Catalytic effect of nickel under carbonization of polyimide films

Bin, Yuezhen; Oishi, Kumiko; Koganemaru, Ai; Zhu, Dan; Matsuo, Masaru

doi:10.1016/j.carbon.2005.01.037

Cited by 51 publications

(46 citation statements)

References 17 publications

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“…Of course, the carbonization thermal behavior was confirmed for the specimen whose nickel content against 1 g PAN was 6.8 mmol. Here it should be noted that such drastic changes observed for PAN have never been observed for polyimide 15 and phenolic resins 12 but the reason remains resolved problems. Figure 6 shows an EDS photo obtained by the LEI (lower secondary electron image) method and element spectrum for a circular particles in the specimen, nickel content being 13.6 mmol against 1 g PAN, heated up at 1400 C. As postulated from established papers, the large nickel spherulites are thought to be the aggregation of melt nickel particles in the presence of carbon and energy irradiation was done for a large spherulite to obtain element spectra from the selected points on the particle surface.…”

Section: Resultsmentioning

confidence: 84%

“…Then it is suggested that the degree of graphitization of turbostratic structures from PAN precursor at 1600 C is much less than that from polyimide prepared at the same condition. 15 The average ratio of G-component to total-component estimated for four specimens carbonized at 1600 C was ca. 0.75.…”

Section: Resultsmentioning

confidence: 93%

“…At 1300 C, the cubic structures tend to change spherulitic structures as shown in image (d), and this tendency becomes more considerable by the carbonization at 1400 C as shown in image (e). Judging from the carbonization of polyimide and nickel composites reported by Lamber et al 27 and Bin et al, 15 it may be expected that the carbonization occurs on the surface of nickel supherulites, and most of particles are surrounded by carbon layers with increasing temperature. Image (f) shows broken carbonaceous structure just as fibrous like textures of the specimen carbonized at 1600 C, in which most of circular particles disappeared.…”

Section: Resultsmentioning

confidence: 97%

“…The drastic structural change of PAN is observed by scanning electron microscopy in detail after the composite films were carbonized at temperatures beyond 800 C. The carbonizations at various temperatures provide thread-like, rod-like and spherulitic structures. Of course, such drastic changes have never been confirmed for polyimide 15 and phenolic resins.…”

mentioning

confidence: 99%

“…They pointed out that nickel particles played an important catalytic effect to improve graphitization of polyimide. Further studies were carried out by Kiselev et al14 and Bin et al 15 for the graphitization degree of polyimide film at lower temperature in terms of catalytic role of nickel particles. Bin et al studied catalytic effect of nickel particles and structural change during carbonization by using the three-layered polyimide film, and they succeeded to prepare tough graphite film (sheet), with the thickness of ca.…”

mentioning

confidence: 99%

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Structural Changes of Polyacrylonitrile Film by Catalytic Effects of Nickel Particles under Carbonization Process

Chen

Jiang

Bin

et al. 2007

Polym J

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ABSTRACT:Structural changes of polyacrylonitrile (PAN) film, prepared by gelation/crystallization from solutions, were studied by the effect of nickel particles on the carbonization at various temperatures under argon atmosphere. The carbonized PAN at 800 C showed thread-like structures extended from nickel particles. At 1000 C, the thread-like structures changed to rod-like structures whose one end side was closed by a nickel particle or the aggregation. The disruption of rod-like structures occurred at 1200 C, and the carbonization at 1400 C provided new growth of carbon layers on the surface of spherulitic nickel particles. At 1600 C, fibrous textures were observed as residual traces of disrupted carbon layers by the overflow of melted nickel due to the thermal expansion. The graphitization degrees for G-and T-components in the films carbonized at 1600 C were investigated on the basis of X-ray diffraction intensity distribution from the (002) plane. The analysis was done in terms of the comparison between the experimental and theoretical diffraction intensity curves. The theoretical calculation was carried out by using a concept concerning the para-crystalline theory proposed by Hoseman and Bagchi from the viewpoint of the lattice fluctuation of the c-axis. Carbon materials with high-performance and functionality have been prepared by carbonization of organic compounds, such as polyimide, mesophase pitch, rayon, et al. [1][2][3][4][5] Recent studies suggested that fine particles of transition metals coexisting with these compounds provided considerable catalytic effect on acquiring the graphite structure at lower temperatures.6-10 Oya et al. 11,12 studied the catalytic graphitization of carbonaceous materials by doping different amount of an organic-nickel compound into a phenolic resin. They found that four kinds of carbon were obtained under different carbonization conditions by a high resolution electron microscope and X-ray diffraction. The effects of catalytic graphitization were termed as D-effect, T-effect, A-effect and Tn-effect. On the other hand, Hatori et al.13 studied the carbonization process, related to the catalytic effect of nickel and structural change during carbonization of polyimide films. They pointed out that nickel particles played an important catalytic effect to improve graphitization of polyimide. Further studies were carried out by Kiselev et al.14 and Bin et al. 15 for the graphitization degree of polyimide film at lower temperature in terms of catalytic role of nickel particles. Bin et al. studied catalytic effect of nickel particles and structural change during carbonization by using the three-layered polyimide film, and they succeeded to prepare tough graphite film (sheet), with the thickness of ca. 150 mm.Polyacrylonitrile (PAN) is also a well-known polymer as precursor to prepare carbon materials. [16][17][18] Kruk et al. prepared mesoporous carbons with sharp distribution pore size from PAN by using ordered and disordered mesoporous silica templates, and the detailed characte...

