Effect of metal halides on thermal, mechanical, and electrical properties of polypyromellitimide films

Varma, I. K.; Saxena, Sneh; Tripathi, A. K.; Goel, T. C.; Varma, D. S.

doi:10.1002/app.1986.070320316

Cited by 6 publications

(5 citation statements)

References 7 publications

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“…For instance, Abdelrazek et al showed that the CoCl 2 filler influences the optical energy bandgap of polyethyl-methacrylate films and enhances their thermal stability, while the logarithm of conductivity decreases with the increase of CoCl 2 content [22]. When polypyromellitimide was used as matrix, it was found that the thermal decomposition was not affected by the presence of Co salt, while the tensile strength and dielectric constant were reduced [23]. However, it appears that for each polymer structure a particular behavior occurs and there are no general rules.…”

Section: Introductionmentioning

confidence: 96%

“…Most studies showed that the CoCl 2 filler is an efficient electron acceptor due to the generation in the polymer matrix of Co 2+ ions [21]. Therefore, this metal halide filler significantly modifies the structure and physical properties of the host polymers [21][22][23][24]. For instance, Abdelrazek et al showed that the CoCl 2 filler influences the optical energy bandgap of polyethyl-methacrylate films and enhances their thermal stability, while the logarithm of conductivity decreases with the increase of CoCl 2 content [22].…”

Section: Introductionmentioning

confidence: 98%

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Insights into the physico-chemical behavior of CoCl2/polyimide hybrid materials

2016

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Hybrid fluorinated polyimide materials have been obtained by incorporation of various quantities of cobalt(II) chloride (CoCl 2 ) into polyimide matrix. Polycondensation reaction of equimolar amounts of 4,4′-diamino-3′3′-dimethyldiphenylmethane and 2,2′-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride has been carried out to produce in the first stage a polyamidic acid solution in which CoCl 2 × 6H 2 O has been placed. Further thermal treatment of this system led to the corresponding imide structure filled with the halide salt. An exhaustive study was directed to the influence of Co 2+ ions on the modified polyimide behavior as a function of its surroundings. To survey the functional properties of as-obtained Co 2+ -containing polyimide systems, several techniques such as FTIR, UV-vis and broadband dielectric spectroscopy, differential scanning calorimetry, and thermogravimetric and scanning electron microscopy were employed. A special concern was directed to the study of the optical properties induced by the addition of CoCl 2 into polymer solutions and films. The magnetic response of the polyimide was investigated in correlation with the salt quantity embedded in the PI film. The variation of the real and imaginary parts of the hybrid films' dielectric permittivity was registered in a broad frequency and temperature range, from 10 to 10 6 Hz and from −130 to 230°C, respectively.

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Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 98%

Insights into the physico-chemical behavior of CoCl2/polyimide hybrid materials

2016

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“…By using formula weights for each component and assuming the density of each component to be as it is in the pure state [1.42 g/cm 3 for polyimide (25), 6.45 g/cm 3 for Co.~O4 (26)], the relative peak areas can be converted to relative volumes. The calculation is cm3PI _( imideoxygen 6 Constant sampling depth (which is assumed) directly implies that the fractional surface coverage of polyimide is 0.82 and by difference the fractional surface coverage of cobalt oxide is 0.18 in the first 50A of the cobaltmodified PMDA/ODA polyimide film.…”

Section: Appendixmentioning

confidence: 99%

“…The properties of polyimides have been modified by many techniques. Modification of conventional polyimides with siloxane (3) to produce materials having superior adhesion to microelectronic devices and resistance to water and modification with dispersed metals (4), metal salts, and metal complexes (5)(6)(7)(8)(9) to produce materials having unique combinations of properties are a few examples.…”

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confidence: 99%

DC Electrical, Thermal, and Spectroscopic Properties of Various Condensation Polyimides Containing Surface Cobalt Oxide

