Preceramic Resins and Polymer-Derived Ceramics

Abstract

The present disclosure relates to organosilicon preceramic resin compositions for forming polymer-derived ceramic materials, particularly high shrinkage polymer-derived ceramic materials. The present disclosure also relates to organosilicon polymer-derived ceramic material articles and methods of forming same.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of Australian Provisional Patent Application No. 2022901435, filed May 27, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to organosilicon-containing preceramic resins that form polymer-derived ceramic materials. The present invention also relates to polymer-derived ceramic materials, methods of forming the polymer-derived ceramic materials, and articles made therefrom. [Background technology]

[0003] Ceramic material articles are widely used in various socio-economically important applications such as sustainable energy generation and storage, pharmaceutical development, environmental and health monitoring, and engineering fields. Specific applications include high speed impellers, heat shields, and wear resistant parts. These uses are due to the fact that ceramic materials are generally characterized by excellent thermal stability and mechanical strength. However, for this reason, ceramic materials are difficult to machine into the specific shapes required for these various applications.

[0004] This is aided by the development of polymer-derived ceramic (PDC) materials, which can be pre-shaped from softer, more malleable preceramic polymer precursors and then the shaped article converted to ceramic.

[0005] A typical process for making PDC materials involves subjecting a preceramic polymer article to pyrolysis conditions at temperatures in excess of 1000° C. This causes a thermally induced conversion of organic materials to inorganic materials (i.e., ceramic) and thermal decomposition of certain components of the preceramic polymer. The decomposition tends to release gases that may include carbon dioxide, carbon monoxide, methane, water, etc. This tends to produce a solid, non-porous PDC material.

[0006] The production of ceramics has been aided by the recent advent of 3D printing, which involves printing and shaping preceramic polymers, silanes, or composites of ceramics and organic binders followed by pyrolysis or sol-gel processing. However, ceramic 3D printing is still in its infancy. Most ceramic 3D printing methods are limited to the use of direct ink writing techniques, which limits their use to the creation of relatively simple articles produced at low resolution. More recently, photopolymerization-based 3D printing techniques such as stereolithography, which are an improvement over direct ink writing, have been investigated for the production of ceramic articles. However, these methods still have significant limitations in resolution and thus can only produce articles of limited size or with features of limited fineness.

[0007] In recent years, aided by the advent of 3D printing technology and the advancement of other technologies such as injection molding, the field of microfabrication has further advanced. However, there are still limitations to how small an article or article feature can be produced using microfabrication technology. For example, microfabrication using 3D printing is primarily limited to a small number of photopolymers, typically composed of short organic chain acrylate and epoxy monomers that cannot be thermally decomposed to produce ceramic materials. These polymeric materials lack a variety of desirable properties, such as chemical and thermal resistance, high mechanical strength, and biocompatibility, precluding their use from many high-value applications. The properties of photopolymers also impose limitations on the resolution that can be achieved, with only limited size articles being produced or articles with features of limited fineness being produced. Although the use of silicon-based ceramics can provide improvements in the properties of articles produced for high-value applications, microfabrication, including 3D printing, of silicon-based ceramics is limited to low-resolution applications, in large part due to the inherent physicochemical properties of the printing materials.

[0008] Although ceramic materials have excellent properties that are desirable to implement in many areas of endeavor that rely on microfabricated articles, limitations in the inherent physicochemical properties of their resins and difficulties in manufacturing methods prevent their adoption in a wider range of applications. It would be beneficial to provide preceramic resins for the production of alternative PDC materials that can be utilized in new and existing microfabricated applications. It would also be beneficial to provide an effective method for producing microfabricated ceramic articles or articles with microstructures. Summary of the Invention

[0009] The present invention is based on the learned knowledge that certain components used in preceramic resins result in PDC materials formed by the pyrolysis process of polymerized green bodies that are characterized by high shrinkage compared to the green bodies, and a manner of taking advantage of that shrinkage.

[0010] Thus, in one aspect, the present invention provides a preceramic resin for forming a polymer-derived ceramic material, the preceramic resin comprising a first functionalized organosilicon monomer having a first ceramic yield of 50% or less; a) a second functionalized organosilicon monomer having a second ceramic yield, the second ceramic yield being at least 5% greater than the first ceramic yield; and b) ceramic particles; and one or more of the following:

[0011] In certain embodiments, the preceramic resin comprises one of the following combinations selected from the following (a)-(c): a) a first functionalized organosilicon monomer having a first ceramic yield of 50% or less, and a second functionalized organosilicon monomer having a second ceramic yield of at least 5% greater than the first ceramic yield; b) a first functionalized organosilicon monomer having a first ceramic yield of 50% or less, and ceramic particles; and c) a first functionalized organosilicon monomer having a first ceramic yield of 50% or less, and a second functionalized organosilicon monomer having a second ceramic yield at least 5% greater than the first ceramic yield, and ceramic particles.

[0012] In another aspect, the present invention provides polymer-derived ceramic materials formed from the preceramic resins described herein.

[0013] In another aspect, the invention provides a polymer-derived ceramic material formed by pyrolysis of a green body, the polymer-derived ceramic material being characterized by a linear shrinkage of 30% or greater and a volumetric shrinkage of about 66% or greater.

[0014] In another aspect, the invention provides a polymer-derived silica ceramic material formed by pyrolysis of a green body, the polymer-derived silica ceramic material being characterized by a linear shrinkage of 20% or greater and a volumetric shrinkage of about 49% or greater.

[0015] In another aspect, the present invention provides a polymer-derived glass-ceramic material.

[0016] In another aspect, the invention provides a manufactured PDC article comprising a flow channel.

[0017] In another aspect, the invention provides a manufactured macrostructured PDC article comprising a microstructure.

[0018] In another aspect, the present invention provides a method of forming a polymer-derived ceramic material, comprising the steps of: a) subjecting a preceramic resin described herein to polymerization conditions to form a preceramic polymer; b) subjecting the preceramic polymer to pyrolysis conditions to form a polymer-derived ceramic material; The present invention provides a method comprising:

[0019] In another aspect, the present invention provides a method of forming a polymer-derived ceramic material, comprising the steps of: a) subjecting a preceramic resin that forms a polymer-derived ceramic material to polymerization conditions to form a preceramic polymer; b) subjecting the preceramic polymer to pyrolysis conditions to form a polymer-derived ceramic material; Including, Provided herein is a method wherein the formation of a polymer-derived ceramic material from a preceramic polymer proceeds through a porous stage and the pyrolysis conditions include a temperature ramp rate of 10° C. / min or less for a period within the porous stage.

[0020] In another aspect, the present invention provides a method of forming a polymer-derived ceramic material, comprising the steps of: a) subjecting a preceramic resin that forms a polymer-derived ceramic material to polymerization conditions to form a preceramic polymer; b) subjecting the preceramic polymer to pyrolysis conditions to form a polymer-derived ceramic material; Including, A method is provided herein, wherein the pyrolysis conditions include a temperature ramp rate of 10° C. / min or less for a period within a temperature range of 200° C. to 900° C.

[0021] In another aspect, the present invention provides a polymer-derived ceramic material formed from the method described herein. [Brief description of the drawings]

[0022] [Figure 1]3D printed and shrink-fabricated glass-ceramic bifurcated microfluidic distributor formed using low ceramic yield PDC monomer and high ceramic yield PDC monomer in a 1:1 weight ratio: (a) top view of the printed distributor, (b) side view of the printed distributor, (c) side view of the pyrolyzed distributor, and (d) SEM image of the closed flow channel. [Diagram 2] FIG. 14 shows material characterization of printed silicon oxycarbide glass-ceramics using (a) energy dispersive X-ray spectroscopy, (b) transmission electron microscopy, (c) Raman spectroscopy, and (d) X-ray diffraction spectroscopy. [Diagram 3] 3D printed and shrink-fabricated glass-ceramic microneedle patches formed using low ceramic yield PDC monomer and high ceramic yield PDC monomer in a 1:1 weight ratio: (a) top view of printed microneedle, (b) side view of printed microneedle, (c) side view of pyrolyzed microneedle, and (d) SEM image of microneedle. [Figure 4] 3D printed and shrunk processed ceramic disks formed using low ceramic yield and high ceramic yield PDC monomers in a 1:2 weight ratio: (a) green body, and (b) pyrolyzed body. [Diagram 5] 3D printed and shrink-machined ceramic disks formed using ceramic particles with a single low ceramic yield PDC monomer: (a) green body, and (b) pyrolyzed body. [Figure 6] FIG. 3D printed and shrink-machined ceramic blocks formed using ceramic particles together with low and high ceramic yield PDC monomers: (a) green body, and (b) pyrolyzed body. [Figure 7]FIG. 3D printed and shrink-machined ceramic blocks formed using ceramic particles together with low and high ceramic yield PDC monomers: (a) green body, and (b) pyrolyzed body. [Figure 8] 3D printed and shrink-processed ceramic disks formed using ceramic particles together with low and high ceramic yield PDC monomers: (a) green body, and (b) pyrolyzed body. [Figure 9] Figure 1 shows an attempt to form 3D printed, shrunk-machined ceramic disks using a single, low ceramic yield PDC monomer: (a) green body, and (b) pyrolyzed body. [Figure 10] 3D printed and shrunk processed ceramic pyramidal bodies with microstructured scaffolds formed using low ceramic yield PDC monomer and high ceramic yield PDC monomer in a 1:1 weight ratio: (a) side view of printed pyramidal body, and (b) side view of pyrolyzed pyramidal body. [Figure 11] FIG. 3D printed and shrink-engineered porous ceramic microfluidic chips formed using ceramic particles along with low and high ceramic yield PDC monomers. [Figure 12] FIG. 1 is a schematic diagram of the real-time Fourier transform infrared (RT-FTIR) spectroscopy setup used to study photopolymerization kinetics. [Figure 13] FIG. 1 includes graphs of RT-FTIR shelf life studies based on the resins of Example 1 and Example 2, observed from the changes in their C═C stretching when the samples are stored at 4° C. for 27 days. [Figure 14] FIG. 1 is a plot of observed resin cure depth and percentage polymerization versus exposure time in an oxygen resistance study for the resins of Examples 1 and 2 (based on thiol-acrylate chemistry) and the resin of Example 8 (based on acrylate chemistry). [Figure 15] FIG. 1 includes graphs of functional group ratio studies of the resin used in Example 1 using various molar ratios of acrylate and thiol functional groups on reaction kinetics: (a) total polymerization percentage, (b) gel point, and (c) resin ceramic yield. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art of the present invention. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, preferred methods and materials are described. For purposes of the present invention, a number of terms are defined throughout.

[0024] The manufactured PDC materials are generally formed by a process that includes polymerizing a preceramic resin to form a preceramic polymer and pyrolyzing the preceramic polymer. Generally speaking, during pyrolysis, the preceramic resin is converted from an organic material to an inorganic material. The inorganic material may exist in one or more material phases depending on the temperature to which the material is exposed. For example, during the increase in pyrolysis temperature, the organic material will generally initially exist in an amorphous phase and then transition to a crystalline phase as the temperature increases. The present invention relates to pyrolyzing a preceramic resin containing certain components as detailed herein to obtain a PDC material characterized by high shrinkage and existing in any selected phase.

[0025] Without wishing to be bound by theory, it is believed that certain components of the preceramic resin detailed herein result in the presence of pores during pyrolysis, which allow liquids and gases to escape more easily and in greater quantities, resulting in controlled shrinkage. In some embodiments, depending on the conditions applied, the pores may subsequently collapse, resulting in a higher degree of overall shrinkage. It is believed that the formation and any collapse of pores reduces the likelihood of loss of integrity of the resulting PDC material. That is, in other words, generally speaking, the components of the preceramic resin are such that they may result in pores contained within the material during pyrolysis.

[0026] It is also believed that certain components of the preceramic resin can result in pyrolyzed glass-ceramic PDC materials that contain both the PDC material as amorphous silica and in a crystalline phase. Glass-ceramic materials can be characterized by particularly favorable mechanical and chemical properties. Thus, the components of the preceramic resin can also be capable of forming glass-ceramic PDC materials.

[0027] As used herein, "polymer-derived ceramic" (PDC) materials are manufactured ceramic materials formed by the pyrolysis of preceramic polymers and are distinct from naturally occurring ceramic materials.

[0028] Amorphous silica-based inorganic materials are often referred to as "glasses." Thus, "glass-ceramics" refers to materials that include PDC glasses and crystalline PDC materials. In alternative terms, PDC glass-ceramics may be described as PDC materials that include glass materials interspersed with, or otherwise coexisting with, phase-separated crystalline PDC materials.

[0029] The term "preceramic" confer the potential for formation into a ceramic material using the step of pyrolysis alone or in combination with other process steps. Thus, a "preceramic polymer" is a polymeric material that can be formed by subjecting a monomer to polymerization conditions and pyrolyzed into a ceramic material. Furthermore, a "preceramic resin" is a material that includes at least one monomer that can be polymerized to form a preceramic polymer. Such monomers are sometimes referred to as "preceramic monomers."

[0030] The present invention relates to resins comprising monomeric materials suitable for being formed into polymeric materials and then formed into manufactured PDC materials. That is, the resins of the present invention are particularly useful in forming PDC material articles manufactured from shaped preceramic polymeric articles (also known as "green bodies"). The resins may be suitable for forming ceramic articles with microstructures.

[0031] As used herein, "microstructure" generally refers to a structure that can be characterized by a dimension less than 1 mm, particularly between about 1 micron and less than 1 mm, including structures that are part of a larger article. "Structure" refers to a physical feature or dimension of an article. As an example, a cylindrical protrusion from a flat surface having a height of 50 microns and a diameter of 50 microns can be described as a microstructure, i.e., a structure having dimensions within the microstructure range. A structure can also be a feature characterized by the absence of material (i.e., a "negative feature"), such as a cylindrical hole in a flat surface having a depth of 50 microns and a diameter of 50 microns. As a further example, a controlled series of steps with a rise of 50 microns and a tread of 50 microns that are incorporated into a larger sized article or "macrostructure" (e.g., a pyramidal body with a square base and a height of 2 cm) can be described as having a microstructure. What distinguishes a microstructure from a microscopic irregularity in a surface is the controlled formation or controlled arrangement of microscale features within the microstructure, as opposed to random or irregular microscopic features.

[0032] In a preferred embodiment, the PDC article comprises a microstructure as part of a larger article. That is, the PDC article itself may be a macrostructure comprising a microstructure. As used herein, "macrostructure" generally refers to a structure that can be characterized by a dimension of 1 mm or greater. For example, a PDC article can be characterized by one or more of the three major dimensions (i.e., typically represented by the X-axis, Y-axis, and Z-axis) of a three-dimensional space of 1 mm to 100 mm, preferably 1 mm to 50 mm, and more preferably 1 mm to 10 mm. An example of an article comprising a microstructure is an article comprising a microchannel as described herein. Of course, the dimensions of the green body will be a multiple that takes into account the degree of shrinkage. For example, the dimensions of a green body used to form a 10 mm cubic PDC article characterized by a linear shrinkage of 50% will be double, i.e., a 20 mm cubic green body.

[0033] It is surprising that the resin of the present invention can be applied to form macrostructures.Previously, the formation of macrostructures has been very difficult because larger articles tend to lose the integrity of the PDC material.However, in the present invention, it has been found that the combination of resin components described herein allows the formation of macrostructures without or with reduced risk of destruction of the PDC material.

