Resins for porous organosilicon polymers

Abstract

The present disclosure relates to resins for forming organosilicon polymeric materials and particularly porous organosilicon polymeric materials, to organosilicon polymeric materials and particularly porous organosilicon polymeric materials, and to methods of formation of organosilicon polymeric materials and particularly porous organosilicon polymeric materials.

Description

RESINS FOR POROUS ORGANOSILICON POLYMERSTECHNICAL FIELD

[0001] The present disclosure relates to resins for forming organosilicon polymeric materials and particularly porous organosilicon polymeric materials, to organosilicon polymeric materials and particularly porous organosilicon polymeric materials, and to methods of formation of organosilicon polymeric materials and particularly porous organosilicon polymeric materials.BACKGROUND ART

[0002] The use of flexible polymeric materials is now widespread in a broad range of emerging technologies, including biomedical devices, wound dressings, electronics, thermal interface materials, seals, personal care products, and soft robotics.

[0003] Among the various polymeric materials explored for these applications, organosilicon polymers have attracted considerable interest owing to desirable chemical and physical properties which may be obtained, including transparency, flexibility, ease of fabrication, chemical and mechanical stability, biocompatibility, and cost-effectiveness.

[0004] In some applications the incorporation of porosity into organosilicon polymers is desirable for providing additional advantageous properties such as increased surface area, enhanced deformability, and reduced weight. However, porous organosilicon polymers, or at least organosilicon polymers having a useful extent of porosity or pores of controlled size or distribution, are not available. One reason for this is that existing techniques for producing organosilicon polymers are not readily adaptable to enable production of internal porous architecture. They face significant challenges in achieving porosity at all, or at least a useful extent of porosity, and control of pore size and distribution, and particularly at the submicron scale which can be crucial for achieving usable mechanical, optical and / or thermal properties in the final material. For example, conventional organosilicon polymer manufacturing is typically based on thermal injection moulding, wherein the intrinsically high temperatures (i.e. greater than 100 °C) used in processing make it difficult or impossible to introduce porosity, or at least a useful extent of porosity or pores of controlled size or distribution, to the organosilicon polymers. These shortcomings have restricted the availability of porous organosilicon polymers including in applications where the advantageous chemical, physical and mechanical propertiesof such materials are in high demand.

[0005] There is a need for increased availability of porous organosilicon polymers, or at least organosilicon polymers having a useful extent of porosity or pores of controlled size, and a need for improved methods of producing porosity in organosilicon polymers. The provision of organosilicon polymers with a controlled extent of porosity, pore size and / or pore distribution, or techniques for the production of such materials, would be highly desirable. Such provision would enable adoption of these materials in many existing and emerging applications.SUMMARY

[0006] The present disclosure is predicated on the acquired knowledge that a resin comprising certain components, and / or the post-polymerisation evacuation processing of a resin comprising certain components, enables the formation of beneficial polymeric materials for forming porous polymeric materials, and enables the formation of porous polymeric materials.

[0007] A first aspect of the present disclosure provides a resin for forming a polymeric material, said resin comprising:a) a functionalised organosilicon monomer; andb) a porogen,wherein the porogen is present in an amount of at least 10 wt% of functionalised organosilicon monomer present in the resin.

[0008] It has surprisingly been found that a resin in accordance with the present disclosure enables the formation of an organosilicon polymeric material having advantageous porosity characteristics. The resin comprising at least 10 wt% porogen based on the weight of functionalised organosilicon monomer present in the resin advantageously contributes to forming meso- and / or macro-scale porosity, in a controllable way, including highly porous materials, when the resin is reacted to form a polymeric material and subject to a postpolymerisation evacuation step as described herein. The control of porosity arises from the selection of porogen, its amount, and the post-polymerisation evacuation step as described herein. Generally speaking, a higher molecular weight porogen enables the formation of comparatively larger pores as compared to use of a lower molecular weight porogen, and a higher amount of porogen enables formation of greater porosity as compared to a lower amount of porogen. It has been found that at least 10 wt% porogen based on the weight of functionalised organosilicon monomer present in the resin is advantageous for providing usable porosity in abroad range of applications. In addition, the porosity of polymeric material formed is predominantly open-cell, which is desirable in a broad range of applications.

[0009] Another aspect of the present disclosure provides a polymeric material formed from a resin according to the first aspect.

[0010] Another aspect of the present disclosure provides an organosilicon polymeric material, said polymeric material comprising:a) a polymerised functionalised organosilicon monomer; andb) a porogenwherein the porogen is present in an amount of at least 10 wt% of polymerised functionalised organosilicon monomer present in the polymeric material.

[0011] Another aspect of the present disclosure provides a macro- and / or meso-porous organosilicon polymeric material comprising polymerised functionalised organosilicon monomer.

[0012] An organosilicon polymeric material in accordance with the present disclosure advantageously contains, or enables the formation of via a post-polymerisation evacuation step as described herein, meso- and / or macro- porosity, including controlled pore size, distribution and extent of porosity. Such porosity enables favourable mechanical, chemical, and / or optical properties such as tunable surface area, enhanced deformability, and reduced weight of the polymeric material.

[0013] Another aspect of the present disclosure provides a method for forming an organosilicon polymeric material, comprising subjecting a resin according to the first aspect to polymerising conditions to form an organosilicon polymeric material.

[0014] Another aspect of the present disclosure provides a method for forming a macro-and / or meso-porous organosilicon polymeric material, comprising:a) subjecting a resin comprising a functionalised organosilicon monomer and a porogen to polymerising conditions to form an organosilicon polymeric material; andb) removing at least a portion of one or both of porogen and unpolymerised functionalised organosilicon monomer from within the organosilicon polymeric material to form a macro- and / or meso-porous organosilicon polymeric material.

[0015] Step b) of this aspect represents the aforementioned post-polymerisation evacuationstep.

[0016] Another aspect of the present disclosure provides a micro- and / or meso-porous organosilicon polymeric material formed by the method of the preceding aspects.DESCRIPTION OF THE FIGURES

[0017] Figure 1 is an SEM micrograph of a porous polydimethylsiloxane polymeric material prepared using an acrylate-functionalised organosilicon monomer, 5% SiO2 and 50% w / w polyethylene glycol (PEG) 200 in accordance with example 1.

[0018] Figure 2 is an SEM micrograph of a porous polydimethylsiloxane polymeric material prepared using an acrylate-functionalised organosilicon monomer, 5% SiCh and 10% w / w PEG 200 in accordance with example 2.

[0019] Figure 3 is an SEM micrograph of a porous polydimethylsiloxane polymeric material prepared using an acrylate-functionalised organosilicon monomer, 5% SiCh and 30% w / w PEG 200 in accordance with example 3.

[0020] Figure 4 is an SEM micrograph of a porous polydimethylsiloxane polymeric material prepared using an acrylate-functionalised organosilicon monomer, 5% SiCh and 70% w / w PEG 200 in accordance with example 4.

[0021] Figure 5 is an SEM micrograph of a porous polydimethylsiloxane polymeric material prepared using an acrylate-functionalised organosilicon monomer, 5% SiCF and 100% w / w PEG 200 in accordance with example 5.

[0022] Figure 6 is an SEM micrograph of a porous polydimethylsiloxane polymeric material prepared using an acrylate resin with acrylate-functionalised organosilicon monomer, 5% SiCh, and 50% w / w PEG 600 in accordance with example 6.

[0023] Figure 7 is an SEM micrograph of a porous polydimethylsiloxane polymeric material prepared using an acrylate-functionalised organosilicon monomer, 5% SiCh, and 50% w / w di(ethylene glycol) in accordance with example 7.

[0024] Figure 8 is an SEM micrograph of a porous polydimethylsiloxane polymeric material prepared using an acrylate resin with 5% SiCh, 50% w / w propylene glycol in accordance with example 8.

[0025] Figure 9 is an SEM micrograph of a porous polydimethylsiloxane polymeric material prepared using an acrylate-functionalised organosilicon monomer, 5% SiCh, and 50% w / wglycidol in accordance with example 9.

[0026] Figure 10 is an SEM micrograph of a porous poly dimethylsiloxane polymeric material prepared with an acrylate resin with 5% SiCh, 25% w / w PEG 400, 25% w / w triethanolamine in accordance with example 10.

[0027] Figure 11 is SEM micrographs of a porous polydimethylsiloxane polymeric material prepared with an acrylate-functionalised organosilicon monomer and 50% w / w PEG 400 in accordance with example 11.

[0028] Figure 12 is SEM micrographs of a porous polydimethylsiloxane polymeric material prepared with an acrylate-functionalised organosilicon monomer, a thiol-functionalised dual monomer, and 25% w / w PEG 400 in accordance with example 12.

[0029] Figure 13 is SEM micrographs of a non-porous poly dimethylsiloxane polymeric material prepared as a negative control in accordance with example 13.

[0030] Figure 14 is thermal analysis traces of a porous polydimethylsiloxane article produced in accordance with Examples 11, as assessed by Thermogravimetric Analysis (TGA), Derivative Thermogravimetry (DTG), Differential Scanning Calorimetry (DSC), and Derivative Differential Scanning Calorimetry (DDSC).

[0031] Figure 15 are chromatograms of the acetonitrile (ACN) or methanol (MeOH) solvents collected from the first (before washing) and last (after washing) wash cycles of a solvent washing procedure applied to a porous polydimethylsiloxane article produced in accordance with example 11 as analysed by High-Performance Liquid Chromatography with Diode Array Detection (HPLC-DAD).DETAILED DESCRIPTION

[0032] Organosilicon polymeric materials are generally composed of networks of repeating silicon atom-containing motifs. One example of organosilicon polymeric materials is poly(dimethyl siloxane) which may be thought of as composed of networks of repeating dimethyl siloxane motifs. Organosilicon polymeric materials often possess properties that are beneficial for use in many industrial applications, such as the property of biocompatibility which is conducive to biomedicine and healthcare applications, also thermal and chemical resistivity which is desirable in the automotive and chemical engineering industry, and advantageous biofouling properties which is useful for food safety.

[0033] Organosilicon polymeric materials are generally formed by a process which involvesthe polymerisation of a polymerisable organosilicon monomer contained within a resin; or in other words, are generally formed by subjecting a resin comprising a functionalised (polymerisable) organosilicon monomer to polymerising conditions.

[0034] Introducing porosity into organosilicon polymeric materials, or at least introducing a useful extent of porosity or pores of controlled size or distribution, has proved to be elusive.

[0035] The present disclosure relates to resins useful for forming organosilicon polymeric materials from which porous organosilicon polymeric materials are formable, to porous organosilicon polymeric materials having meso- and / or macro- porosity, and to processes for preparing the organosilicon polymeric materials. That is, the present disclosure is concerned with resins which contain certain components as detailed herein, being at least a functionalised organosilicon monomer and a porogen, to give organosilicon polymeric materials which may comprise a porogen. The present disclosure is concerned with porous organosilicon polymeric materials which may be formed from organosilicon polymeric materials comprising a porogen, by a post-polymerisation evacuation step. The porous organosilicon polymeric materials may generally be said to be meso- and / or macro-porous and to comprise polymerised functionalised organosilicon monomer. That is, the resins of the present disclosure find particular utility in forming organosilicon polymeric materials using a step of polymerisation. The step of polymerisation as preferably performed as part of a 3D printing process and as such the functionalised organosilicon monomer is preferably polymerisable as part of a 3D printing process. The present disclosure also relates to methods for forming organosilicon polymeric materials using a step of polymerisation, or in other words by subjecting a functionalised organosilicon monomer to polymerising conditions, which materials may comprise a porogen, and to porous organosilicon polymeric materials using a post-polymerisation evacuation step in which at least a portion of one or both of porogen and unpolymerised organosilicon monomer are removed from the un-evacuated material.

[0036] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure, preferred methods and materials are described. For the purposes of the present disclosure, a number of terms are defined throughout.Resins

[0037] In embodiments, resins for forming a polymeric material comprise a functionalised organosilicon monomer and a porogen, including wherein the porogen is present in an amount of at least 10 wt% of functionalised organosilicon monomer present in the resin.Functionalised Organosilicon Monomer

[0038] An “organosilicon compound” is a chemical compound with a chemical structure that contains silicon atoms covalently bonded to carbon atoms. A “organosilicon polymeric material” is a material formed by the polymerisation of at least one functionalised organosilicon monomer. A “functionalised organosilicon monomer” is an organosilicon compound capable of polymerising to form an organosilicon polymeric material. Generally speaking, a functionalised organosilicon monomer may be thought of as an organosilicon compound containing a polymerisable functional group. In other words, a functionalised organosilicon monomer may be said to be “based on” an organosilicon compound, being an organosilicon compound that has been functionalised with a polymerisable functional group. The organosilicon compound may itself be a polymer, containing a backbone structure of repeating silicon atom-containing motifs. The polymerisable functional group may be substituted at one or more points of the organosilicon compound including, in the case of organosilicon polymeric monomers, at any point(s) along a backbone structure. Alternatively, or in addition, and especially in the case of organosilicon monomers, the polymerisable functional group may be terminally substituted, i.e. at one or more end groups of a backbone structure. By “substituted” in reference to a functionalised organosilicon monomer is meant that any one or more non-polymerisable chemical groups (in context of the intended polymerisation reaction) bound to an atom under consideration of an organosilicon compound is replaced by a polymerisable functional group, provided that the atom's valence is not exceeded and a stable compound results.