Rancourt¹,

Boggess²,

Horning³

et al. 1987

J. Electrochem. Soc.

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Doping polyimides with cobalt ion causes the room temperature direct current electrical resistivity to decrease relative to the polymer alone, the reduction being most pronounced for the air-side of the cobalt modified polyimides. At a constant electrical field, resistivity for the volume, air-side and glass-side modes decreases yet further with an increase in temperature as expected for semiconductors and insulators. X-ray photoelectron spectroscopy indicates the air-side of the cobalt modified polyimides is predominately Co304. The bulk resistivity of the air-side and activation energy of conduction for this surface are comparable to high purity sintered Co304. Charging characteristics at room temperature indicate a substantial polymer matrix contribution to both the glass-side and volume mode measurements but a negligible contribution to the air-side electrical properties. Volume electrical resistivity for similar additive levels is reduced by increasing the molecular flexibility of the host polymer.Polyimides, having useful mechanical properties over a wide temperature range (1), have extensive applications as specialty engineering materials because of their favorable properties such as radiation resistance, hydrolytic and thermo-oxidative stability, low crystallinity, and extremely high electrical resistivity (2). The properties of polyimides have been modified by many techniques. Modification of conventional polyimides with siloxane (3) to produce materials having superior adhesion to microelectronic devices and resistance to water and modification with dispersed metals (4), metal salts, and metal complexes (5-9) to produce materials having unique combinations of properties are a few examples.One of the systems evaluated by our research group is cobalt modified condensation polyimides, chosen because the cobalt ion can be probed by a variety of spectroscopic techniques (10). Polyamic acid solutions were obtained by the condensation reaction between various dianhydrides and diamines in N,N-dimethylacetamide at room temperature. Cobalt(II) chloride was next dissolved in the polyamic acid solution. A film was then cast which, after thermal imidization, resulted in a cobalt modified polyimide film. Highly flexible films were obtained wherein one film surface exhibited a tightly adhering cobalt oxide surface. Because a principal goal of the laboratory work was to produce materials having substantially modified electrical properties, direct current electrical resistivity (bulk and each surface) of the polyimide films has now been measured at both room temperature in air and elevated temperature in vacuum. The field dependence and time dependence of the electrical current as well as the time dependence of charge accumulation have been evaluated. Data pertaining to the lowered resistivity of a variety of polyimides, each of which has been comparably doped with COC12, have been obtained. A discussion of these results constitutes the focus of this report. Experimental Polymer film preparation.--Monomers and cobalt(II...

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“…Also, Varma et al have reported, based on IR data, the absence of interactions between polypyromellitimide and CoCl 2 . Nevertheless, the dopant had an influence on the cyclodehydration reaction, and the tensile strength of the polyimide was reduced in its presence [36]. Through investigation of the same polyimide for the purpose of creating a moisture indicator, Halper and Villahermosa have assumed, by taking into consideration an IR analysis, that CoCl 2 did not inhibit imidization [37].…”

Section: Introductionmentioning

confidence: 99%

Temperature-Controlled Chain Dynamics in Polyimide Doped with CoCl2 Probed Using Dynamic Mechanical Analysis

Ionita,

Cristea,

Sava

et al. 2024

Materials

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Cobalt(II) chloride (CoCl2) being in the vicinity of polyimide chains entails modifications in terms of the molecular dynamics, which are mainly governed by the possible presence of amic acid residual groups, by the transition-metal-type characteristics of cobalt and by the CoCl2 content. Polyimide was synthesized using poly(amic acid) according to the reaction of 2,2′-bis(3,4-dicarboxylphenyl)hexafluoropropane dianhydride (6FDA) with 3,3′-dimethyl-4,4′-diaminodiphenylmethane (MMDA) in N,N-dimethylacetamide. CoCl2 was added before the thermal imidization of the poly(amic acid). An experimental approach was designed to establish the interaction between the polyimide and CoCl2 and whether the interaction depends on the quantity of the salt. Evidence for the existence of residual amic acid groups was obtained using second derivative Fourier Transform Infrared Spectroscopy (FTIR) and with the help of 2D correlation spectroscopy (2D-COS). Moreover, FTIR, along with X-ray photoelectron spectroscopy (XPS), revealed the interaction between the polymer and CoCl2, primarily in the form of Co(II)-N coordinated bonds. Nevertheless, the coordination of cobalt with suitable atoms from the amic acid groups is not precluded. The results of dynamic mechanical analysis (DMA) featured a specific relaxation assigned to the presence of CoCl2 in the polymeric film and demonstrated that its (non)reinforcing effect depends on its content in the polyimide.

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Effect of metal halides on thermal, mechanical, and electrical properties of polypyromellitimide films

Cited by 6 publications

References 7 publications

Insights into the physico-chemical behavior of CoCl2/polyimide hybrid materials

Insights into the physico-chemical behavior of CoCl2/polyimide hybrid materials

DC Electrical, Thermal, and Spectroscopic Properties of Various Condensation Polyimides Containing Surface Cobalt Oxide

Temperature-Controlled Chain Dynamics in Polyimide Doped with CoCl2 Probed Using Dynamic Mechanical Analysis

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