DE102016116732A1 - A method for producing porous ceramics and a porous ceramic product - Google Patents

Abstract

A method for producing porous ceramics comprises: forming (S110) a mixture comprising ceramic precursors and a solvent; a crosslinking method (S115); Heating (S120) the mixture with a particular temperature profile; Cool (S130) the heated mixture.

Description

Field of the invention

The present invention relates to a process for producing porous ceramics and a porous ceramic product, and more particularly to a synthesis without fillers of mesoporous oxide and non-oxide ceramics from preceramic polymers via a solvent-assisted approach.

background

Microporous and mesoporous materials exist as oxide and non-oxide ceramics and are of high interest for a variety of significant technological energy applications, such as gas adsorption, gas separation membranes, or catalyst supports. In addition, micro / mesoporous ceramic materials can be used as dielectric materials for gas sensing applications or as electrode materials for energy storage and transducer devices. Micro / mesoporous oxide ceramics are used successfully in various industrial applications, such as catalysts, gas adsorption and separation. Synthesis of non-oxide microporous mesoporous ceramics, however, remains an ambitious goal and is of particular interest since non-oxide ceramics are known for their superior properties, for example higher impact resistance in reducing atmospheres, higher hydrothermal stability than their oxide counterparts. Proven sol-gel synthesis is typically used to make porous oxide ceramics, but is not suitable for the synthesis of non-oxide ceramics.

A powerful process for the production of non-oxide ceramics is the so-called approach for polymer-derived ceramics (Polymer Derived-Ceramics, PDC). Using ceramic precursors, such as chemical compounds, oligomers and polymers are subjected to cleavage of the chemical bonds in a thermal treatment (pyrolysis) at temperatures above 500 ° C, which serves to produce ceramics. In these methods, during the cleavage of the bonds, a gaseous species such as hydrogen, organic compounds, etc. are formed and may lead to the porous character of the ceramic material.

Another known method is in US 5,059,267 wherein the porous ceramic materials are made by using templates (e.g., tubes or other polysilane filled articles) to make the material. Another procedure will be in US 6,624,228 wherein the porous ceramic material is produced using finely divided particles (called fillers) whose pyrolysis product results in the formation of the porous structure. Yet another conventional method (see WO 2011/007001 A2 ) for producing porous ceramic materials based on a sacrificial agent which is thermally decomposed thereby providing the porous structure. Other conventional methods use supercritical drying (see Pradeep VS, Ayana DG, Graczyk-Zajac M, Soraru GD, Riedel R "High Rate Capability of SiOC Ceramic Aerogels with Tailored Porosity as Anode Materials for Li-ion Batteries". Electrochimica Acta 157: 41-45, 2015 ).

The materials thus produced are still insufficient for various reasons. For example, the porosity is only stable up to a temperature of 900 to 1000 ° C. Moreover, there is still no synthesis of low / high carbon ceramics (for example, SiCN, SiOC, SiC) wherein the micro / meso porosity is controllable and stable at pyrolysis temperatures of 500 to 1400 ° C, and does not involve fillers or supercritical drying ,

Therefore, there is a need for alternative methods of making porous materials that can solve at least some of these problems.

Overview

At least some of the problems described above are solved by a method for producing porous ceramics according to claim 1 and a porous ceramic product according to claim 12. The dependent claims relate in particular to further advantageous implementations of the subject matter of the independent claims.

The present invention relates to a process for producing porous ceramics. The method comprises forming a mixture comprising ceramic precursors and a solvent; a networking process; heating the mixture with a particular temperature profile and cooling the heated mixture. The crosslinking procedure involves at least one or all of the following reactions: a reaction of the polymer with a crosslinking agent, a thermal treatment of the mixture with a particular temperature profile, irradiation of the mixture with, for example, UV, Vis and synchrotron radiation. The crosslinking procedure takes place with or without the catalyst and leads to the formation of a solid in the presence of the above-mentioned solvent.

According to further embodiments, the ceramic precursors comprise oligomers or polymers of from 5 to about 99 parts by weight of a ceramic precursor and from about one to less than 95 parts by weight of the solvent, the solvent having compounds selected from the group comprising ethers and about 0 to less than 1 part by weight of a catalyst, and from about 0 to less than 70 parts by weight of the crosslinking agent.

Optionally, the solvent comprises a suitable solvent from the group comprising ethers such as di-n-butyl ether and tetrahydrofuran as well as aromatic and aliphatic hydrocarbons such as benzene, toluene and hexane, as well as the mixtures thereof.

