °C in merely 2 min, significantly shortening the bonding period and decreasing thermal stress. It is found that the plasma activation generates hydrophilic groups on the polyimide surface, and the wetting process further introduces more −OH groups and water molecules on the activated polyimide surface. The synergistic process of plasma activation and wetting facilitates the bridging of polyimide interfaces to achieve bonding, providing an alternative path for adhesive bonding in 3D integration.

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Rowe, R. V. A., M. H. Kunita, M. F. Porto, E. C. Muniz, A. F. Rubira, R. C. Nery, E. Radovanovic, L. T. Taylor, and N. Nazem. "Low-resistance films of polyimides with impregnated copper sulfide." Journal of Materials Research 16, no. 11 (November 2001): 3097–106. http://dx.doi.org/10.1557/jmr.2001.0427.

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Surface modification of polyimides has been used to obtain better interaction with an inorganic material. Copper sulfide incorporation onto the surface of commercial Kapton® polyimide showed that treatment with base was necessary for adherence of the copper sulfide to the polymeric matrix. The optimized conditions for composite preparation, obtained by response surface methodology, was pH 1.4 at 80 °C for 3.67 h. Using these conditions, we obtained electrical resistance as low as 1.0 ohm for CuS\Kapton® composites. These optimized conditions were used to prepare other low-resistance polyimide composites. The resulting composites were analyzed by photoelectron spectroscopy. The presence of S(2p) and Cu(2p) peaks demonstrated the incorporation of copper sulfide onto the polyimide surface. Scanning electron microphotographs and the images from atomic force microscopy showed a homogeneous CuS distribution in all composites.

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Dong, Weibing, Yue Guan, and Dejing Shang. "Novel soluble polyimides containing pyridine and fluorinated units: preparation, characterization, and optical and dielectric properties." RSC Advances 6, no. 26 (2016): 21662–71. http://dx.doi.org/10.1039/c6ra00322b.

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To acquire low dielectric constant polyimide films with good mechanical and thermal properties and low CTE applied in microelectronic fields, three novel polyimides containing pyridine and –C(CF₃)₂– groups were firstly designed and synthesized.

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35

Didenko, Andrei, Danila Kuznetcov, Gleb Vaganov, Valentina Smirnova, Elena Popova, Alexey Ivanov, Boris Chernitsa, Valentin Svetlichnyi, Vladimir E. Yudin, and Vladislav Kudryavtsev. "The Thermal Stability and Mechanical Properties of Non-Segregating Blends of Polyimides with Copoly(Urethane-Imide)s." Key Engineering Materials 869 (October 2020): 280–95. http://dx.doi.org/10.4028/www.scientific.net/kem.869.280.

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The series of compositions containing thermodynamically incompatible flexible blocks of aliphatic polyesters and rigid blocks of aromatic bis (urethane) imides in the volume of polymers was obtained on the basis of multiblock (segmented) poly (urethane-imides) and related aromatic polyimides. The series includes segmented poly (urethane-imides) with different relative content of flexible and rigid blocks, non-segregating mixtures of poly (urethane-imides) and thermoplastic partially crystalline polyimide, statistical copolymers of poly (urethane-imide) with imide, and non-segregating mixtures of statistical copolymers with thermoplastic polyimide. The derived polymer systems were studied using thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. The deformation and strength properties of film samples are determined. It is shown that the properties of the studied polymers change as their content of imides blocks increases, and the transition from thermoplastic poly (urethane-imide) elastomers to thermoplastic polyimides is observed.

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36

Chao, Min. "Synthesis and Characterization of Semicrystalline Polyimides Containing Bridged Linkages." International Journal of Polymer Science 2018 (August 7, 2018): 1–7. http://dx.doi.org/10.1155/2018/8590567.