[0034] The green body can be formed by any molding process known in the art. Particularly applicable molding processes to the present invention are injection molding methods such as liquid silicone rubber injection molding, and 3D printing methods such as stereolithography, digital light projection, two-photon lithography, continuous liquid interface method, direct ink writing, and inkjet printing. These methods are generally known in the art.

[0035] PDC materials are particularly suitable for forming into microfabricated and microstructured ceramic articles because the resins described herein, when formed into green bodies and pyrolyzed, tend to undergo high linear and volumetric shrinkage, thereby forming PDC materials that are much smaller than the original green bodies pyrolyzed. This is because during pyrolysis, the materials will generally undergo a certain degree of linear and volumetric shrinkage as the preceramic polymer undergoes a thermally induced organic to inorganic conversion, expelling liquids and gases. The inventors have found that resins that have porosity prior to pyrolysis or that introduce porosity into the material during pyrolysis can experience a greater degree of linear and volumetric shrinkage than resins that have no or lesser degrees of porosity. Without wishing to be limited by theory, it is believed that the porosity present at least for a period of time during pyrolysis allows for greater amounts of liquid and gas to escape, both by providing escape routes and by subjecting the increased surface area of ​​the material to pyrolysis conditions to cause pyrolysis. The fundamental insight of pore formation in the formation of PDC materials is described in the specification for Australian Patent Application No. 2022900557, which is incorporated herein by reference in its entirety. The formation of pores also helps to reduce the likelihood of or avoid deformation, cracking, and / or otherwise losing the integrity of the PDC material by allowing liquids and gases to escape, which helps to avoid pressure build-up within the material that could cause such losses. The pores may then be collapsed as pyrolysis continues, which may result in higher degrees of linear and volumetric shrinkage of the resulting PDC material.

[0036] "Porous" or "porous" means that pores are included. A "pore" is a space that is free of solid matter that constitutes a substance. Pores can be considered hierarchically in terms of pore size, such as micropores, mesopores, and macropores. "Micropores" refer to pores with a diameter of less than 2 nm. "Mesopores" refer to pores with a diameter of 2 nm to 50 nm. "Macropores" refer to pores with a diameter of 50 nm to 100 micrometers. Macropores can be further considered as sub-macropores, inter-macropores, and super-macropores, which refer to macropores with diameters of 50 nm to 1 micrometer, 1 micrometer to 10 micrometers, and 10 micrometers to 100 micrometers, respectively. "Diameter" does not limit the shape of the pore, but refers to the maximum axial dimension. Similarly, "microporous" refers to including micropores, while "mesoporous" refers to including mesopores, and "macroporous" refers to including macropores. Pore ​​size may be experimentally determinable using methods known in the art. Known methods include gas adsorption (including the use of a BET surface analyzer), scanning electron microscopy, and liquid immersion (including mercury porosimetry). Similarly, porosity is directly related to specific surface area, with greater porosity resulting in greater specific surface area. Specific surface area may be experimentally determinable using methods known in the art, including gas adsorption (including the use of a BET surface analyzer) and liquid immersion (including mercury porosimetry).

[0037] Traditionally, shrinkage has been viewed as a negative attribute in producing PDC materials from preceramic resins, and efforts have been made to minimize or prevent shrinkage. However, the present inventors have realized that shrinkage can be exploited, particularly when applied to microfabrication techniques, and have developed preceramic resins as described herein in which the presence of pores during pyrolysis results in increased shrinkage (without wishing to be limited by theory).

[0038] Methods for determining linear and volumetric shrinkage are known in the art and are based on measurements of the physical dimensions, e.g., length, of the PDC material article compared to the preceramic polymer article or green body. Linear shrinkage can be classified as high, medium, and low. "High linear shrinkage" refers to a linear shrinkage of 20% or more. "Moderate linear shrinkage" refers to a linear shrinkage between 15% and 20%. "Low linear shrinkage" refers to a linear shrinkage of 15% or less. Volumetric shrinkage can be similarly classified, where "high volumetric shrinkage" refers to a volumetric shrinkage of 48.8% (i.e., about 49%) or more, "moderate volumetric shrinkage" refers to a volumetric shrinkage between 38.6% (i.e., about 39%) and 48.8% (i.e., about 49%), and "low volumetric shrinkage" refers to a volumetric shrinkage of 38.6% (i.e., about 39%) or less. The present invention provides PDC materials with high linear shrinkage and high volumetric shrinkage, and in some embodiments, a linear shrinkage of about or greater than 30%, or even about or greater than 45%, or about or greater than 50%, and a volumetric shrinkage of about or greater than 65.7% (i.e., about 66%), or even about or greater than 83.4% (i.e., about 84%), or about or greater than 87.5% (i.e., about 88%), which may also be described as "very high linear shrinkage" and "very high volumetric shrinkage", respectively.

[0039] This allows the production of PDC articles with smaller microstructures than previously obtainable. It also allows the production of sub-resolution PDC articles with microstructures smaller than the minimum practical resolution obtainable by the method used to form the green body. For example, many benchtop 3D printers have a minimum practical resolution of about 500 microns (determined by the properties of the resin printed, e.g., viscosity, etc.). By utilizing the high shrinkability of the preceramic resin formulated according to the present invention, microstructures with much lower resolution can be formed in response to the high shrinkage. This includes sub-resolution dimensions. That is, by utilizing the high shrinkability of the resin of the present invention in forming a PDC material, it is possible to form, for example, a preceramic polymer shaped article itself or a preceramic polymer shaped article with microstructures printed using a benchtop 3D printer with a minimum practical resolution of about 500 microns, and, depending on the shrinkage of the PDC material during pyrolysis, PDC articles or microstructures with much smaller dimensions, e.g., about 250 microns, can be formed.

[0040] As used herein, the term "linear shrinkage" is used interchangeably with the term isometric shrinkage, as is commonly understood in the art, i.e., may be defined by shrinkage in the three major dimensions of three-dimensional space for a green body (i.e., typically represented by the X-, Y-, and Z-axes), or may generally be understood to be shrinkage in all directions. "Volumetric shrinkage" refers to shrinkage in volume. Linear shrinkage and volumetric shrinkage are directly related. For example, a PDC article characterized by a linear shrinkage of 30% for a green body can also be characterized by a volumetric shrinkage of about 66%. This relationship is illustrated by the relationship between a starting dimension of 10 cm in the three major dimensions and a starting volume of 1000 cm. 3 This is shown using the following chart for a cubic green body.

[0041] [Table 1]

[0042] The resulting articles can be used in many engineering and scientific fields where ceramic materials are used, and because the PDC materials can be highly shrunk compared to their green bodies, this opens up new applications for the PDC materials in applications using microstructures, including microfluidic and medical devices. This is particularly true for applications using channels, since the present invention allows for the formation of PDC articles with channels. The PDC article itself may be a channel, or the PDC article may be formed with one or more channel features. The channels can be tailored to any size depending on the purpose, for example, having diameters from micrometers to millimeters, or even centimeters or larger, but find particular utility in small diameter applications.

[0043] That is, microfluidic devices and medical devices are particularly suitable examples since the present invention allows the fabrication of PDC articles with minute-sized channels, such as microfluidic distributors and microneedle patches, or in other words, microchannels. This includes channels having diameters of 500 microns or less, preferably 400 microns or less, preferably 300 microns or less, preferably about 250 microns or 150 microns. Examples of channel diameters may be expressed as ranges. For example, suitable channel diameters are about 50 microns to about 500 microns, preferably about 100 microns to about 400 microns, preferably about 100 microns to about 300 microns, preferably about 100 microns to about 250 microns, or about 150 microns. A "channel" is a structure capable of transporting liquid in a directionally, and includes both open and closed channels (e.g., capillaries). In a preferred embodiment, the channel is a microchannel, a microstructure that forms part of a macrostructured PDC article.

[0044] The preceramic resins described herein can also provide dense PDC structures, including dense glass-ceramic structures. In some embodiments, the density of the glass-ceramic PDC structures is greater than about 1500 kg / m 3More than or about 1600 kg / m 3 More than or about 1700 kg / m 3 More than or about 1800 kg / m 3 More than or about 1900 kg / m 3 More than or about 2000 kg / m 3 The density of the formed glass-ceramic structure may be expressed as a range. In some embodiments, the density is greater than about 1500 kg / m 3 to 3000kg / m 3 Between 1600 kg / m 3 to 3000kg / m 3 Between 1700 kg / m 3 from 2800kg / m 3 Between 1800 kg / m 3 from 2800kg / m 3 Between 1900 kg / m 3 from 2700kg / m 3 Between 2000 kg / m 3 from 2600kg / m 3 As discussed further below, the present disclosure advantageously provides high density glass-ceramic structures.

[0045] Preceramic Monomer A preceramic monomer can be characterized by a ceramic yield. "Ceramic yield" refers to the mass of PDC material obtainable by pyrolysis expressed as a percentage of the mass of the preceramic monomer (i.e., the mass of converted PDC material expressed as a percentage of the preceramic material). For example, if 10 g of PDC material is formed by pyrolysis of 11 g of preceramic monomer, then the preceramic monomer has a ceramic yield of (10 / 11) x 100 = 91%.

[0046] The ceramic yield of a preceramic monomer is a chemical property that is generally influenced by the chemical structure of the monomer. Methods for determining the ceramic yield of a preceramic monomer are known in the art and generally involve subjecting the preceramic monomer to pyrolysis conditions in a thermogravimetric analyzer (TGA). Generally, in the TGA, the weight of the preceramic monomer is measured as it undergoes conversion to a PDC material during pyrolysis. The maximum pyrolysis temperature is usually at least about 600° C., and often about 850° C. to ensure complete conversion to a PDC material. Complete conversion is generally indicated by an experimentally determined zero weight change between the time points at the maximum pyrolysis temperature. The TGA can determine the starting weight and the final weight after pyrolysis, from which the ceramic yield can be calculated. A detailed methodology is provided in the Examples. In a preferred embodiment, the ceramic yield is determined using this method, which is referred to herein as "TGA". 850 Ceramic Yield" or "TGA 850 This is sometimes referred to as the "850" method, where "850" represents the maximum temperature reached during the analysis.

[0047] Ceramic yields may be classified as high, medium, and low. "High ceramic yield" refers to a ceramic yield of 60% or greater. "Medium ceramic yield" refers to a ceramic yield between 30% and 60%. "Low ceramic yield" refers to a ceramic yield of 30% or less. The present invention also relates to ceramic yields of 20% or less (TGA), which may be referred to as "very low ceramic yields." 850 Organosilicon monomers having a ceramic yield are used.

[0048] The present invention uses a preceramic resin that contains a functionalized organosilicon monomer.

[0049] An "organosilicon" is a chemical compound having a chemical structure that includes a silicon atom covalently bonded to a carbon atom. Preceramic organosilicon monomers are generally based on a long chain backbone structure of repeating motifs that include silicon atoms, and in that sense, they are generally polymeric materials themselves. Examples applicable to the present invention include polysiloxanes, polycarbosiloxanes, polysilsesquioxanes, polycarbosilanes, polysilylcarbodiimides, polysilsesquicarbodiimides, polysilazanes, polysilsesquiazanes, polyborosilanes, polyborosiloxanes, and polyborosilazanes. Since silicon and carbon atoms are generally tetravalent, organosilicon containing backbone structures of polymeric monomers are generally substituted with carbon-containing organic chemical groups. "Substituted" with respect to organosilicon means that any one or more hydrogen atoms bonded to the atom under consideration may be replaced, as long as the valence of the atom is not exceeded and a stable compound is obtained. Non-limiting examples of suitable substituents include the R group substituents defined below.

[0050] First organosilicon monomer In a preferred embodiment, the first organosilicon monomer has the chemical structure of Formula 1, Formula 2, Formula 3, Formula 4, and Formula 5: [ka] (In the formula, n represents a main chain structure of a repeating motif containing a silicon atom, and is independently an integer of 2 to 15; R1, R2, R3, and R4 are independently selected from H, C1 to C 18 Substituted or unsubstituted alkyl, C1-C 18substituted or unsubstituted alkyl ether, phenyl, and halide, with the proviso that the pair of R1 and R2 and the pair of R3 and R4 are not both H, alkyl ether, or halide for all integers of n. Preferably, the pair of R1 and R2 and the pair of R3 and R4 are not both H, alkyl ether, or halide for any integer of n. Preferably, each of the pair of R1 and R2 and the pair of R3 and R4 is the same for all integers of n.

[0051] In formula 2, formula 3, and formula 5, the hydrogen atoms of the CH2 and NH groups may be substituted with one or more groups as defined for R1. As mentioned above, organosilicon is a chemical compound having a chemical structure that includes a silicon atom covalently bonded to a carbon atom, which includes organosilicon monomers of formula 1-5, where n is an integer equal to 1. That is, in formula 1-5, n may independently be an integer of 1 or greater, or an integer of 1-15.

[0052] The first organosilicon monomer may be a polyoctahedral silsesquioxane, preferably selected from one or more of polysilsesquioxanes, polysilsesquicarbodiimides, and polysilsesquiazanes substituted with one or more groups defined for R1. In other words, the polyoctahedral silsesquioxane is a C1-C 18 substituted or unsubstituted alkyl, C1-C 18 may be substituted with one or more groups selected from the group consisting of substituted or unsubstituted alkyl ether, phenyl, and halide.

[0053] The first organosilicon monomer has the chemical structure of Formula 6, Formula 7, and Formula 8 below: [ka] (In the formula, n represents a main chain structure of a repeating motif containing a silicon atom, and is independently an integer of 2 to 15; R1, R2, R3, and R4 are as defined above, and R5 and R6 are independently H, OH, C1 to C 18 substituted or unsubstituted alkyl, C1-C 18 and phenyl). Preferably, R5 and R6 are the same for all n integers, as are R1, R2, R3, and R4.

[0054] In a more preferred embodiment, the first organosilicon monomer is selected from one or more of polysiloxanes, polycarbosiloxanes, and polycarbosilanes, where n is independently an integer from 2 to 5, and R1, R2, R3, and R4 are the same for all integers of n and are independently selected from the group consisting of H, methyl, and isobutyl, with the proviso that the pair of R1 and R2 and the pair of R3 and R4 are not both H and are polysilsesquioxanes substituted with groups defined for R1, preferably isobutyl.

[0055] In a most preferred embodiment, the first organosilicon monomer is a polysiloxane, where n is independently an integer from 2 to 5, and R1, R2, R3, and R4 are the same for all integers of n and are independently selected from the group consisting of H, methyl, and isobutyl, with the proviso that the pair of R1 and R2 and the pair of R3 and R4 are not both H.

[0056] As discussed above, organosilicon is a chemical compound having a chemical structure that includes a silicon atom covalently bonded to a carbon atom, including organosilicon monomers of Formulae 6-8, where n is an integer equal to 1. That is, in Formulae 6-8, n can independently be an integer of 1 or greater, or an integer from 1 to 15.

[0057] Since the preceramic monomer is a polymerizable monomer, a "functionalized" organosilicon monomer is one that contains a polymerizable functional group. The polymerizable functional group may be substituted at one or more points on the organosilicon, including substitution at any point(s) along the backbone structure in the case of polymeric organosilicon monomers. Alternatively or additionally, particularly in the case of polymeric organosilicon monomers, the polymerizable functional group may be substituted at a terminal, i.e., at one or more end groups of the backbone structure. "Substituted" in the context of functionalized organosilicon means that any one or more non-polymerizable chemical groups attached to the atom under consideration are replaced by a polymerizable functional group, so long as the valence of the atom is not exceeded and a stable compound is obtained. Non-limiting examples of suitable substitutes include the substitutes of the polymerizable functional group defined below.