Optionally, the oligomers or polymers have a number average molecular weight in the range of about 100 to about 100,000 g / mole.

Optionally, the heating step is performed by converting the crosslinked precursors into ceramic material.

Optionally, the temperature in the crosslinking step (first stage) is in a range between 0 ° C and 400 ° C. The temperature during the second stage may be maintained in a range between 400 ° C and 1500 ° C.

Optionally, the temperature may be maintained during the heating step as necessary to achieve the temperature required to carry out the desired reaction (for example, by converting the crosslinked precursors into ceramic material), then cooling may commence.

According to further embodiments, the heating step is carried out in the presence of any atmosphere (including oxidizing, reducing gases and / or vacuum) or an inert atmosphere, in particular with or without hydrogen, CO ₂ , ammonia, nitrogen, helium, argon, oxygen, air, Vacuum or a mixture of them. In particular, the heating step (for example, one or both of the heating steps) may be performed without the presence of hydrogen or other reactive atmosphere (ammonia).

Optionally, the ceramic precursors comprise at least one of the following materials: polysilanes, polycarbosilanes, polyborosilanes, polysilazanes, polycarbosilazanes, polysiloxanes, polycarbosiloxanes, polyborosiloxanes, polysilsesquioxanes, polysilsesquiazanes, polysilylcarbodiimides, polysilsesquicarbodiimides, vinylpolysilanes, polyboranes, polyborazines, polyborazylenes, aminoboranes, polyphenylborazanes, Carboranesiloxanes, polysilastyrenes, polytitanocarbosilanes, polyaluminocarbosilanes, polyalans, alumanes, polyalazanes and like materials, as well as mixtures thereof.

Optionally, the solvent comprises di-n-butyl ether and / or the crosslinking agent comprises divinylbenzene.

The present invention also relates to a porous ceramic product comprising a (ceramic) material, which material is characterized by: a surface area greater than 30 m ² / g, a porous structure having a pore volume greater than about zero , 1 cm ³ g ^-1 , has an open-pore microporous or mesoporous cell structure, the pores having an average width smaller than 50 nm.

Optionally, the ceramic material has an amorphous (micro) / mesoporous structure and a surface area above 30 m ² / g ^-1 , preferably above 100 m ² / g ^-1 or in the range from about 50 to about 1000 m ² / g ^-1 . The porous structure may have a pore volume of greater than 0.01 cm ³ g ^-1 , preferably greater than 0.5 cm ³ g ^{-1 of} the ceramic.

According to further embodiments, the porous structure comprises: a ceramic micropore volume of 0.01 to 0.1 cm ³ / g; and a ceramic mesopore volume of 0.01 to 0.9 cm ³ / g, wherein the volume fraction of micropores in the ceramic product is between about 5% to about 32%.

Optionally, the porous ceramic product is free of fillers.

The present invention also relates to a preceramic intermediate composition comprising a mixture of a ceramic precursor and a solvent, with or without catalyst, with or without crosslinking agent, the pyrolysis product of which is in any atmosphere (including oxidizing, reducing gases and / or vacuum). at temperatures of up to less than about 1500 ° C to the porous ceramics of the invention.

Therefore, embodiments solve at least some of the above-mentioned problems by solvent-assisted synthesis of micro / mesoporous ceramics from preceramic polymers.

• • Elektrodenmaterialien für Energiespeicher- und Umwandlungseinrichtungen,
• • Katalysatorträger zur Verwendung in Brennstoffzellen,
• • poröse Membrane in rauen Umgebungen und bei hohen Temperaturen,
• • mögliches Kandidatenmaterial für CO₂-Sorption aufgrund der angepassten Porosität und der Möglichkeit basische Gruppen (zum Beispiel, -NH-, -NH₂) in die Keramikzusammensetzung durch die geeignete Auswahl von polymeren Präkursoren einzufügen.
• • Materialien zur H₂-Speicherung.
• • Füllstoffe, vor allem Zusatzstoffe für die Materialien, die einige Eigenschaften verbessern (zum Beispiel Verstärken, Erhöhen der thermischen Stabilität usw.) oder den Verbrauch von teureren Bindungsmaterialien senken.