[0039] Examples of organosilicon compounds upon which the functionalised organosilicon monomers are based, include polysiloxanes (such as poly (dimethyl siloxane)), polycarbosiloxanes, polysilsesquioxanes, polycarbosilanes, polysilylcarbodiimides, polysilsesquicarbodiimides, polysilazanes, polysilsesquiazanes, polyborosilanes, polyborosiloxanes and polyborosilazanes. As silicon and carbon atoms are generally tetravalent, an organosilicon compound, including the backbone structure of organosilicon polymericorganosilicon polymeric compounds, is generally substituted with carbon-containing organic chemical groups. By “substituted” in reference to an organosilicon compound is meantthat any one or more hydrogen atoms bound to an atom under consideration is replaced, provided that the atom's valence is not exceeded and a stable compound results. Non-limiting examples of suitable substituents include those of the R-groups as defined below.

[0040] In some embodiments, the organosilicon compound upon which the functionalised organosilicon monomer is based is a polysiloxane. In some embodiments, the organosilicon compound is poly(dimethyl siloxane).

[0041] In some embodiments, the organosilicon compound upon which a functionalised organosilicon monomers is based is selected from one or more of a polysiloxane, polycarbosiloxane, polycarbosilane, polysilylcarbodiimide and a polysilazane having the following chemical structures of Formula 1, Formula 2, Formula 3, Formula 4 and Formula 5, respectively:Formula 4 Formula 5wherein:n represents a backbone structure of repeating silicon atom-containing motifs and is independently an integer of from 2 to 15; andRi, R2, R3 and R4 are independently selected from the group consisting of H, a Ci-Cis substituted or unsubstituted alkyl, a Ci-Cis substituted or unsubstituted alkyl ether, a phenyl and a halide, independently for each integer of n, with the proviso that the pairs of Ri and R2 and R3 and R4 are not both H, alkyl ether or halide for every integer of n. In some embodiments, the pairs of Ri and R2 and R3 and R4 are not both H, alkyl ether or halide for any integer of n. embodiments, each of Ri and R2 and R3 and R4 are identical for every integer of n.

[0042] In Formulas 2, 3 and 5, the hydrogen atoms of the CH2 and NH groups may also be substituted with one or more groups as defined for Ri. As stated above, an organosilicon compound is a chemical compound with a chemical structure that contains silicon atoms covalently bonded to carbon atoms, which includes organosilicon monomers of Formulas 1 to 5 where n is an integer equal to 1. That is, in Formulas 1 to 5, n may independently be an integerof 1 or more, or an integer of from 1 to 15.

[0043] In some embodiments, the organosilicon compound upon which a functionalised organosilicon monomers is based is a polyoctahedral silsesquioxane, in some embodiments being selected from one or more of a polysilsesquioxane, polysilsesquicarbodiimide and a polysilsesquiazane substituted with one or more groups as defined for Ri. In other words, in these embodiments, the polyoctahedral silsesquioxane is substituted with one or more groups selected from the group consisting of a Ci-Cis substituted or unsubstituted alkyl, a Ci-Cis substituted or unsubstituted alkyl ether, a phenyl and a halide.

[0044] In some embodiments, the organosilicon compound upon which a functionalised organosilicon monomer is based is selected from one or more of a polyborosilane, a polyborosiloxane and a polyborosilazane having the following chemical structures of Formula 6, Formula 7 and Formula 8, respectively:Formula 6 Formula 7 Formula 8 wherein:n represents a backbone structure of repeating silicon atom-containing motifs and is independently an integer of from 2 to 15;Ri, R2, R3 and R4 are as defined above; andR5 and Rs are independently selected from the group consisting of H, OH, a Ci-Cis substituted or unsubstituted alkyl, a Ci-Cis substituted or unsubstituted alkyl ether and a phenyl, independently for each integer of n. Like for Ri, R2, R3 and R4, in some embodiments R5 and Re are identical for every integer of n.

[0045] As stated above, an organosilicon is a chemical compound with a chemical structure that contains silicon atoms covalently bonded to carbon atoms, which includes organosilicon compounds of Formulas 6 to 8 where n is an integer equal to 1. That is, in Formulas 6 to 8, n may independently be an integer of 1 or more, or an integer of from 1 to 15.

[0046] In some embodiments, the organosilicon compound is selected from one or more of a polysiloxane, polycarbosiloxane and a polycarbosilane wherein n is independently an integer of from 2 to 5 and Ri, R2, R3 and R4 are identical for every integer of n and independentlyselected from the group consisting of H, methyl and isobutyl, with the proviso that the pairs of Ri and R2 and R3 and R4 are not both H, and a polysilsesquioxane substituted with a group as defined for Ri and in some embodiments isobutyl.

[0047] In some embodiments, the organosilicon compound is a polysiloxane wherein n is independently an integer of from 2 to 5 and Ri, R2, R3 and R4 are identical for every integer of n and independently selected from the group consisting of H, methyl and isobutyl, with the proviso that the pairs of Ri and R2 and R3 and R4 are not both H.

[0048] A functionalised organosilicon monomer in accordance with the present disclosure is an organosilicon compound as described above that contains a polymerisable functional group. The functionalised organosilicon monomer may be functionalised with other, non-polymerisable functional groups, provided the organosilicon compound monomer is functionalised with at least one polymerisable functional group.

[0049] In embodiments, a functionalised organosilicon monomer may be obtained by substituting any one or more of Ri, R2, R3 and R4 as defined above, or a terminal group(s), of an organosilicon compound, with one or more of one or more types of polymerisable functional groups. Polymerisable functional groups of different “types” are those having different chemical structures. The type of polymerisable functional group(s) used is not particularly critical provided that it provides for polymerisation of the organosilicon monomer(s). One type of polymerisable functional group may be used, selected such that it reacts with itself, or alternatively two or more types of polymerisable functional groups may be used, selected such that they react with (i.e. are complementary to) each other. Alternatively, or in addition, polymerisable functional groups may be selected such that they react with a crosslinking agent and / or functionalised organic monomer added to the resin.

[0050] Functionalised organosilicon monomers tend to be characterisable by different reactivities inasmuch as forming polymeric materials characterised by different degrees of polymerisation. As in, a functionalised organosilicon monomer may react with itself or with another functionalised organosilicon monomer (optionally via a crosslinking agent) to form polymeric materials characterised by a low, moderate or high degree of polymerisation. Functionalised organosilicon monomer may be selected based on a degree of polymerisation that it forms in polymerising; or in other words, may be selected for forming a polymeric material that is characterised by a particular degree of polymerisation.

[0051] The term “degree of polymerisation” refers to the polymerisation yield, being the ratioof reacted (polymerised / crosslinked) polymerisable functional groups or monomers to total (reacted and unreacted (unpolymerised / uncrosslinked)) polymerisable functional groups or monomers in a polymeric material (i.e. relative to what it is intended to polymerise with, for example itself and / or another functionalised monomer(s), including optionally via a crosslinker group). Degree of polymerisation may be analytically determined once a functionalised organosilicon monomer is exposed to polymerising conditions. Any suitable analysis technique for determining degree of polymerisation may be applied, including, for example, Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance Spectroscopy (NMR), or mass differential analysis. In some embodiments, degree of polymerisation is recited as determined by FTIR. Functionalised organosilicon monomer may be selected for a high degree of polymerisation, being a polymerisation yield that is greater than 80% and even a “very high degree of polymerisation” that is greater than or equal to 90%, even greater than or equal to 95% or greater than or equal to 98%, and also includes “complete polymerisation” that is greater than or equal to 99% or practically detectably 100%. Functionalised organosilicon monomer may similarly be selected for a “medium degree of polymerisation” being a polymerisation yield of between 60% and 80%. Functionalised organosilicon monomers may similarly be selected for a “low degree of polymerisation” being a polymerisation yield of less than or equal to 60%, 50%, 40%, or 30%. In some embodiments, functionalised organosilicon monomer is selected for a degree of polymerisation of between 20% and 90%, 30% and 80%, 35% and 70%, or of between 40% and 60%, or of around 50%, say of between 45% and 55%.

[0052] It is appreciated by those skilled in the art that “degree of polymerisation” of a polymeric material may be altered by reaction conditions under which polymerisation occurs. For instance, a functionalised organosilicon monomer characterisable by being capable of providing a “very high degree of polymerisation” under certain reaction conditions may, through manipulation of reaction conditions, provide a polymeric material with a lower degree of polymerisation. Likewise, a functionalised organosilicon monomer characterisable by being capable of providing a “medium degree of polymerisation” under certain reaction conditions may, through manipulation of reaction conditions, provide a polymeric material with a lower degree of polymerisation. That said, a polymerisable organosilicon monomer characterisable by being capable of providing a “low degree of polymerisation” will tend to provide only as much as a low degree of polymerisation, irrespective of reaction conditions. Reaction conditions include any variable that may be altered and / or controlled before or during thepolymerisation reaction, other than selection of the functionalised organosilicon monomer components. Examples include temperature, mixing, application and intensity of stimulus, reaction time, solvent, and vessel etc. As such, a degree of polymerisation is referred to herein based on the degree of polymerisation obtainable in the polymeric material formed under any particular reaction conditions.

[0053] Selecting monomers based on a degree of polymerisation advantageously contributes to the control of porosity that may be formed. Generally speaking, a degree of polymerisation is representative of a proportion of unreacted monomer remaining within the polymeric material. As unreacted monomer may be removed in a post-polymerisation evacuation step to create porosity, a high degree of polymerisation will tend to contribute less porosity by its removal than a low degree of polymerisation, in addition to the porosity created by porogen removal.

[0054] In some embodiments, a low or medium degree of polymerisation is applicable for forming porous polymeric materials. In some embodiments, a medium degree of polymerisation is applicable.

[0055] Selection of functionalised organosilicon monomers based on degree of polymerisation may generally be achieved through the selection of the polymerisable functional group.

[0056] In some embodiments, because the resins of this disclosure find particular utility in forming shaped polymer articles by 3D printing and injection moulding methods which often rely on thermal- and / or photopolymerisation, the polymerisable functional group is compatible and as such is thermal- or photopolymerisable. “Photopolymerisation” is light-induced polymerisation (either directly or by the use of a photoinitiator) while “thermopolymerisation” is heat-induced polymerisation. A functionalised monomer which is capable of participating in photopolymerisation is “photopolymerisable” while a functionalised monomer which is capable of participating in thermopolymerisation is “thermopolymerisable”. Similarly, a “photopolymerised” polymeric material is a polymeric material formed using, either alone or with other steps of a method, a step of photopolymerisation while a “thermopolymerised” polymeric material is a polymeric material formed using, either alone or with other steps of a method, a step of thermopolymerisation. For photo- or thermopolymerisation, the polymerisable functional group(s) are in some embodiments selected from a group, or a group containing a motif, selected from one or more of an ester, amine, hydroxyl, epoxide, vinyl, allyl, ethynyl, thiol, glycidyl, isocyanurate, alkacrylate, cyano, cyanate and thiocyanate. In someembodiments, the functionalised organosilicon monomer contains one or more polymerisable functional group type, which is in some embodiments an allyl, a vinyl, a thiol, a methacrylate, or an acrylate.

[0057] In some embodiments, the polymerisable functional group(s) is selected for ability to participate in thiol-ene, thiol -acrylate or acrylate polymerisation chemistry. It has been found that functionalised organosilicon monomer(s) which participate in thiol-ene or thiol-acrylate chemistry are highly reactive and tend to form polymeric materials characterised by a high degree of polymerisation, while functionalised organosilicon monomer(s) which participate in acrylate chemistry tend to be less reactive and form polymeric materials characterised by a comparatively lower degree of polymerisation, generally being a medium degree of polymerisation.

[0058] In some embodiments functionalised organosilicon monomer is selected for ability to participate in acrylate polymerisation chemistry. In some embodiments functionalised organosilicon monomer is methacryloxypropyl terminated polydimethylsiloxane.

[0059] In some embodiments, the functionalised organosilicon monomer comprises one or two types of polymerisable functional group. The polymerisable functional group may undergo polymerisation reactions by step-growth polymerisation, by chain-growth polymerisation, or by a combination of both step-growth and chain-growth polymerisation. In some embodiments, the polymerisable functional group is selected from an allyl, vinyl, thiol and acrylic. In some the embodiments the functionalised organosilicon monomer comprises a vinyl and / or acrylic polymerisable functional group. Examples of suitable vinyl and acrylic functional groups are acrylate, methacrylate, acrylamide, methacrylamide, styrenic, and vinyl ether functional groups. In these embodiments, the functionalised organosilicon monomer may participate in free radical polymerisation and / or cationic polymerisation. Those skilled in the art appreciate that radical and cationic polymerisation proceed through a chain-growth mechanism.