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Section: Resultsmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 97%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Structural Changes of Polyacrylonitrile Film by Catalytic Effects of Nickel Particles under Carbonization Process

Chen

Jiang

Bin

et al. 2007

Polym J

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Thermally Conductive Phase Change Composites Featuring Anisotropic Graphene Aerogels for Real‐Time and Fast‐Charging Solar‐Thermal Energy Conversion

Peng

Liu

et al. 2018

Adv Funct Materials

306

172

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Phase change materials (PCMs) have triggered considerable attention as candidates for solar‐thermal energy conversion. However, their intrinsic low thermal conductivity prevents the rapid spreading of heat into the interior of the PCM, causing low efficiencies in energy storage/release. Herein, anisotropic and lightweight high‐quality graphene aerogels are developed by directionally freezing aqueous suspensions of polyamic acid salt and graphene oxide to form vertically aligned monoliths, followed by freeze‐drying, imidization at 300 °C and graphitization at 2800 °C. After impregnating with paraffin wax, the resultant phase change composite (PCC) exhibits a high transversal thermal conductivity of 2.68 W m−1 K−1 and an even higher longitudinal thermal conductivity of 8.87 W m−1 K−1 with an exceptional latent heat retention of 98.7%. When subjected to solar radiation, solar energy is converted to heat at the exposed surface of the PCC. As a result of the PCC's high thermal conductivity in the thickness direction, heat can spread readily into the interior of the PCC enabling a small temperature gradient of <3.0 K cm−1 and a fast charging feature. These results demonstrate the potential for real‐time and fast‐charging solar‐thermal energy conversion using phase change materials with tailored anisotropy in their thermal properties.

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Graphite carbon foam films prepared from porous polyimide with in situ formed catalytic nickel particles

Luo

Chen

Zhu

et al. 2010

J of Applied Polymer Sci

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This article describes the preparation of porous polyimide composites and carbon foam films with uniform and controllable porous structures, using nickel oleate as a pore-forming agent and as a precursor for catalyst formation for the carbonization process. Pore formation occurs by a phase separation initially producing a dispersion of nickel oleate liquid in the polyamide acid film. Subsequent heat treatment induces decomposition of the nickel oleate accompanied by the evolution of foam forming gas. Small nickel particles, formed by the decomposition of nickel oleate, melt as the process temperature rises above 1200 C and these molten nickel particles then play an important catalytic role in promoting the graphitization of the polyimide composites as part of a dynamic process forming pores proceeding through the thickness of the film. These porous structures are maintained after the removal of the nickel by pyrolysis. The thermal behavior and structure of the porous polyimide films were examined and the porosity and stacking structures of the carbon foam films formed by polyimide pyrolysis were investigated. The results indicate that the pore size of the carbon foams could be controlled over a broad range by varying the nickel oleate content participating in the polymerization reaction.

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Catalytic effect of nickel under carbonization of polyimide films

Cited by 51 publications

References 17 publications

Structural Changes of Polyacrylonitrile Film by Catalytic Effects of Nickel Particles under Carbonization Process

Structural Changes of Polyacrylonitrile Film by Catalytic Effects of Nickel Particles under Carbonization Process

Thermally Conductive Phase Change Composites Featuring Anisotropic Graphene Aerogels for Real‐Time and Fast‐Charging Solar‐Thermal Energy Conversion

Graphite carbon foam films prepared from porous polyimide with in situ formed catalytic nickel particles

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