[0058] Thus, the first functionalized organosilicon monomer can be obtained by replacing any one or more of R1, R2, R3, and R4, or the end group(s) of the monomer, with one or more of one or more types of polymerizable functional groups. Different "types" of polymerizable groups are groups with different chemical structures. The type of functional group(s) used is not particularly important, as long as it results in polymerization of the monomer(s).

[0059] In a resin that includes a first functionalized organosilicon monomer but not a second functionalized organosilicon monomer, one type of polymerizable functional group selected to react with itself may be used, or alternatively, two or more types of functional groups selected to react with each other (i.e., be complementary) may be present on the first functionalized organosilicon monomer. Alternatively or additionally, the first functionalized organosilicon monomer may be crosslinked with a crosslinking agent (containing a crosslinking group) to crosslink the monomers of the resin.

[0060] In a preferred embodiment, the resin of the present invention is particularly useful in forming shaped preceramic polymer articles by 3D printing and injection molding, which often rely on thermal polymerization and / or photopolymerization, so the polymerizable functional group is compatible with these methods and is therefore thermally or photopolymerizable.In this case, the polymerizable functional group(s) is preferably selected from a group or group containing a motif selected from one or more of ester, amine, hydroxyl, epoxide, vinyl, allyl, ethynyl, thiol, glycidyl, isocyanurate, alkacrylate, cyano, cyanate, and thiocyanate.In a preferred embodiment, the first functionalized organosilicon monomer contains one type of polymerizable functional group, preferably allyl, vinyl, thiol, or acrylate, more preferably thiol or acrylate.

[0061] In a preferred embodiment, the first functionalized organosilicon monomer can be characterized by a high degree of polymerization. "Degree of polymerization" refers to the polymerization yield, i.e., the ratio of crosslinked functional groups to non-crosslinked functional groups in the green body (i.e., for example, to those intended to polymerize with itself or with a second functionalized organosilicon monomer). "High degree of polymerization" refers to a polymerization yield of more than 80%, including a "very high degree of polymerization" of 90% or more, even 95% or more, or 98% or more, and also including a "complete polymerization" of 99% or more, or even 100% to the extent that it is substantially detectable. This is in contrast to "moderate polymerization", which is a polymerization yield between 60% and 80%, and "low polymerization", which is a polymerization yield of 60% or less. It is surprising that the first functionalized organosilicon monomer can be characterized by a high degree of polymerization and can be applied to obtain a high shrinkage PDC material. Conventionally, it is believed that a low degree of polymerization is conducive to obtaining a high shrinkage PDC material. This is because the higher degree of residual non-crosslinked monomers remaining that burn off during pyrolysis removes a larger amount of material, leading to higher shrinkage. However, in the present invention, without wishing to be limited by theory, it has been found that the preceramic resins described herein that are capable of forming pores during pyrolysis can result in high shrinkage PDC materials even with monomers having a high degree of polymerization. This is advantageous in minimizing wasted material and obtaining relatively strong, dense PDC materials that are less susceptible to cracking or other losses in the integrity of the PDC material. This is particularly advantageous in the formation of silica PDC materials and other PDC materials that do not contain carbon, since it is believed that carbon helps maintain the integrity of the PDC material. Thiol-ene and thiol-acrylate chemistries are particularly preferred for providing a high degree of polymerization, meaning that in a preferred embodiment, the first functionalized organosilicon monomer contains a polymerizable functional group that is preferably an allyl, vinyl, thiol, or acrylate, more preferably a thiol or acrylate, especially when a second organosilicon monomer is included as described below.

[0062] The first functionalized organosilicon monomer is, as described above, a first ceramic yield (preferably as determined by TGA) of 50% or less. 850 A first functionalized organosilicon monomer having a low ceramic yield can be selected, including a first ceramic yield anywhere from 5% to 50%, for example, with a lower limit for the range being any of 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, or 45%, and an upper limit for the range being 50%. In a preferred embodiment, the first functionalized organosilicon monomer has a low ceramic yield, including a first ceramic yield anywhere from 5% to 30%, for example, with a lower limit of 5%, and a maximum of 10%, 15%, 20%, 25%, or 30%. Preferably, the first functionalized organosilicon monomer has a very low ceramic yield, including a first ceramic yield of any of from 5% to 20%, such as 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%.

[0063] The first ceramic yield of 50% or less brings about the advantages of the present invention.Without wishing to be limited by theory, it is believed that having one or more second functionalized organosilicon monomers and ceramic particles with a first ceramic yield of 50% or less and a second ceramic yield of at least 5% greater than the first ceramic yield leads to the formation of high porosity during pyrolysis, allowing a larger volume of liquid and gas to escape, which then collapses during pyrolysis and causes high shrinkage.Generally speaking, the lower the first ceramic yield, the greater this advantage.

[0064] In a preferred embodiment, the first functionalized organosilicon monomer is the polysiloxane methacryloxypropyl terminated polydimethylsiloxane. This functionalized organosilicon monomer has a ceramic yield (TGA) of 50% or less. 850 In particular, the ceramic yield is about 12% (TGA 850 (including ceramic yield).

[0065] The first functionalized organosilicon monomer may be present in an amount of at least about 15%, 20%, 25%, 30%, or at least about 35% by weight of the preceramic resin, and up to about 98%, 95%, 90%, or about 80% by weight of the preceramic resin. The first functionalized organosilicon monomer may also be present in the preceramic resin in an amount of at least about 10%, 15%, 20%, 25%, or at least about 30% by volume of the preceramic resin. The amount of the first functionalized organosilicon monomer may be up to about 95%, 90%, 80%, 75%, or up to about 70% by volume of the preceramic resin. Any minimum and maximum values ​​may be combined without limitation. For example, the amount may be between 15% and 98% by weight of the preceramic resin, between 15% and 80% by weight of the composition, etc. In embodiments that include a first functionalized organosilicon monomer but not a second functionalized organosilicon monomer, the first functionalized organosilicon monomer may be present in an amount of at least about 60% to about 95% by weight, preferably between about 65% to about 90% by weight, more preferably between about 70% to about 85% by weight, for example between 75% to 80% by weight.

[0066] Second organosilicon monomer In addition to the first functionalized organosilicon monomer, in certain preferred embodiments, the preceramic resin includes a second functionalized organosilicon monomer having a second ceramic yield at least 5% greater than the first ceramic yield. That is, in certain preferred embodiments, the preceramic resin includes a first functionalized organosilicon monomer having a first ceramic yield of 50% or less, and a second functionalized organosilicon monomer having a second ceramic yield at least 5% greater than the first ceramic yield. In virtue of including the first functionalized organosilicon monomer and the second functionalized organosilicon monomer, ceramic particles may also be included.

[0067] The second functionalized organosilicon monomer can be selected from the group described above for the first functionalized organosilicon monomer described above for the first functionalized organosilicon monomer, so long as it has a second ceramic yield that is at least 5% higher than the first ceramic yield. Otherwise, the broad classes and functional groups from which the second functionalized organosilicon monomer is selected are as described above for the first functionalized organosilicon monomer, including polymerizable functional groups. This includes those related to preferred features. In general, the second ceramic yield that differs from the first ceramic yield will be caused by the chemical structure of the second functionalized organosilicon monomer being different from the chemical structure of the first functionalized organosilicon monomer, whether through the backbone or the polymerizable functional group.

[0068] That is, in preferred embodiments, the second functionalized organosilicon monomer has the structure of Formula 1, Formula 2, Formula 3, Formula 4, Formula 5, Formula 6, Formula 7, or Formula 8, or comprises the polysilsesquioxanes, polysilsesquicarbodiimides, and polysilsesquiazanes defined above, which are substituted with one or more polymerizable functional groups selected from one or more of esters, amines, hydroxyls, epoxides, vinyls, allyls, ethynyls, thiols, glycidyls, isocyanurates, alkaacrylates, cyanos, cyanates, and thiocyanates, more preferably one or more of vinyls, allyls, thiols, and acrylates, most preferably groups containing a group or motif selected from thiols or acrylates, provided that the ceramic yields differ.

[0069] In certain embodiments, polysilsesquioxanes, polysilsesquicarbodiimides, or polysilsesquiazanes can be advantageously used as the second functionalized organosilicon monomer since they tend to produce larger pores during pyrolysis, or even toward the macropore size range, allowing collapse with high shrinkage after liquid and gas escape.

[0070] The second functionalized organosilicon monomer may contain a polymerizable functional group that is different from but complementary to the polymerizable functional group of the first functionalized organosilicon monomer, such that under polymerization conditions, the first polymerizable functional group and the second polymerizable functional group react with each other, optionally with a crosslinking agent, to crosslink the monomers together. Alternatively, the second functionalized organosilicon monomer may contain a polymerizable functional group that is the same as the polymerizable functional group of the first functionalized organosilicon monomer, such that under polymerization conditions, the first polymerizable functional group and the second polymerizable functional group react with each other, optionally with a crosslinking agent, to crosslink the monomers together.

[0071] The preceramic resin may include a crosslinker that includes a crosslinker group. The crosslinker is generally a chemical compound that may be considered functionalized in that it includes at least two or more functional groups that are complementary to the functional groups described above for the polymerizable functional groups of any one or all of the functionalized organosilicon monomers included in the preceramic resin. The functional groups of the crosslinker react with the polymerizable functional groups of the functionalized organosilicon monomer(s), resulting in a crosslinker group within the structure of the preceramic polymer. Examples of crosslinkers include functionalized silane monomers or oligomers, diacrylates, and dithiols, among others. If present, the crosslinker with the crosslinker group will be selected based on the polymerizable functional groups of the functionalized organosilicon monomer(s). Thus, the crosslinker group may be selected from the polymerizable functional groups described above for the first functionalized organosilicon monomer and the second functionalized organosilicon monomer, which in preferred embodiments include those selected from one or more of vinyl, allyl, thiol, and acrylate.

[0072] In a preferred embodiment, the second functionalized organosilicon monomer contains a polymerizable functional group that is different from but complementary to the polymerizable functional group of the first functionalized organosilicon monomer, such that under polymerization conditions, the first polymerizable functional group and the second polymerizable functional group react with each other in the absence of a crosslinker group. A preferred example includes the combination of a thiol functional group and an acrylate functional group that are photopolymerizable with each other.

[0073] The second functionalized organosilicon monomer may be characterized by a high degree of polymerization, just like the first functionalized organosilicon monomer described above, for the same reasons and with the same advantages. Here again, thiol-ene and thiol-acrylate chemistry is particularly preferred to provide a high degree of polymerization. That is, in a preferred embodiment, when a second organosilicon monomer is included, the second functionalized organosilicon monomer comprises a polymerizable functional group, which is preferably allyl, vinyl, thiol, or acrylate, more preferably thiol or acrylate. The polymerizable functional group is intended to be complementary to the corresponding functional group of the preferred first functionalized organosilicon monomer, which is applicable to thiol-ene and thiol-acrylate chemistry. Nevertheless, a degree of polymerization of the second monomer lower than that of the first monomer is also applicable. That is, in a resin comprising a first functionalized organosilicon monomer and a second functionalized organosilicon monomer, the monomers may be present in a stoichiometric amount that is comparable to a high degree of polymerization, or even complete polymerization (crosslinking of the polymerizable functional group). That is, the first functionalized organosilicon monomer and the second functionalized organosilicon monomer may be present in a ratio of 1:1 with respect to the polymerizable functional group. However, it has also been found that the second functionalized organosilicon monomer may be present in excess, thus, for example, the first functionalized organosilicon monomer and the second functionalized organosilicon monomer may be present in a ratio of 1:3 or a ratio of 1:2 with respect to the polymerizable functional group, preferably in a ratio of 1:1 to 1:2. This may help to lead the polymerization of the first functionalized organosilicon monomer to a high degree of polymerization or complete polymerization, giving the preceramic resin more advantageous rheological properties suitable for 3D printing, while still obtaining a strong and dense PDC material, in some cases, by avoiding the loss of integrity of the PDC material due to the high degree of polymerization of the first functionalized organosilicon monomer. The remaining non-crosslinked second functionalized organosilicon monomer may then burn off during pyrolysis, which may help to obtain high shrinkage.

[0074] A first functionalized organosilicon monomer having a "first ceramic yield" and a second functionalized organosilicon monomer having a "second ceramic yield" are meant to be different from each other. That is, a first functionalized organosilicon monomer having a first ceramic yield is a monomer having a ceramic yield that is different from the ceramic yield of a second functionalized organosilicon monomer having a second ceramic yield. The difference is at least 5%, which means that the second ceramic yield is 5% or more greater than the first ceramic yield. For example, if the first ceramic yield is 15%, the second ceramic yield will be 20% or more.

[0075] The second organosilicon monomer with a second ceramic yield at least 5% greater than the first ceramic yield of the first organosilicon monomer provides the advantages of the present invention. Without wishing to be limited by theory, it is believed that the monomer combination with ceramic yields differing by at least 5% or more leads to the formation of porosity during pyrolysis, allowing a larger volume of liquid and gas to escape, which then collapses during pyrolysis, resulting in high shrinkage. In particular, it is believed that this allows the formation of mesopores and macropores, and (to a lesser extent) micropores, during pyrolysis. It is believed that organosilicon monomers with ceramic yields differing by 5% or more undergo different degrees of linear and volumetric shrinkage when converted to ceramic materials under pyrolysis conditions, which results in the formation of these pores during pyrolysis, followed by collapse with shrinkage. Generally speaking, the greater the difference between the two ceramic yields, the greater the advantage. For example, the use of a preceramic resin comprising a first and a second organosilicon monomer having ceramic yields differing by about 30% or more will tend to result in greater porosity and greater shrinkage during pyrolysis compared to preceramic resins comprising a first and a second organosilicon monomer having ceramic yields differing by less than 30%, and of course even less than 5% where no porosity may be formed at all.

[0076] The second ceramic yield is at least 5% greater than the first ceramic yield, which may be, for example, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40% or more, such as 41%, 42%, 43%, 44%, 45%, or 50% or more. The second ceramic yield may be as much as 55%, 60%, 70%, 80%, or even 90% greater than the first ceramic yield. In a preferred embodiment, the second ceramic yield differs from the first ceramic yield by 10% or more, preferably 20% or more, preferably 30% or more, or even 40% or more, which may be, for example, between 10% and 80%, between 20% and 70%, or between 30% and 60%, or any combination of the upper and lower limits without restriction. In certain preferred embodiments, the second ceramic yield is about 40% to 50% greater than the first ceramic yield, including 40%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, or 49% greater, particularly by TGA. 850 This is also true when considering ceramic yields.

[0077] Thus, in a preferred embodiment where the first functionalized organosilicon monomer has a first ceramic yield that is anywhere from 5% to 20%, which is a very low ceramic yield, the second functionalized organosilicon monomer may have a second ceramic yield that is anywhere from 10% to 60% greater, which is a second ceramic yield of 15% to 80%. Similarly, where the second functionalized organosilicon monomer has a preferred second ceramic yield that is anywhere from 40% to 50% greater than the first ceramic yield, the second ceramic yield may be 45% to 70%, which is within the range of a medium to high ceramic yield. Again, the TGA 850 Ceramic yields are applicable.