[0060] In some embodiments when a second functionalised organosilicon monomer is included in the resin, the first and second functionalised organosilicon monomers comprise polymerisable functional group which are complementary, suitably being one type of polymerisable functional group each which react with each other, or the same type of functional group which reacts with itself. For example, a functionalised organosilicon monomer may be selected having a thiol or acrylate polymerisable functional group, while a second functionalised organosilicon monomer may be selected having the other of thiol or acrylatepolymerisable functional group. Those skilled in the art appreciate that thiol-ene, for example thiol-acrylate polymerisations proceed through a step-growth mechanism. In another example, a functionalised organosilicon monomer may be selected having an acrylate polymerisable functional group, while a second functionalised organosilicon monomer may also be selected having an acrylate polymerisable functional group, as acrylates tend to be self-reacting.

[0061] A functionalised organosilicon monomer may be present in the resin in an amount of at least about 15%, 20%, 25%, 30% or at least about 35% by weight of the resin and up to an amount of about 80%, 85%, 88%, or about 90% by weight of the resin. A functionalised organosilicon monomer may also be present in the resin in an amount of at least about 10%, 15%, 20%, 25% or at least about 30% by volume of the resin. The amount of the functionalised organosilicon monomer may be not more than about 95%, 90%, 80%, 75% or not more than about 70% by volume of the preceramic resin. Any minimum and maximum can be combined without restriction. For example, the amount may be between 15% and 90% by weight of the resin, etc. In some embodiments, the functionalised organosilicon monomer may be present in an amount of at least about 60 wt% to about 90 wt%, between about 65 wt% to about 90 wt%, and / or between about 70 wt% to about 85 wt%, say between 75 wt% and 80 wt%.Porogen

[0062] The weight ratio of the porogen to the functionalised organosilicon monomer in the resin assists in the control of the relative proportion of pores contained in an organosilicon polymeric material formed from the resin and by a post-polymerisation evacuation step. This enables control of porosity. Generally speaking, a higher amount of porogen enables formation of greater porosity as compared to a lower amount of porogen.

[0063] A “porogen” is an organic compound that is capable of being removed from an organosilicon polymeric material formed from the resin. A porogen is generally liquid at room temperature and standard pressure. Without wishing to be limited by theory, it is thought that a porogen interrupts the continuous phase of the organosilicon polymeric material formed by polymerisation of functionalised organosilicon monomer. Therefore, when functionalised organosilicon monomer is polymerised, the porogen forms regions within the polymer that are substantially absent of polymerised functionalised organosilicon monomer. A porogen is generally unreactive with other components in the resin (under the conditions used to form the resin and organosilicon polymeric material, as applicable).

[0064] Porogen is suitably capable of being removed from the so-formed polymer by washing, heating, or extraction to vacate porogen from regions in the polymer, which regions remain as pores. Pores that are created by porogens are typically mesopores and / or macropores. The size of the pores introduced to an organosilicon polymeric material by a porogen depend on the size of the porogen itself, and on the interaction between the porogen and the functionalised organosilicon monomer in the resin. Generally speaking, a higher molecular weight porogen enables the formation of comparatively larger pores, such as macropores, as compared to use of a lower molecular weight porogen which may form mesopores, and a higher amount of porogen enables formation of greater porosity as compared to a lower amount of porogen. Similarly, chemical and / or physical interaction between the porogen and the functionalised organosilicon monomer in the resin may modify pore formation in a polymer formed from the resin. For example, when a porogen is miscible with and / or soluble in a functionalised organosilicon monomer, formation of comparatively smaller pores such as mesopores may be provided. In other embodiments, where the porogen is less miscible with and / or soluble in a functionalised organosilicon monomer, phase separation of the porogen from the functionalised organosilicon monomer may provide comparatively larger pores, such as macropores. The use of a porogen thus gives rise to an advantage of the present disclosure as it allows for the in situ introduction of pores to an organosilicon polymeric material and provides for enhanced control over the porosity of the resulting organosilicon polymeric material. That is, it enables “tuning” of the porosity of the organosilicon polymeric material.

[0065] In some embodiments, the porogen is removable from the formed organosilicon polymer material by washing with a solvent. Suitable solvents include polar organic liquids, such as methanol, acetonitrile, ethanol, tetrahydrofuran, dimethylformamide, and N-methyl-2-pyrrolidone (NMP). In which case, in embodiments a porogen is suitably soluble in or miscible with a polar organic liquid.

[0066] In some embodiments, the porogen is a liquid with low volatility. By having low volatility, the porogen possesses low vapourisation potential and therefore has a relatively high boiling point. A porogen having low volatility is advantageous by allowing the porogen to remain as a liquid in the resin without vaporising or evaporating from the resin when the resin is moderately heated. Moderate heating may be expected in embodiments where the resin is thermopolymerised, or is polymerisable by free radical polymerisation, which tends to be an exothermic reaction. Vaporisation of the porogen from a resin can result in large voids to formwithin the resin, which can result in an organosilicon polymeric material with reduced mechanical properties and less controlled porosity. In some embodiments, the porogen has a boiling point at standard atmospheric pressure of at least 120°C, 130°C, 140°C, 150°C, 160°C, or at least 170°C, which may be of up to 450°C, 420°C, 400°C, 370°C, 350°C, or 320°C. Any minimum and maximum can be combined without restriction. For example, porogen may have a boiling point at standard atmospheric pressure of between 120°C and 450°C, of 120°C and 320°C, of 170°C and 320°C, etc. In some embodiments, porogen has a boiling point at standard atmospheric pressure of between 120°C and 450°C.

[0067] In some embodiments the resin comprises a meso porogen and / or a macro porogen. In general, a “meso porogen” is a porogen which will tend to result in mesopores (and may also result in micropores) while a “macro porogen” is a porogen which will tend to result in macropores (and may also result in mesopores). As described above, whether a compound is a meso porogen or a macro porogen generally results from the size (molecular weight) of the porogen, and from the chemical and / or physical interaction of the porogen with the functionalised organosilicon monomer, but is ultimately determined by the pore sizes primarily formed.

[0068] Two or more porogens may be used. In some embodiments the resin comprises one or more meso porogens. In some embodiments the resin comprises one or more macro porogens. In some embodiments the resin comprises both a meso porogen and a macro porogen. A combination of porogens may allow further tuning of porosity. For instance, a meso porogen and a macro porogen will tend to result in a combination of mesopores and macropores.

[0069] Examples of suitable porogens include:a) glycidol, triethanolamine, toluene, methanol, cyclohexanol, hexane, dodecanol, 1,2-popanediol, water, 1 -propanol, 1,4-butandiol, dimethylformamide, acetonitrile, decane and decanol; andb) polyethylene glycol (PEG) such as PEG 100, PEG 200, PEG 400, PEG 600, PEG 800, PEG 1500, PEG 5000, and PEG 20,000, and ethylene glycol, propylene glycol, oligo(ethylene glycol), 1,3-propane diol, hexylene glycol, dipropylene glycol, and neopentyl glycol.

[0070] As described above, a meso porogen or a macro porogen is defined by the pore sizes primarily formed, but generally speaking, in some embodiments the porogens of category a) may be meso porogens while the porogens of category b) may be macro porogens. In someembodiments the resin comprises a porogen that is a PEG with a molecular weight of from 100 g / mol to 1500 g / mol. In some embodiments the resin comprises PEG 200, 400 or 600 as porogen, having an average molecular weight of 200, 400 or 600 g / mol, respectively.

[0071] At least 10 wt% porogen based on the weight of functionalised organosilicon monomer present in the resin is advantageous for providing usable porosity in a broad range of uses of the porous organosilicon polymeric material so-formed. For clarity, a specified wt% of porogen against functionalised organosilicon monomer present in the resin is based on all functionalised organosilicon monomer present, including when there are two or more functionalised organosilicon monomers present. By the same token, a specified wt% of porogen against polymerised functionalised organosilicon monomer present in the polymeric material is based on all polymerised functionalised organosilicon monomer present, including when there are two or more polymerised functionalised organosilicon monomers present. The porogen may be present in an amount of at least about 10 wt% including 11%, 12%, 14%, 15%, 17%, 18% or 20% by weight based on the weight of functionalised organosilicon monomer in the resin. The porogen may be present in an amount up to about 35% 40%, 45%, 50%, 55%, or 60% by weight of functionalised organosilicon monomer. Any minimum and maximum can be combined without restriction. For example, the amount may be between 10 wt% and 20 wt%, between 10 wt% and 60 wt%, between 20 wt% and 50 wt%, between 5 wt% to 50 wt%, etc. In some embodiments the porogen is present in an amount of from about 10% to 60%, or 20% to 55%, or 40% to 55% by weight of functionalised organosilicon monomer.

[0072] That said, in some embodiments, at least 10 wt% porogen based on the weight of functionalised organosilicon monomer present in the resin is not necessary. In these embodiments, porogen may be present in lesser amounts such as 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt% or 9 wt%.

[0073] Those skilled in the art will appreciate that the weight ratio of porogen in the resin can also be expressed as a volume ratio by understanding the density of the resin components. For example, when the densities of the porogen and the functionalised organosilicon monomer(s) are each close to 1 g / cm3, the weight % (wt%) ratios described above may be directly converted to volume % (vol%) ratios. That is, the porogen may be present in an amount of at least about 1%, 2%, 3%, 4%, 5%, 6 %, 7%, 8 % or 9%, or greater than 10 vol% including 11%, 12%, 14%, 15%, 17%, 18% or 20% by volume based on the volume of functionalised organosilicon monomer in the resin. The porogen may be present in an amount up to about 35% 40%, 45%,or 50% by volume of functionalised organosilicon monomer. Any minimum and maximum can be combined without restriction. For example, the amount may be between 10 vol% and 20 vol%, between 10 vol% and 50 vol%, between 20 vol% and 50 vol%, between 5 vol% to 50 vol%, etc. The amount of porogen typically does not exceed about 50 vol% or about 60 vol% of the volume of functionalised organosilicon monomer in the resin. In some embodiments the porogen is present in an amount of from about 10% to 50%, or 20% to 55%, or 40% to 55% by volume of functionalised organosilicon monomer. That said, in embodiments requiring at least 10 wt% porogen based on the weight of functionalised organosilicon monomer present in the resin, the porogen will be present in a vol% corresponding to that at least 10 wt% porogen amount.Other components

[0074] Various other components may be included in the resins of the present disclosure. This includes but is not limited to one or more of a crosslinking agent, structural particles, a second or further functionalised organosilicon monomer, a functionalised organic monomer, a polymerisation initiator, a free radical inhibitor, a photoblocker, a 3D printing resolution agent, a colouring compound, a surfactant, a dispersant, and an emulsifier. Some common examples of surfactants and emulsifiers include fatty acids, sodium lauryl sulfates, and alpha-olefin sulfonates.Structural particles

[0075] Structural particles may be included in the resin and used to advantage as they tend to result in a comparatively stronger polymeric materials formed from the resin; that is, less prone to breakdown in the integrity of the material formed. This is particularly advantageous in the formation of porous materials, especially those of high porosity, where the high proportion of pores may reduce the structural integrity of the organosilicon polymeric material. It is thought that structural particles assist to reduce the risk of breakdown of the material under stress. Structural particles that are porous may also be used to add porosity to an organosilicon polymeric material, which may create additional porosity to that formed by the porogen.

[0076] A structural particle is generally a solid particulate substance that is not reactive with the other components (under the conditions used to form the resin and polymeric material as applicable) and remains in existence as a solid substance in an organosilicon polymeric materialformed from the resin. Structural particles are identifiable to persons skilled in the art in the context of the present disclosure.

[0077] As polymeric materials described herein are based on functionalised organosilicon monomers, then in some embodiments the structural particles are suitably silicon-based ceramic particles. Examples include SiCh, SisN4, SiC, SiCN, SiCO, SiCNO, SiBCN, SiBCO, SiAlCN, and SiAlCO. In some embodiments, the ceramic particles are silica (SiCh) particles.

[0078] The structural particles may be porous or non-porous. Non-porous structural particles assist to form denser organosilicon polymeric materials. Porous structural particles may assist to add porosity to polymeric materials formed from the resin. Porous structural particles are typically microporous and / or mesoporous so as to provide micropores and mesopores in the organosilicon polymeric material.

[0079] The structural particles may be of any size fit for purpose. Particle sizes of up to 1 mm are useable with many 3D printing methods, while particle sizes of up to several millimetres are useable with many injection moulding methods. That said, smaller particles are preferrable for improved rheological properties of the resin (especially for 3D printing) and improved distribution in the resin. In some embodiments, the particles are microparticles. By “microparticles” is meant a plurality of particles having a particle size falling between 1 pm and 1 mm. It is common for particulate substances to be supplied with a specified particle size range which usually reflects that at least a majority portion of those particles have a size within that range. This may be described as a particle size distribution. The particles may be predominantly within that particle size rage (e.g., >95%, >99%) or entirely within the particle size range. In some embodiments, at least 90%, 95%, 98%, 99%, 99.5% and even 99.9% of microparticles included in the resin have a size falling within the particle size range. In some embodiments, the microparticles have a size of between about 1 pm to about 100 pm, in some embodiments between about 1 pm and 50 pm, in some embodiments between about 1 pm and 25 pm, and in further embodiments between about 1 pm and 15 pm. In some embodiments, the particles are nanoparticles. By “nanoparticles” is meant a plurality of particles having a particle size falling under 1 pm. In some embodiments, at least 90%, 95%, 98%, 99%, 99.5% and even 99.9% of the nanoparticles included in the resin have a size of under 1 pm, in some embodiments under 500 nm, under 200 nm and even under 100 nm. In some embodiments, the nanoparticles have a size of between about 1 nm to about 100 nm, in some embodiments between about 1 nm and 25 nm, and in some embodiments between about 1 nm and 10 nm.