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A series of polyimides (PI) containing bridged linkages were prepared successfully through a three-step technique. The results indicated that the glass transition temperature (Tg) of polyimides was affected by flexibility of polymer chain and the intermolecular interactions. ODPA-TPER-based polyimide possesses the lowest Tg, which was 214°C. All polyimides had semicrystalline characteristics, and ODPA-TPER-based PI exhibited the lowest melting temperature (Tm) at 316°C. The polyimides had high weight loss temperatures, which indicated that bridged linkages can reduce the softening temperature, meanwhile keeping excellent thermal stability.

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37

Hatchard, T. D., R. A. Fielden, and M. N. Obrovac. "Sintered polymeric binders for Li-ion battery alloy anodes." Canadian Journal of Chemistry 96, no. 7 (July 2018): 765–70. http://dx.doi.org/10.1139/cjc-2017-0728.

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The cycling performance in lithium half cells of Si alloy electrodes with polyvinylidene fluoride or polyimide binders were evaluated after the electrodes were cured at temperatures below and above the binder carbonization temperature. After carbonization, the cycling performance of electrodes using polyvinylidene fluoride binder improved considerably but still suffered from capacity fade. Electrodes with carbonized polyimide binder had superior performance and showed no capacity fade after 100 cycles. The superior performance of carbonized polyimide electrodes is thought to be related to polyimide’s high carbon yield upon heating, resulting in the formation of a uniform carbon coating on alloy surfaces. These results suggest that new high performance binders for alloy electrodes might be derived by the carbonization of polymers with a high carbon yield that lead to the formation of uniform carbon coatings on alloy particles.

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38

Barzic, Andreea Irina, Raluca Marinica Albu, Emil Ghiocel Ioanid, and Camelia Hulubei. "Molecular design of some semi-alicyclic polyimides as a route to improve refraction and dielectric properties for liquid crystal display applications." High Performance Polymers 30, no. 7 (August 21, 2017): 776–86. http://dx.doi.org/10.1177/0954008317726358.

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The study establishes an adequate monomer combination for achieving the best balance of properties required in obtaining polyimide alignment layers for display devices. The molecular design of some aliphatic/aromatic polyimides was performed by using dianhydride monomers with distinct configurations in terms of rigidity, size, and symmetry. The polyimides based on semi-flexible and nonsymmetric dianhydride moieties present lower refractive index and dielectric constant (<3) than those obtained from symmetric and rigid dianhydride units. This determines faster traveling of visible and microwave radiations as required for liquid crystal alignment purposes. The interactions of samples with the N-(4-Methoxybenzylidene)-4-butylaniline, cyanobiphenyl, and 4-pentyl-4-cyanobiphenyl nematics were assessed. The analyzed polyimides have higher surface tensions than the ones of the liquid crystals, determining a parallel arrangement of the nematic molecules. As the dispersive interactions at the polymer surface are lower, the work of spreading is higher as a result of improved adhesion of liquid crystal with the polyimide alignment layer. The sample containing rigid, symmetric, noncoplanar dianhydride units (PI.4) and the one based on semi-flexible, nonsymmetric dianhydride moieties are the most transparent for visible and microwave radiations, allowing low cohesion interaction at interface with nematics. These aspects recommend the two studied polyimides as candidates for alignment layers.

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Ji, Xiaodong, Jingling Yan, Xiuju Liu, Zikun Wang, and Zhen Wang. "Synthesis and properties of polyimides derived from bis(4-aminophenyl)isohexides." High Performance Polymers 29, no. 2 (July 28, 2016): 197–204. http://dx.doi.org/10.1177/0954008316634443.

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Several partially bio-based polyimides have been successfully synthesized by polycondensation between bis(4-aminophenyl)isohexides with various commercial dianhydrides. Flexible and free-standing films were readily obtained from their poly(amic acid) or polyimide solutions. A systematic investigation of the structure–property relationship of polyimides highlights the significant impact of the isohexides moieties on their physical and mechanical properties (glass transition temperature, inherent viscosity, thermal stability, solubility, and mechanical properties). The results revealed that these polyimides exhibited comparable thermal stability and mechanical properties to those of petrochemical-based ones.