[0078] It has been found that the best results are obtained by combining a first ceramic yield with a very low ceramic yield and a second ceramic yield with a moderate ceramic yield. Thus, in a preferred embodiment where the first functionalized organosilicon monomer is polysiloxane methacryloxypropyl terminated polydimethylsiloxane (12% ceramic yield, very low), the second functionalized organosilicon monomer is polysiloxane (mercaptopropyl) methylsiloxane homopolymer. This second functionalized organosilicon monomer has a ceramic yield of 55% (TGA 850 10, which is a moderate ceramic yield that is about 43% different from the first ceramic yield.

[0079] The amount of the second functionalized organosilicon monomer, when present in the preceramic resin, may be at least about 15%, 20%, 25%, 30%, or at least about 35% by weight of the preceramic resin, and up to about 80%, 75%, 70%, or about 65% by weight of the preceramic resin. The second functionalized organosilicon monomer may also be present in the preceramic resin in an amount of at least about 5%, 10%, 15%, 20%, or at least about 25% by volume of the preceramic resin. The amount of the second functionalized organosilicon monomer may be up to about 75%, 70%, 65%, 60%, or up to about 55% by volume of the preceramic resin. All minimum and maximum values ​​may be combined without limitation. For example, the amount may be between 15% and 80% by weight of the preceramic resin, between 15% and 65% by weight of the preceramic resin, etc.

[0080] When present, the first functionalized organosilicon monomer and the second functionalized organosilicon monomer may be present in a combined amount of at least about 30%, 40%, 50%, 60%, or at least about 70% by weight of the preceramic resin, and up to about 98%, 95%, 90%, or about 80% by weight of the preceramic resin. The first functionalized organosilicon monomer and the second functionalized organosilicon monomer may also be present in the preceramic resin in an amount of at least about 10%, 15%, 20%, 25%, or at least about 30% by volume of the preceramic resin. The amount of the first functionalized organosilicon monomer and the second functionalized organosilicon monomer may be up to about 95%, 90%, 80%, 75%, or up to about 70% by volume of the preceramic resin. Any minimum and maximum values ​​may be combined without limitation. For example, the amount can be between 30% and 98% based on the weight of the preceramic resin, between 30% and 80% based on the weight of the composition, etc. In a preferred embodiment, the first functionalized organosilicon monomer and the second functionalized organosilicon monomer together can be present in an amount of at least about 60% to about 90% by weight of the preceramic resin, preferably between about 65% and about 85% by weight, and more preferably between about 70% and about 80% by weight.

[0081] Ceramic particles In certain preferred embodiments, the preceramic resin comprises ceramic particles in addition to a first functionalized organosilicon monomer having a first ceramic yield of 50% or less. In the resin comprising the first functionalized organosilicon monomer and ceramic particles, a second functionalized organosilicon monomer may be included having a second ceramic yield that differs from the first ceramic yield by at least 5%.

[0082] The ceramic particles can be porous or non-porous. Ceramic particles can be used advantageously. Without wishing to be limited by theory, it is believed that porosity is formed during pyrolysis, allowing a larger volume of liquid and gas to escape, thereby resulting in high shrinkage. It is believed that porosity is formed because the organosilicon monomer undergoes shrinkage during conversion to ceramic material, while the ceramic particles do not shrink, or at least shrink to a lesser extent, so that the ceramic particles act as a scaffold around which the organosilicon monomer shrinks to form pores. The use of porous ceramic particles provides greater advantages. Porous ceramic particles, by having pre-existing porosity, can introduce larger porosity through pores of sizes that may not otherwise exist or be able to form in such volumes during pyrolysis, and coupled with other pore sizes present during pyrolysis via other means described herein, can result in the release of a larger volume of liquid and gas during pyrolysis, forming a PDC material characterized by high shrinkage. As pyrolysis continues, the pores can then collapse, resulting in even higher shrinkage. For example, the use of microporous ceramic particles can introduce micropores during pyrolysis. Similarly, the use of mesoporous ceramic particles can introduce micropores and / or mesopores during pyrolysis. The use of ceramic particles can also result in a relatively strong and dense PDC material that is less susceptible to cracking or other losses in integrity of the PDC material. This is particularly advantageous in the formation of silica PDC materials and other PDC materials that do not contain carbon, since it is believed that carbon helps maintain the integrity of the PDC material. The availability of ceramic particles to obtain high shrinkage PDC materials is also surprising, given that ceramic particles do not tend to undergo shrinkage during pyrolysis, at least not in large or even moderate amounts. However, in the present invention, it has been discovered that the ability to form pores during pyrolysis can result in high shrinkage PDC materials even in the presence of ceramic particles.

[0083] Since PDC materials are based on organosilicon monomers that form silicon-based ceramic materials after pyrolysis, the ceramic particles are preferably also formed from silicon ceramic materials. Examples of silicon ceramic materials from which ceramic particles can be made include SiO2, Si3N4, SiC, SiCN, SiCO, SiCNO, SiBCN, SiBCO, SiAlCN, and SiAlCO. These forms of ceramic particles can be described as silicon ceramic particles. In a preferred embodiment, the ceramic particles are silica (SiO2) particles.

[0084] The ceramic particles can be of any size depending on the purpose. For example, particle sizes up to 1 mm are acceptable for many 3D printing processes, while particle sizes up to a few millimeters are acceptable for many injection molding processes. However, smaller ceramic particles are preferred, as it is believed that smaller particles provide better rheological properties (especially for 3D printing), while a higher volume percent distribution provides more uniform structural support. Thus, in some embodiments, the ceramic particles are microparticles. By "microparticles" is meant a plurality of particles having a particle size comprised between 1 μm and 1 mm. Preferably, the microparticles have a size comprised between 1 μm and 500 μm, between 1 μm and 200 μm, between 1 μm and 100 μm, and between 1 μm and 50 μm. Granular materials are generally supplied in a specified particle size range, which usually means that at least a majority of the particles have a size within that range. This can be described as a particle size distribution. The particles may be predominantly (e.g., greater than 95%, greater than 99%) or entirely within the particle size range. In some embodiments, at least 90%, 95%, 98%, 99%, 99.5%, or even 99.9% of the ceramic microparticles in the resin have a size between about 1 μm and 200 μm, between about 1 μm and 100 μm, or between about 1 μm and 50 μm. In other embodiments, the ceramic particles are nanoparticles. By "nanoparticles" is meant a plurality of particles having a particle size comprised below 1 μm. Preferably, the nanoparticles have a size comprised below 500 nm, below 200 nm, or even below 100 nm. In preferred embodiments, at least 90%, 95%, 98%, 99%, 99.5%, or even 99.9% of the ceramic nanoparticles in the resin have a size comprised between about 1 nm and about 100 nm, preferably between about 1 nm and 50 nm, and more preferably between about 5 nm and 20 nm.In some embodiments, the ceramic particles include both microparticles and nanoparticles, in which case the preceramic resin can be considered to include ceramic particles having a particle size where a plurality of particles are included in less than 1 mm. Preferably, the ceramic particles have a size of less than 500 μm, less than 200 μm, less than 100 μm, or less than 50 μm. In preferred embodiments, at least 90%, 95%, 98%, 99%, 99.5%, or even 99.9% of the ceramic particles included in the resin have a size between about 1 nm and 1 mm, between about 1 nm and 500 μm, between about 1 nm and 200 μm, between about 1 nm and 100 μm, or between about 1 nm and 50 μm. Methods for determining particle size and particle size distribution are known in the art and include small angle X-ray scattering, dynamic light scattering, and transmission electron microscopy. Preferably, the particle size distribution is determined using transmission electron microscopy (TEM).

[0085] When porous ceramic particles are used, they may contain pores of various sizes, but in preferred embodiments, the porous ceramic particles are microporous and / or mesoporous such that microporosity and mesoporosity, or a greater volume thereof, is produced during pyrolysis. Porous ceramic particles can be determined as microporous, mesoporous, and / or macroporous, for example, using BET surface analysis and / or mercury porosimetry, techniques known in the art.

[0086] When ceramic particles are present, they may be present in the preceramic resin in an amount of at least about 0.5%, 1%, 2%, 5%, 8%, or 10%, 15%, or at least about 20% based on the weight of the preceramic resin. When present, the amount of ceramic particles is preferably about 95% or less, 90%, 80%, 70%, 50%, or about 30% or less based on the weight of the preceramic resin. The amount of ceramic particles based on the weight of the preceramic resin may be affected by the size and density of the particles, and therefore may be included in the preceramic resin by volume, in which case the ceramic particles may be present in the preceramic resin in an amount of at least about 0.1%, 0.5%, 1%, 2%, 5%, 8%, or at least about 10% based on the volume of the preceramic resin. The amount of ceramic particles may be about 98% or less, 95%, 90%, 80%, or about 70% or less based on the volume of the preceramic resin. Any minimum and maximum values ​​may be combined without limitation. For example, the amount may be between 0.5% and 95% by weight of the preceramic resin, between 0.5% and 30% by weight of the preceramic resin, between about 0.1% and 98% by volume of the preceramic resin, or between 0.1% and 70% by volume of the preceramic resin, etc. For example, for nanoparticles, amounts of between about 2% and about 35% by weight of the preceramic resin, preferably between about 5% and about 30% by weight, more preferably between about 10% and about 25% by weight, and especially 10%, 20%, or 25% by weight have been found to be applicable for forming high shrinkage PDC materials.

[0087] Other Ingredients The resins of the present invention may include a variety of other ingredients, including, but not limited to, one or more of porogens, free radical initiators, free radical inhibitors, light blocking agents, 3D printing resolution agents, colorants, surfactants, dispersants, and emulsifiers, which are generally known in the art.

[0088] A "porogen" is an organic compound that, when added to a preceramic resin, is capable of escaping during pyrolysis of the preceramic polymer in the process of forming a PDC material.

[0089] Porogens may be used advantageously. Without wishing to be limited by theory, it is believed that the porogen escapes as a gas during pyrolysis, leaving behind pores upon escape that may collapse with shrinkage after other gases and liquids have escaped. The size of the pores introduced by the porogen during pyrolysis depends on the size of the porogen itself, but are typically mesopores and / or macropores. That is, mesoporogens tend to result in mesopores (which may also result in micropores) and macroporogens tend to result in macropores (which may also result in mesopores). Similarly, the combination of mesoporogens and macroporogens tends to result in a combination of mesopores and macropores.

[0090] Examples of preferred mesoporogens include toluene, methanol, cyclohexanol, hexane, dodecanol, 1,2-propanediol, water, 1-propanol, 1,4-butanediol, dimethylformamide, acetonitrile, decane, and decanol, and examples of preferred macroporogens include polyethylene glycols (PEGs) such as PEG 200, PEG 400, and PEG 20000, and polyethylene glycol diacrylates (PEGDAs) such as PEGDA 250 and PEGDA 575. In a preferred embodiment, the mesoporogen is toluene and the macroporogen is PEG 400.

[0091] When present, the porogen may be present in an amount between about 1% and about 50% by weight, preferably between about 2% and about 20% by weight, and more preferably between about 5% and about 15% by weight of the preceramic resin.

[0092] As explained above, since the resins of the present invention are particularly useful in forming shaped preceramic polymeric articles and PDC articles using 3D printing and injection molding techniques, the polymerizable functional group of the organosilicon monomer(s) is preferably thus compatible and therefore in many embodiments is thermally or photopolymerizable. In that case, the resin may often further comprise a free radical generator such as a thermal initiator or photoinitiator that forms free radicals that catalyze the reaction of the thermally or photopolymerizable functional groups, respectively. When present, the thermal initiator or photoinitiator may be present in an amount of between about 0.01% and about 20% by weight of the preceramic resin, preferably between about 0.1% and about 5% by weight, more preferably between about 0.2% and about 1% by weight.

[0093] Examples of thermal initiators include benzoyl peroxide, dicumyl peroxide, and 2,2'-azobisisobutyronitrile.

[0094] Examples of photoinitiators include 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone, camphorquinone, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), benzophenone, and benzoyl peroxide. In a preferred embodiment, the photoinitiator is BAPO.

[0095] Examples of light blocking agents include 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBOT), 4,4'-bis(benzoxazolyl)-cis-stilbene, and 4,4-diamino-2,2-stilbene disulfonic acid. In a preferred embodiment, the light blocking agent is BBOT.

[0096] For example, in a preferred embodiment where the polymerizable functional groups of the functionalized organosilicon monomer(s) are acrylate and thiol groups, the free radical generator is a photoinitiator that forms free radicals under ultraviolet light (wavelengths of about 100 nm to about 405 nm). A preferred example is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0097] The resin may further include a free radical inhibitor (also known as a free radical scavenger). Examples include hydroquinone, methylhydroquinone, ethylhydroquinone, methoxyhydroquinone, ethoxyhydroquinone, monomethyletherhydroquinone, propylhydroquinone, propoxyhydroquinone, tert-butylhydroquinone (TBHQ), and n-butylhydroquinone. In a preferred embodiment, the free radical inhibitor is tert-butylhydroquinone. When present, the free radical inhibitor may be present in an amount between about 0.01% and about 20% by weight of the preceramic resin, preferably between about 0.05% and about 5% by weight, and more preferably between about 0.1% and about 2% by weight.

[0098] When a light blocking agent is included, a preferred light blocking agent is 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBOT). When present, the light blocking agent may be present in an amount of between about 0.01% and about 20% by weight of the preceramic resin, preferably between about 0.1% and about 5% by weight, and more preferably between about 0.2% and about 1% by weight.

[0099] Another component that may be included in the resin of the present invention is a third or subsequent functionalized organosilicon monomer. The third or subsequent functionalized organosilicon monomer may be selected in the same manner as the first and second functionalized organosilicon monomers described above, and with the same identity and polymerizable functional group. The polymerizable functional group of the third functionalized organosilicon monomer is selected to react with one or more of the polymerizable functional groups of the first and / or second functionalized organosilicon monomers, optionally via a crosslinker group. It is not necessary for the third or subsequent functionalized organosilicon monomer to have a ceramic yield different from the first and / or second functionalized organosilicon monomers. However, if it has a (third) ceramic yield different from the first and second ceramic yields, this may further contribute to the formation of pores during pyrolysis, increasing the advantages described herein.

[0100] When present, the third or subsequent functionalized organosilicon monomer is preferably a polysiloxane, polysilsesquioxane, polycarbosilane, or polycarbosilazane. The third (or subsequent) functionalized organosilicon monomer may be selected from one or more of methacryloxypropyl terminated polydimethylsiloxane, vinylmethoxysiloxane homopolymer, methacryloxypropyl substituted poly(isobutyl-t8-silsesquioxane), allylhydridopolycarbosilane, and methylvinylhydrogenpolycarbosilazane. When present, the third or subsequent functionalized organosilicon monomer may be present in an amount of about 1% to about 50% by weight of the preceramic resin, preferably between about 5% and about 30% by weight, and more preferably between about 10% and about 20% by weight.

[0101] Another component that can be included in the resins of the present invention is a functionalized organic monomer.

[0102] An "organic monomer" is a carbon-containing chemical compound, other than the organosilicon monomers described herein. An organic monomer is typically a silicon-free organic monomer. Organic compounds tend to contain carbon-carbon and carbon-hydrogen covalent bonds, and often contain covalently bonded heteroatoms such as oxygen and nitrogen. Organic compounds are identifiable to those skilled in the art. A "functionalized" organic monomer is one that contains two or more reactive functional groups, each of which is reactive with at least a first functionalized organosilicon monomer to form crosslinks. This may be by crosslinking with the organosilicon monomer functional groups. Thus, the functional group of the functionalized organic monomer may be referred to as a polymerizable functional group. The portion of the chemical structure between the reactive groups may be referred to as a "spacer". Thus, a functionalized organic monomer may be of the formula: Spacer (L) n where Spacer is a spacer group, L is a reactive group reactive with at least the first functionalized organosilicon monomer, and n is an integer equal to or greater than 2. In a preferred embodiment, n is an integer from 2 to 4, preferably 2.