[0080] In some embodiments, the particles include both microparticles and nanoparticles, in which case the resin may be said to comprise particles wherein a plurality of particles have a particle size falling under 1 mm. In some embodiments, at least 90%, 95%, 98%, 99%, 99.5% and even 99.9% of the particles included in the resin have a size of between about 1 nm and 1 mm, between about 1 nm and 100 pm, between about 1 nm and 50 pm, between about 1 nm and 25 pm, or between about 1 nm and 15 pm. 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. In some embodiments, the particles size distribution is determined using transmission electron microscopy (TEM).

[0081] Structural particles may be present in the resin in an amount of at least about 0.5%, 1%, 2%, 5%, 8% or 10% by weight of the resin. When present, the amount of the structural particles is in some embodiments not more than about 95%, 90%, 80%, 70%, 50% or 30% by weight of the resin. Any minimum and maximum can be combined without restriction. In some embodiments, structural particles when present are included in an amount of between about 0.5 wt% to about 20 wt%, in some embodiments between about 1 wt% to about 15 wt%, more in some embodiments between about 1 wt% to about 10 wt%, and especially 2 wt% to about 8 wt% of the resin.Second and subsequent functionalised organosilicon monomer

[0082] The resins of the present disclosure may contain second and subsequent functionalised organosilicon monomer. When a resin contains two or more functionalised organosilicon monomers, a “first functionalised organosilicon monomer” is synonymous with a “functionalised organosilicon monomer” simpliciter. as described herein, while a “second”, “third” etc. functionalised organosilicon monomer may be referred to as such. The terms “first”, “second” etc. are not intended to imply any order or hierarchy, but simply to distinguish between functionalised organosilicon monomers.

[0083] A second functionalised organosilicon monomer may be as described above in respect of the first functionalised organosilicon monomer, though it will have a different chemical structure to the first functionalised organosilicon monomer, whether that be by way of the backbone, substituents or polymerisable functional group.

[0084] That is, in some embodiments, a second functionalised organosilicon monomer has a structure of Formula 1, Formula 2, Formula 3, Formula 4, Formula 5, Formula 6, Formula 7 orFormula 8, or is a polysilsesquioxane, polysilsesquicarbodiimide or a polysilsesquiazane as described above, substituted with one or more polymerisable functional groups as described above.

[0085] The second functionalised organosilicon monomer may be selected based on a degree of polymerisation of a organosilicon polymeric material formed from a resin containing it, as described above in respect of the first functionalised organosilicon monomer.

[0086] The polymerisable functional group of a second functionalised organosilicon monomer need not be complementary to a polymerisable functional group of the first functionalised organosilicon monomer. Rather, for a second functionalised organosilicon monomer, one polymerisable functional group may be selected such that it reacts with itself under polymerising conditions, but not with a polymerisable functional group of the first functionalised organosilicon monomer. Alternatively, two or more types of polymerisable functional groups may be used, selected such that they react with (i.e. are complementary to) each other under polymerising conditions, but are not reactive with a polymerisable functional group of the first functionalised organosilicon monomer. Alternatively, or in addition, polymerisable functional groups may be selected such that they react with a crosslinking agent added to the resin.

[0087] In some embodiments, the polymerisable functional group(s) of a second functionalised organosilicon monomer is selected such that it is complementary to a polymerisable functional group of the first functionalised organosilicon monomer. In such embodiments, the polymerisable functional groups of a second functionalised organosilicon monomer may be selected from the group consisting of a hydroxyl, epoxide, vinyl, allyl, ethynyl, thiol, glycidyl, acrylate, and thiocyanate.

[0088] In some embodiments, the polymerisable functional group(s) of a second functionalised organosilicon monomer is selected for their ability to participate in thiol-ene, thiol-acrylate or acrylate polymerisation chemistry and accordingly, in some embodiments, a second functionalised organosilicon monomer comprises one or two types of polymerisable functional group selected from an allyl, vinyl, thiol and acrylate. In some embodiments a first functionalised organosilicon monomer comprises one type of polymerisable functional group selected from a thiol, acrylate, allyl or vinyl and a second functionalised organosilicon monomer comprises one type of polymerisable functional group being complementary thereto, for example a thiol, acrylate, allyl or vinyl.

[0089] In some embodiments, the amount of a second functionalised organosilicon monomer included in a resin is such that the first and second functionalised organosilicon monomers are present in a 1:1 ratio in respect of the polymerisable functional groups. In other embodiments, one functionalised organosilicon monomer is present in excess relative to another, in respect of the polymerisable functional groups. This may be, for example, a ratio of between 1:1 to 1:10, or 1:1 to 1:5, or 1:1 to 1:3, or 1:1 to 1.2, such as 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2. An excess may be used for example to drive the polymerisation of the functionalised organosilicon monomer present as the limiting reagent to a greater extent than may otherwise occur. An excess may also be used so that unpolymerised functionalised organosilicon monomer remains in the organosilicon polymeric material formed, which may be removed in a post-polymerisation evacuation step as described herein so as to form porosity.

[0090] The amount of the second functionalised organosilicon monomer, when present in the resin, may be present in an amount of at least about 15%, 20%, 25%, 30% or at least about 35% by weight of the resin and up to an amount of about 80%, 75%, 70%, or about 65% by weight of the resin. The second functionalised organosilicon monomer may also be present in the resin in an amount of at least about 5%, 10%, 15%, 20% or at least about 25% by volume of the resin. The amount of the second functionalised organosilicon monomer may be not more than about 75%, 70%, 65%, 60% or not more than about 55% by volume of the resin. Any minimum and maximum can be combined without restriction. For example, the amount may be between 15% and 80% by weight of the resin, between 15% and 65% by weight of the resin, etc.

[0091] In some embodiments where a first and second functionalised organosilicon monomer is present in the resin, exemplary combinations are (mercaptopropyl) methylsiloxane homopolymer with methacryloxypropyl terminated polydimethylsiloxane and (mercaptopropyl) methylsiloxane homopolymer with vinylmethoxysiloxane homopolymer.

[0092] A third or further functionalised organosilicon monomer may be selected in the same way as the second functionalised organosilicon monomers described above. When present, the third and subsequent functionalised organosilicon monomer may be present in an amount of about 1 wt% to about 50 wt%, or between about 5 wt% to about 30 wt%, or between about 10 wt% to about 20 wt% of the resin.

[0093] When second or further functionalised organosilicon monomers are present, the functionalised organosilicon monomers may, together with the first functionalised organosilicon monomer, be present in the resin in a combined amount of at least about 30%,40%, 50%, 60% or at least about 70% by weight of the resin and up to an amount of about 90%, 85%, 80%, or about 75% by weight of the resin. The functionalised organosilicon monomers may also be present in the resin in a combined amount of at least about 10%, 15%, 20%, 25% or at least about 30% by volume of the resin. The amount of the functionalised organosilicon monomers together may be not more than about 90%, 85%, 80%, 75% or not more than about 70% by volume of the resin. Any minimum and maximum can be combined without restriction. For example, the amount may be between 30% and 90% by weight of the resin, between 30% and 80% by weight of the composition, etc. In some embodiments, the functionalised organosilicon monomers may together be present in a combined amount of at least about 60 wt% to about 90 wt%, or between about 65 wt% to about 85 wt%, or between about 70 wt% to about 80 wt% of the resin.Functionalised organic monomer

[0094] A “functionalised organic monomer” is an oligomeric or polymeric carbon-containing chemical compound which contains one or more polymerisable functional groups and which is other than a functionalised organosilicon monomer as described herein, or in other words is an oligomeric or polymeric organic compound that is substituted to contain one or more polymerisable functional groups and is other than a functionalised organosilicon monomer as described herein.

[0095] Oligomeric and polymeric organic compounds are identifiable to those of skill in the art. They tend to be based on a backbone chain structure of repeating motifs containing covalent carbon-carbon bonds and carbon-hydrogen bonds, and often contain covalently-bonded heteroatoms such as oxygen, nitrogen and / or sulphur.

[0096] The polymerisable functional group of a functionalised organic monomer may be substituted at two or more points of the organic compound including terminally substituted, i.e., at one or more end groups of the organic compound. One or more types of polymerisable functional groups may be selected as described above in respect of the first functionalised organosilicon monomer and are in some embodiments selected to be complementary to one or more polymerisable functional groups of one or more functionalised organosilicon monomers. The functionalised organic monomer is typically a silicon-free organic monomer.

[0097] The backbone chemical structure of a functionalised organic monomer to which one or more polymerisable functional groups may be connected may be referred to as a “spacer group”.A functionalised organic monomer may thus be represented by the following formula:Spacer(L)nwherein Spacer is a spacer group, L is a polymerisable functional group, and n is an integer of greater than or equal to 1. In some embodiments, n is an integer of from 2 to 4, and is in some embodiments 2. The spacer group may be based on an optionally branched backbone structure comprising repeat units of, for example ethylene, ethylene glycol, propylene, polypropylene glycol, ethylamine, propylamine, etc. and may thus be based on an optionally branched backbone structure comprising polyethylene, polyethylene glycol, polypropylene, polyproypylene glycol, polyethyleneimine, and polypropyleneimine etc., respectively. In some embodiments, the polymerisable functional groups are terminally substituted. In some embodiments, one type of polymerisable functional group is used. In some embodiments, the polymerisable functional group is selected for reactivity with the first functionalised organosilicon monomer as described above in respect of the second functionalised organosilicon monomer, and is thus in some embodiments selected from a group, or a group containing a motif, selected from one or more of a hydroxyl, epoxide, vinyl, allyl, ethynyl, thiol, glycidyl, acrylate, and thiocyanate. In some embodiments, the reactive group is an allyl, a vinyl, a thiol or an acrylate so as to participate in thiol-acrylate or acrylate polymerisation chemistry, e.g., with a functionalised organosilicon monomer having a complementary polymerisable functional group.

[0098] Representative functionalised organic monomers include polyethylene glycol diacrylate, polyethylene glycol dithiol, polyethylene glycol divinyl ether, and polyethylene glycol diallyl ether.

[0099] A functionalised organic monomer may be included in stoichiometric amounts equating to complete, or as near as possible complete, reactivity of the polymerisable functional groups of the functionalised organosilicon monomer(s) and the functionalised organic monomer. The functionalised organosilicon monomers may be present in a 1:1 ratio with functionalised organosilicon monomers in respect of the polymerisable functional groups. Alternatively, an excess amount of functionalised organic monomer or functionalised organosilicon monomer may be used. This may be, for example, a ratio of between 1.01:1 to 2:1 of functionalised organic monomer to functionalised organosilicon monomer, or of functionalised organosilicon monomer to functionalised organic monomer, in respect of the polymerisable functional groups. An excess may be used to drive the reaction towards complete reactivity of the functionalisedorganosilicon monomer or the functionalised organic monomer. An excess may also be used to leave unpolymerised monomer in the polymeric material formed, which may be removed using a post-polymerisation evacuation step as described herein so as to form porosity.

[0100] In terms of physical amounts, the amount of functionalised organic monomer when present may at least about 1%, 2%, 5%, 8% or 10%, 15%, 20%, 25%, 30% or at least about 35% by weight of the resin and up to an amount of about 60%, 55%, 50%, or about 45% by weight of the resin. Any minimum and maximum can be combined without restriction. For example, the amount may be between 1% and 60% by weight of the resin, between 15% and 60% by weight of the composition, etc. Many functionalised organic monomers are of lower molecular weight than functionalised organosilicon monomers and as such, the physical amount will tend to be less than the functionalised organosilicon monomer and tend to be between about 1% and 25% by weight of the resin, encompassing for example about 1%, 2%, 5%, 8%, 10%, 12%, 15%, 18% 20%, 22%, 24%, or about 25%.Crosslinking agent

[0101] In some embodiments, the organosilicon polymeric material is formed by functionalised organosilicon monomer(s) reacting together via a crosslinking agent. A crosslinking agent is a chemical species that comprises a crosslinker group and two or more polymerisable functional groups that react with (i.e. are complementary to) one or more polymerisable functional groups of any one or more functionalised organosilicon monomer(s) present in the resin, and is such that, after crosslinking has occurred, polymerisable functional groups of the functionalised organosilicon monomer(s) are crosslinked via the crosslinker group in the structure of the organosilicon polymeric material. When present, a crosslinking agent will generally be selected based on the polymerisable functional groups of the functionalised organosilicon monomer(s), to have complementary polymerisable functional group(s) as described above. A crosslinking agent differs from a functionalised organic monomer in that a crosslinking agent is not itself oligomeric or polymeric. Representative crosslinking agents include ethylene glycol diacrylate, ethylene glycol dithiol, ethylene glycol divinyl ether, ethylene glycol diallyl ether and hexanedi thiol. In some embodiments, a crosslinking agent is not added to the resin or in other words, the resin is absent of a crosslinking agent. In some embodiments, where the functionalised organosilicon monomer comprises two or more polymerisable functional groups, the functionalised organosilicon monomer itself maycontribute to crosslinking in the polymeric material.Polymerisation initiator

[0102] Because the resins of the present disclosure find particular utility in forming polymeric articles using 3D printing and injection moulding processes, the polymerisable functional group of the functionalised organosilicon monomer(s) is in some embodiments so-compatible. As such, in some embodiments the functionalised organosilicon monomer(s) is polymerisable by thermal and / or photo initiation. In these embodiments, the resin may further comprise a polymerisation initiator, such as a thermal initiator or photoinitiator, which typically form free radicals or charged ionic species which catalyse the reaction of thermal- or photopolymerisable functional groups, respectively. In some embodiments, low or no polymerisation initiator is present in the resin. In these embodiments, the polymerisable group(s) of the functionalised organosilicon monomer may react under thermal and / or photo stimulus to initiate polymerisation. When present, the thermal or photoinitiator may be present in an amount of between about 0.01 wt% to about 20 wt%, in some embodiments between about 0.1 wt% to about 5 wt%, and more in some embodiments between about 0.2 wt% to about 1 wt% of the resin.