Embodiments of the present invention may be used for various applications. In particular, the materials produced by embodiments of the present invention have advantages as:

• Electrode materials for energy storage and conversion devices,
• Catalyst support for use in fuel cells,
• Porous membranes in harsh environments and at high temperatures,
• Possible candidate material for CO ₂ sorption due to the adapted porosity and the possibility of incorporating basic groups (for example, -NH-, -NH ₂ ) into the ceramic composition by the appropriate selection of polymeric precursors.
• • Materials for H ₂ storage.
• • Fillers, especially additives for the materials that improve some properties (eg strengthening, increasing the thermal stability, etc.) or reduce the consumption of more expensive bonding materials.

Brief description of the drawings

Some aspects of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:

1 Fig. 10 is a flowchart of a method according to an embodiment of the present invention; and

2 a temperature profile used in further embodiments shows.

Detailed description

Various examples will now be described with reference to the accompanying drawings, in which some examples are illustrated.

1 shows a flow chart for a method for producing porous ceramics. The method comprises: forming (S110) a mixture comprising ceramic precursors, a solvent, performing a crosslinking procedure S115; Heat S120 of the mixture with a given temperature profile; and cooling S130 the heated mixture.

Various polymers or oligomers can be used as ceramic precursors. In particular, PHPS (perhydropolysilazane) - a preceramic polysilazane (PSZ) polymer - can be used for silicon nitride ceramics. HTT-1800 - a preceramic polysilazane (PSZ) polymer available from KiON Specialty Polymers - can be used as a precursor to silicon carbonitride ceramics. Moreover, SMP-10 - be used as a precursor for silicon carbide ceramics - a preceramic polycarbosilane (PCS) polymer which can be obtained from staffier ^® system. Finally, SPR-212 - are used as precursor for Siliziumoxycarbidkeramik - a preceramic Polysilane- (PSO) polymer which can be obtained from staffiere ^® system.

However, the present invention should not be limited to these specific examples. According to further embodiments of the present invention, precursor ceramic materials include and Oligomers and polymers such as polysilanes, polycarbosilanes, polyborosilanes, polysilazanes, polycarbosilazanes, polysiloxanes, polycarbosiloxanes, polyborosiloxanes, polysilsesquioxanes, polysilsesquiazanes, polysilylcarbodiimides, polysilsesquicarbodiimides, vinylpolysilanes, polyboranes, polyborazines, polyborazylenes, aminoboranes, polyphenylborazanes, carboranesiloxanes, polysilastyrenes, polytitanocarbosilanes, polyaluminocarbosilanes , Polyalans, alumanes, polyalazanes and similar materials, as well as mixtures thereof, the pyrolysis products of which give ceramic compounds having structural units with bonding compounds selected from Si-C, Si-N, Si-CN, Si-B, Si-BN , Si-BC, Si-CNB, Si-Al-NC, Si-Al-N, Al-N, BN, Al-NB and BNC, as well as oxycarbide and oxynitride bonding compounds such as Si-ON, Si-Al -ON and Ti-OC. The oligomers and polymers may have a number average molecular weight ranging from about 100 to about 100,000 g / mole, more preferably from about 400 to about 20,000 g / mole. The chemistry of these oligomeric and polymeric precursors is further disclosed in US Pat Monograph "Inorganic Polymers", JE Mark, HR Allcock, and R. West, Prentice Hall, 1992 ,

Solvents comprise a suitable solvent from the groups containing organic solvents, preferably an inert inorganic solvent. It is preferred that the solvent not react with the silicon-containing component nor with another component in the reaction mixture. The solvent comprises an ether such as di-n-butyl ether, tetrahydrofuran, aromatic aliphatic hydrocarbons such as benzene, toluene and hexane, xylene, ethylbenzene, diethylbenzene, trimethylbenzene or triethylbenzene; an alicyclic hydrocarbon solvent such as cyclohexane, cyclohexene, decahydronaphthalene, ethylcyclohexane, methylcyclohexane, p-menthine, dipentene (limonene); or other solvents, such as anisole, acetone, 3-pentanone, 2-heptanone, ethyl acetate, n-propyl acetate, n-butyl acetate, ethyl lactate, ethanol, 2-propanol, dimethylacetamide, propylene glycol methyl ether acetate, solvents having the functional groups C - O - C (ethers ), - CO - (ketones), - CO - O (esters), - CO - N - (amides) and solvents containing a variety of these functional groups, as well as mixtures thereof. The crosslinking procedure S115 involves at least one or all of the following reactions: a reaction of the polymer with a crosslinking agent, a thermal treatment of the mixture with a particular temperature profile, exposure of the mixture of the radiation. The radiation is defined as radiation or transmission of energy in the form of waves or particles through space or through a material medium, for example electromagnetic radiation, acoustic radiation, gravitational radiation or particle radiation. The crosslinking procedure S115 takes place with or without the catalyst and results in the formation of a solid in the presence of the above-mentioned solvent.