[0103] The spacer group may be based on short or long chain, arbitrarily branched backbone structures, including, for example, ethylene, ethylene glycol, polyethylene, polyethylene glycol propylene, polypropylene glycol, polypropylene, polypropylene glycol, ethylamine, polyethyleneimine, propylamine, polypropyleneimine, etc. "Substituted" in reference to the organic monomer means that any one or more atoms or chemical groups attached to the atoms of the backbone are replaced, as long as the valence of the atom is not exceeded and a stable compound is obtained. The reactive group may be substituted at any position(s) of the backbone, and is preferably substituted at the terminals, i.e., at the two end groups of the backbone structure. The at least two reactive groups may be the same or different, depending on the desired crosslinking with the first functionalized organosilicon monomer and the second functionalized organosilicon monomer. The two or more reactive groups are preferably the same. The reactive group is preferably selected from a group or group containing motifs selected from one or more of ester, amine, hydroxyl, epoxide, vinyl, allyl, ethynyl, thiol, glycidyl, isocyanurate, alkaacrylate, cyano, cyanate, and thiocyanate. In a preferred embodiment, the reactive group is an allyl, vinyl, thiol, or acrylate.

[0104] Exemplary preferred functionalized organic monomers include ethylene glycol diacrylate, polyethylene glycol diacrylate, ethylene glycol dithiol, polyethylene glycol dithiol, ethylene glycol divinyl ether, polyethylene glycol divinyl ether, ethylene glycol diallyl ether, and polyethylene glycol diallyl ether.

[0105] In some cases, the crosslinking agent described above constitutes a functionalized organic monomer.

[0106] The advantage of using functionalized organic monomers is that they tend to be more reactive under the polymerization conditions than functionalized organosilicon monomers, which can help increase the rate of polymerization and the extent of crosslinking, and help produce porosity formed within the polymer-derived ceramic material at appropriate pyrolysis conditions temperatures.

[0107] When present, the functionalized organic monomer is included in a stoichiometric amount that matches the complete reactivity, or as close to complete reactivity as possible, of the polymerizable functional groups of the first functionalized organosilicon monomer and the second functionalized organosilicon monomer. Within this preferred parameter range, the amount of functionalized organic monomer, when present in the preceramic resin, can be present in an amount of at least about 1%, 2%, 5%, 8%, or 10%, 15%, 20%, 25%, 30%, or at least about 35% based on the weight of the preceramic resin, and up to about 80%, 75%, 70%, or about 65% based on the weight of the preceramic resin. Any minimum and maximum values ​​can be combined without limitation. For example, the amount can be between 1% and 80% based on the weight of the preceramic resin, between 15% and 65% based on the weight of the composition, etc.

[0108] Methods of the Invention The method of the present invention involves subjecting a preceramic resin to polymerization conditions to form a preceramic polymer, and pyrolyzing the preceramic polymer to form a PDC material.

[0109] "Polymerization conditions" are conditions under which a polymerization reaction occurs. Numerous polymerization reaction chemistries are applicable, including, but not limited to, step-growth polymerizations, including condensation reactions, and chain-growth polymerizations, including cationic or anionic addition reactions, or thermal or photocatalytic free radical reactions. The polymerization conditions selected will depend on the polymerizable functional groups of the functionalized organosilicon monomer(s) that are intended to crosslink the monomers together.

[0110] In a preferred embodiment, the components of the preceramic resin are such that they are capable of producing pores contained within the material during pyrolysis. Such preceramic resins are as described herein. In a most preferred embodiment, the preceramic resin is as described herein in its preferred embodiment.

[0111] As noted above, the polymerizable functional groups are thus compatible and preferably photopolymerizable, since the resins of the present invention are particularly useful in forming shaped preceramic polymeric and PDC material articles using 3D printing and injection molding processes. Thus, in a preferred embodiment, the polymerization conditions include the presence of other components in the preceramic resin that aid in photopolymerization, as described above.

[0112] "Pyrolysis" is the thermally induced conversion of a preceramic polymer from an organic material to an inorganic (i.e., PDC) material. Similarly, "pyrolysis conditions" are conditions that include the elevated temperature at which pyrolysis occurs. During pyrolysis, the inorganic material formed may exist in one or more material phases depending on the temperature to which it is exposed, for example, the inorganic material may progress through an amorphous phase and then transition to a crystalline phase as the temperature is increased. Similarly, when a preceramic resin includes a component that includes pores (e.g., porous ceramic particles) or a component that can form pores during pyrolysis (e.g., a preceramic resin described herein), the amorphous phase may encompass a "porous phase" and a "nonporous phase." A porous phase is characterized by including pores, whereas a nonporous phase is other than a porous phase. A nonporous phase occurs at a higher temperature than a porous phase, which occurs due to the collapse of pores present in the porous phase. The temperature at which a porous phase is no longer present and a nonporous phase is present may be referred to as the "porosity transition temperature."

[0113] The temperature ranges at which the porous and non-porous phases exist may vary depending on the composition of the preceramic resin. Generally speaking, the greater the number of components in the preceramic resin, the higher the porosity transition temperature tends to be. For example, a preceramic resin that includes a first functionalized organosilicon monomer, a second functionalized organosilicon resin, ceramic particles, a photoinitiator, a free radical generator, and a light blocking agent may exhibit a higher porosity transition temperature than a preceramic resin that does not have one of these components, such as a preceramic resin that includes a first functionalized organosilicon monomer, a second functionalized organosilicon resin, a photoinitiator, a free radical generator, and a light blocking agent (i.e., no ceramic particles). In embodiments that include a greater number of components, the porosity transition temperature may be as high as about 1100°C, for example. However, generally speaking, the porous phase may occur within the range of about 300°C to 1000°C, and often within the range of about 300°C to 900°C. For example, in embodiments where the porous phase ceases to exist at 900°C, 900°C is taken to be the porosity transition temperature. Whether a PDC material is formed by pyrolysis at a maximum temperature below the porosity transition temperature, i.e., within the porous stage, can be determined by measuring the porosity of the material formed, e.g., using BET surface analysis as described herein. The porosity transition temperature can likewise be determined, e.g., by analyzing the porosity of PDC materials formed at various temperatures. Thus, by controlling the temperature of pyrolysis, porous and non-porous PDC materials can be produced; porous PDC materials can be produced by not exceeding the porosity transition temperature, whereas non-porous PDC materials can be produced by exceeding the porosity transition temperature.

[0114] Pyrolysis conditions for non-porous PDC materials Thus, to produce a non-porous PDC material, the pyrolysis conditions of the methods of the invention include a minimum temperature (i.e., a minimum temperature that must be reached during pyrolysis) that is equal to or greater than the porosity transition temperature. In a preferred embodiment, the minimum temperature is at least about 900° C. By "minimum temperature" it is meant that the temperature during pyrolysis is increased to a value above the given "minimum temperature."

[0115] This high minimum temperature is utilized to induce the necessary organic to inorganic conversion of the preceramic polymer to form the PDC material and also to cause pore collapse during pyrolysis resulting in a high shrinkage PDC material. Even higher temperatures are applicable, such as temperatures towards the amorphous to crystalline phase transition, and in preferred embodiments the temperature reached during pyrolysis is at least a minimum of 950°C, 1000°C, 1050°C, 1100°C, 1150°C, 1200°C, or 1250°C. This minimum temperature can also be combined with a maximum temperature of pyrolysis, which in preferred embodiments can be up to 1600°C. By "maximum temperature" it is meant that the maximum temperature reached during pyrolysis does not exceed the given "maximum temperature" value. It is preferred to reach a temperature of at least 900°C but not more than 1600°C during pyrolysis, since this causes pore collapse and shrinkage while avoiding higher temperatures that may cause the PDC material to start approaching its melting point. Lower maximum temperatures are applicable and more preferred to achieve the same results, including 1550°C, 1500°C, 1450°C, 1400°C, or 1350°C. Thus, expressed as ranges, in preferred embodiments, to form a non-porous PDC material, pyrolysis is carried out to reach a temperature between 900°C and 1600°C, between 1000°C and 1550°C, preferably between 1050°C and 1500°C, between 1100°C and 1450°C, more preferably between 1150°C and 1400°C, or between 1200°C and 1350°C. Most preferably, pyrolysis is carried out at about 1300°C.

[0116] Pyrolysis conditions for porous PDC materials To produce porous PDC materials, the pyrolysis conditions of the methods of the invention are characterized by a maximum temperature below the porosity transition temperature, hi a preferred embodiment, the maximum temperature is less than about 900°C.

[0117] This maximum temperature is utilized to induce the necessary organic to inorganic conversion of the preceramic polymer to form the PDC material, but also to preserve porosity in the PDC material, i.e., to preserve at least some of the pores formed or otherwise present during pyrolysis. This may be assisted by a lower maximum temperature, which in preferred embodiments is 850°C, 800°C, 750°C, or 700°C, including 650°C and even 600°C. This maximum temperature may also be combined with a minimum temperature for pyrolysis, which in preferred embodiments may be as low as about 300°C. This minimum temperature is preferred for efficient conversion of organic to inorganic materials. Higher minimum temperatures, including 325°C, 350°C, 375°C, 400°C, 425°C, or 500°C, are applicable and preferred to achieve the same results. Expressed as ranges, in preferred embodiments, pyrolysis is carried out at temperatures between 300° C. and 900° C., between 325° C. and 850° C., preferably between 350° C. and 800° C., between 375° C. and 750° C., more preferably between 400° C. and 700° C., and in some embodiments between 425° C. and 650° C., or between 450° C. and 600° C. Most preferably, to form a porous PDC material, pyrolysis is carried out at a maximum temperature of between about 600° C. and 700° C.

[0118] Pyrolysis conditions To produce both porous and non-porous PDC materials, the pyrolysis conditions of the method of the invention may be characterized by a temperature ramp rate of 10° C. / min or less for the period within the porous phase. This ramp rate of 10° C. / min or less (or slower as described below) is referred to as a "slow ramp rate". It is advantageous to use a temperature ramp (i.e., increase) rate of 10° C. / min or less for the period within the porous phase. Heretofore, relatively fast temperature ramp rates of over 10° C. / min have been used during pyrolysis. In the present invention, without wishing to be bound by theory, it is believed that the use of slower ramp rates of 10° C. / min or less allows pores of various sizes and greater degrees of porosity to be formed more slowly during pyrolysis using a preceramic resin capable of forming pores during pyrolysis. It is also believed that a slow ramp rate allows pores to exist for a longer period of time, through which liquids and gases can escape, resulting in high shrinkage, including shrinkage at temperatures above the porous transition temperature when the pores collapse. It may also slow the rate at which liquids and gases form and diffuse out of the material, thereby reducing the risk of pressure build-up and cracking or other loss of integrity of the PDC material.

[0119] This advantage is enhanced over a certain period of time within the temperature range of the porous stage at ramp rates even slower than 10° C. / min. Thus, in preferred embodiments, the ramp rate is 7° C. / min or less, preferably 5° C. / min or less, preferably 3° C. / min or less, more preferably 2° C. / min or less, and most preferably 1° C. / min or less. In certain preferred embodiments, the ramp rate may be even slower, even 0.5° C. / min or less, or even 0.3° C. / min or less. In other words, expressed as a range, the ramp rate may preferably be between 0.1° C. / min and 10° C. / min, between 0.1° C. / min and 7° C. / min, between 0.1° C. / min and 5° C. / min, between 0.2° C. / min and 3° C. / min, between 0.2° C. / min and 2° C. / min, preferably between 0.3° C. / min and 1° C. / min, within the temperature range of the porous stage. In certain embodiments, the ramp rate may be specifically about 0.3° C. / min or about 1° C. / min within the temperature range of the porous stage.

[0120] A slow ramp rate may be used for the entire period within the temperature range of the porous stage, or for a portion of the period within the temperature range of the porous stage. In some embodiments, a slow ramp rate is used at least up to the conversion temperature. The "conversion temperature" is the temperature at which the preceramic polymer is converted to the PDC material. In other words, in a preferred embodiment, the pyrolysis conditions of the method of the present invention are characterized by a slower ramp rate of 10°C / min or less, preferably slower than those described herein, for the period within the temperature range from 100°C to at least the conversion temperature. The conversion temperature varies somewhat for various resins and their components, but is generally around 500°C to 650°C or 700°C, with some materials sometimes beginning to convert around 300°C, in which case in a preferred embodiment, a slow ramp rate is used for the period within the temperature range of 100°C to at least about 500°C to 650°C or 700°C. Similarly, in some embodiments, a slow ramp rate is used at least from near the pore formation temperature (even though pores are pre-existing from the use of porous ceramic particles). The "pore formation temperature" is the temperature at which pores begin to form during pyrolysis, which generally occurs shortly after the preceramic polymer has been thermally cured, and often occurs between about 100°C and 300°C. In other words, in a preferred embodiment, the pyrolysis conditions of the method of the invention are characterized by a temperature ramp rate of 10°C / min or less, preferably slower than those described herein, over the period of time within the temperature range from the pore formation temperature to at least the conversion temperature. The pore formation temperature varies somewhat for various resins and their components, but is generally around 200°C to 300°C, in which case in a preferred embodiment a slow ramp rate is used over the period of time within the temperature range of at least about 200°C to 700°C or otherwise up to the maximum pyrolysis temperature.

[0121] Thus, to produce both porous and non-porous PDC materials, the pyrolysis conditions of the methods of the invention may be characterized by a ramp (i.e., increase) rate of 10°C / min or less over a period within a temperature range of 100°C-900°C, which may be a period within a temperature range of about 100°C-700°C, 200°C-700°C, about 200°C-600°C, about 300°C-700°C, or about 300°C-600°C.

[0122] Preferably, a ramp rate slower than 10° C. / min is used over a certain period of time within the temperature range of 100° C.-900° C. Thus, in a preferred embodiment, the temperature ramp rate is 7° C. / min or less, preferably 5° C. / min or less, preferably 3° C. / min or less, more preferably 2° C. / min or less, and most preferably 1° C. / min or less. In certain preferred embodiments, the temperature ramp rate may be even slower, even 0.5° C. / min or less, or even 0.3° C. / min or less. In other words, expressed as a range, the temperature ramp rate may be between 0.1° C. / min and 10° C. / min, between 0.1° C. / min and 7° C. / min, between 0.1° C. / min and 5° C. / min, between 0.2° C. / min and 3° C. / min, between 0.2° C. / min and 2° C. / min, preferably between 0.3° C. / min and 1° C. / min, within the temperature range of 100° C.-900° C. In certain embodiments, the ramp rate may specifically be about 0.3° C. / min or about 1° C. / min.

[0123] A slow ramp rate may be used over the entire period within the temperature range of 100°C to 900°C, or over a portion of the period within the temperature range of 100°C to 900°C. For example, a slow ramp rate may be used over the entire period within the temperature range of about 100°C to 700°C, about 100°C to 600°C, about 200°C to 700°C, about 200°C to 600°C, about 300°C to 700°C, or about 300°C to 600°C. In a preferred embodiment, a slow temperature ramp rate is used from at least near the pore formation temperature (albeit with pre-existing pores from the use of porous ceramic particles) to at least the conversion temperature. In other words, in a preferred embodiment, the pyrolysis conditions of the method of the present invention are characterized by a temperature ramp rate of 10°C / min or less, preferably slower than those described herein, over the period within the temperature range from the pore formation temperature to 900°C or at least to the conversion temperature. In a preferred embodiment, a slow ramp rate is used over a period of time within the temperature range of 100° C. to 900° C., or at least about 200° C. to 600° C. That is, a slow ramp rate (i.e., less than 10° C. / min or less as discussed above) is preferably maintained over the period of time as the temperature progresses from about 200° C. to 600° C.

