Hierarchically porous biomorphic polymer derived C–SiOC ceramics

RSC Advances ◽  
2016 ◽  
Vol 6 (98) ◽  
pp. 95897-95902 ◽  
Author(s):  
Abhisek Choudhary ◽  
Swadesh K. Pratihar ◽  
Shantanu K. Behera
Keyword(s):  
Inert Atmosphere ◽  
Silicon Oxycarbide ◽  
Hierarchically Porous ◽  
Preceramic Polymers

Pinewood derived carbon templates were infiltrated with preceramic polymers and pyrolyzed in inert atmosphere to fabricate hierarchically porous biomorphic silicon oxycarbide amorphous ceramics with ∼80% porosity.

Study on Morphology of Electrospun SiOC Fibers

2015 ◽  
Vol 1123 ◽  
pp. 223-226
Author(s):  
Jan Setiawan ◽  
Slamet Pribadi ◽  
Pranjono ◽  
Suhardjo Poertadji ◽  
Sigit
Keyword(s):  
Applied Voltage ◽  
Thermal Process ◽  
Inert Atmosphere ◽  
Solvent Evaporation ◽  
Silicon Oxycarbide ◽  
Oxygen Atmosphere ◽  
Curing Process

Polycarbosilane (PCS) solution was used to form PCS fibers by electrospinning and curing them by thermal process. The cured PCS fibers were then pyrolized under inert atmosphere to obtain silicon oxycarbide (SiOC) fibers. The PCS solution contained 1.2 g/mL PCS with 30% N, N-dimethylformamide (DMF)/70% toluene. The needle inner diameters used for spinning were 0.5 and 0.3 mm and variation for the applied voltage were 10, 12 and 14 kV. The electrospun PCS fibers were cured at 200°C in oxygen atmosphere for 1 hour and then pyrolyzed at 1000°C in inert atmosphere for 1 hour. Nonwoven SiOC fibers diameter ranging between 3 to 8 µm were analyzed by SEM and EDS. The oxygen embodied on the surface of cured PCS fibers arising during the curing process resulted in the SiOC fibers with larger diameters. Rapid solvent evaporation during the pyrolysis caused the SiOC fibers to have ribbon-shapes.

Comparison of Microwave Hybrid and Conventional Heating of Preceramic Polymers to Form Silicon Carbide and Silicon Oxycarbide Ceramics

2004 ◽  
Vol 83 (7) ◽  
pp. 1617-1625 ◽  
Author(s):  
Gene A. Danko ◽  
Richard Silberglitt ◽  
Paolo Colombo ◽  
Eckhard Pippel ◽  
Jörg Woltersdorf
Keyword(s):  
Silicon Carbide ◽  
Silicon Oxycarbide ◽  
Conventional Heating ◽  
Preceramic Polymers

scholarly journals Electrically conductive silicon oxycarbide thin films prepared from preceramic polymers

2021 ◽  
Author(s):  
Emmanuel III Ricohermoso ◽  
Florian Klug ◽  
Helmut Schlaak ◽  
Ralf Riedel ◽  
Emanuel Ionescu
Keyword(s):  
Thin Films ◽  
Silicon Oxycarbide ◽  
Electrically Conductive ◽  
Preceramic Polymers

Aerosol-generated mesoporous silicon oxycarbide particles

2009 ◽  
Vol 81 (8) ◽  
pp. 1449-1457 ◽  
Author(s):  
Alberto Pauletti ◽  
Guillaume Moskowitz ◽  
Thomas Millan ◽  
Cristina Fernández-Martín ◽  
Cédric Boissière ◽  
...  
Keyword(s):  
Inert Atmosphere ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Silicon Oxycarbide ◽  
Magic Angle ◽  
Mesoporous Silicon ◽  
Mesoporous Organosilica ◽  
Transmission Electron ◽  
Angle Spinning ◽  
Adsorption Desorption

Aerosol-generated mesoporous organosilica submicronic spheres have been converted into porous silicon oxycarbide (SiCO) glasses by pyrolysis at 1000 °C in an inert atmosphere. Spherical mesoporous particles obtained from acidic solutions of 1,2-bis(triethoxysilyl)ethane and Pluronic® F127 structuring agent were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption/desorption, and multinuclear solid-state magic-angle spinning (MAS) NMR. These particles were then pyrolyzed at 1000 °C and transformed into a SiCO phase as evidenced by 29Si MAS NMR, while TEM shows preserved mesoporosity, unfortunately difficult to access owing to the presence of an outer layer of dense silica.

scholarly journals Structure and Thermodynamics of Silicon Oxycarbide Polymer-Derived Ceramics with and without Mixed-Bonding

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4075
Author(s):  
Casey Sugie ◽  
Alexandra Navrotsky ◽  
Stefan Lauterbach ◽  
Hans-Joachim Kleebe ◽  
Gabriela Mera
Keyword(s):  
Phenyl Group ◽  
Silicon Oxycarbide ◽  
Enthalpies Of Formation ◽  
Hydroxyl Groups ◽  
Preceramic Polymers ◽  
Calorimetric Measurements ◽  
Polymer Derived Ceramic ◽  
Carbon Nanoscrolls ◽  
Carbon Substitution ◽  
Heat Of Dissolution

