Porous polymer‐derived ceramics: Flexible morphological and compositional controls through sol–gel chemistry

Hasegawa, George; Kanamori, Kazuyoshi; Nakanishi, Koji

doi:10.1111/jace.18130

Cited by 11 publications

(10 citation statements)

References 238 publications

(626 reference statements)

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“…The polymer‐to‐ceramic transformation of BPSi aerogel takes place in two main stages accompanied by the release of gaseous H 2 ( m / z = 2), CH 4 ( m / z = 16), C 2 H 2 ( m / z = 26), C 2 H 4 , CO, N 2 ( m / z = 28), and SiH 4 ( m / z = 32) 27,36,40,41 . The distinct weight loss ranging from 300 to 700°C reflects the release of organic gases (C 2 H 4 , CO, N 2 , CH 4 ) and volatile silanes.…”

Section: Resultsmentioning

confidence: 99%

“…39 The polymer-to-ceramic transformation of BPSi aerogel takes place in two main stages accompanied by the release of gaseous H 2 (m/z = 2), CH 4 (m/z = 16), C 2 H 2 (m/z = 26), C 2 H 4 , CO, N 2 (m/z = 28), and SiH 4 (m/z = 32). 27,36,40,41 The distinct weight loss ranging from 300 to 700 • C reflects the release of organic gases (C 2 H 4 , CO, N 2 , CH 4 ) and volatile silanes. At higher temperatures (>700 • C), the second large weight loss along with the conspicuous escape of H 2 and CH 4 was detected, which is attributed to the cleavage of C-H and Si-C bonds and the hydrogen abstraction leaving SiOCN ceramics.…”

Section: Resultsmentioning

confidence: 99%

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Bridged polysilsesquioxane‐derived SiOCN ceramic aerogels for microwave absorption

Shao

Ding

et al. 2022

J Am Ceram Soc.

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The development of high‐performance microwave absorption materials in harsh environment is highly desirable but challenging. Herein, lightweight silicon oxycarbonitride (SiOCN) ceramic aerogels were fabricated by the pyrolysis of bridged polysilsesquioxane aerogels, which was presynthesized by a sol–gel method followed by vacuum drying. The structural order and content of free carbon phase determined by pyrolysis temperature play a critical role in modulating the impedance matching and attenuation capacity. The as‐prepared SiOCN aerogel pyrolyzed at 1000°C achieves a minimal reflection loss of −64.2 dB at 8.96 GHz and a broad bandwidth of 5.4 GHz at a low thickness of 2.15 mm. The hierarchical pore structure, abundant heterogeneous amorphous SiOCN/free carbon interfaces, and conductive free carbon phase benefit the superior absorption performance by forming good impedance matching, multiple scattering, interface polarization, and conduction losses. This work provides an insight for the rational design of polymer‐derived ceramic aerogel‐based microwave absorption materials for potential application under extreme conditions such as high‐temperature and oxidation environments.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Bridged polysilsesquioxane‐derived SiOCN ceramic aerogels for microwave absorption

Shao

Ding

et al. 2022

J Am Ceram Soc.

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“…[ 183 ] They can also be used for sensing and heat insulation because of the low thermal conductivity derived from high porosity. [ 184 ] Furthermore, it has been proposed that the continuous porous structure in the optical length scale can be a scattering medium for a random laser, for example, a multidirectional coherent light source. Furthermore, such porous materials can be used as bio‐scaffolds.…”

