Preparation of finely macroporous SiOC foams with high mechanical properties and with hierarchical porosity via pyrolysis of a siloxane/epoxide composite

Strachota, Adam; Černý, Martin; Chlup, Zdeněk; Rodzeń, Krzysztof; Depa, Katarzyna; Halasová, Martina; Šlouf, Miroslav; Schweigstillová, Jana

doi:10.1016/j.ceramint.2015.03.037

Cited by 19 publications

(7 citation statements)

References 19 publications

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“…Without the use of adhesive resins and heat, the reprocessed composites grew equally well, achieving a higher ratio of axial strength to density. They outperformed other moderate-density materials, such as fly ash geopolymer (curing at 60 °C), macroporous SiOC foams (curing at 120 °C), high-density Si 3 N 4 foams (600 and 1700 °C sintering), foam ceramics (800–1100 °C), and inorganic polymer (curing at 80 °C) . Inorganic porous materials, such as lightweight aggregate and foamed concrete, are often fabricated without any heat treatment; however, they are intrinsically brittle with low strength.…”

Section: Results and Discussionmentioning

confidence: 99%

Elytra-Mimetic Aligned Composites with Air–Water-Responsive Self-Healing and Self-Growing Capability

Bei

Yang

et al. 2020

ACS Nano

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Room-temperature self-healing and self-growing of the exoskeleton with aligned structures in insects has few analogs in synthetic materials. Insect cuticle, such as elytra in beetles, with a typical lightweight lamellar structure, has shown this capability, which is attributed to the accumulation of phenol oxidase with polyphenol and amine-rich compounds in the hard cuticle. In this study, laminar-structure-based intelligence is imitated by incorporating adaptable and growable pyrogallol (PG)-borax dynamiccovalent bonds into a poly(acrylamide)-clay network. The events that lead to crack formation and water accumulation quickly trigger the deprotection of PG. Subsequently, atmospheric O 2 , as a regeneration source, activates PG oxidative self-polymerization. Multiple permanent and dynamic cross-links, with the involvement of the sacrificed borax, and initiation of a series of intelligent responses occur. The fabricated composites with an aligned lamellar structure exhibit outstanding characteristics, such as air/water-triggered superstrong adhesion, self-repairing, self-sealing and resealing, and reprocessing. Moreover, the strategy endows the composites with a self-growing capability, which leads to a 4-to 10-fold increase in its strength in an outdoor climate (up to 51 MPa). This study could lead to advances in the development of air/water-responsive composite materials for applications such as adaptive barriers.

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Section: Results and Discussionmentioning

confidence: 99%

Elytra-Mimetic Aligned Composites with Air–Water-Responsive Self-Healing and Self-Growing Capability

Bei

Yang

et al. 2020

ACS Nano

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“…[7][8][9][10] Various processing techniques such as polymer foam replication, sacrificial templating, melt foaming using a blowing agent, emulsion templating, and 3D printing are employed for the synthesis of SiOC foams from preceramic polymers. [11][12][13][14][15][16][17][18][19] In polymer foam replication, a polysiloxane coated on the web and struts of polyurethane (PU) foam by infiltration of its solution followed by squeezing and drying is subsequently cross-linked and then subjected to pyrolysis to produce SiOC foam of pore structure similar to that of the PU foam. 11,12 In the sacrificial template method, the polysiloxane blended with fugitive particles such as polymethyl methacrylate (PMMA) microbeads and epoxy powder is thermally cross-linked in a mold to produce a composite.…”

Section: Introductionmentioning

confidence: 99%

“…High-temperature pyrolysis of the composite removes the pore template that results in engineered pores in the resulting SiOC glass. 13,14 In melt foaming, the gas bubbles generated by a blowing agent in the molten polysiloxane are stabilized by setting by further polymerization and cross-linking to produce a preceramic polymer foam. 15,16 Subsequent pyrolysis of the preceramic polymer foam produces SiOC glass-ceramic foam.…”