According to further embodiments, the crosslinking agent may be DVB (divinylbenzene) and the solvent may comprise DNBTETHR (di-n-butyl ether).

2 Figure 11 illustrates the temperature profile used in heating step S120 in thermal crosslinking of the polymer. According to the illustrated temperature profile, the mixture is heated at the start to a first temperature T1 up to a first time t1. The temperature of the mixture is maintained at or about the first temperature T1 for a first time period (first exposure time) t2 to t1 ≥ 0. At a second time t2, the mixture is reheated to the second temperature T2 ( _Tmax ) until a third time t3. After the time t3, the temperature of the mixture remains constant for approximately a second period of time (second reaction time) t4 to t3 ≥ 0. At a fourth time t4, the mixture is cooled until a fifth time t5.

During the first exposure time, the ceramic precursors show crosslinking. The first temperature T1 and the crosslinking agent are selected to start this process in the mixture. During the second exposure time, the polymers or oligomers in the mixture are thermodynamically decomposed into the ceramic material (pyrolysis). The second temperature T2 and the second exposure time are selected so that this process starts and is performed for the entire mixture.

The temperature of the mixture may increase or decrease at a certain rate. The rate may be such that the processes are initiated / terminated uniformly for the entire mix (and without causing thermal stress, for example, by cooling). An exemplary value for the rate of temperature increase / decrease may be in the range of 50 to 500 ° C per hour or at about 100 ° C per hour.

The first temperature T1 and / or the second temperature T2 can be adapted to the actual materials (see the examples below).

Moreover, during the first exposure time and the second exposure time, the first and second temperatures T1, T2 may also vary (eg +/- 10% or + / + 30%) as long as the processes (cross-linking and pyrolysis) are initiated and successfully completed of the mixture to obtain a desired result, ie, the amorphous (micro) / mesoporous ceramic materials having the desired properties.

According to embodiments, the resulting amorphous (micro) / mesoporous ceramic materials have a surface area above 30 m ² g ^-1 , preferably above 100 m ² g ^-1 and an open-pore (micro-) / mesoporous cell structure, the pores having a mean width ( Diameter) of less than 50 nm, and wherein the porous structure has a pore volume of greater than 0.01 cm ³ g ^-1 , preferably greater than 0.5 cm ³ g ^{-1 of} the ceramic.

According to another embodiment, a preceramic intermediate composition comprises a mixture of a ceramic precursor and a solvent, with or without catalyst, with or without crosslinking agent, the pyrolysis product of which in an inert atmosphere or in vacuum at temperatures up to less than about 1500 ° C porous ceramics of the invention leads.

• a) Ausbilden einer innigen Mischung, die ein keramisches Präkursor-Oligomer oder -Polymer und ein Lösungsmittel aufweist,
• b) Allmähliches Erhitzen der Mischung bei Vorhandensein einer beliebigen Atmosphäre (einschließlich einer inerten, oxidierenden, reduzierenden Gasen und/oder Vakuum) und
• c) Abkühlen des porösen Keramikprodukts.

Therefore, the process for producing or producing porous ceramics of the invention according to the embodiments comprises the steps of:

• a) forming an intimate mixture comprising a ceramic precursor oligomer or polymer and a solvent,
• b) gradually heating the mixture in the presence of any atmosphere (including inert, oxidizing, reducing gases and / or vacuum) and
• c) cooling the porous ceramic product.

The ceramic precursor may have from 5 to 99 parts by weight and / or may have a number average molecular weight in the range from about 100 to about 100,000 g / mole. The solvent may be from about 1 ppm to less than 95 parts by weight and may be selected from the group consisting of various ethers.

Optionally, the mixture may comprise a catalyst and / or a crosslinking agent. The catalyst may be from about 0 to less than 1 part by weight and the crosslinking agent may be from about 0 to less than 70 parts by weight.