[0103] Examples of thermal initiators include benzoyl peroxide, dicumyl peroxide and 2,2'-azobi si sobuty ronitril e .

[0104] 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.

[0105] In some embodiments, the polymerisation initiator is a photoinitiator which forms free radicals under UV light (wavelength of about 100 to about 405 nm). In some embodiments, the polymerisation initiator is phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide.

[0106] When a free radical generator is included as polymerisation initiator, the resin may also further comprise a free radical inhibitor (also known as a free radical scavenger). Examples include hydroquinone, methylhydroquinone, ethylhydroquinone, methoxyhydroquinone, ethoxyhydroquinone, monomethylether hydroquinone, propylhydroquinone, propoxyhydroquinone, tert-butylhydroquinone (TBHQ) and n-butylhydroquinone. In some embodiments the free radical inhibitor is tert-butylhydroquinone. When present, the free radical inhibitor may be present in an amount of about 0.01 wt% to about 20 wt%, or between about0.05 wt% to about 5 wt%, or between about 0.1 wt% to about 2 wt% of the resin.

[0107] When the resins of the present disclosure are polymerised using photoinitation, addition of a photoblocker to the resin may be advantageous to modify or improve spatial or temporal control over polymerisation. Examples of suitable photoblockers include 4-nitrophenyl phenyl sulfide, 2,5-Bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBOT), 4,4'-bis(benzoxazolyl)-cis-stilbene and 4,4-diamino-2,2-stilbenedisulfonic acid. In some embodiments the photoblocker is BBOT. In some embodiments the photoblocker is 4-nitrophenyl phenyl sulfide. When present, a photoblocker may be present in an amount of from about 0.01 wt% to about 20 wt%, or from about 0.1 wt% to about 5 wt%, or from about 0.2 wt% to about 1 wt% of the resin.Organosilicon polymeric material

[0108] Organosilicon polymeric materials are formable from the reasons of the present disclosure. Organosilicon Polymeric materials are generally formed by a process which involves the polymerisation of a functionalised organosilicon monomer contained within a resin; or in other words, are generally formed by subjecting a resin comprising a functionalised organosilicon monomer to polymerising conditions, or in other words by performing a polymerisation step. As the resins contain a porogen, the organosilicon polymeric materials so-formed may comprise a porogen. Organosilicon polymeric materials comprising a porogen (and optionally unreacted functionalised organosilicon monomer) may be referred to as “unevacuated” material though this is synonymous with organosilicon polymeric material simpliciter. These materials generally do not contain meso- and / or macropores, inasmuch as porogen (and optionally unreacted functionalised organosilicon monomer) remains within regions within the polymer.

[0109] When the resin contains porogen in an amount of at least 10 wt% of functionalised organosilicon monomer, the amount of porogen in the formed un-evacuated organosilicon polymeric material will generally be, assuming no loss of porogen, at least 10 wt% of polymerised functionalised organosilicon monomer present in the polymeric material, even when the degree of polymerisation is 100%. When the degree of polymerisation is less than 100%, the amount of porogen in the un-evacuated polymer material relative to the polymerised functionalised organosilicon monomer will generally increase proportionally. That said, the present disclosure also provides for resins containing less than 10 wt% porogen based on the functionalised organosilicon monomer present in the resin, in which case organosiliconpolymeric materials comprising less than 10 wt% porogen based on the polymerised functionalised organosilicon monomer are also provided. But whatever the case, and assuming no loss of porogen, the amount of porogen in the formed un-evacuated organosilicon polymeric material will generally be at least the same as present in the resin, even when the degree of polymerisation is 100%, and will increase proportionally when the degree of polymerisation is less than 100%.

[0110] The amount of porogen present assists to determine the porosity in a porous organosilicon polymeric material formed from the un-evacuated polymeric material once the porogen is removed using a post-polymerisation evacuation step. The porogen may be present in an organosilicon polymeric material an amount of at least about 5%, 10%, 12%, 14%, 15%, 17%, 18% or 20% by weight based on the weight of polymerised functionalised organosilicon monomer present in the polymeric material, and up to an amount of about 35% 40%, 45%, 50%, 55%, 60% by weight of polymerised functionalised organosilicon monomer. Any maximum and minimum can be combined without restriction. For example, the amount may be between 10% and 20%, between 10% and 60%, between 20% and 50%, between 5% to 50%, by weight of polymerised functionalised organosilicon monomer, etc. In some embodiments the porogen is present in an amount of from about 10% to 60%, or 20% to 55%, or 40% to 55% by weight of polymerised functionalised organosilicon monomer. In some embodiments, the porogen is present in an amount of at least about 10%, 20%, or at least 25% of the weight of polymerised functionalised organosilicon monomer. Where a polymeric material comprises more than one polymerised functionalised organosilicon monomer, the weight basis for the porogen content is the total weight of polymerised functionalised organosilicon monomer in the polymeric material.

[0111] Any one or more of the functionalised organosilicon monomers disclosed herein may be polymerised to form the polymeric organosilicon material. That is, the polymerised functionalised organosilicon monomer that is comprised in the organosilicon polymeric material may be based on a structure of Formula 1, Formula 2, Formula 3, Formula 4, Formula 5, Formula 6, Formula 7 or Formula 8, or is a polysilsesquioxane, polysilsesquicarbodiimide or a polysilsesquiazane as described above, substituted with one or more polymerisable functional groups as described above, wherein the polymerisable functional groups have been at least partly polymerised. In some embodiments, the polymerised functionalised organosilicon monomer is based on a polysiloxane, such as polydimethylsiloxane. In someembodiments, the polymerised functionalised organosilicon monomer is polymerised methacryloxypropyl terminated polydimethylsiloxane.

[0112] The presence of the porogen in the organosilicon polymeric material serves to form regions within the polymer material that are substantially absent of polymerised functionalised organosilicon monomer, but which contain porogen. When porogen is removed by a postpolymerisation evacuation step, suitably by washing, heating, or extraction, this vacates porogen-containing regions in the polymer and creates pores. This forms a macro- and / or mesoporous organosilicon polymeric material.

[0113] Any one or more of the porogens disclosed in accordance with the resin of the first aspect may constitute the porogen comprised in the organosilicon polymeric material. That is, all of the properties of the porogen described above apply equally to porogen comprised in the organosilicon polymeric material. For instance, in some embodiments, the porogen is a liquid at room temperature that exhibits low volatility as described above and to the advantage described above. In some embodiments, the porogen has a boiling point under standard atmospheric pressure as specified above, in some embodiments of at least 120°C, 130°C, 140°C, 150°C, 160°C, or at least 170°C, in some embodiments of between 120°C and 450°C. The organosilicon polymeric material may comprise two or more porogens. Examples of suitable porogens are as described above, including in some embodiments glycidol, triethanolamine, toluene, methanol, cyclohexanol, hexane, dodecanol, 1,2-popanediol, water, 1 -propanol, 1,4-butandiol, dimethylformamide, acetonitrile, decane and decanol, polyethylene glycol (PEG) such as PEG 100, PEG 200, PEG 400, PEG 600, PEG 800, PEG 1500, PEG 5000, and PEG 20,000, and ethylene glycol, propylene glycol, oligo(ethylene glycol), 1,3-propane diol, hexylene glycol, dipropylene glycol, neopentyl glycol. In some embodiments the polymeric material comprises a porogen that is a PEG with a molecular weight of from 100 g / mol to 1500 g / mol. In some embodiments the polymeric material comprises PEG 200 as porogen, having an average molecular weight of 200 g / mol.

[0114] A “pore” is a space which is devoid of the polymeric material that makes up the organosilicon polymeric material and devoid of the solid or liquid material comprised in the resin used to form the organosilicon polymeric material; for instance, devoid of porogen and unpolymerised finctionalised organosilicon monomer. In other words, a pore may be thought of as a space under vacuum or containing only gaseous substance. In the porous polymeric materials of the present disclosure, pores may be considered hierarchically in terms of pore size,as micropores, mesopores and macropores. A “micropore” refers to a pore with a diameter of less than 2 nm. A “mesopore” refers to a pore with a diameter of from 2 nm to 50 nm. A “macropore” refers to a pore with a diameter of from 50 nm to 100 micrometres. Macropores may further be considered as sub-, inter- and super-macropores, which refers to a macropore with a diameter of from 50 nm to 1 micrometre, from 1 micrometre to 10 micrometres, and from 10 micrometres to 100 micrometres, respectfully. The “diameter” does not limit the shape of a pore and refers to the greatest axial dimension. Similarly, “microporous” refers to the containing of micropores, while “mesoporous” refers to the containing of mesopores, and “macroporous” refers to the containing of macropores.

[0115] Pore size, and porosity is experimentally determinable using methods known in the art. Known methods include gas adsorption (including using a BET surface analyser), scanning electron microscopy, densitometry (using, for example, specific gravity analysis and / or computed tomography (CT) analysis) and liquid intrusion (including mercury porosimetry), X-ray tomography, and inverse gas chromatography. In some embodiments, a BET surface analysis and / or mercury porosimetry is used for comparing pore sizes of different materials.

[0116] The term "porosity" refers to the volume fraction of pore space within the organosilicon polymeric material relative to the total volume of the organosilicon polymeric material. Those skilled in the art will appreciate the relationship of porosity of an organosilicon polymeric material with the density of that same material, wherein an organosilicon polymeric material having greater porosity will tend to exhibit lower density, than an organosilicon polymeric material having lower porosity which will tend to exhibit higher density. For a given porosity, the density of a porous organosilicon polymeric material is also related to the pore architecture including pore size and pore size distribution of the organosilicon polymeric material. An organosilicon polymeric material having "greater porosity" refers to a material having a higher relative volume percentage of pore space. Conversely, an organosilicon polymeric material having "lesser porosity" or “lower porosity” refers to a material having a lower relative volume percentage of pore space. It should be understood that references to "greater" or "lesser" porosity are relative terms, and the specific porosity ranges considered to be "greater" or "lesser" may vary depending on the particular embodiment of organosilicon polymeric material.

[0117] By means as described herein, the porous organosilicon polymeric materials may contain micropores, mesopores and / or macropores (i.e. be microporous, mesoporous and / or macroporous). The different size pores may also be present in different quantities. Together,this results in porous polymeric materials formed with varying porosity. That is, by changing the relative amounts and / or components in the resin composition, it is possible to design porous organosilicon polymeric materials with micropores, mesopores and / or macropores as desired to achieve a target porosity - they are “tunable”. This is explained in further detail below. Generally speaking, it is the selection of porogen, amount of porogen, and amount of unreacted functionalised organosilicon monomer (i.e., degree of polymerisation) that may determine meso- and / or microporosity. Herein, once organosilicon polymeric materials are subject to a post-polymerisation evacuation step to remove porogen and optionally unreacted functionalised organosilicon monomer, the formed porous polymeric materials contain one or both of mesopores and macropores; i.e. are meso- and / or macroporous.

[0118] The porous organosilicon polymeric materials may exhibit either open-cell or closedcell porosity, or combinations thereof. Open-cell porosity refers to pores that are interconnected through channels or pathways, forming a partly or fully continuous porous network in the material. In other words, in such structures, the pores are in communication with one another and typically with the external surface of the material. The degree of interconnectivity may vary, and the channels connecting the pores may have different dimensions than the pores themselves. Closed-cell porosity is other than open-cell porosity. It may be characterised by discrete pores that are isolated from one another by walls of the organosilicon polymeric material. With closed cell porosity, each pore may be thought of as existing as a separate internal region, not connected to other pores in the material. Closed-cell pores may typically be dispersed throughout the polymer material in a random or ordered arrangement. The morphology of the porous structure typically influences the polymeric material physical and mechanical properties. Open-cell structures typically exhibit higher permeability and lower density, while closed-cell structures often provide enhanced mechanical properties and better insulation characteristics. The porous organosilicon polymeric materials of the present disclosure will generally contain at least some open-cell porosity. This is by virtue of the means of formation of porosity by a post-polymerisation evacuation step. As porogen and optionally unreacted functionalised organosilicon monomer escapes the material it creates interconnecting channels between pores. Open-cell porosity is to advantage. This interconnected nature of the pores advantageously allows for the passage of fluids through the material which is desired in many applications.