[0124] The duration of the slow ramp rate may additionally or alternatively be expressed in reference to a period of time. The duration of the period during which the slow ramp rate is used may vary depending on the ramp rate, pore formation temperature, and maximum pyrolysis temperature used. In a preferred embodiment, the duration of the period during which the slow ramp rate is used is at least 30 minutes, preferably at least 1 hour. The period may be longer, for example at least 1.5 hours, 2 hours, 3 hours, 5 hours, 10 hours, 15 hours, 20 hours, or longer. The period may be up to 40 hours, 45 hours, 50 hours, or 55 hours. Expressed as a range, the slow ramp rate may be used for a duration of 1 hour to 55 hours, or 1.5 hours to 50 hours, or 2 hours to 45 hours, or 3 hours to 40 hours, or 15 hours to 40 hours, for example 20 hours to 25 hours. In a preferred embodiment where a slow temperature ramp rate is used throughout the entire period within the temperature range from 100°C to at least the conversion temperature, and the conversion temperature is, for example, 650°C, the duration of the period can be about 55 minutes (using a 10°C / min ramp rate), about 1 hour 19 minutes (using a 7°C / min ramp rate), 1 hour 50 minutes (using a 5°C / min ramp rate), 3 hours 3 minutes (using a 3°C / min ramp rate), 4 hours 35 minutes (using a 2°C / min ramp rate), 9 hours 10 minutes (using a 1°C / min ramp rate), 18 hours 20 minutes (using a 0.5°C / min ramp rate), and 30 hours 33 minutes (using a 0.3°C / min ramp rate).

[0125] Slower ramp rates may be used, where applicable, even at periods of higher temperature including the maximum pyrolysis temperature noted above, i.e., ramp rates of 10°C / min or less, preferably slower than those described herein, may be used for periods in the temperature range of 100°C to 900°C, but also above 900°C, e.g., up to 950°C, 1000°C, 1050°C, 1100°C, 1150°C, 1200°C, 1250°C, 1300°C, or up to the maximum pyrolysis temperature, or for any period in the range from 900°C to the maximum pyrolysis temperature.

[0126] Pyrolysis may be carried out in an inert or reactive atmosphere. A reactive atmosphere is generally characterized by the presence of a reactive gas, i.e., a gas that is reactive with at least one component of the preceramic polymeric material under pyrolysis conditions. An inert atmosphere is generally characterized by the absence of a reactive gas. Examples of reactive gases include oxygen, carbon dioxide, water (e.g., water vapor), methane, iodine, and ammonia. Air is an example of a reactive gas that includes oxygen, carbon dioxide, and potentially water. An example of an inert environment is a nitrogen gas environment or an environment under vacuum.

[0127] The pyrolysis conditions may also include a hold time during which the temperature is held at a particular temperature for a period of time. Examples of suitable times to use hold times include near the pore formation temperature, near the conversion temperature, maximum pyrolysis temperature, and collapse temperature. By "collapse temperature" is meant the temperature at which the pores present in the material begin to collapse during pyrolysis. The collapse temperature varies slightly for different resins and their components, but is generally about 700°C to 1100°C, in which case hold times may be used at temperatures within the range of about 700°C to about 1000°C, usually about 1000°C.

[0128] Hold times may be used to advantage. Without wishing to be bound by theory, it is believed that hold times can be used to drive ongoing chemical processes at any given pyrolysis temperature to completion. For example, hold times at temperatures near the conversion temperature can help achieve full conversion of the preceramic polymer to PDC material while maintaining the existing porous structure and allowing liquids and gases to escape, hold times at temperatures near the collapse temperature can help achieve full collapse of pores with high shrinkage, while hold times at the highest pyrolysis temperature can help achieve full conversion of the preceramic polymer to a strong, dense PDC material.

[0129] Thus, in a preferred embodiment, the pyrolysis conditions are characterized by hold times near one or more of the conversion temperature, the maximum pyrolysis temperature, and the collapse temperature.

[0130] The duration of the hold time at any given temperature may be, for example, between 30 and 300 minutes, or between 60 and 240 minutes, preferably between 60 and 180 minutes. The duration of the hold time may vary at various hold time temperatures. For example, the duration of the hold time at the conversion temperature may be relatively long to maximize the benefits of maintaining the existing porous structure and helping to direct the complete conversion of the preceramic polymer to the PDC material while allowing liquids and gases to escape. The duration of the hold time at the conversion temperature is preferably about 180 minutes. The durations of the hold times at the collapse temperature and maximum pyrolysis temperature, if used, may be relatively shorter, preferably about 60 minutes each.

[0131] The method of pyrolysis is known to those skilled in the art. Generally speaking, the preceramic polymeric material is placed in a cold furnace, the temperature is increased to a maximum value, and the temperature is decreased again at a specified rate (or rates). For example, although an increase is discussed, the decrease rate can be selected based on the thermogravimetric profile of the organosilicon monomer used, as known to those skilled in the art. In a preferred embodiment, the decrease rate is controlled in the same manner as described herein for the increase rate, which is generally 10°C / min or less, and can be slower over a certain period of time, for example, between about 0.5°C / min and 1°C / min or 2°C / min.

[0132] The total duration of pyrolysis from room temperature back down to room temperature can take several hours. This is in contrast to previous processes for pyrolytic conversion of green bodies to PDC materials, which tended to use fast ramp-up and ramp-down rates and short, if any, hold times. Generally speaking, the preferred conditions described herein for the formation of PDC materials are much milder, resulting in the controlled formation of materials with high shrinkage.

[0133] Formed PDC material The particular PDC material produced will depend on the composition of the preceramic resin, as it will result from the identity of the functionalized organosilicon monomer(s) and the ceramic particles (if any) selected. The use of organosilicon monomers produces silicon-based PDC materials. Depending on the composition of the preceramic polymer and the pyrolysis conditions, PDC materials that may be produced include SiO, Si3N4, SiC, SiCN, SiCO, SiCNO, SiBCN, SiBCO, SiAlCN, SiAlCO, SiON, and / or SiBN.

[0134] The particular PDC material produced may also depend on certain parameters of the pyrolysis conditions used. For example, the presence of a reactive environment will generally affect the nature of the gases that escape the material during pyrolysis, and thus the nature of the PDC material produced. For example, pyrolysis of a preceramic polymer formed from a polysiloxane organosilicon monomer in an inert atmosphere will generally produce a silicon oxycarbide ceramic material. On the other hand, pyrolysis of a preceramic polymer formed from a polysiloxane organosilicon monomer in a reactive air environment will produce a silica ceramic material. This is because the gases in the air (e.g., O2) react with the carbon atoms in the organosilicon backbone structure of the polysiloxane and escape as carbon-containing gases. The fundamental understanding of the formation of silica PDC materials is described in the specification for Australian Patent Application No. 2022900557, which is incorporated herein by reference in its entirety.

[0135] In addition, the maximum temperature used during pyrolysis may also affect the properties of the PDC material produced. For example, pyrolysis of a preceramic polymer formed from an organosilicon monomer in an inert atmosphere using a maximum pyrolysis temperature within the temperature range of the non-porous stage but below the crystallization temperature may induce phase separation of the PDC material to produce a glass-ceramic material. By "crystallization temperature" is meant the temperature at which the pyrolyzed silicon-based PDC material changes from an amorphous phase to a crystalline phase. In particular, pyrolysis of a preceramic polymer formed from a polysiloxane organosilicon monomer in an inert atmosphere using a maximum pyrolysis temperature below the crystallization temperature but within the temperature range of the non-porous stage may produce a silicon oxycarbide glass-ceramic material. In particular, this may produce a glass that contains interspersed free carbon in crystalline form. Thus, in some embodiments, the PDC material that constitutes the glass portion of the glass-ceramic material is silica, while the PDC material that constitutes the ceramic portion of the glass-ceramic material is crystalline carbon. Thus, in some embodiments, the glass-ceramic material is silicon oxycarbide.

[0136] The provision of glass-ceramic materials by the present disclosure is particularly advantageous because glass-ceramic materials exhibit unique chemical and mechanical properties that are often better than glass and ceramic materials themselves, such as significant chemical inertness, oxidation resistance, creep resistance, crystallization resistance, increased Young's modulus, hardness, and glass transition temperature.

[0137] The crystallization temperature will vary slightly for various resins and their components, but is generally above 1200° C. For example, the crystallization temperature may be in the range of 1200° C. to 1400° C. In some embodiments, the maximum pyrolysis temperature for forming a glass-ceramic PDC material is in the range of 1200° C. to 1400° C., preferably 1250° C. to 1350° C., such as around 1300° C. The minimum pyrolysis temperature for forming a glass-ceramic PDC material is 900° C., preferably 1000° C., more preferably 1100° C., since this temperature is generally within the range of the non-porous phase.

[0138] Previous methods of making glass-ceramic materials generally require very high temperatures that tend to cause the material to crack or otherwise lose integrity of the manufactured article, especially when attempting to form dense ceramic structures. The glass-ceramic PDC structures provided herein do not require as high temperatures during manufacture by the methods described herein and are less prone to cracking and other losses, although the preceramic resins used herein tend to form dense ceramic and glass-ceramic structures. Advantageously, the present disclosure provides dense glass-ceramic structures.

[0139] Within the non-porous stage, it is less important to use a slow temperature rise (as opposed to the porous stage described above), although a slow ramp rate is advantageous. In a preferred embodiment, the temperature ramp rate during the non-porous stage is 15° C. / min or less, preferably 10° C. / min, preferably 8° C. / min or less, more preferably 7° C. / min or less. In some embodiments, slow ramp rates of, for example, 5° C. / min, 3° C. / min, 2° C. / min, 1° C. / min, 0.5° C. / min, and 0.3° C. / min may be used. Expressed as a range, the temperature ramp rate within the temperature range of the non-porous stage may be between 3° C. / min and 15° C. / min, or between 5° C. / min and 8° C. / min. In certain embodiments, the ramp rate may be specifically about 7° C. / min. EXAMPLES

[0140] TGA to determine ceramic yields of organosilicon monomers 850 The law is as follows:

[0141] A known amount of functionalized organosilicon monomer (preferably between 10 mg and 20 mg) was transferred to an alumina crucible approved for use in a thermogravimetric analyzer. The crucible was placed in the analyzer and its weight change versus time and temperature was determined according to the manufacturer's instructions. The sample crucible was subjected to a thermal cycle from room temperature to 850°C under nitrogen and then returned to room temperature. The sample was equilibrated at 30°C for 30 minutes and the resulting weight was tared before the temperature was increased from 30°C to 850°C at a ramp rate of 1°C / min. The sample was further equilibrated at 850°C for 60 minutes and then cooled from 850°C to room temperature at a rate of 5°C / min. The percentage of weight change of the sample during this thermal cycle is used to calculate the ceramic yield, where the percentage of ceramic yield is calculated as (1-weight loss of sample / initial weight of sample) x 100.

[0142] A real-time Fourier transform infrared (RT-FTIR) spectroscopy method was developed to study the photopolymerization kinetics relevant to some of the examples presented below. The setup for the kinetic studies is shown diagrammatically in Figure 12. All RT-FTIR measurements were performed on a Fourier transform infrared spectrometer at 4000 cm. -1 ~600cm -1 The data were collected in the range of 0.1 to 1.0 nm. The data were analyzed using OPUS software with atmospheric correction and extended ATR correction implemented. All samples were illuminated with a 3 mm focusing lens (λmax = 405 nm and 20 mW / cm 2 A monochromatic UV LED with a 1000 mA output (having an intensity of 1000 mA) was used. A basic electrical circuit was used to power the LED while monitoring the current to prevent any damage. The LED and sample were aligned and an LED cover was custom designed and 3D printed to prevent the sample from being exposed to ambient light prior to the experiment. The LED was positioned 3 mm above the ATR stage. The sample was exposed to air during reaction monitoring to account for the effect of oxygen inhibition on the photopolymerization kinetics. All experiments were performed at room temperature and under ambient conditions.

[0143] Approximately 939cm -1 and about 1637 cm -1The -CH=CH bending peak and stretching peak of were monitored to calculate the gel time and polymerization percentage, respectively. The gel point can be defined as the time after which crosslinking occurs and the photopolymerization reaction can still proceed. The thiol conversion was determined by monitoring the -CH=CH bending peak and stretching peak of the thiol. -1 The height of the -CH=CH2 deformation peak centered at was monitored over time according to equation (1), where X t is the thiol conversion at time (t), A0 is the initial absorbance, and A t is the absorbance at time (t).

[0144] 1650cm -1 ~1620cm -1 in the range of about 1637 cm -1 The peak area at was integrated at the subsequent time (t) and the polymerization percentage (%) at that time was calculated according to formula (2), where P t is the percentage of polymerization at time (t), A0 is the initial absorbance, and A t is the absorbance at time (t). Formula (1):X t =(A0-A t ) / A0 Formula (2):P t =(A0-A t ) / A0×100

[0145] The materials and pyrolysis conditions used to produce the high shrinkage PDC materials are outlined in Table 1.

[0146] [Table 2]

[0147] Example 1 - Silicon Oxycarbide Glass Ceramic Microfluidic Dispenser A first functionalized organosilicon monomer with a high ceramic yield and a second functionalized organosilicon monomer with a low ceramic yield were used at a T of 0.3°C and a T of 1300°C. max It was thermally decomposed at .

[0148] A resin was prepared by mixing 100 parts (wt / wt) of (mercaptopropyl)methylsiloxane homopolymer (about 55% ceramic yield) and 100 parts (wt / wt) of methacryloxypropyl terminated polydimethylsiloxane (about 12% ceramic yield) (i.e., a 1:1 weight ratio of the first functionalized organosilicon monomer to the second functionalized organosilicon monomer) with 0.4 parts (wt / wt) of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), 0.23 parts (wt / wt) of 2,5-bis(5-tert-butylbenzoxazol-2-yl)thiophene (BBOT), and 0.8 parts (wt / wt) of tert-butylhydroquinone (TBHQ).

[0149] After thoroughly mixing the resin components in a vortex mixer and ultrasonic bath, the prepared resin was purged with nitrogen and vacuumed for 1 hour.

[0150] This resin was used to 3D print a bifurcated microfluidic distributor using a digital light projection (DLP) printer (Miicraft Ultra) according to the manufacturer's standard operating procedures to generate a 3D printed green body.

[0151] The printed distributor was pyrolyzed in a tube furnace under a constant (3 L / min) nitrogen flow. Pyrolysis was carried out from 20°C to 100°C at a ramp rate of 1°C / min, followed by 100°C to 600°C at a ramp rate of 0.3°C / min, and held at 600°C for 180 minutes. This was followed by a further ramp to 1300°C at 7°C / min, with holds at 850°C and 1150°C for 60 minutes each. The temperature was held at 1300°C for 60 minutes, followed by a ramp rate of 7°C / min to 500°C, with holds at 850°C and 500°C for 60 minutes each. It was then cooled to 20°C at a ramp rate of 2°C / min, with a hold at 300°C for 60 minutes each.