Optionally, the gradual heating of the mixture is performed in the presence of an inert, reducing or oxidizing atmosphere (such as hydrogen, CO ₂ , ammonia, nitrogen, helium, argon, O ₂ , air, vacuum or a mixture thereof). In addition, a gradual heating of the mixture may continue in successive stages with / without exposure times at intermediate temperatures (see 2 ) be performed. Furthermore, a maximum exposure temperature (T2) may range from about 400 ° C to less than about 1500 ° C and may be present over a period of total heating. The exposure time may be over 2 hours to form a porous ceramic product.

The disclosed method offers a possibility of optimizing the porosity, ie, for example, to obtain only micro / mesopores without macropores, etc. The porous ceramics produced according to embodiments of the invention generally have a surface area in the range of about 30 to about 1000 m ² / g, and ceramic micropore volumes of 0.01 to about 0.1 cm ³ / g, as well as ceramic mesopore volumes greater than 0.01 to about 0.9 cm ³ / g, wherein the volume fraction of the micropores in the ceramic product is between about 5 to about 32%.

Advantages of the embodiments can be summarized as follows:
The ceramics produced according to embodiments are particularly useful in bulk adsorption applications as active layers in membrane separation structures, catalyst supports, electrode material for Li / Na ion batteries, hydrogen storage, for CO ₂ deposition and as electrode material for Li-S and Li-air batteries. The porous ceramics produced according to embodiments are also useful as fillers, especially additives to materials that improve some properties (e.g., reinforce, increase thermal stability, etc.) or decrease the consumption of more expensive binder materials.

In particular, unlike conventional processes, the porosity thus produced is stable up to 900-1000 ° C in harsh environments, especially in corrosive, highly oxidative, etc. environments. Embodiments further enable the synthesis of low / high ceramics Carbon content, for example, with a controlled micro / mesoporosity, which is stable at a pyrolysis temperature of 500 to 1400 ° C without fillers.

Furthermore, embodiments of the present invention produce ceramics (oxide and / or non-oxide ceramics), whereby in the cleavage of bonds no gaseous species such as hydrogen, organic compounds, etc. are formed to obtain the porous character of the ceramic. In particular embodiments do not use templates, fillers, sacrificial agents, supercritical drying, or the presence of auxiliary gases such as H ₂ / NH _3.

The following examples further illustrate aspects of the invention, but the invention is not limited thereto. In addition, the values given in the examples may also be varied in certain ranges (for example +/- 10% or +/- 50%) while achieving the same result.

Tabelle 1. veranschaulicht die Syntheseprozedur und die Porositätseigenschaften der aus Polysilazan-Polymeren hergestellten Keramiken: PHPS und HTT-1800 (wird ein Lösungsmittel verwendet, ist dies DNBTETHR).

Table 1 illustrates the synthesis procedure and porosity properties of ceramics made from polysilazane polymers: PHPS and HTT-1800 (if a solvent is used, this is DNBTETHR).

1. EXAMPLE

A mixture of 3.375 g PHPS was dissolved in 11.625 g DNBTETHR and mixed with 9.260 g DVB. A concentration of ~10 ppm of a Pt catalyst was added to the obtained reaction mixture, and a crosslinking reaction was initiated under reflux at 120 ° C for 6 hours under AR. As a result, the polymeric crosslinked intermediates were transferred to quartz crucibles in Schlenk quartz tubes and pyrolyzed to T _max at 500, 700, 800, 900, and 1100 ° C, respectively, resulting in ceramic samples PSZ-1 to PSZ-5 (see Table 1). In addition, a cross-linking step was performed at 250 ° C on all samples applied. The sample pyrolyzed at T _max of 1400 ° C, PSZ-6, was first pyrolyzed at 1100 ° C and subsequently transferred to an aluminum crucible and then further pyrolyzed in an aluminum tube furnace. To avoid oxygen / moisture contamination, all manufacturing steps were performed in the glove box. The heating and cooling rates were adjusted to 100 ° C per hour. The reaction time at the crosslinking temperature (T1) and _Tmax of pyrolysis was set at 3 hours. The AR flow was kept constant throughout the pyrolysis procedure. The ceramic samples synthesized by the solvent-assisted Ar atmosphere method are mesoporous and have Type IV nitrogen adsorption isotherms with specific surface areas (SSAs) in the range of 100 to 500 m ² / g and a total pore volume in the range of 0 , 46 to 0.90 cm ³ / g, while the samples synthesized in the absence of the solvent are non-porous, for example PSZ-7 (see Table 1).