[0119] In some embodiments, the micro- and / or meso-porosity of porous organosilicon polymeric material fully or substantially comprises open cells. In some embodiments, themicro- and / or meso-porosity of organosilicon polymeric material is comprised fully of open cells.

[0120] Porosity of an organosilicon polymeric material may be directly related to specific surface area of that same material. The relationship between porosity and specific surface area of an organosilicon polymeric material is typically a positive, proportional relationship. The porosity and specific surface area relationship may be a linear relationship, or a non-linear relationship. The pore architecture (i.e. pore size, pore connectivity, pore size distribution, etc.) and density affect the relationship between porosity and specific surface area for an organosilicon polymeric material. In general, where the density of an organosilicon polymeric material is constant, a greater porosity results in a greater specific surface area for that material. In some embodiments, the organosilicon polymeric material exhibits high porosity. Having high porosity refers to an organosilicon polymeric material containing a large volume fraction of pore space relative to the volume of polymer matrix. In some embodiments, the organosilicon polymeric material contains pore space comprising greater than about 20%, 30% or 40% of the total volume of the organosilicon polymeric material. In some embodiments, the void space may comprise greater than about 50%, about 60%, about 70%, or about 80% of the total volume.

[0121] In embodiments where the porosity of an organosilicon polymeric material is comprised predominantly of mesopores and macropores, an organosilicon polymeric material exhibits high specific surface area. As such, a specific surface area characteristic of the porous organosilicon polymeric material may be used as a proxy for porosity. As for porosity and pore architecture, specific surface area is experimentally determinable using methods known in the art including gas adsorption (including using a BET surface analyser) and liquid intrusion (including mercury porosimetry). In some embodiments, a BET surface analysis and / or mercury porosimetry should be used for comparing the porosity, specific surface area and pore architecture of different materials.

[0122] A BET surface analyser is generally considered to be capable of reliably analyzing micropores and mesopores. Mercury porosimetry is generally considered to be capable of reliably analyzing macropores. BET surface analysis generally relies on measurements of pressure as representative of gas (often N2) adsorption and desorption, while mercury porosimetry generally relies on measurements of volume as representative of liquid ingress. Both test a sample of the porous polymeric material, usually a sample of less than 100 mg. From both, pore size and specific surface area are calculable and presentable in a plot of specificsurface area vs pore size, which may be referred to as a “pore size distribution plot”. BET surface analysis of a microporous and / or mesoporous polymeric material will result in a pore size distribution plot which shows that micropores and / or mesopores contribute to a specific surface area of the material. Similarly, mercury porosimetry analysis of a macroporous porous polymeric material will result in a pore size distribution plot which shows that macropores contribute to a specific surface area of the material. The area under the curve is representative of the total specific surface area of the material provided by those pore sizes. Together, BET surface analyses and mercury porosimetry may provide the total specific surface area.

[0123] Micropores may contribute at least about 5%, 10%, 20%, 30%, 40%, 50%, 60% or even 70% specific surface area of an organosilicon polymeric material of the present disclosure. Mesopores may contribute at least about 5%, 10%, 20%, 30%, 40%, 50%, 60% or even 70% specific surface area of an organosilicon polymeric material of the present disclosure. As otherwise generally used herein, and unless context indicates otherwise, the specific surface area refers to the total specific surface area of an organosilicon polymeric material as described herein, which has micropores, mesopores and / or macropores.

[0124] Specific surface area may be classified as high, medium and low. “High specific surface area” as it relates to specific surface area refers to a specific surface area which is greater than 150 m2 / g. “Medium specific surface area” refers to a specific surface area which is between 70 and 150 m2 / g. “Low specific surface area” refers to a specific surface area which is less than 70 m2 / g. An organosilicon polymeric material in accordance with the present disclosure which contains macropores only will tend to have a surface area not exceeding 50 m2 / g as characterisable by BET analysis, which is of low specific surface area, and low porosity. In some embodiments, the present disclosure provides for organosilicon polymeric materials of high porosity and high specific surface area, and even with a specific surface area of greater than even 200 m2 / g as characterisable by BET analysis, which may be described as “very high porosity”. The present disclosure also provides organosilicon polymeric materials with a specific surface area of greater than 250, 300, 400 and even upwards of 500 m2 / g as characterisable by BET analysis. Accordingly, in some embodiments, the organosilicon polymeric material is characterised by a high or very high porosity, with a specific surface area of greater than or equal to 150 m2 / g, or in some embodiments even greater than 200 m2 / g. Further, in some embodiments, the organosilicon polymeric material is characterised by a high or very high porosity when analysed by BET surface analysis alone. That is, in certainembodiments, the organosilicon polymeric material is characterised by a high or very high BET specific surface area, and in other words a high or very high combined macro- and mesoporosity.

[0125] The present disclosure also provides organosilicon polymeric materials with a combined meso- and macroporosity, i.e., a specific surface area for which meso- and / or macropores are responsible, of greater than 100 m2 / g as characterisable by BET analysis. The present disclosure also provides organosilicon polymeric materials with a combined meso- and macroporosity of greater than 150, 200, 250 and even upwards of 300 m2 / g as characterisable by BET analysis. In some embodiments, the organosilicon polymeric material is characterised by a high or very high combined meso- and macroporosity.

[0126] The organosilicon polymeric material may be characterisable by the degree of polymerisation of the functionalised organosilicon monomer used to form the polymeric material, as described above, inasmuch as in context of a polymeric material, the term “degree of polymerisation” refers to the polymerisation yield, being the ratio of reacted (polymerised / crosslinked) polymerisable functional groups or functionalised organosilicon monomers to total polymerisable functional groups or functionalised organosilicon monomers in a polymeric material (i.e. relative to what it is intended to polymerise with, for example itself and / or another monomer(s), including optionally via a crosslinker group contained within the starting resin). In some embodiments the organosilicon polymeric material is characterisable by a high degree of polymerisation as defined above, while in some embodiments the organosilicon polymeric material is characterisable by a “medium degree of polymerisation” as defined above, while in some embodiments the organosilicon polymeric material is characterisable by a “low degree of polymerisation” as defined above. In some embodiments, the organosilicon polymeric material is characterisable by a degree of polymerisation of 80% or less. In some embodiments, the organosilicon polymeric material is characterisable by a degree of polymerisation of between 60% and 80%, or between 50% and 70%. In some embodiments, the organosilicon polymeric material is characterisable by a degree of polymerisation of between 20% and 90%, 30% and 80%, 40% and 70%, or of between 40% and 60%, or of around 50%, say of between 45% and 55%. Degree of polymerisation may be analytically determined once a functionalised organosilicon monomer has been exposed to polymerisation conditions to form an organosilicon polymeric material. Any suitable analysis technique for determining degree of polymerisation may be applied, including, for example, FTIR, NMR, or mass differentialanalysis.

[0127] A feature of an organosilicon polymeric material with an “incomplete” degree of polymerisation, that is a degree of polymerisation less than 100%, is the presence of a residual quantity of unreacted functionalised organosilicon monomer within the polymeric material. In embodiments with incomplete degree of polymerisation, the unreacted organosilicon monomer may contribute further to forming pores within the porous organosilicon polymeric material when removed in a post-polymerisation evacuation step. The skilled person will recognise that low, or medium degrees of polymerisation may result in considerable pore formation in the polymeric material. Generally, these pores will be meso- and / or macropores.

[0128] In some embodiments, the porous organosilicon polymeric material is substantially free of porogen and optionally unreacted functionalised organosilicon monomer and optionally functionalised organic monomer, and optionally crosslinking agent. In other words, in some embodiments substantially all of the porogen and unreacted monomeric materials used to form the polymeric material (e.g., functionalised organosilicon monomer, functionalised organic monomer, crosslinking agent) are removed from the organosilicon polymeric material by the post-polymerisation evacuation step in forming the porous (macro- and / or mesoporous) organosilicon polymeric material. The term "substantially free," as used herein in means that the e.g., porogen is present in no more than residual amounts such that it does not materially affect the porosity of the polymeric material in an intended application. This does not require complete removal of the porogen, as trace amounts may remain without affecting the material's intended function. Generally speaking, a porous organosilicon polymeric material that is substantially free of e.g., porogen means that at least about 90% by weight of the porogen originally present is absent as determined by BET analysis of the porous organosilicon polymeric material. In certain embodiments, at least about 95% by weight of the porogen has been removed, or at least about 98% by weight, or at least about 99% by weight of the porogen has been removed. The degree of porogen removal may be determined by various analytical techniques known in the art, such as thermogravimetric analysis, spectroscopic methods, or chromatographic techniques. In embodiments, porogen and optionally unreacted monomeric materials used to form the polymeric material are detectably absent in porous organosilicon polymeric material.Methods for forming an organosilicon polymeric material

[0129] The present disclosure provides a method for forming an organosilicon polymeric material, comprising subjecting a resin as described herein to polymerising conditions to form an organosilicon polymeric material.

[0130] The specific polymerisation conditions will generally be determined by the nature of the polymerisable functional groups of the functionalised organosilicon monomer but are not otherwise particularly limited. Any polymerisation conditions that result in polymerisation of the functionalised organosilicon monomer to form an organosilicon polymeric material suitably with at least a low degree of polymerisation may be employed. Those skilled in the art will appreciate that the specific polymerisation (reaction) conditions may be manipulated to achieve a particular degree of polymerisation, as described above. A number of polymerisation reaction chemistries are applicable including but not limited to step-growth polymerisation including condensation reactions, and chain-growth polymerisation including cationic or anionic addition reactions or thermal- or photo-catalysed free radical reactions. In some embodiments, the polymerisation conditions comprise a step of free radical polymerisation. In some embodiments, the polymerisation conditions comprise a step of photopolymerisation.

[0131] Resins suitable for forming the organosilicon polymeric material may generally be formed by mixing the resin components together. In some embodiments, the resin components are mixed sufficiently so as to form a homogenous resin. A homogenous resin comprises a uniform consistency of components dispersed throughout the volume of the resin. All components of the resin may be placed together and subject to one mixing step, or the components may be added together in any particular order and mixed in between additions. Preparation of the resin may be undertaken immediately prior to polymerisation, or a length of time prior to polymerisation, for example, 30 mins, 1 hour, 2 hours, or 24 hours. In some embodiments, the resin is prepared immediately prior to polymerisation.

[0132] In some embodiments a dispersant is used, wherein a suspension of one or more of the resin components is prepared separately - or in other words, the one or more resin component(s) are suspended in a dispersant, and the suspension is then placed together with further components of the resin, and subject to a mixing step. At least a portion of the dispersant may be removed prior to the resin being subjected to polymerising conditions. The removal of the at least a portion of the dispersant may be performed using a drying step such as by leaching, canulation, decanting and / or evaporation, such as under a negative pressure i.e. vacuum. In some embodiments, all but trace amounts of the dispersant is removed. In other embodiments,a dispersant may double as a porogen and all or a portion of the dispersant may be retained in the resin to function as porogen.

[0133] Polymerisation of the resin may be undertaken in any suitable vessel or process unit known in the art that is compatible with the selected polymerisation conditions. For example, in embodiments employing free radical polymerisation, polymerisation may be undertaken in a container, pipe, tank, or vat. Polymerisation may be undertaken in the presence of oxygen, or under reduced-oxygen conditions. In some embodiments, dissolved gas is at least partly removed from the resin prior to polymerisation. In some embodiments, the polymerisation conditions are applied during a 3D printing process; that is, the step of polymerisation is applied during a 3D printing process. A 3D printing process generally uses a 3D printing apparatus and comprises a shaping step where resin is deposited to form a shaped article, and a curing step where the deposited resin is subject to polymerising conditions to form a polymeric material. The shaping and curing steps may be performed together or separately. That is, the deposited resin may be cured as it is deposited or during deposition, or the deposited resin may be cured after deposition and the shaped article is wholly formed. In some embodiments, the 3D printing conditions comprise a step of photopolymerisation. In some embodiments, the 3D printing conditions comprise a step of free radical photopolymerisation. The present disclosure accordingly provides in some embodiments for 3D printed organosilicon polymeric materials for forming porous organosilicon polymeric materials; that is, organosilicon polymeric materials formed by a 3D printing process using a step of photopolymerisation.

[0134] For forming porous organosilicon polymeric materials from (un-evacuated) organosilicon polymeric materials, the presently disclosed method comprises in some embodiments a further step of removing at least a portion of porogen, optionally together with removal of one or more of the monomeric materials used to form the polymeric material (e.g., functionalised organosilicon monomer, functionalised organic monomer, crosslinking agent), from within the organosilicon polymeric material. Removal of at least a portion of porogen and optionally monomeric materials used to form the polymeric material from within the organosilicon polymeric material forms meso- and / or macropores within the organosilicon polymeric material, generally of an open cell structure.

[0135] The specific method for removing the porogen and optionally monomeric materials used to form the polymeric material is not particularly limited. It may include washing with solvent, dialysis, and / or evaporation, including evaporation under reduced pressure (i.e.vacuum).