Silicon oxycarbides synthesized through a conventional polymeric route show characteristic nanodomains that consist of sp2 hybridized carbon, tetrahedrally coordinated SiO4, and tetrahedrally coordinated silicon with carbon substitution for oxygen, called “mixed bonds.” Here we synthesize two preceramic polymers possessing both phenyl substituents as unique organic groups. In one precursor, the phenyl group is directly bonded to silicon, resulting in a SiOC polymer-derived ceramic (PDC) with mixed bonding. In the other precursor, the phenyl group is bonded to the silicon through Si-O-C bridges, which results in a SiOC PDC without mixed bonding. Radial breathing-like mode bands in the Raman spectra reveal that SiOC PDCs contain carbon nanoscrolls with spiral-like rolled-up geometry and open edges at the ends of their structure. Calorimetric measurements of the heat of dissolution in a molten salt solvent show that the SiOC PDCs with mixed bonding have negative enthalpies of formation with respect to crystalline components (silicon carbide, cristobalite, and graphite) and are more thermodynamically stable than those without. The heats of formation from crystalline SiO2, SiC, and C of SiOC PDCs without mixed bonding are close to zero and depend on the pyrolysis temperature. Solid state MAS NMR confirms the presence or absence of mixed bonding and further shows that, without mixed bonding, terminal hydroxyls are bound to some of the Si-O tetrahedra. This study indicates that mixed bonding, along with additional factors, such as the presence of terminal hydroxyl groups, contributes to the thermodynamic stability of SiOC PDCs.

scholarly journals Ceramic microparticles and capsules via microfluidic processing of a preceramic polymer

2010 ◽  
Vol 7 (suppl_4) ◽  
Author(s):  
Congwang Ye ◽  
Anthony Chen ◽  
Paolo Colombo ◽  
Carlos Martinez
Keyword(s):  
Porous Ceramic ◽  
Double Emulsion ◽  
Inert Atmosphere ◽  
Single Step ◽  
Fluid Composition ◽  
Void Space ◽  
Preceramic Polymer ◽  
Preceramic Polymers ◽  
Oxycarbide Glass ◽  
Emulsion Drops

We have developed a robust technique to fabricate monodispersed solid and porous ceramic particles and capsules from single and double emulsion drops composed of silsesquioxane preceramic polymer. A microcapillary microfluidic device was used to generate the monodispersed drops. In this device, two round capillaries are aligned facing each other inside a square capillary. Three fluids are needed to generate the double emulsions. The inner fluid, which flows through the input capillary, and the middle fluid, which flows through the void space between the square and inner fluid capillaries, form a coaxial co-flow in a direction that is opposite to the flow of the outer fluid. As the three fluids are forced through the exit capillary, the inner and middle fluids break into monodispersed double emulsion drops in a single-step process, at rates of up to 2000 drops s −1 . Once the drops are generated, the silsesquioxane is cross-linked in solution and the cross-linked particles are dried and pyrolysed in an inert atmosphere to form oxycarbide glass particles. Particles with diameters ranging from 30 to 180 µm, shell thicknesses ranging from 10 to 50 µm and shell pore diameters ranging from 1 to 10 µm were easily prepared by changing fluid flow rates, device dimensions and fluid composition. The produced particles and capsules can be used in their polymeric state or pyrolysed to ceramic. This technique can be extended to other preceramic polymers and can be used to generate unique core–shell multimaterial particles.

Fabrication of porous SiC-based ceramic microchannels via pyrolysis of templated preceramic polymers

2006 ◽  
Vol 21 (6) ◽  
pp. 1543-1549 ◽  
Author(s):  
Quoc Dat Nghiem ◽  
Amit Asthana ◽  
In-Kyung Sung ◽  
Dong-Pyo. Kim
Keyword(s):  
Early Stage ◽  
Inert Atmosphere ◽  
Silicon Carbonitride ◽  
Silica Spheres ◽  
Void Space ◽  
Polystyrene Spheres ◽  
Ceramic Phase ◽  
Preceramic Polymers ◽  
Polymer Sphere ◽  
Porous Sic

This article reports conversion chemistry of preceramic polymer to ceramic phase during the fabrication of high-temperature stable silicon carbide and silicon carbonitride monolithic porous microchannels. The micromolding in capillariesmethod is used to fabricate porous channels by the initial infiltration of a solution of 1.5-μm diameter silica spheres or 1-μm diameter polystyrene spheres into polydimethylsiloxane channels followed by filling the void space among the spheres by using viscous commercial polymeric precursors. Subsequently, the polymer-sphere composite channel was cured and pyrolysed at 1200 °C under inert atmosphere, and final wet etching step of silica spheres with 10% hydrofluoric acid solution developed the pore structures by removing the silica spheres, whereas polystyrene sphere decomposes at the early stage of pyrolysis.

ChemInform Abstract: Comparison of Microwave Hybrid and Conventional Heating of Preceramic Polymers to Form Silicon Carbide and Silicon Oxycarbide Ceramics.

ChemInform ◽  
2000 ◽  
Vol 31 (43) ◽  
pp. no-no
Author(s):  
Gene A. Danko ◽  
Richard Silberglitt ◽  
Paolo Colombo ◽  
Eckhard Pippel ◽  
Joerg Woltersdorf
Keyword(s):  
Silicon Carbide ◽  
Silicon Oxycarbide ◽  
Conventional Heating ◽  
Preceramic Polymers
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