Polyimides containing cycloaliphatic segments for low dielectric material

Popovici, Dumitru; Hulubei, Camelia; Cozan, Vasile; Lisă, Gabriela; Brumă, Maria

doi:10.1177/0954008311435798

Cited by 22 publications

(13 citation statements)

References 16 publications

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“…In previous investigations [21–23], we have synthesized different polyimide structures based on cycloaliphatic dianhydrides, such as homo‐ and co‐polyimides. We have also studied some special properties of various polyimide‐based blend systems, related to morphological and structural‐rheological aspects [24], blood compatibility [25], or different novel approaches for patterning such type of polymers [26].…”

Section: Introductionmentioning

confidence: 99%

Origin of dielectric response and conductivity of some alicyclic polyimides

Ioan¹,

Hulubei²,

Popovici³

et al. 2012

Polymer Engineering & Sci

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High‐performance alicyclic‐containing polyimides for advanced applications, derived from 5‐(2,5‐dioxotetrahydrofurfuryl)‐3‐methyl‐3‐cyclohexene‐1,2‐dicarboxylic acid anhydride or bicyclo[2.2.2]oct‐7‐ene‐2,3,5,6‐ tetracarboxylic dianhydride and two flexible aromatic diamines, were synthesized by a classical two‐step polycondensation reaction. The dielectric spectra behavior over wide frequency and temperature ranges of 1 Hz‐1 MHz and –150°C÷+250°C, respectively, was investigated according to chemical and micro‐structural aspects. The dielectric constants have low values and are dependent on dianhydride flexibility and diamine links, in relation with the charge–transfer complex (CTC) and free volume, and, consequently, with packing of the polymer chains and polarizable groups per volume units. All polyimide films develop two relaxation processes, i.e., γ and β relaxation, involving different enthalpy and entropy contributions induced by their chemical structures. Frequency–temperature‐dependent conductivity showed that conductivity increased with frequency and also that energy bandgap representation could be suitable for explaining the temperature influence on AC‐conductivity. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

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Section: Introductionmentioning

confidence: 99%

Origin of dielectric response and conductivity of some alicyclic polyimides

Ioan¹,

Hulubei²,

Popovici³

et al. 2012

Polymer Engineering & Sci

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“…In short, it is a two‐step process, involving the preparation of the poly(amic acid) (PAA) in N‐methyl‐2‐pyrrolidone (NMP) and followed by the transformation (thermal imidization) into the corresponding polyimide. Details regarding the synthesis of this polymer are presented somewhere else (Cristea et al ., ; Popovici et al .,). The chemical structure of the obtained polyimide is presented in Scheme .…”

Section: Methodsmentioning

confidence: 99%

Establishing proper scanning conditions in atomic force microscopy on polyimide and polyurethane samples and their effect on 3D surface texture parameters

Stoica

Hitruc²,

Ţîmpu³

et al. 2015

Scanning

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Several atomic force microscopy (AFM) tests have been carried out on both smooth (polyimide) and rough (polyurethane) surfaces so that to obtain the best results; subsequently, the optimization of experiments performed is presented. A special emphasis has been put on the effect of tip geometry, image pre-processing procedure, scanning area, resolution, pixel size, and cantilever oscillation amplitude in tapping mode, as well as on the quality of the topographical images and 3D surface texture parameters. After viewing the scanning tip and finding out its sharpness, degradation, and contamination, a simultaneous calibration in X, Y, and Z directions, lateral calibration of SPM scanners and detection of lateral non-linearity, hysteresis, creep, and cross-coupling effects has been made. We have established the following experimental parameters: proper scanning resolution (512 × 512 pixels), adequate pixel size (between 2.9 and 19.5 nm) and suitable intermittent contact region (moderate tapping) for which the AFM images present good contrast and resolution. Using these parameters, the values of 3D texture parameters remain constant. These kinds of measurements are extremely important to conduct further AFM experiments on polyimide and polyurethane surfaces under optimal conditions, thus avoiding unwanted artifacts on the morphological images or unrealistic values for the 3D surface texture parameters that might occur.

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“…The two benchmark polymer dielectric materials, biaxially oriented polypropylene (BOPP) and polyvinylidene fluoride (PVDF), have dielectric constants of 2.2 and 10, respectively. [14][15][16][17][18][19][20][21][22] In our research, we focus on the opposite end of the polyimide chemical space in which an increase of the dielectric constant of the polymer is sought. The fact that make polyimides even more desirable is that they are thermally stable at temperatures exceeding 250 C, twice the operating temperature of most com-mon dielectric materials, making them able to withstand the heat generation that these capacitor banks will give rise to and there is less need for cooling the entire capacitor bank.…”

Section: Introductionmentioning

confidence: 99%

“…The introduction of space-filling groups, such as aromatics, increases the free volume and thus decreasing the dipolar and atomic polarizability, whereas fluorine replacement will reduce the total polarizability through the heightening of the hydrophobicity of the polymer. [14][15][16][17][18][19][20][21][22] In our research, we focus on the opposite end of the polyimide chemical space in which an increase of the dielectric constant of the polymer is sought. This is done by the polymerization of a common aromatic dianhydride with various alkyl diamines producing an overall reduction of the free volume as well as maintaining a high-imide functional group density in the polymer backbone.…”

Section: Introductionmentioning

confidence: 99%

Structure–property relationship of polyimides based on pyromellitic dianhydride and short‐chain aliphatic diamines for dielectric material applications

Baldwin

Wang

Ramprasad

et al. 2013

J of Applied Polymer Sci

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Most polyolefins that are used for dielectric materials exhibit a low dielectric constant and operating temperatures up to 70 C. Polyimides offer a means to a higher dielectric constant material by the introduction of a polar group in the polymer backbone and are thermally stable at temperatures exceeding 250 C. A common dianhydride, pyromellitic dianhydride (PMDA), is reacted with various short-chain diamines to produce polymers with high imide density. Homopolymers and copolymers synthesized had dielectric constants ranging from 3.96 to 6.57. These materials exhibit a dielectric constant twice that of biaxially oriented polypropylene and therefore a twofold increase in capacitance as well as maintaining low dissipation factors that are acceptable for this application. The experimental dielectric constants of these materials are also compared to density functional theory calculations and exhibit a close relationship.

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Polyimides containing cycloaliphatic segments for low dielectric material

Cited by 22 publications

References 16 publications

Origin of dielectric response and conductivity of some alicyclic polyimides

Origin of dielectric response and conductivity of some alicyclic polyimides

Establishing proper scanning conditions in atomic force microscopy on polyimide and polyurethane samples and their effect on 3D surface texture parameters

Structure–property relationship of polyimides based on pyromellitic dianhydride and short‐chain aliphatic diamines for dielectric material applications

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