[0136] In embodiments where a solvent is used, the skilled person will appreciate that generally a portion of all soluble materials will be removed from the organosilicon polymeric material, which alongside porogen may include one or more monomeric materials used to form the polymeric material such as unreacted functionalised organosilicon monomer. In embodiments using a solvent, and without wishing to be limited by theory, the solvent is believed to enter the regions of the polymeric material containing porogen and optionally monomeric materials used to form the polymeric material and physically displace porogen and optionally monomeric materials used to form the polymeric material from these regions. It is believed that these regions may be substantially filled with solvent during washing. The use a positive pressure and or agitation, such as sonication, may assist to force or encourage solvent to penetrate the material. A subsequent drying step, wherein the washing solvent is removed from the organosilicon polymeric material may suitably be applied. This may use reduced pressure (vacuum) and / or heating. The solvent may be a single solvent or a mixture of solvents. The solvent employed will depend on the solubility of the porogen and optionally monomeric materials used to form the polymeric material in that solvent. For example, in embodiments employing PEG as porogen and polydimethylsiloxane-based functionalised organosilicon monomers, a polar organic solvent such as NMP is suitable for removing porogen and unreacted functionslised organosilicon monomer from the organosilicon polymeric material. In some embodiments, at least a portion of the porogen and unpolymerised functionalised organosilicon monomer is removed from the organosilicon polymeric material by washing with a solvent. In some embodiments, the solvent is a polar organic solvent selected from the group comprising methanol, acetonitrile, ethanol, tetrahydrofuran, dimethylformamide, and N-methyl-2-pyrrolidone (NMP). In some embodiments, the solvent is N-methyl-2-pyrrolidone (NMP).EXAMPLES

[0137] A summary of exemplary materials and synthesis conditions used for producing organosilicon polymeric materials in accordance with the present disclosure is provided below.

[0138] Example 1: Acrylate-functionalised organosilicon monomer with 50 parts of polyethylene glycol (average Mn 200) as porogen

[0139] A resin was prepared by mixing 100 parts of methacryloxypropyl terminated polydimethylsiloxane 5 parts of porous silicon dioxide nanoparticles (spherical, 5-20 nm), 50parts of polyethylene glycol (average Mn 200) with 0.9 parts of phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, 0.8 parts of w / w tert-Butylhydroquinone (TBHQ), and 0.46 parts of 4-nitrophenyl phenyl sulfide. The resin components were mixed thoroughly on a vortex mixer (10 min.) and sonication bath (2 min.), and then the prepared resin was vacuumed for 10 minutes. The resin was 3D printed using a digital light projection (DLP) printer, Miicraft Ultra, as per the manufacturer’s standard operating procedure.

[0140] The 3D-printed organosilicon polymeric material object was initially cleaned with isopropyl alcohol. It was then sonicated in Dynasolve™ M-10 for 20 minutes and vacuum dried at 90°C overnight to produce a macro- and / or mesoporous organosilicon polymeric material object.

[0141] Figure 1 shows SEM micrographs of the resulting porous poly dimethyl siloxane using the acrylate resin with 5% SiO2 and 50% w / w PEG 200.

[0142] Example 2: Acrylate-functionalised organosilicon monomer with 10 parts of polyethylene glycol (average Mn 200) as porogen

[0143] A resin was prepared by mixing 100 parts of methacryloxypropyl terminated poly dimethylsiloxane 5 parts of porous silicon dioxide nanoparticles (spherical, 5-20 nm), 10 parts of polyethylene glycol (average Mn 200) with 0.9 parts of phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, 0.8 parts of w / w tert-Butylhydroquinone (TBHQ), and 0.46 parts of 4-nitrophenyl phenyl sulfide. The resin components were mixed thoroughly on a vortex mixer (10 min.) and sonication bath (2 min.), and then the prepared resin was vacuumed for 10 minutes. The resin was 3D printed using a digital light projection (DLP) printer, Miicraft Ultra, as per the manufacturer’s standard operating procedure.

[0144] The 3D-printed organosilicon polymeric material object was initially cleaned with isopropyl alcohol. It was then sonicated in Dynasolve™ M-10 for 20 minutes and vacuum dried at 90°C overnight to produce a macro- and / or mesoporous organosilicon polymeric material object.

[0145] Figure 2 shows SEM micrographs of the resulting porous poly dimethyl siloxane using the acrylate resin with 5% SiCh and 10% w / w PEG 200.

[0146] Example 3: Acrylate-functionalised organosilicon monomer with 30 parts of polyethylene glycol (average Mn 200) as porogen

[0147] A resin was prepared by mixing 100 parts of methacryloxypropyl terminated polydimethylsiloxane 5 parts of porous silicon dioxide nanoparticles (spherical, 5-20 nm), 30parts of polyethylene glycol (average Mn 200) with 0.9 parts of phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, 0.8 parts of w / w tert-Butylhydroquinone (TBHQ), and 0.46 parts of 4-nitrophenyl phenyl sulfide. The resin components were mixed thoroughly on a vortex mixer (10 min.) and sonication bath (2 min.), and then the prepared resin was vacuumed for 10 minutes. The resin was 3D printed using a digital light projection (DLP) printer, Miicraft Ultra, as per the manufacturer’s standard operating procedure.

[0148] The 3D-printed organosilicon polymeric material object was initially cleaned with isopropyl alcohol. It was then sonicated in Dynasolve™ M-10 for 20 minutes and vacuum dried at 90°C overnight to produce a macro- and / or mesoporous organosilicon polymeric material object.

[0149] Figure 3 shows SEM micrographs of the resulting porous poly dimethyl siloxane using the acrylate resin with 5% SiO2 and 30% w / w PEG 200.

[0150] Example 4: Acrylate-functionalised organosilicon monomer with 70 parts of polyethylene glycol (average Mn 400) as porogen

[0151] A resin was prepared by mixing 100 parts of methacryloxypropyl terminated polydimethylsiloxane 5 parts of porous silicon dioxide nanoparticles (spherical, 5-20 nm), 70 parts of polyethylene glycol (average Mn 400) with 0.9 parts of phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, 0.8 parts of w / w tert-Butylhydroquinone (TBHQ), and 0.46 parts of 4-nitrophenyl phenyl sulfide. The resin components were mixed thoroughly on a vortex mixer (10 min.) and sonication bath (2 min.), and then the prepared resin was vacuumed for 10 minutes. The resin was 3D printed using a digital light projection (DLP) printer, Miicraft Ultra, as per the manufacturer’s standard operating procedure.

[0152] The 3D-printed organosilicon polymeric material object was initially cleaned with isopropyl alcohol. It was then sonicated in Dynasolve™ M-10 for 20 minutes and vacuum dried at 90°C overnight to produce a macro- and or mesoporous organosilicon polymeric material object.

[0153] Figure 4 shows SEM micrographs of the resulting porous poly dimethyl siloxane using the acrylate resin with 5% SiO2 and 70% w / w PEG 200.

[0154] Example 5: Acrylate-functionalised organosilicon monomer with 100 parts of polyethylene glycol (average Mn 200) as porogen

[0155] A resin was prepared by mixing 100 parts of methacryloxypropyl terminated poly dimethylsiloxane 5 parts of porous silicon dioxide nanoparticles (spherical, 5-20 nm), 100parts of polyethylene glycol (average Mn 200) with 0.9 parts of phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, 0.8 parts of w / w tert-Butylhydroquinone (TBHQ), and 0.46 parts of 4-nitrophenyl phenyl sulfide. The resin components were mixed thoroughly on a vortex mixer (10 min.) and sonication bath (2 min.), and then the prepared resin was vacuumed for 10 minutes. The resin was 3D printed using a digital light projection (DLP) printer, Miicraft Ultra, as per the manufacturer’s standard operating procedure.

[0156] The 3D-printed organosilicon polymeric material object was initially cleaned with isopropyl alcohol. It was then sonicated in Dynasolve™ M-10 for 20 minutes and vacuum dried at 90°C overnight to produce a macro- and or mesoporous organosilicon polymeric material object.

[0157] Figure 5 shows SEM micrographs of the resulting porous poly dimethyl siloxane using the acrylate resin with 5% SiCh and 100% w / w PEG 200.

[0158] Example 6: Acrylate-functionalised organosilicon monomer with 50 parts of polyethylene glycol (average Mn 600) as porogen

[0159] A resin was prepared by mixing 100 parts of methacryloxypropyl terminated polydimethylsiloxane 5 parts of porous silicon dioxide nanoparticles (spherical, 5-20 nm), 50 parts of polyethylene glycol (average Mn 600) with 0.9 parts of phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, 0.8 parts of w / w tert-Butylhydroquinone (TBHQ), and 0.46 parts of 4-nitrophenyl phenyl sulfide. The resin components were mixed thoroughly on a vortex mixer (10 min.) and sonication bath (2 min.), and then the prepared resin was vacuumed for 10 minutes. The resin was 3D printed using a digital light projection (DLP) printer, Miicraft Ultra, as per the manufacturer’s standard operating procedure.

[0160] The 3D-printed organosilicon polymeric material object was initially cleaned with isopropyl alcohol. It was then sonicated in Dynasolve™ M-10 for 20 minutes and vacuum dried at 90°C overnight to produce a macro-and / or mesoporous organosilicon polymeric material object.

[0161] Figure 6 shows SEM micrographs of the resulting porous poly dimethyl siloxane using the acrylate resin with 5% SiCh, 50% w / w PEG 600.

[0162] Example 7: Acrylate-functionalised organosilicon monomer with 50 parts of di(ethylene glycol) as porogen

[0163] A resin was prepared by mixing 100 parts of methacryloxypropyl terminated polydimethylsiloxane 5 parts of porous silicon dioxide nanoparticles (spherical, 5-20 nm), 50parts of di(ethylene glycol) with 0.9 parts of phenylbi s(2, 4, 6-trimethylbenzoyl) phosphine oxide, 0.8 parts of w / w tert-Butylhydroquinone (TBHQ), and 0.46 parts of 4-nitrophenyl phenyl sulfide. The resin components were mixed thoroughly on a vortex mixer (10 min.) and sonication bath (2 min.), and then the prepared resin was vacuumed for 10 minutes. The resin was 3D printed using a digital light projection (DLP) printer, Miicraft Ultra, as per the manufacturer’s standard operating procedure.

[0164] The 3D-printed organosilicon polymeric material object was initially cleaned with isopropyl alcohol. It was then sonicated in Dynasolve™ M-10 for 20 minutes and vacuum dried at 90°C overnight to produce a macro- and / or mesoporous organosilicon polymeric material object.

[0165] Figure 7 shows SEM micrographs of the resulting porous poly dimethyl siloxane using the acrylate resin with 5% SiCh, 50% w / w Di(ethylene glycol).

[0166] Example 8: Acrylate-functionalised organosilicon monomer with 50 parts of propylene glycol as porogen

[0167] A resin was prepared by mixing 100 parts of methacryloxypropyl terminated polydimethylsiloxane 5 parts of porous silicon dioxide nanoparticles (spherical, 5-20 nm), 50 parts of propylene glycol with 0.9 parts of phenylbis(2, 4, 6-trimethylbenzoyl) phosphine oxide, 0.8 parts of w / w tert-Butylhydroquinone (TBHQ), and 0.46 parts of 4-nitrophenyl phenyl sulfide. The resin components were mixed thoroughly on a vortex mixer (10 min.) and sonication bath (2 min.), and then the prepared resin was vacuumed for 10 minutes. The resin was 3D printed using a digital light projection (DLP) printer, Miicraft Ultra, as per the manufacturer’s standard operating procedure.

[0168] The 3D-printed organosilicon polymeric material object was initially cleaned with isopropyl alcohol. It was then sonicated in Dynasolve™ M-10 for 20 minutes and vacuum dried at 90°C overnight to produce a macro- and / or mesoporous organosilicon polymeric material object.

[0169] Figure 8 shows SEM micrographs of the resulting porous poly dimethyl siloxane using the acrylate resin with 5% SiCh, 50% w / w Propylene Glycol.

[0170] Example 9: Acrylate-functionalised organosilicon monomer with 50 parts of glycidol as porogen

[0171] A resin was prepared by mixing 100 parts of methacryloxypropyl terminated polydimethylsiloxane 5 parts of porous silicon dioxide nanoparticles (spherical, 5-20 nm), 50parts of glycidol with 0.9 parts of phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, 0.8 parts of w / w tert-Butylhydroquinone (TBHQ), and 0.46 parts of 4-nitrophenyl phenyl sulfide. The resin components were mixed thoroughly on a vortex mixer (10 min.) and sonication bath (2 min.), and then the prepared resin was vacuumed for 10 minutes. The resin was 3D printed using a digital light projection (DLP) printer, Miicraft Ultra, as per the manufacturer’s standard operating procedure.

[0172] The 3D-printed organosilicon polymeric material object was initially cleaned with isopropyl alcohol. It was then sonicated in Dynasolve™ M-10 for 20 minutes and vacuum dried at 90°C overnight to produce a macro-and / or mesoporous organosilicon polymeric material object.

[0173] Figure 9 shows SEM micrographs of the resulting porous poly dimethyl siloxane using the acrylate resin with 5% SiCh, 50% w / w Glycidol.