2. EXAMPLE

A mixture of 3.375 g PHPS was dissolved in 11.625 g DNBTETHR and mixed with 9.260 g DVB. A concentration of ~10 ppm of a Pt catalyst was added to the obtained reaction mixture, and a crosslinking reaction was initiated under reflux at 120 ° C for 6 hours under AR. The polymeric cross-linked intermediates were subsequently transferred to quartz crucibles in Schlenk-quartz tubes and pyrolyzed to T _max at 900 and 1100 ° C under an Ar / H ₂ mixture (5 volume percent H ₂ in Ar, forming gas) resulting in the ceramic samples PSZ- 8 to PSZ-9 (see Table 1) resulted. In addition, a crosslinking step was applied at 250 ° C. To avoid oxygen / moisture contamination, all manufacturing steps were performed in the glove box. The heating and cooling rates were adjusted to 100 ° C per hour. The reaction time at the crosslinking temperature and T _max of pyrolysis were set at 3 hours. The Formiergasfluss was kept constant for the entire pyrolysis procedure. Ceramic samples synthesized under formation gas using the solvent-assisted procedure are mesoporous and have Type IV nitrogen adsorption isotherms with SSAs ≈ 100 m ² / g and total pore volume ≈ 0.40 cm ³ / g.

3. EXAMPLE

A mixture of 3.375 g PHPS was dissolved in 11.625 g DNBTETHR and mixed with 9.260 g DVB. A concentration of -10 ppm of a Pt catalyst was added to the obtained reaction mixture, and a crosslinking reaction was initiated under reflux at 120 ° C for 6 hours under AR. The polymeric crosslinked intermediates were subsequently transferred to quartz crucibles in Schlenk quartz tubes and pyrolyzed to T _max at 900 and 1100 ° C, respectively, resulting in ceramic samples PSZ-10 to PSZ-11 (see Table 1). In addition, a crosslinking step was applied at 130 ° C. To avoid oxygen / moisture contamination, all manufacturing steps were performed in the glove box. The heating and cooling rates were adjusted to 100 ° C per hour. The exposure time at the crosslinking temperature was set at 10 hours, while at _{Tmax of} the pyrolysis was 3 hours. The AR flow was kept constant throughout the pyrolysis procedure. Ceramic samples synthesized by the solvent-assisted Ar atmosphere method are mesoporous and have Type IV nitrogen adsorption isotherms with SSA of 206 m ² / g and a total pore volume of 0.59 cm ³ / g for PSZ-10 and ≈ 100 m ² / g and a total pore volume of 0.40 cm ³ / g for PSZ-11.

4. EXAMPLE

A mixture of 3,000 g of HTT-1800 was dissolved in 3,000 g of DNBTETHR and mixed with 9,260 g of DVB. A concentration of -10 ppm of a Pt catalyst was added to the resulting reaction mixture, and a crosslinking reaction was initiated under reflux at 120 ° C for 6 hours under AR. The polymeric crosslinked intermediates were subsequently transferred to quartz crucibles in Schlenk quartz tubes and pyrolyzed to T _max at 900 and 1100 ° C, respectively, resulting in ceramic samples PSZ-12 to PSZ-13 (see Table 1). In addition, a crosslinking step was applied at 250 ° C. To avoid oxygen / moisture contamination, all manufacturing steps were performed in the glove box. The heating and cooling rates were adjusted to 100 ° C per hour. The reaction time at the crosslinking temperature and T _max of pyrolysis were set at 3 hours. The AR flow was kept constant throughout the pyrolysis procedure. The ceramic samples synthesized by the solvent-assisted Ar atmosphere method are mesoporous and have Type IV nitrogen adsorption isotherms with SSAs in the range of 30 m ² / g and total pore volume 0.1 cm ³ / g, while the samples prepared in Absence of the solvent synthesized are non-porous, for example PSZ-13 and PSZ-14 (see Table 1).

Tabelle 2. veranschaulicht die Syntheseprozedur und die Porositätseigenschaften der aus Polysiloxan-Polymer hergestellten Keramiken: SPR-212a; wird ein Lösungsmittel verwendet, dann ist dies DNBTETHR.

Table 2 illustrates the synthesis procedure and porosity properties of ceramics made from polysiloxane polymer: SPR-212a; if a solvent is used then this is DNBTETHR.