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Chen, Ying, Rumin Huang, Qiuyu Zhang, Wanlu Sun, and Xiaobo Liu. "Synthesis and properties of highly soluble branched polyimide based on 2,4,6-triaminopyrimidine." High Performance Polymers 29, no. 1 (July 28, 2016): 68–76. http://dx.doi.org/10.1177/0954008315627854.

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A series of novel soluble polyimides was synthesized from commercially available 2,4,6-triaminopyrimidine (TAP), 2,2-bis(3,4-dicarboxylphenyl) hexafluoropropane dianhydride (6FDA), α,ω-aminopropylpoly(dimethylsiloxane) and 1,3-bis(3-aminophenoxy)benzene. TAP is the branched monomer, and polymerization process had been improved in three ways by using TAP to prepare soluble polyimides. The polyimides were characterized by Fourier transform infrared spectra, proton nuclear magnetic resonance, ultraviolet–visible spectrometer analysis, wide-angle X-ray diffraction, and size-exclusion chromatography with multiangle laser light-scattering detection. The branched polyimides showed excellent solubility both in strong polar solvents and in common low-boiling point solvents. Differential scanning calorimetric and thermogravimetric analyses showed high glass transition temperatures and excellent thermal stability for branched polyimides with moderate content of TAP. Polyimide membranes were formed at relatively low temperature, and the mechanical properties were tested. These results ensure that soluble polyimides with moderate content of TAP showed outstanding combined features and are desirable candidate materials for advanced applications.

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41

Chuang, S. F., T. S. Kuan, and M. Pomerantz. "High-resolution imaging of ordered structure in thin polyimide films." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 1052–53. http://dx.doi.org/10.1017/s0424820100089573.

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Polyimides are excellent insulating materials for use in microelectronics because of their high thermal stability, low dielectric constant, good mechanical strength, and resistance to moisture. The molecule main chain of polyimides consists of a rigid, planar structure of aromatic and/or heterocyclic rings. These polymers are usually highly disordered, but local crystallization is feasible between these regular and strongly interacting planar ring groups. In principle, it is possible to synthesize polyimides in crystalline form, with the exception of crosslinked materials, or those with long and bulky side groups. Spin-on technique is most often used to apply polyimide films onto substrates in semiconductor industry. This technique, however, is not suitable for preparation of smooth films with thickness less than a few hundred angstrons. Recently, monolayer-by-monolayer depositions of polyamic acids (precursors to polyimides) onto substrates using the Langmuir-Blodgett technique have been reported. This technique offers more precise control of film thickness and may allow highly ordered polymer films to be synthesized.

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42

ASANO, MASAYA, and MASAO TOMIKAWA. "Properties of polyimides formed from photosensitive polyimide precursors." Journal of Photopolymer Science and Technology 9, no. 2 (1996): 305–8. http://dx.doi.org/10.2494/photopolymer.9.305.

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43

Gutiérrez, Jon, Andoni Lasheras, Jose Manuel Barandiaran, Jose Luis Vilas, Alberto Maceiras, and Luis Manuel León. "Improving the Performance of High Temperature Piezopolymers for Magnetoelectric Applications." Key Engineering Materials 543 (March 2013): 439–42. http://dx.doi.org/10.4028/www.scientific.net/kem.543.439.

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Piezoelectricity in amorphous polymers is mainly due to the orientation polarization of the molecular dipoles. Aromatic polyimides are high-performance polymeric materials possessing large molecular dipoles. We already reported good magnetoelectric performance of laminate composites with Vitrovac 4040®as magnetostrictive component and the 2,6(b-CN)APB/ODPA (poli 2,6) polyimide as the piezoelectric. Although the piezoelectric response of this polyimide is good, its mechanical properties can be improved. To combine the best mechanical and piezoelectric response in the same polymer, copolyimides have been synthesized by reaction of the 4,4-oxydiphtalic anhydride (ODPA) with a mixture of 1,3-Bis-2-cyano-3-(3-aminophenoxy) phenoxybenzene (diamine 2CN) and 1,3-Bis (3-aminophenoxy) benzene (diamine 0CN). We present the piezoelectric, mechanical and ME performance of laminate composites of these copolyimides.