Section: Introductionmentioning

confidence: 99%

“…The SiOC and SiBOC glass–ceramic foams are realized from preceramic polymers such as polysiloxanes and polyborosiloxane, respectively 7–10 . Various processing techniques such as polymer foam replication, sacrificial templating, melt foaming using a blowing agent, emulsion templating, and 3D printing are employed for the synthesis of SiOC foams from preceramic polymers 11–19 . In polymer foam replication, a polysiloxane coated on the web and struts of polyurethane (PU) foam by infiltration of its solution followed by squeezing and drying is subsequently cross‐linked and then subjected to pyrolysis to produce SiOC foam of pore structure similar to that of the PU foam 11,12 .…”

Section: Introductionmentioning

confidence: 99%

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Preparation of cellular SiBOC foams by thermo‐foaming of polymethylvinylborosiloxane–wheat flour dough

Painuly,

Saraswathy,

Prabhakaran

2023

Int J Applied Ceramic Tech

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A novel method for the preparation of SiBOC foams from a polymethylvinylborosiloxane (MVBS) solution in ethanol using wheat flour as a foam stabilizer and pore template has been reported. A dough prepared by mixing the MVBS solution and wheat flour undergoes foaming at 180°C due to the stabilization of bubbles created by ethanol vapor by the adsorption of wheat flour particles on their surface. The ceramization of the foamed body at 1500°C followed by burnout of carbon produced from the wheat flour results in SiBOC foams of hierarchical pore structure. The foam density (.68–.44 g cm−3), average cell size (1.81–.58 mm), compressive strength (3.9–1.7 MPa), and thermal conductivity (.33–.21 W m−1 K−1) decrease with an increase in wheat flour to MVBS weight ratio from .25 to 1. The population of smaller pores (∼5–50 μm) created by wheat flour particles on cell walls and struts increases with an increase in wheat flour to MVBS weight ratio. The presence of β‐SiC and turbostratic graphite nanodomains in amorphous SiBOC is evidenced by X‐ray diffraction and transmission electron microscopy analysis.

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“…In their previous work, some of the authors investigated synthesis routes to PANI, its properties and its potential applications, in another, they optimized the synthesis of polysiloxanes, which were subsequently pyrolyzed to silicon oxycarbide glasses . As part of the latter investigations, the authors also prepared polysiloxane composites with epoxy powder as a sacrificial organic filler, in order to obtain highly porous pyrolytic SiOC foams as final product.…”

Section: Introductionmentioning

confidence: 99%

Preparation of conducting polysiloxane/polyaniline composites

Depa

Strachota

Stejskal

et al. 2015

J of Applied Polymer Sci

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Polysiloxane/polyaniline microcomposites were prepared, in which polyaniline particles act as filler, thus combining the mechanical properties of polysiloxane matrix with conductivity of polyaniline. Two syntheses were evaluated: (1) homogeneous dispersion of a polyaniline colloid in the reaction mixture from which the polysiloxane matrix subsequently formed, and (2) the blending of previously prepared dry polyaniline particles with a liquid oligomeric siloxane resin followed by cure (“heterogeneous method”). Both methods lead to composites with evenly distributed filler. Electrical conductivity was achieved above 40 wt % of polyaniline, which is better obtained by the “heterogeneous” method. During the composite cure, the polyaniline particles, which are softer than the matrix, act as a catalyst and cause more efficient matrix crosslinking, thus leading to somewhat raised moduli. Although particulate fillers usually deteriorate the impact toughness, in the case of the prepared composites, the impact toughness was preserved due to the softer consistence of the filler, which hinders crack propagation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42429.

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Preparation of finely macroporous SiOC foams with high mechanical properties and with hierarchical porosity via pyrolysis of a siloxane/epoxide composite

Cited by 19 publications

References 19 publications

Elytra-Mimetic Aligned Composites with Air–Water-Responsive Self-Healing and Self-Growing Capability

Elytra-Mimetic Aligned Composites with Air–Water-Responsive Self-Healing and Self-Growing Capability

Preparation of cellular SiBOC foams by thermo‐foaming of polymethylvinylborosiloxane–wheat flour dough

Preparation of conducting polysiloxane/polyaniline composites

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