Preparation of Polycarbosilane Using a Catalytic Process and Its Practical Uses

Kim, Young Hee; Shin, Dong Geun; Kim, Hyung Rae; Park, Hong Sik; Riu, Doh‐Hyung

doi:10.4028/www.scientific.net/kem.287.108

Cited by 6 publications

(5 citation statements)

References 4 publications

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“…The additional strong peak at high Mw region (at around 20 min) was caused by further polymerization. Comparison of 2100 cm -1 (Si-H stretching), 1400 cm -1 (Si-CH3 deformation), 1360 cm -1 (C-H2 stretching in Si-CH2-Si), 1242 cm -1 (Si-CH3 deformation) in FT-IR spectra also showed the increase of polymerization in the sample (b) [9][10][11] . Weight changes were started at 240 ºC as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Polycarbosilane (PCS) was synthesized from the Kumada rearrangement of polydimethylsilane (PDMS) under normal pressure in the presence of the zeolite as a catalyst 9,10 . The mixture of PDMS with 0.5-5.0 wt % of catalyst was loaded into the high pressure vessel and subsequently heated to 350 and 400 ºC after purging with argon gas for the conversion of PDMS into carbosilane structure and polymerization of them.…”

Section: Methodsmentioning

confidence: 99%

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Fabrication of Dense Carbon Fiber Reinforced SiC Composites by Controlling the Rheology of Polycarbosilane Solution

Shin¹

2014

Asian J. Chem.

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Dense carbon fiber reinforced silicon carbide composites were prepared by polymer impregnation and pyrolysis with rheological properties of polycarbosilane such as different molecular weight and solution concentrations. During polymer impregnation and pyrolysis process, the densification mechanism of inter-/intra-bundle pores in the carbon fiber preform was also studied by using Hg-porosimeter. Almost of the pores in the carbon preform were filled within 3rd polymer impregnation and pyrolysis cycles when 60 wt % of highly viscous polycarbosilane solution. Inter-bundle pores ranging from 20 to 400 µm were previously filled and the small pores less than 1 µm were newly formed after pyrolysis.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Fabrication of Dense Carbon Fiber Reinforced SiC Composites by Controlling the Rheology of Polycarbosilane Solution

Shin¹

2014

Asian J. Chem.

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“…6, two peaks were observed in both the curves before and after the re nement of PCS precursors. The absorption peaks at the −17 and 0 ppm chemical shifts represent the presence of SiC 3 H and SiC 4 , respectively [9]. The relative intensity of SiC 4 /SiC 3 H increased after re nement, indicating that the amount of linear structures in low molecular weight SiC 3 H decreased.…”

Section: Si Nmr Differences Before and After Re Nement Of Pcs Precmentioning

confidence: 99%

Application of Electrospinning to SiC Fiber Synthesis

Hu¹,

Dai²,

Wu³

et al. 2020

Preprint

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Silicon carbide (SiC) possesses unique properties and is widely applied in household and military uses. This study explored the manufacturing process of SiC fibers. In the experiment, polycarbosilane (PCS) was dissolved in a mixed solvent of C8H10 and dimethylformamide (DMF) to form a solution, and electrospinning was employed to synthesize PCS fibers. PCS fibers underwent a curing process and a 2-h calcination at 1200°C in N2 atmosphere to convert PCS fibers into β-SiC fibers. The solute recruitment, solvent mixing ratio, and voltage in the experiment were defined as process parameters through which to examine the influence each parameter had on electrospinning. The PCS fibers were discovered to exhibit the most even size under the following condition: PCS recruitment of 1.0 g/ml, DMF constituting 30% of the solvent volume, voltage of 25 kV, spraying speed of 1.0 ml/h, and spinning distance of 15 cm. Under electron microscopy, the diameter of each PCS fiber was determined to be 1.0 μm, and the diameter of each β-SiC fiber was 0.8 μm.

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“…[17][18][19][20] Zeolite catalysts was reported to allow the PCS to be synthesized under milder conditions and with a higher yield than those in the Yajima process. 21,22 However, there were no clues on how the additives and processes worked on improvement of the polymer yield.…”

Section: Introductionmentioning

confidence: 99%

Effect of high‐pressure carbon dioxide on thermal conversion process of polydimethylsilane to Si–C backbone polymers

et al. 2019

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Polycarbosilane (PCS) is synthesized from polydimethylsilane (PDMS) by thermal condensation reaction in an inert atmosphere. In the new process described in this article, CO2 at high pressure (2–10 bar) was introduced into the system before the condensation reaction of PDMS. Si–C backbone formation process was accelerated at 340‐360ºC, and brown “PCS” liquid was obtained at 380ºC. Polymer recovery increased from 60% (in a pressure vessel with a N2 atmosphere) to >95% in CO2 atmosphere at 10 bar. The apparent viscosity also increased at high CO2 pressures. Spectrum analysis indicates the existence of the Si–CH2–Si, Si–O–Si bridges, and Si–H bonds in the heat‐treated product. The viscous liquid “PCS” obtained at 380ºC is stable up to 200ºC. However, at temperatures of 200–600ºC, the volatilization of macromolecular species proceeded, and the resulting ceramic yield at 1000ºC was 29 mass%. In the CO2 treatment, product solidified at 420ºC and ceramic yield increased to 56%. The volatilization of macromolecules, however, proceeded in two steps at 200–400ºC and 600–800ºC. When the product was heated beyond 400ºC, it probably contained infinite PCS network with shorter chains.

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Preparation of Polycarbosilane Using a Catalytic Process and Its Practical Uses

Cited by 6 publications

References 4 publications

Fabrication of Dense Carbon Fiber Reinforced SiC Composites by Controlling the Rheology of Polycarbosilane Solution

Fabrication of Dense Carbon Fiber Reinforced SiC Composites by Controlling the Rheology of Polycarbosilane Solution

Application of Electrospinning to SiC Fiber Synthesis

Effect of high‐pressure carbon dioxide on thermal conversion process of polydimethylsilane to Si–C backbone polymers

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