[0174] Example 10: Acrylate-functionalised organosilicon monomer with 25 parts of polyethylene glycol (average Mn 400) and 25 parts of Triethanolamine as porogen

[0175] A resin was prepared by mixing 100 parts of methacryloxypropyl terminated polydimethylsiloxane 5 parts of porous silicon dioxide nanoparticles (spherical, 5-20 nm), 25 parts of polyethylene glycol (average Mn 400) and 25 parts of Triethanolamine with 0.9 parts of phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, 0.8 parts of w / w tert-Butylhydroquinone (TBHQ), and 0.46 parts of 4-nitrophenyl phenyl sulfide. The resin components were mixed thoroughly on a vortex mixer (10 min.) and sonication bath (2 min.), and then the prepared resin was vacuumed for 10 minutes. The resin was 3D printed using a digital light projection (DLP) printer, Miicraft Ultra, as per the manufacturer’s standard operating procedure.

[0176] The 3D-printed organosilicon polymeric material object was initially cleaned with isopropyl alcohol. It was then sonicated in Dynasolve™ M-10 for 20 minutes and vacuum dried at 90°C overnight to produce a macro- and / or mesoporous organosilicon polymeric material object.

[0177] Figure 10 shows SEM micrographs of the resulting porous poly dimethylsiloxane using the acrylate resin with 5% SiCh, 25% w / w PEG 400, 25% w / w Triethanolamine.

[0178] Example 11: Acrylate-functionalised organosilicon monomer with 50 parts of polyethylene glycol (average Mn 400) as porogen

[0179] A resin was prepared by mixing 100 parts of methacryloxypropyl terminatedpolydimethylsiloxane, 5 parts of porous silicon dioxide nanoparticles (spherical, 5-20 nm), 50 parts of polyethylene glycol (average Mn 400) with 0.9 parts of phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, 0.8 parts of w / w tert-Butylhydroquinone (TBHQ), and 0.46 parts of 4-nitrophenyl phenyl sulfide. The resin components were mixed thoroughly on a vortex mixer (10 min) and sonication bath (2 min), and then the prepared resin was vacuumed for 10 minutes. The resin was 3D printed using a digital light projection (DLP) printer, Miicraft Ultra, as per the manufacturer’s standard operating procedure to produce a organosilicon polymeric material object.

[0180] Figure 11 shows SEM micrographs of the resulting polydimethylsiloxane.

[0181] Example 12: Acrylate-functionalised and thiol-functionalised dual organosilicon monomer system with 50 parts of polyethylene glycol (average Mn 400) as porogen

[0182] A resin was prepared by mixing 100 parts of methacryloxypropyl terminated poly dimethylsiloxane with 100 parts of (mercaptopropyl)methylsiloxane homopolymer, 5 parts of porous silicon dioxide nanoparticles (spherical, 5-20 nm), 50 parts of polyethylene glycol (average Mn 400) with 0.9 parts of phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, 0.8 parts of w / w tert-Butylhydroquinone (TBHQ), and 0.46 parts of 4-nitrophenyl phenyl sulfide. The resin components were mixed thoroughly on a vortex mixer (10 min) and sonication bath (2 min), and then the prepared resin was vacuumed for 10 minutes. The resin was 3D printed using a digital light projection (DLP) printer, Miicraft Ultra, as per the manufacturer’s standard operating procedure to produce a organosilicon polymeric material.

[0183] Figure 12 shows SEM micrographs of the resulting polydimethylsiloxane.

[0184] Example 13: organosilicon monomer without any porogen (control example)

[0185] A resin was prepared by mixing 100 parts of methacryloxypropyl terminated polydimethylsiloxane, 5 parts of porous silicon dioxide nanoparticles (spherical, 5-20 nm) with 0.9 parts of phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, 0.8 parts of w / w tert-Butylhydroquinone (TBHQ), and 0.46 parts of 4-nitrophenyl phenyl sulfide. The resin components were mixed thoroughly on a vortex mixer (10 min) and sonication bath (2 min), and then the prepared resin was vacuumed for 10 minutes. The resin was 3D printed using a digital light projection (DLP) printer, Miicraft Ultra, as per the manufacturer’s standardoperating procedure.

[0186] Figure 13 shows SEM micrographs of the resulting poly dimethylsiloxane.CHARACTERISATION

[0187] Thermal Stability Properties: The thermal stability properties of a porous polydimethylsiloxane article produced in accordance with example 11 was assessed by Therm ogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). Therm ogravimetric analysis was performed using a Netzsch STA 449 F5 Jupiter instrument. Approximately 15 mg of porous poly dimethylsiloxane sample was placed in an aluminium oxide crucible and heated from 25 °C to 800 °C at 10 °C min1under a flow of high-purity nitrogen. Differential scanning calorimetry (DSC) measurements were carried out on a Netzsch Caliris 300 system. Samples were sealed in aluminium crucibles prior to analysis. Thermal transitions were examined over a temperature range of -4 °C to 200 °C, using three successive heating-cooling cycles. All scans were conducted at a constant heating rate of 10 °C min-1. Exemplary thermal analysis data including Derivative Thermogravimetry (DTG) and Derivative Differential Scanning Calorimetry (DDSC) traces are shown in Figure 14. The porous polydimethylsiloxane article exhibits two principal mass-loss features in the TG / DTG traces at approximately 297 °C and 411 °C. Without wishing to be bound by theory, the first peak is consistent with main-chain scission and / or degradation of uncrosslinked or low-molecular-weight polydimethylsiloxane fractions, and the second with degradation of higher-molecular-weight or crosslinked segments. No significant DSC transitions were observed between 0-220 °C.

[0188] Surface hydrophobicity: Static water contact angles were measured on representative porous polydimethylsiloxane articles produced in accordance with example 11. Static water contact angles between 93-116° were measured, with no statistically significant differences observed on three replicate measurements (paired t-tests; one-way ANOVA, a = 0.05). The static water contact angle measurements greater than 90° confirms the hydrophobic character of materials in accordance with an embodiment of the present disclosure.

[0189] Post-polymerisation washing: Representative porous polydimethylsiloxane articles produced in accordance with example 11 were fully submerged in either 100% acetonitrile or 100% methanol and were agitated on an orbital shaker at 50 rpm to remove residual unreacted monomer, photoinitiator, UV absorber, and free-radical scavenger from the articles. The articleswere subjected to the washing procedure a total of 25 times, with the solvent being replaced for each wash cycle. The washed articles were then dried and their mass compared before and after washing. Mean mass loss of between 17.3-24.9% was measured across 5 replicate articles, indicating removal of residual components from the polymer articles. The methanol or acetonitrile wash solvents collected from the first and last wash cycles were analysed by High-Performance Liquid Chromatography with Diode Array Detection (HPLC-DAD) and compared, showing a reduction in solvent extracted compounds following the washing procedure (Figure 15).

[0190] The above examples are only the preferred examples of the present disclosure. It shall be pointed out that various improvements and modifications could be made by those ordinarily skilled in the art without deviating from the principle of the present disclosure, which shall fall within the protection scope of the present disclosure.

[0191] It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

[0192] In the claims which follow and in the preceding description of the disclosure, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the disclosure.

[0193] As used herein, except where the context requires otherwise due to 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

WHAT IS CLAIMED IS:

1. A resin for forming an organosilicon polymeric material, said resin comprising:a) a functionalised organosilicon monomer; andb) a porogen,wherein the porogen is present in an amount of at least 10 wt% of functionalised organosilicon monomer present in the resin.

2. The resin according to claim 1, wherein the functionalised organosilicon monomer is based on an organosilicon compound selected from the group consisting of a polysiloxane, polycarbosiloxane, polysilsesquioxane, polycarbosilane, polysilylcarbodiimide, polysilsesquicarbodiimide, polysilazane, polysilsesquiazane, polyborosilane, polyborosiloxane and polyborosilazane.

3. The resin according to claim 1 or 2, wherein the functionalised organosilicon monomer is based on an organosilicon compound selected from the group consisting of:a) an organosilicon compound having a chemical structure of Formula 1, Formula 2, Formula 3, Formula 4 or Formula 5:wherein:n represents a backbone structure of repeating silicon atom-containing motifs and is independently an integer of from 2 to 15; andRi, R2, R3 and R4 are independently selected from the group consisting of H, a Ci-Cis substituted or unsubstituted alkyl, a Ci-Cis substituted or unsubstituted alkyl ether, a phenyl and a halide, independently for each integer of n, with the proviso that the pairs of Ri and R2 and R3 and R4 are not both H, alkyl ether or halide forevery integer of n; andb) an organosilicon compound having a chemical structure of Formula 6, Formula 7 or Formula 8:Formula 6 Formula 7 Formula 8 wherein:n represents a backbone structure of repeating silicon atom-containing motifs and is independently an integer of from 2 to 15;Ri, R2, R3 and R4 are as defined above; andR5 and Rs are independently selected from the group consisting of H, OH, a Ci- Ci8 substituted or unsubstituted alkyl, a Ci-Cis substituted or unsubstituted alkyl ether and a phenyl, independently for each integer of n.

4. The resin according to any one of claims 1 to 3, wherein the functionalised organosilicon monomer contains one or more polymerisable functional group(s) capable of undergoing step-growth, or chain-growth polymerisation.

5. The resin according to any one of claims 1 to 4, wherein the functionalised organosilicon monomer contains one or more polymerisable functional group(s) selected from the group consisting of hydroxyl, epoxide, vinyl, allyl, ethynyl, thiol, glycidyl, acrylate, methacrylate, and thiocyanate groups.

6. The resin according to any one of claims 1 to 5, wherein the functionalised organosilicon monomer comprises two or more polymerisable vinyl functional groups, preferably selected from the group consisting of acrylate, methacrylate, acrylamide, methacrylamide, styrenic, or vinyl ether functional groups, more preferably acrylate or methacrylate.

7. The resin according to any one of claims 1 to 6, wherein the functionalised organosilicon monomer is methacryloxypropyl terminated polydimethylsiloxane.

8. The resin according to any one of claims 1 to 7, wherein the porogen is an organic liquid with a boiling point of at least 150 °C at standard pressure.

9. The resin according to any one of claims 1 to 8, wherein the porogen is selected from the group consisting of triethanolamine, ethylene glycol, propylene glycol, oligo(ethylene glycol) poly(ethylene glycol), 1,3 -propane diol, hexylene glycol, dipropylene glycol, neopentyl glycol, and glycidol.

10. The resin according to any one of claims 1 to 9, wherein the porogen is polyethylene glycol) having a number average molecular weight in a range of from 100 g / mol to 1500 g / mol.

11. The resin according to any one of claims 1 to 10, wherein porogen is present in an amount of from 10 wt% to 60 wt%, preferably of from 20 wt% to 50 wt%, of functionalised organosilicon monomer present in the resin.

12. The resin according to any one of any one of claims 1 to 11, further comprising one or more of:a) structural particles;b) a second functionalised organosilicon monomer; andc) a functionalised organic monomer.

13. The resin according to claim 12, wherein the structural particles are ceramic particles, preferably microporous ceramic particles.

14. A polymeric material formed from a resin according to any one of claims 1 to 13.

15. An organosilicon polymeric material, said polymeric material comprising:a) a polymerised functionalised organosilicon monomer; andb) a porogen,wherein the porogen is present in an amount of at least 10 wt% of polymerised functionalised organosilicon monomer present in the polymeric material.

16. A macro- and / or meso-porous organosilicon polymeric material comprising polymerised functionalised organosilicon monomer.

17. The organosilicon polymeric material of claim 15 or 16, wherein the organosilicon polymeric material is substantially free of porogen and / or unpolymerised monomer.

18. The organosilicon polymeric material of any one of claims 15 to 17, wherein the functionalised organosilicon monomer is as defined in any one of claims 2 to 7.

19. The organosilicon polymeric material according to any one of claims 15 to 18, characterisable by a specific surface area of at least 150 m2 / g.

20. The organosilicon polymeric material according to any one of claims 15 to 19, characterisable by a degree of polymerisation of 80% or less, preferably of between 40% and 80%, more preferably of between 40% and 60%.

21. A method for forming an organosilicon polymeric material, comprising subjecting a resin according to any one of claims 1 to 13 to polymerising conditions to form an organosilicon polymeric material.

22. A method for forming a macro- and / or meso-porous organosilicon polymeric material, comprising:a) subjecting a resin comprising a functionalised organosilicon monomer and a porogen to polymerising conditions to form an organosilicon polymeric material; andb) removing at least a portion of one or both of porogen and unpolymerised functionalised organosilicon monomer from within the organosilicon polymeric material to form a macro- and / or meso-porous organosilicon polymeric material.

23. The method according to claim 22, wherein the polymerising conditions include a step of radical polymerisation.

24. The method according to claim 22 or 23, wherein the radical polymerisation is undertaken during a 3D printing process.

25. The method according to any one of claims 22 to 24, wherein the step of removing at least a portion of one or both of the porogen and / or unpolymerised monomer includes washingthe polymeric material with a solvent.

26. The method according to claim 25, wherein the solvent is an alcohol and / or A-Methyl-2-pyrrolidone.

27. A macro- and / or meso-porous organosilicon polymeric material formed by the method of any one of claims 22 to 26.

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