[0152] The distributor was designed with 0.5 mm inner diameter channels and four bifurcated branches at 140° each, resulting in 16 parallel channels. The printed distributor, shown in Figure 1(a) (top view), was found to accurately reproduce the design, indicating the reliable printing performance of the resin. As shown in Figure 1(b), the side view of the printed distributor before pyrolysis suggests the presence of semicircular channels with inner diameters of approximately 0.5 mm, which are often the smallest channel dimensions obtainable using low-cost DLP-based printers. As shown in Figure 1(c) (side view of pyrolyzed distributor), these channels were found to shrink isotopically by 50%, producing channels with inner diameters of 0.25 mm (measured 250 ± 16 μm). Similarly, closed channels with printed dimensions of 845 μm diameter were pyrolyzed to channels with diameters of 422 μm, as shown in the SEM image of the closed channels in Figure 1(d). Thus, a two-fold increase in resolution was observed between pre- and post-pyrolysis, where an 87.5% reduction in the volume of the printed microchannels was observed.

[0153] The pyrolyzed material was analyzed to be a silicon oxycarbide glass ceramic. Energy dispersive X-ray spectroscopy, shown in FIG. 2(a), suggests the presence of 35.7 at. % Si, 5.7 at. % C, 58.4 at. % O, and 0.16 at. % S in the silica regions, consistent with the elemental composition for a silicon oxycarbide glass ceramic. A transmission electron microscope image, shown in FIG. 2(b), shows phase separation between silica and carbon. Raman spectroscopy, shown in FIG. 2(c), confirmed that carbon was present as free carbon, with 29 wt. % free carbon interspersed. X-ray diffraction spectroscopy, shown in FIG. 2(d), indicated that the silica phase was amorphous.

[0154] Visual inspection and SEM imaging confirmed the absence of any cracks or pores, and BET analysis confirmed the non-porous nature of the sinter, with 0m 2It was confirmed that the sintered body has a BET surface area of ​​700 kg / mm2 / g. The Vickers hardness and electrical conductivity are 700 kg / mm2. 2 and 600 S / m, which are consistent with hardness and conductivity values ​​expected for silicon oxycarbide glass ceramics. The density of the pyrolyzed structure was about 2600 kg / m 3 It was measured to be.

[0155] In a functional group ratio study, methacryloxypropyl terminated polydimethylsiloxane monomer was titrated with (mercaptopropyl)methylsiloxane homopolymer monomer to study the effect of various molar ratios of acrylate to thiol functional groups on the reaction kinetics, total polymerization percentage, and gel point of the resin. The corresponding effect on the weight ratio of monomers and therefore the ceramic yield of the resin and the structural integrity of the pyrolysate was also noted.

[0156] More than 12 molar ratios of thiol to acrylate functional groups were investigated ranging from 0:1 to 3:1. As shown in FIG. 15, methacryloxypropyl terminated polydimethylsiloxane monomer (0:1) without any (mercaptopropyl)methylsiloxane homopolymer monomer (i.e., resin of Example 8) resulted in less than 65% polymerization at gel point and less than 80% total polymerization. Addition of (mercaptopropyl)methylsiloxane homopolymer monomer resulted in a concomitant increase in the polymerization percentage at gel point and the total polymerization percentage. Complete polymerization of the acrylate was observed at a 1.25:1 ratio of thiol:acrylate (FIG. 15(a)), while further increasing the (mercaptopropyl)methylsiloxane homopolymer monomer increased the rate of photopolymerization as evidenced by a decrease in the gel point (FIG. 15(b)) and the time to reach complete polymerization (FIG. 15(c)). However, increasing the amount of (mercaptopropyl)methylsiloxane homopolymer monomer beyond the 1.25:1 molar ratio resulted in increased amounts of residue in the 3D printed bodies and did not improve the ceramic yield of the pyrolysate. As shown in Figure 15(c), a 1.25:1 ratio of thiol:acrylate resulted in the highest ceramic yield and the best structural integrity of the pyrolysate.

[0157] Example 2 - Silicon Oxycarbide Glass Ceramic Microneedle Patch A first functionalized organosilicon monomer with a high ceramic yield and a second functionalized organosilicon monomer with a low ceramic yield were used at a T of 0.3°C and a T of 1300°C. max It was thermally decomposed at .

[0158] A resin was prepared by mixing 100 parts (wt / wt) of (mercaptopropyl)methylsiloxane homopolymer (about 55% ceramic yield) and 100 parts (wt / wt) of methacryloxypropyl terminated polydimethylsiloxane (about 12% ceramic yield) (i.e., a 1:1 weight ratio of the first functionalized organosilicon monomer to the second functionalized organosilicon monomer) with 0.4 parts (wt / wt) of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), 0.23 parts (wt / wt) of 2,5-bis(5-tert-butylbenzoxazol-2-yl)thiophene (BBOT), and 0.8 parts (wt / wt) of tert-butylhydroquinone (TBHQ).

[0159] After thoroughly mixing the resin components in a vortex mixer and ultrasonic bath, the prepared resin was purged with nitrogen and vacuumed for 1 hour.

[0160] This resin was used to 3D print microneedle patches using a digital light projection (DLP) printer (Miicraft Ultra) according to the manufacturer's standard operating procedures to generate 3D printed green bodies.

[0161] The printed patches were pyrolyzed in a tube furnace under a constant (3 L / min) flow of nitrogen. Pyrolysis was performed from 20° C. to 100° C. at a ramp rate of 1° C. / min, followed by a ramp rate of 0.3° C. / min from 100° C. to 600° C., with a hold at 600° C. for 180 min. This was followed by a further ramp at 7° C. / min to 1300° C., with holds at 850° C. and 1150° C. for 60 min each. The temperature was held at 1300° C. for 60 min, followed by a ramp rate of 7° C. / min to 500° C., with holds at 850° C. and 500° C. for 60 min each. It was then cooled to 20° C. at a ramp rate of 2° C. / min, with a hold at 300° C. for 60 min.

[0162] The patch was designed with a 7x7 array of microneedles with 1mm height and base and 0.067mm diameter tip. The printed microneedle patch shown in Figure 3(a) (top view) was found to accurately reproduce the design, indicating the reliable printing performance of the resin. As shown in Figure 3(b), the side view of the printed microneedles before pyrolysis suggests the presence of microneedles with a base diameter of about 1mm and a height of 1mm, which are often the smallest microstructure dimensions obtainable using low-cost DLP-based printers. As shown in Figure 3(c) (side view of pyrolyzed microneedle patch), these needles were found to shrink isotopically by 50%, producing a base diameter of about 0.5mm (measured 498±23μm) and a height of about 0.5mm (measured 494±6μm). As shown in Figure 3(d) (SEM image of the microneedle), single pixel resolution was obtained and maintained during the printing and pyrolysis process. Here, a projected pixel of 30 μm × 30 μm resulted in a post-pyrolysis pixel of approximately 15 μm (measured 16 ± 1 μm), thus a 2-fold increase in resolution between pre-pyrolysis and post-pyrolysis was observed, where a 87.5% reduction in the volume of the printed microstructures was observed.

[0163] Example 3 - Silicon Oxycarbide Disc A first functionalized organosilicon monomer with a high ceramic yield and a second functionalized organosilicon monomer with a low ceramic yield were used at a T of 0.3°C and a T of 1300°C. max It was thermally decomposed at .

[0164] The resin was prepared by mixing 100 parts (wt / wt) of methacryloxypropyl-terminated polydimethylsiloxane (about 12% ceramic yield) with 200 parts (wt / wt) of (mercaptopropyl)methylsiloxane homopolymer (about 55% ceramic yield) (i.e., a 1:2 weight ratio of a first functionalized organosilicon monomer to a second functionalized organosilicon monomer), 0.4 parts (wt / wt) of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), 0.23 parts (wt / wt) of 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBOT), and 0.8 parts (wt / wt) of tert-butylhydroquinone (TBHQ).

[0165] After thoroughly mixing the resin components in a vortex mixer and ultrasonic bath, the prepared resin was purged with nitrogen and vacuumed for 1 hour.

[0166] The resin was photopolymerized under a wavelength of 365 nm by pouring it into a disk-shaped mold (diameter of 10 mm and thickness of 2 mm) to generate a 3D printed green body.

[0167] The resulting green bodies were pyrolyzed in a tube furnace under a constant (3 L / min) nitrogen flow. Pyrolysis was carried out from 20°C to 100°C at a ramp rate of 1°C / min, followed by a ramp rate of 0.3°C / min from 100°C to 600°C, with a hold at 600°C for 180 min. This was followed by a further ramp at 7°C / min to 1300°C, with holds at 850°C and 1150°C for 60 min each. The temperature was held at 1300°C for 60 min, followed by a ramp rate of 7°C / min to 500°C, with holds at 850°C and 500°C for 60 min each. It was then cooled to 20°C at a ramp rate of 2°C / min, with a hold at 300°C for 60 min.

[0168] As shown in Figure 4, pyrolysis of the green body (Figure 4(a)) to silicon oxycarbide (Figure 4(b)) retained all the characteristics of the shaped structure and resulted in a linear shrinkage of about 55% and a volumetric shrinkage of about 91%.

[0169] Example 4 - Silicon Oxycarbide Disc The first functionalized organosilicon monomer and ceramic particles with low ceramic yield were treated with a 0.3°C increase and a T of 1300°C. max It was thermally decomposed at .

[0170] The resin was prepared by mixing 100 parts (wt / wt) methacryloxypropyl-terminated polydimethylsiloxane (approximately 12% ceramic yield) with 20 parts (wt / wt) nonporous silica nanoparticles (particle size of 10 nm to 20 nm), 0.4 parts (wt / wt) phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), 0.23 parts (wt / wt) 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBOT), and 0.8 parts (wt / wt) tert-butylhydroquinone (TBHQ).

[0171] After thoroughly mixing the resin components in a vortex mixer and ultrasonic bath, the prepared resin was purged with nitrogen and vacuumed for 1 hour.

[0172] The resin was photopolymerized under a wavelength of 365 nm by pouring it into a disk-shaped mold (diameter of 10 mm and thickness of 2 mm) to generate a 3D printed green body.

[0173] The resulting green bodies were pyrolyzed in a tube furnace under a constant (3 L / min) nitrogen flow. Pyrolysis was carried out from 20°C to 100°C at a ramp rate of 1°C / min, followed by a ramp rate of 0.3°C / min from 100°C to 600°C, with a hold at 600°C for 180 min. This was followed by a further ramp at 7°C / min to 1300°C, with holds at 850°C and 1150°C for 60 min each. The temperature was held at 1300°C for 60 min, followed by a ramp rate of 7°C / min to 500°C, with holds at 850°C and 500°C for 60 min each. It was then cooled to 20°C at a ramp rate of 2°C / min, with a hold at 300°C for 60 min.

[0174] As shown in Figure 5, pyrolysis of the green body (Figure 5(a)) into silicon oxycarbide (Figure 5(b)) retained all the characteristics of the shaped structure and resulted in a linear shrinkage of about 60% and a volumetric shrinkage of about 94%.

[0175] Example 5 - Silicon Oxycarbide Block A first functionalized organosilicon monomer having a high ceramic yield and a second functionalized organosilicon monomer having a low ceramic yield and ceramic particles were subjected to a 1° C. increase and a T of 1000° C. max It was thermally decomposed at .

[0176] The resin was prepared by mixing 100 parts (wt / wt) of methacryloxypropyl-terminated polydimethylsiloxane (about 12% ceramic yield) with 100 parts (wt / wt) of (mercaptopropyl)methylsiloxane homopolymer (about 55% ceramic yield) (i.e., a 1:1 weight ratio of a first functionalized organosilicon monomer to a second functionalized organosilicon monomer), 10 parts (wt / wt) of nonporous silica nanoparticles (particle size of 10 nm to 20 nm), 0.4 parts (wt / wt) of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), 0.23 parts (wt / wt) of 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBOT), and 0.8 parts (wt / wt) of tert-butylhydroquinone (TBHQ).

[0177] After thoroughly mixing the resin components in a vortex mixer and ultrasonic bath, the prepared resin was purged with nitrogen and vacuumed for 1 hour.

[0178] This resin was 3D printed using a digital light projection (DLP) printer (Miicraft Ultra) following the manufacturer's standard operating procedures to generate 3D printed green bodies.

[0179] The resulting green bodies were pyrolyzed under nitrogen in a tube furnace from 27° C. to 1000° C. at a ramp rate of 1° C. / min, followed by a 60 min hold at 1000° C. Then they were cooled down to 27° C. at a ramp rate of 1° C. / min.

[0180] As shown in Figure 6, pyrolysis of the green body (Figure 6(a)) into silicon oxycarbide (Figure 6(b)) retained all the features of the printed structure and resulted in a linear shrinkage of about 25% and a volumetric shrinkage of about 58%.

[0181] Example 6 - Silica Block A first functionalized organosilicon monomer having a high ceramic yield and a second functionalized organosilicon monomer having a low ceramic yield and ceramic particles were subjected to a 1° C. increase and a T of 1000° C. max It was thermally decomposed at .

[0182] Polydimethylsiloxane (about 12% ceramic yield) was mixed with 100 parts (wt / wt) of (mercaptopropyl)methylsiloxane homopolymer (about 55% ceramic yield) (i.e., a 1:1 weight ratio of a first functionalized organosilicon monomer to a second functionalized organosilicon monomer), 10 parts (wt / wt) of nonporous silica nanoparticles (particle size of 10 nm to 20 nm), 0.4 parts (wt / wt) of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), 0.23 parts (wt / wt) of 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBOT), and 0.8 parts (wt / wt) of tert-butylhydroquinone (TBHQ).

[0183] After thoroughly mixing the resin components in a vortex mixer and ultrasonic bath, the prepared resin was purged with nitrogen and vacuumed for 1 hour.

[0184] This resin was 3D printed using a digital light projection (DLP) printer (Miicraft Ultra) following the manufacturer's standard operating procedures to generate 3D printed green bodies.

[0185] The resulting green bodies were pyrolyzed under oxygen in a tube furnace from 27° C. to 1000° C. at a ramp rate of 1° C. / min, followed by a 60 min hold at 1000° C. Then they were cooled down to 27° C. at a ramp rate of 1° C. / min.

[0186] As shown in Figure 7, pyrolysis of the green body (Figure 7(a)) to silica (Figure 7(b)) preserved all the features of the printed structures and resulted in a linear shrinkage of about 25% and a volumetric shrinkage of about 58%.

[0187] Example 7 - Silica disk A first functionalized organosilicon monomer having a high ceramic yield and a second functionalized organosilicon monomer having a low ceramic yield and ceramic particles were subjected to a 1° C. increase and a T of 1000° C. max It was thermally decomposed at .

[0188] The resin was prepared by mixing 100 parts (wt / wt) methacryloxypropyl-terminated polydimethylsiloxane (about 12% ceramic yield) with 100 parts (wt / wt) (mercaptopropyl)methylsiloxane homopolymer (about 55% ceramic yield), 25 parts (wt / wt) nonporous silica nanoparticles (particle size 10 nm to 20 nm), 0.4 parts (wt / wt) phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), 0.23 parts (wt / wt) 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBOT), and 0.8 parts (wt / wt) tert-butylhydroquinone (TBHQ).

[0189] After thoroughly mixing the resin components in a vortex mixer and ultrasonic bath, the prepared resin was purged with nitrogen and vacuumed for 1 hour.

[0190] The resin was photopolymerized under a wavelength of 365 nm by pouring it into a disk-shaped mold (diameter of 10 mm and thickness of 2 mm) to generate a 3D printed green body.