5. EXAMPLE

A mixture of 6.000 g of SPR-212a was dissolved in 10.333 g of DNBTETHR and mixed with 2.670 g of DVB. A concentration of -10 ppm of a Pt catalyst was added to the resulting reaction mixture, and a crosslinking reaction was initiated under reflux at 120 ° C for 6 hours under air. The polymeric cross-linked intermediates were subsequently transferred to quartz crucibles in Schlenk quartz tubes and pyrolyzed to T _max at 900 and 1100 ° C, respectively, resulting in ceramic samples PSO-1 to PSO-2 (see Table 2). In addition, a crosslinking step was applied at 250 ° C. The production steps were carried out in air. The heating and cooling rates were adjusted to 100 ° C per hour. The reaction time at the crosslinking temperature and T _max of pyrolysis were set at 3 hours. The AR flow was kept constant throughout the pyrolysis procedure. The ceramic samples synthesized by the solvent-assisted Ar atmosphere method are mesoporous and have Type IV nitrogen adsorption isotherms with SSAs ranging from 50 to 100 m ² / g and a total pore volume ranging from 0.07 to 0.13 cm ³ / g, while the samples synthesized in the absence of the solvent are non-porous, for example PSO-3 and PSO-4 (see Table 2).

Tabelle 3. veranschaulicht die Syntheseprozedur und die Porositätseigenschaften der aus Polycarbolsilan-Polymeren hergestellten Keramiken: SMP-10; wird ein Lösungsmittel verwendet, dann ist dies DNBTETHR.

Table 3 illustrates the synthesis procedure and porosity properties of ceramics made from polycarbosilane polymers: SMP-10; if a solvent is used then this is DNBTETHR.

6. EXAMPLE

A mixture of 5.000 g of SPR-10 was dissolved in 17.222 g of DNBTETHR and mixed with 14.150 g of DVB. A concentration of -10 ppm of a Pt catalyst was added to the resulting reaction mixture, and a crosslinking reaction was initiated under reflux at 120 ° C for 6 hours under AR. As a result, the polymeric crosslinked intermediates were transferred to quartz crucibles in Schlenk quartz tubes and pyrolyzed to T _max at 900 and 1100 ° C, respectively, resulting in ceramic samples PCS-1 and PCS-2 (see Table 3). In addition, a crosslinking step was applied at 250 ° C. The manufacturing steps were carried out in the glove box in air. The heating and cooling rates were adjusted to 100 ° C per hour. The reaction time at the crosslinking temperature and T _max of pyrolysis were set at 3 hours. The AR flow was kept constant throughout the pyrolysis procedure. The ceramic samples synthesized by the solvent-assisted Ar atmosphere method are mesoporous and have Type IV nitrogen adsorption isotherms with SSAs ≈70 m ² / g and total pore volume ≈ 0.22 cm ³ / g while the samples in the absence non-porous, for example, PCS-3 and PCS-4 (see Table 3).

Unless defined otherwise, all terms (including technical and scientific) used in this document have the same meanings as commonly understood by one of ordinary skill in the art to which the examples belong. It is further understood that terms, for example those defined in commonly used dictionaries, are to be interpreted as having a meaning consistent with their meaning in the context of the prior art and not being interpreted in an idealized or overly formal manner, except it is expressly defined in this document.

It should be further appreciated that the methods disclosed in the specification or in the claims may be implemented by a device having means for performing each of the respective operations of these methods.

Further, it should be understood that the disclosure of several acts or features disclosed in the specification or claims is not to be interpreted as having a particular order. Therefore, the disclosure of multiple acts or functions does not limit them to any particular order unless such acts or functions are not interchangeable for technical reasons. Further, in some examples, a single operation may include or may be subdivided into sub-operations. Such sub-processes may be included in the disclosure and be part of that particular process unless explicitly excluded.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5059267 [0004]
• US 6624228 [0004]
• WO 2011/007001 A2 [0004]

Cited non-patent literature

• Pradeep VS, Ayana DG, Graczyk-Zajac M, Soraru GD, Riedel R "High Rate Capability of SiOC Ceramic Aerogels with Tailored Porosity as Anode Materials for Li-ion Batteries". Electrochimica Acta 157: 41-45, 2015 [0004]
• Monograph "Inorganic Polymers", JE Mark, HR Allcock, and R. West, Prentice Hall, 1992 [0031]

Claims (15)