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44

Jang, Steven Lee Hou, Wee Ming Tan, Ying Jun Mao, Ramana Murthy, and Nagarajan Ranganathan. "Gapfill Study of Polyimides for MEMS Applications." Advanced Materials Research 254 (May 2011): 54–57. http://dx.doi.org/10.4028/www.scientific.net/amr.254.54.

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Various types of polyimide have been used widely in the manufacturing of integrated circuits and MEMS’ (Micro Electrical Mechanical Systems) such as sensors. These organic spin-on polymers exhibit a wide range of mechanical and electrical properties and have been commonly used for electrical insulation as well as device passivation and protection. In addition, these organic spin-on polymers serve as excellent sacrificial materials for forming cavities on MEMS structures. This work studies the gapfill properties of several polyimides after spin-coating and curing. In addition, this work examines and compares the gapfilling and planarization properties of a number of different polyimides, including multiple layers of polyimides for gapfilling and planarization.

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Schwartz, Willis T., Mary K. Cocoman, Jeffrey S. Stults, and Frank J. Dinan. "4,4',5,5'-Dioxydiphthalic dianhydride, a new polyimide monomer." High Performance Polymers 6, no. 2 (April 1994): 155–63. http://dx.doi.org/10.1177/095400839400600206.

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4,4',5,5'-Dioxydiphthalic dianhydride (DODA), a new monomer for the synthesis of polyimide resins, has been prepared by the action of a base on a 4,5-dihalophthalic anhydride in a polar aprotic solvent. Both potassium carbonate and a combination of potassium fluoride and water have afforded DODA in a high-yielding single-step reaction. The product was purified by crystallization of its di-n-butyl ester. A variety of polyimides and copolyimides incorporating DODA were prepared, and afforded creasable films having good physical properties.

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Lee, Juheon, Seungho Baek, Jinsu Kim, Sangrae Lee, Jinyoung Kim, and Haksoo Han. "Highly Soluble Fluorinated Polyimides Synthesized with Hydrothermal Process towards Sustainable Green Technology." Polymers 13, no. 21 (November 5, 2021): 3824. http://dx.doi.org/10.3390/polym13213824.

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Polyimides, a widely used engineering plastic, require use of large amounts of toxic and hazardous organic solvents which threaten our daily lives, calling for new and easy synthetic methods for sustainable environmentally friendly development. In this paper, highly soluble fluorinated polyimides based on 4,4′-(hexafluoroisopropylidene) diphthalic anhydride were synthesized via hydrothermal process without using any toxic organic solvents and the advantages of the newly demonstrated synthetic methods are shown by comparative analysis performed with the two conventional synthetic methods using organic solvent: thermal and chemical imidization. Lower temperature is required (~200 °C) compared to thermal imidization and functional groups for high fusibility formed more easily compared to chemical imidization. According to the comparative analysis, hydrothermally synthesized PIs showed excellent solubility and maintained high thermal stability (>500 °C) and glass transition temperature (>300 °C) compared to conventional PI. The hydrothermally synthesized polyimide is much more convenient to store and manage than other form of polyimide which is much more stable when it is exposed to humidity as it is a powder form. The hydrothermal synthetic method is verified to be a “Green” and facile method for sustainable PI synthesis.

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Rosenauer, Philipp, Christoph Kratzer, Silvia Larisegger, and Stefan Radl. "Extraction of Mechanical Parameters via Molecular Dynamics Simulation: Application to Polyimides." Polymers 16, no. 6 (March 14, 2024): 813. http://dx.doi.org/10.3390/polym16060813.