Section: Applications Of Polymer‐derived Nonoxidesmentioning

confidence: 99%

Polymer‐Derived High‐Temperature Nonoxide Materials: A Review

Zhou

2023

Adv Eng Mater

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The synthesis of polymer-derived nonoxide materials such as carbides, borides, and nitrides started in the 1970s and slowly progressed into the 1980s, with silicon carbide (SiC) fibers as the prime examples. [1] In the 1990s, the research activities in this area became more intensive, with multiple efforts devoted to understanding the polymer-to-ceramic conversion mechanisms, resulting microstructures, and mechanical properties. In the 2000s, relying on the liquid precursor nature and advancement in chemistry, new techniques (e.g., electrospinning, coating, and precursor infiltration) and new precursors were introduced. Understanding of the crosslinking and thermal conversion process was improved. For example, SiC fibers were improved from amorphous silicon oxycarbide (SiOC) to low-oxygen SiC fibers and then to near-stoichiometric SiC fibers. SiC thin films of 8-190 μm thickness were reported in 2009. [2] These films can stand alone, and high mechanical properties and optoelectronic properties were achieved. Because of these advantages, they were proposed to be used in microelectromechanical systems (MEMS) and optoelectronic devices. In recent decades, additive manufacturing was used to form complex shapes. [3] Also, different one-pot precursor synthesis approaches were reported. [4] The pyrolyzed ceramic systems were frequently used in a powder format and can be further processed with traditional forming processes such as spark plasma sintering, hot pressing, thermal treatment, etc. [5,6] The advantages of using the polymerderived approach for such high-temperature nonoxide material formations involve several aspects. Compositions can be designed based on molecular-level interactions and conversion of polymeric precursors to composites. Through a synergistic selection and combination of polymer molecules of different architectures and additives, a large family of functional, structural, resilient, and versatile materials can be created. Pyrolysis conditions can also be varied to create different property systems. Species intermixing can be achieved at the true atomic level. It enables functional properties for inert systems and harsh environmental stability for far-from-equilibrium conditions. Additional advantages include low processing temperature (such as a few hundred degrees Celsius lower) and versatile shape achievement. The final materials can be fibers, coatings, membranes, powders, bulk parts, porous forms, infiltrating phases, and complex 3D-printed shapes, [3a] among others. Using the polymer-derived approach to form high-temperature ceramics also enables composition homogeneity and purity, thanks to the uniform mixing of different precursors and additives and high-purity chemical precursors. It can also create compositions that may be impossible with conventional routes, [7] such as sintering.The common challenges are as follows. Polymer-derived nonoxide composites are in a metastable state. At high temperatures, the composition and microstructure can continue to evolve and

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“…[1][2][3] The route used to prepare these ceramics proceeds via the pyrolysis of preceramic polymers, which involves crosslinking and the cleavage of functional bonds in the organic polymer to produce an inorganic ceramic structure. Most polymeric precursors are organosilicon compounds, [4][5][6][7] including polysilanes (-R 1 R 2 Si-), polysiloxanes (-R 1 R 2 Si-O-), 8,9 polycarbosilanes (-R 1 R 2 Si-C-), 10 polysilazanes (-R 1 R 2 Si-NQ), 11 poly(boro)silazanes (-R 1 R 2 Si-N(R 3 R 4 B)-), 12 and polysilylcarbodiimides (-R 1 R 2 Si-NQCQN-). 13 Compared with traditional fabrication methods involving ceramic powders, the PDC route shows many important advantages, not only because of its ease of use and direct shaping method but also because of its design/ control of the structure of the ceramic products at the molecular or atomic level through the precursor molecular structure.…”

Section: Introductionmentioning

confidence: 99%

“…13 Compared with traditional fabrication methods involving ceramic powders, the PDC route shows many important advantages, not only because of its ease of use and direct shaping method but also because of its design/ control of the structure of the ceramic products at the molecular or atomic level through the precursor molecular structure. 8 As liquids with suitable viscosity, preceramic polymers can be processed in a variety of ways, using injection moulding, extrusion moulding, casting or tape casting, coating, electrospinning, and three-dimensional (3D) printing methods, amongst others. The structural and microstructural order of the final ceramic materials can be adjusted according to the design of the precursors, including the polymer backbone, elemental composition, and active groups.…”

Section: Introductionmentioning

confidence: 99%

Recent advances in precursor-derived ceramics integrated with two-dimensional materials

Chen

Ding

Shan

et al. 2022

Phys. Chem. Chem. Phys.

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Porous polymer‐derived ceramics: Flexible morphological and compositional controls through sol–gel chemistry

Cited by 11 publications

References 238 publications

Bridged polysilsesquioxane‐derived SiOCN ceramic aerogels for microwave absorption

Bridged polysilsesquioxane‐derived SiOCN ceramic aerogels for microwave absorption

Polymer‐Derived High‐Temperature Nonoxide Materials: A Review

Recent advances in precursor-derived ceramics integrated with two-dimensional materials

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