A method for producing porous ceramics comprising Forming (S110) a mixture comprising ceramic precursors, a solvent; Performing a crosslinking process (S115); Heating (S120) the mixture with a particular temperature profile; and Cool (S130) the heated mixture. The process of claim 1, wherein the ceramic precursors comprise oligomers or polymers of from about 5 to about 99 parts by weight of a ceramic precursor and from about 1 ppm to less than 95 parts by weight of the solvent, the solvent comprising an ether, such as di-n-butyl ether, tetrahydrofuran aromatic, aliphatic hydrocarbons, such as benzene, toluene and hexane, xylene, ethylbenzene, diethylbenzene, trimethylbenzene or triethylbenzene; an alicyclic hydrocarbon solvent such as cyclohexane, cyclohexene, decahydronaphthalene, ethylcyclohexane, methylcyclohexane, p-menthine, dipentene (limonene); or other solvents, such as anisole, acetone, 3-pentanone, 2-heptanone, ethyl acetate, n-propyl acetate, n-butyl acetate, ethyl lactate, ethanol, 2-propanol, dimethylacetamide, propylene glycol methyl ether acetate, solvents having the functional groups C - O - C (ethers ), CO - (ketones), - CO - O (esters), - CO - N - (amides), and solvents containing a variety of these functional groups, as well as mixtures thereof, and from about 0 to less than 1 part weight by catalyst weight. The method of claim 1 of claim 2, wherein the crosslinking method (S115) has at least one or all of the following reactions: a reaction of the polymer with a crosslinking agent; a thermal treatment of the mixture with a specific temperature profile, Irradiating the mixture with radiation, in particular with UV, Vi- and synchrotron radiation. A method according to any one of the preceding claims, wherein the crosslinking process (S115) takes place with or without a catalyst. A method according to any one of the preceding claims, wherein the crosslinking process (S115) is carried out in an inert, oxidizing or reduced atmosphere and / or vacuum or mixture thereof. The method of claim 1 or claim 2, wherein the oligomers or polymers have a number average molecular weight in the range of about 100 to about 100,000 g / mole. A method according to any one of the preceding claims, wherein the heating step (S120) is performed with a temperature profile comprising two stages: a first step of forming crosslinking between the ceramic precursors; and a second stage for converting the crosslinked precursors into ceramic material. Method according to one of claims 3 to 7, wherein the radiation is defined as radiation or transmission of energy in the form of waves or particles through the space or through a material medium, in particular electromagnetic radiation, acoustic radiation, gravitational radiation or particle radiation. Method according to one of the preceding claims, wherein the step of heating (S120) is carried out in the presence of an inert atmosphere, with or without oxidizing or reducing atmosphere and / or vacuum or mixture thereof or in any atmosphere, the oxidizing, reducing gases and / or or a vacuum. Process according to one of the preceding claims, wherein the ceramic precursors comprise one of the following materials: polysilanes, polycarbosilanes, polyborosilanes, polysilazanes, polycarbosilazanes, polysiloxanes, polycarbosiloxanes, polyborosiloxanes, polysilsesquioxanes, polysilsesquiazanes, polysilylcarbodiimides, polysilsesquicarbodiimides, vinylpolysilanes, polyboranes, polyborazines, polyborazylenes , Aminoboranes, polyphenylborazanes, carboranesiloxanes, polysilastyrols, polytitanocarbosilanes, polyaluminocarbosilanes, polyalans, alumanes, polyalazanes, and like materials, as well as mixtures thereof. A process according to any one of the preceding claims, wherein the solvent comprises di-n-butyl ether and / or the crosslinking agent comprises divinylbenzene. Porous ceramic product comprising a material characterized by: a surface area of from 30 to 1000 m ² / g; a porous structure having a pore volume greater than about 0.01 cm ³ g ^-1 ; an open-pore microporous or mesoporous cell structure, the pores having an average width of less than 50 nm. Porous ceramic product according to claim 11, wherein a porous structure comprises: a ceramic microporous volume of between 0.01 to 0.1 cm ³ / g; and a ceramic mesopore volume is between 0.01 to 0.9 cm ³ / g, with a volume fraction of micropores in the ceramic product is between about 5% to about 32% by weight. Porous ceramic product according to claim 11 or claim 12, which is free of fillers. A pre-ceramic intermediate composition comprising a mixture of a ceramic precursor and a solvent, with or without catalyst, with or without crosslinking agent, their pyrolysis product in an inert or reactive atmosphere or in vacuum at temperatures of up to less than about 1500 ° C, the porous ceramics of the invention provides.

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