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Polyimides feature a vast number of industrial applications due to their high thermal stability and insulation properties. These polymers exhibit an exceptional combination of thermal stability and mechanical toughness, which allows the semiconductor industry to use them as a mechanical stress buffer. Here, we perform all-atom molecular dynamics (MD) simulations for such materials to assess their predictive capability with respect to their mechanical properties. Specifically, we demonstrate that the OPLS-AA force field can be used to successfully describe an often-used polyimide (i.e., Kapton®) with respect to its Young’s modulus and Poisson’s ratio. Two different modes to extract these mechanical properties from MD simulations are presented. In particular, our continuous deformation mode simulations almost perfectly replicate the results from real-world experimental data and are in line with predictions using other MD force fields. Our thorough investigation of Kapton® also includes an analysis of the anisotropy of normal stresses, as well as the effect of simulation properties on the predicted Young’s moduli. Furthermore, the polyimide pyromellitic dianhydride/2-(4-aminophenyl)-1H-benzimidazole-5-amine (PMDA-BIA) was investigated to draw a more thorough picture of the usability of the OPLS-AA force field for polyimides.

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48

Jung, Cheolsoo, Tetsuya Aoyama, Tatsuo Wada, Hiroyuki Sasabe, Mitsutoshi Jikei, and Masa-Aki Kakimoto. "The Photorefractive Effect in Monolithic Structural Polyimides." High Performance Polymers 12, no. 1 (March 2000): 205–12. http://dx.doi.org/10.1088/0954-0083/12/1/317.

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We report here the photorefractive effect in monolithic structural polyimides containing the triphenylamino-( p-nitrophenyl)-ethylene group as a nonlinear optical (NLO) chromophore and hole transfer. Three types of polyimides were synthesized to control the loading ratio of the NLO chromophore; 50, 30 and 17 mol% for polyimides 1, 2 and 3 respectively. In the two-beam coupling experiment, asymmetric energy transfer was observed in the case of polyimides 1 and 2, providing evidence for a phaseshifted grating after corona-poling treatment, whereas the energy transfer of polyimide 3 was not observed. This result denotes that the NLO chromophore plays an important role in monolithic photorefractive materials, and a greater than 30 mol% concentration of NLO chromophore is required for creating sufficient space charge distribution.

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Hay, J. N., B. Woodfine, and M. Davies. "Toughening of Epoxy Resins by Polyimides Synthesized from Bisanilines." High Performance Polymers 8, no. 1 (March 1996): 35–56. http://dx.doi.org/10.1088/0954-0083/8/1/003.

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A range of thermoplastic polyimides has been synthesized and used to modify a DGEBA-DDS epoxy thermoset. The influence of polyimide end-group functionality and particle size has been examined. Increases in fracture toughness of up to three times that of the neat resin have been achieved, together with no loss of modulus. Thermal capability is little affected across the range of modifying polyimides. The influence of copoly(imide–imide)s has also been studied. Morphological examination has revealed a range of structures in the blends, including some which are unusual. A particulate toughening mechanism is proposed for one high fracture toughness system.

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Bezuk, S. J., R. J. Baseman, C. Kryzak, K. Warner, and G. Thomes. "Pyrolytic Laser Direct Writing of Nickel Over Polyimides." MRS Proceedings 75 (1986). http://dx.doi.org/10.1557/proc-75-75.

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AbstractPolyimides are of great interest as insulators for microelectronic fabrication due to their low dielectric constant and planarizing properties. However, they are thermally sensitive films. Nonetheless, preliminary results clearly demonstrate that nickel lines readily can be laser-pyrolytically drawn over polyimide films.While elevated laser power will damage underlying polyimide films, microelectronic quality nickel lines can be drawn using nickel carbonyl at relatively low laser intensities over polyimides with little or no change in the electrical characteristics. Polyimide's lower thermal conductivity relative to silicon dioxide facilitates increased nickel deposition rates. Self-limiting effects have been observed during the deposition that can lead to near microelectronically ideal line cross sections.

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Journal articles on the topic 'Polyimide'

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