[0191] The resulting green bodies were pyrolyzed under oxygen in a tube furnace from 27° C. to 1000° C. at a ramp rate of 1° C. / min, followed by a 60 min hold at 1000° C. Then they were cooled down to 27° C. at a ramp rate of 1° C. / min.

[0192] As shown in Figure 8, pyrolysis of the green body (Figure 8(a)) to silica (Figure 8(b)) preserved all the features of the printed structures and resulted in a linear shrinkage of about 25% and a volumetric shrinkage of about 58%.

[0193] Example 8 (Comparative) – Silicon Oxycarbide The first functionalized organosilicon monomer with low ceramic yield was used with a 0.3°C increase and a T of 1300°C. max It was thermally decomposed at .

[0194] A resin was prepared by mixing 100 parts (wt / wt) of methacryloxypropyl-terminated polydimethylsiloxane (approximately 12% ceramic yield) with 0.4 parts (wt / wt) of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), 0.23 parts (wt / wt) of 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBOT), and 0.8 parts (wt / wt) of tert-butylhydroquinone (TBHQ).

[0195] After thoroughly mixing the resin components in a vortex mixer and ultrasonic bath, the prepared resin was purged with nitrogen and vacuumed for 1 hour.

[0196] The resin was photopolymerized under a wavelength of 365 nm by pouring it into a disk-shaped mold (diameter of 10 mm and thickness of 2 mm) to generate a 3D printed green body.

[0197] The resulting green bodies were pyrolyzed in a tube furnace under a constant (3 L / min) nitrogen flow. Pyrolysis was carried out from 20°C to 100°C at a ramp rate of 1°C / min, followed by a ramp rate of 0.3°C / min from 100°C to 600°C, with a hold at 600°C for 180 min. This was followed by a further ramp at 7°C / min to 1300°C, with holds at 850°C and 1150°C for 60 min each. The temperature was held at 1300°C for 60 min, followed by a ramp rate of 7°C / min to 500°C, with holds at 850°C and 500°C for 60 min each. It was then cooled to 20°C at a ramp rate of 2°C / min, with a hold at 300°C for 60 min.

[0198] As shown in Figure 9, when a green body (Figure 9(a)) is pyrolyzed into silicon oxycarbide (Figure 9(b)), the shape or structural integrity of the green body is not retained.

[0199] Example 9 - Silicon oxycarbide glass ceramic microstructure scaffold A first functionalized organosilicon monomer with a high ceramic yield and a second functionalized organosilicon monomer with a low ceramic yield were used at a T of 0.3°C and a T of 1300°C. max It was thermally decomposed at .

[0200] The resin was prepared by mixing 100 parts (wt / wt) of (mercaptopropyl)methylsiloxane homopolymer (about 55% ceramic yield) and 100 parts (wt / wt) of methacryloxypropyl terminated polydimethylsiloxane (about 12% ceramic yield) (i.e., a 1:1 weight ratio of the first functionalized organosilicon monomer to the second functionalized organosilicon monomer) with 0.4 parts (wt / wt) of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), 0.23 parts (wt / wt) of 2,5-bis(5-tert-butylbenzoxazol-2-yl)thiophene (BBOT), and 0.8 parts (wt / wt) of tert-butylhydroquinone (TBHQ).

[0201] After thoroughly mixing the resin components in a vortex mixer and ultrasonic bath, the prepared resin was purged with nitrogen and vacuumed for 1 hour.

[0202] This resin was used to 3D print pyramidal bodies with microstructured scaffolding using a digital light projection (DLP) printer (Miicraft Ultra) following the manufacturer's standard operating procedures to generate 3D printed green bodies.

[0203] The printed pyramids were pyrolyzed in a tube furnace under a constant (3 L / min) flow of nitrogen. Pyrolysis was carried out from 20°C to 100°C at a ramp rate of 1°C / min, followed by 100°C to 600°C at a ramp rate of 0.3°C / min, with a hold at 600°C for 180 min. This was followed by a further ramp to 1300°C at 7°C / min, with holds at 850°C and 1150°C for 60 min each. The temperature was held at 1300°C for 60 min, followed by a ramp rate of 7°C / min to 500°C, with holds at 850°C and 500°C for 60 min each. It was then cooled to 20°C at a ramp rate of 2°C / min, with a hold at 300°C for 60 min.

[0204] The printed pyramid body was designed with an equilateral triangular framework, where each arm of the triangle that constitutes the framework is 3.9 mm long and the overall height of the pyramid body is 10 mm. The printed pyramid body was elevated 1 mm from the base. The printed pyramid body shown in FIG. 10(a) (side view) was found to accurately replicate the design, indicating the reliable printing performance of the resin. In FIG. 10(b) a side view of the pyramid body that was pyrolyzed is shown. The overall height of the pyrolyzed pyramid body was found to be 5 mm and each arm of the triangle that constitutes the framework was found to be 2 mm. Thus, a 2-fold increase in resolution was observed between pre-pyrolysis and post-pyrolysis, where a 87.5% reduction in the volume of the printed microstructure was observed.

[0205] Example 10 - Silicon oxycarbide porous microfluidic chip A first functionalized organosilicon monomer having a high ceramic yield and a second functionalized organosilicon monomer having a low ceramic yield and porous ceramic particles were prepared by heating at a T of 0.3° C. and a T of 600° C. max It was thermally decomposed at .

[0206] The resin was prepared by mixing 100 parts (wt / wt) of methacryloxypropyl-terminated polydimethylsiloxane (about 12% ceramic yield) with 100 parts (wt / wt) of (mercaptopropyl)methylsiloxane homopolymer (about 55% ceramic yield) (i.e., a 1:1 weight ratio of a first functionalized organosilicon monomer to a second functionalized organosilicon monomer), 5 parts (wt / wt) of porous silica nanoparticles (particle size of 10 nm to 20 nm), 0.4 parts (wt / wt) of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), 0.23 parts (wt / wt) of 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBOT), and 0.8 parts (wt / wt) of tert-butylhydroquinone (TBHQ).

[0207] After thoroughly mixing the resin components in a vortex mixer and ultrasonic bath, the prepared resin was purged with nitrogen and vacuumed for 1 hour.

[0208] The microfluidic chip was 3D printed using this resin using a digital light projection (DLP) printer (Miicraft Ultra) following the manufacturer's standard operating procedures to generate a 3D printed green body.

[0209] The printed chips were pyrolyzed under vacuum in a tube furnace. Pyrolysis was carried out from 25° C. to 100° C. at a ramp rate of 1° C. / min, followed by 100° C. to 600° C. at a ramp rate of 0.5° C. / min. The temperature was held at 600° C. for 180 minutes, followed by cooling at a ramp rate of 2° C. / min to 450° C. and held for 60 minutes, then cooling at a ramp rate of 2° C. / min to 300° C. and held for 60 minutes. Cooling then continued to 25° C. at a ramp rate of 2° C. / min.

[0210] The microfluidic chip was designed with a cylindrical channel with an inner diameter of 360 μm and a length of 100 mm, as shown in FIG. 11 (left). The resulting inner diameter of the channel was 354 μm. After pyrolysis, the channel diameter shrunk to 190 μm, as shown in FIG. 11. A 1.8-fold increase in resolution was observed between pre- and post-pyrolysis, and an 84.2% reduction in the volume of the microfluidic chip was observed.

[0211] Example 11 - Resin Shelf Life Study method Using RT-FTIR spectroscopy, the resins exemplified in Examples 1 and 2 were studied over a period of 27 days to understand their stability when stored at 4° C. The C═C bond (1620 cm) at various times was -1 ), C=O bond (1750cm -1 ~1690cm -1 ), Si-(CH3)2 bond (1335cm -1 ~1280cm -1 ), and Si–O–Si bonds (1163 cm -1 ) changes were studied.

[0212] result The results are presented in Figure 13. The resins did not show any signs of decomposition during the course of this study. Similar results were seen for the gel point (time to gelation during photopolymerization). Resins stored at 4°C did not show any significant change in gel point throughout this study. This study demonstrates that the stability of the exemplified resins containing a first functionalized organosilicon monomer and a second functionalized organosilicon monomer is not reduced when stored at low temperatures.

[0213] Example 12 - Study of Resin Oxygen Resistance method The oxygen resistance of the resins illustrated in Examples 1 and 2 and the resin illustrated in Example 8 was studied. To minimize the effect of additives, the resins were prepared with BAPO rather than TBHQ or BBOT.

[0214] A cylindrical mold with an inner diameter of 10 mm and a height of 2 mm was designed and 3D printed. The inner surface of the mold was sprayed with Teflon spray to minimize resin adhesion. Samples with a volume of approximately 160 μL were transferred into the mold and then exposed to light with a wavelength of 365 nm using a UV crosslinker. The polymerization percentage for these resins was also studied using real-time FTIR.

[0215] result The cure depth and polymerization percentage were observed versus exposure time. Figure 14 shows the much more controlled and rapid cure of the resins of Examples 1 and 2 compared to the resin of Example 8, which is advantageous for photopolymerization-based 3D printing. This study demonstrates the rapid and controlled cure of the illustrated resins of Examples 1 and 2 compared to the resin of Example 8.

[0216] The above embodiments are merely preferred examples of the present disclosure. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present disclosure, and they shall fall within the protection scope of the present disclosure.

[0217] Where any prior art publication is referenced in this specification, it should be understood that such reference is not an admission that this publication forms part of the common general knowledge in the art in Australia or any other country.

[0218] In the appended claims and the above detailed description of the invention, unless the context otherwise requires, either by express language or necessary implication, the term "comprise" or variations such as "comprises" or "comprising" are used in their inclusive sense, i.e., they are used to specify the presence of stated features but are not used to exclude the presence or addition of further features in various embodiments of the invention.

[0219] As used herein, unless the context otherwise requires by express language or necessary implication, the articles "a" and "an" are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. By way of example, "an element" means one element or more than one element.

Claims

1. A preceramic resin for forming a polymer-derived ceramic material, comprising a first functionalized organosilicon monomer having a first ceramic yield of 50% or less, a) A second functionalized organosilicon monomer having a second ceramic yield, wherein the second ceramic yield is at least 5% greater than the first ceramic yield, and b) Ceramic particles, A pre-ceramic resin containing one or more of the following.

2. The first ceramic yield is 30% or less, and / or The second ceramic yield is 10% or more greater than the first ceramic yield. The preceramic resin according to claim 1.

3. The first functionalized organosilicon monomer is The chemical structures of the following equations 1, 2, 3, 4, and 5 are as follows: 【Chemistry 1】 (In the formula, n represents the main chain structure of repeating motifs containing silicon atoms, and is an independent integer between 2 and 15, and R １ 、 R ２ 、 R ３ 、 and R ４ are each independently, for each integer n, selected independently from the group consisting of H, C １ to C １８ substituted or unsubstituted alkyl, C １ to C １８ substituted or unsubstituted alkyl ether, phenyl, and halide, provided that the pair of R １ and R ２ and the pair of R ３ and R ４ are not both H, alkyl ether, or halide for all integers n), having polysiloxane, polycarbosiloxane, polycarbosilane, polysilylcarbodiimide, and polysilazane, C １ ~C １８ Substituted or unsubstituted alkyl, C １ ~C １８ Polysilsesquioxanes, polysilsesquicarbodiimides, and polysilsesquiazanes substituted with one or more groups selected from the group consisting of substituted or unsubstituted alkyl ethers, phenyls, and halides, The chemical structures of formulas 6, 7, and 8 are as follows: 【Chemistry 2】 (In the formula, n represents the main chain structure of repeating motifs containing silicon atoms, and is an independent integer between 2 and 15. R １ , R ２ , R ３ , and R ４ This is as defined above, and, R ５ and R ６ For each integer n, H, OH, and C are independent. １ ~C １８ Substituted or unsubstituted alkyl, C １ ~C １８ Polyborosilanes, polyborosiloxanes, and polyborosilazanes having (independently selected from the group consisting of substituted or unsubstituted alkyl ethers and phenyl) The preceramic resin according to claim 1 or 2, which is based on an organosilicon monomer independently selected from the group consisting of the following.

4. The preceramic resin according to claim 1 or 2, wherein the first functionalized organosilicon monomer is functionalized with a thermopolymerizable functional group and / or a photopolymerizable functional group.

5. The preceramic resin according to claim 1 or 2, wherein the first functionalized organosilicon monomer is a polysiloxane methacrylateoxypropyl-terminated polydimethylsiloxane.

6. The preceramic resin according to claim 1 or 2, wherein the second functionalized organosilicon monomer is present and is a polysiloxane (mercaptopropyl)methylsiloxane homopolymer.

7. The preceramic resin according to claim 1 or 2, wherein the first functionalized organosilicon monomer and the second functionalized organosilicon monomer are present in the preceramic resin in a ratio of 1:1 to 1:2 with respect to their polymerizable functional groups.

8. The preceramic resin according to claim 1 or 2, wherein the second functionalized organosilicon monomer is present, and one of the first functionalized organosilicon monomer and the second functionalized organosilicon monomer is functionalized with an acrylate polymerizable functional group, and the other is functionalized with a thiol polymerizable functional group.

9. The preceramic resin according to claim 1 or 2, wherein the ceramic particles are present.

10. A polymer-derived ceramic material formed from the preceramic resin according to claim 1 or 2.

11. A polymer-derived ceramic material formed by the thermal decomposition of a green body, characterized by a linear shrinkage of 30% or more and a volume shrinkage of approximately 66% or more.

12. A polymer-derived silica ceramic material formed by the thermal decomposition of a green body, characterized by a linear shrinkage of 20% or more and a volume shrinkage of approximately 49% or more.

13. A polymer-derived glass ceramic material formed by thermal decomposition of a green body, comprising the preceramic resin described in claim 1 or 2.

14. A method for forming a polymer-derived ceramic material, a) Forming a preceramic polymer by subjecting the preceramic resin according to claim 1 or 2 to polymerization conditions, b) Subjecting the preceramic polymer to thermal decomposition conditions to form a polymer-derived ceramic material, Methods that include...

15. A method for forming a polymer-derived ceramic material, a) Forming a preceramic polymer by subjecting a preceramic resin, which forms a polymer-derived ceramic material, to polymerization conditions, b) Subjecting the preceramic polymer to thermal decomposition conditions to form a polymer-derived ceramic material, Includes, Herein, the formation of the polymer-derived ceramic material from the preceramic polymer proceeds through a porous stage, and the thermal decomposition conditions include a temperature rise rate of 10°C / min or less over a period of time within the range of the porous stage.

16. A method for forming a polymer-derived ceramic material, a) Forming a preceramic polymer by subjecting a preceramic resin, which forms a polymer-derived ceramic material, to polymerization conditions, b) Subjecting the preceramic polymer to thermal decomposition conditions to form a polymer-derived ceramic material, Includes, Here, the thermal decomposition conditions include a method in which the temperature rise rate is 10°C / min or less over a period of time within a temperature range of 200°C to 900°C.

17. The method according to claim 15 or 16, wherein the rate of increase is used over a period of time within a temperature range of 200°C to 600°C.

18. The method according to claim 15 or 16, wherein the thermal decomposition conditions include a maximum temperature below the porous transition temperature of the polymer-derived ceramic material; and / or a minimum temperature above the porous transition temperature.

19. The method according to claim 15 or 16, further comprising a preliminary step of shaping the preceramic resin using a 3D printer.

20. A polymer-derived ceramic material formed by the method described in claim 15 or 16.

Images