A silicone foam and a method of making the same

Abstract

The application discloses a kind of organic silicon foams and preparation method thereof.The organic silicon foam is obtained by heat curing of water-in-oil high internal phase Pickering emulsion, and the mass composition of the water-in-oil high internal phase Pickering emulsion is as follows: 100 parts of organic silicon prepolymer; 0.1-5 parts of amphiphilic inorganic nanoparticles; 10-100 parts of lipophilic solvent; 100-1000 parts of dispersed phase.The water-in-oil Pickering emulsion of the application uses solid nanoparticles with amphiphilic properties as emulsifier, and compared with small molecule surfactant, it has less dosage and can stabilize high internal phase, with extremely high emulsion stability.Water droplets in the emulsion are in multi-stage distribution, which serves as a template for forming cells, realizing multi-stage dispersed cell structure of the organic silicon foam, and this multi-stage distributed cell structure can significantly improve the mechanical properties of the organic silicon foam;in addition, the amphiphilic inorganic nanoparticles are embedded on the cell surface of the organic silicon foam.Therefore, the organic silicon foam of the application has excellent mechanical properties.

Description

Technical Field

[0001] This invention relates to an organosilicon foam and its preparation method, belonging to the field of materials technology. Background Technology

[0002] Organosilicon foam is a high-performance foam material. The hydrophobic and flexible polysiloxane molecular chains endow organosilicon foam with excellent hydrophobicity, elasticity, biocompatibility, and air permeability. The cross-linked covalent bonds give the polysiloxane network high mechanical strength, good chemical stability, and heat resistance. The porous structure of organosilicon foam gives it low density, good sound absorption, and good shock resistance. Therefore, compared with other polymer foam materials, organosilicon foam has superior high and low temperature resistance, good aging resistance, excellent electrical insulation and chemical stability, outstanding hydrophobicity, moisture resistance, and physiological inertness. As an ideal lightweight foam material, organosilicon foam is expected to replace or partially replace carbon-based polymer foam materials and is widely used in electronic components, instruments, oil-water separation, wearable electronic devices, high-adsorption resins, and nano-triboelectric power generation.

[0003] Currently, the most commonly used method for preparing silicone foam materials is the chemical foaming method. This method utilizes a chemical reaction to generate gas, causing the silicone polymer matrix to foam. One foaming method involves introducing a foaming agent (such as azobisisobutyronitrile, urea, sodium bicarbonate, etc.) into the polymer, heating it to decompose and release gas, thus causing foaming. This method produces toxic gases at high temperatures, results in uneven cell structure, and makes it difficult to control the degree of foaming, leading to poor mechanical properties. Another foaming method utilizes the chemical reaction between the various silicone polymer components to release gas (e.g., the reaction of Si-OH and Si-H to generate hydrogen). However, because crosslinking and foaming occur simultaneously, the cell structure is difficult to control, resulting in large and uneven cell size. To address the above issues, numerous improved technologies based on chemical foaming methods have been developed to reduce cell size and improve cell uniformity. For example, CN107434854A discloses an organosilicon foam material and its preparation method, which uses a chemical reaction between Si-H and Si-OR groups to release alkanes to prepare the organosilicon foam material, avoiding problems such as uncontrollable cell structure, toxicity caused by high-temperature decomposition of the foaming agent, and easy poisoning and deactivation of platinum catalysts. CN109942873B discloses a method for preparing organosilicon foam material, which relies on oxygen generated by the reaction of oxidant and catalyst during the crosslinking process of mercaptopolysiloxane as the foaming agent. The resulting organosilicon foam material has good compressibility, low density, and high porosity. CN101490144B discloses an organopolysiloxane composition with a density of less than 15000 mPa·s, which is used to obtain a low density of less than 0.20 g / cm³ after crosslinking with good mechanical properties. 3While current improvements to the chemical foaming process have increased porosity, improved mechanical properties, and refined pore structure, they have not fundamentally solved the problem of excessively large pore size and distribution caused by chemical foaming, resulting in very limited improvements in mechanical properties. Therefore, it is necessary to develop new pore-forming methods to effectively control pore size and distribution, thereby obtaining silicone foam materials with high porosity and excellent mechanical properties.

[0004] Emulsion template method is a new technology for preparing silicone foam materials developed in recent years. Compared with chemical foaming method, its advantage is that the pore structure is determined by the size of the dispersed phase in the emulsion, and the pore size and size distribution are easy to control. For example, US10857758B2 discloses a method for preparing silicone foam from a water-in-oil emulsion of a silicone resin precursor stabilized by a non-polar emulsifier. The foam has a pore size of less than 80 micrometers, an open porosity of more than 90%, and a density of 0.2–0.7 g / cm³. 3 The elastic modulus remains stable under high and low temperature conditions. CN110182816A discloses a method using a water-in-oil emulsion as a polymerization template, with two organosilanes dissolved in the oil phase as monomers and stabilizers for the emulsion, to obtain a flexible silica aerogel. The silica aerogel has a porosity of over 80%, a hierarchical porous structure, macropore sizes of 1–400 μm, and micropore sizes of 3–20 nm. Although the above technology can better control the pore structure and improve the uniformity of pore size distribution, its disadvantages include: the prepared silicone foam is not soft enough, has poor tensile properties, and a short service life; the pore structure is prone to collapse due to capillary forces during the drying and pore-forming process; and emulsifier residues in the product reduce mechanical properties and increase toxicity, limiting its application in biomedical materials. Due to these disadvantages, the emulsion template method for preparing silicone foam materials has not been used on a large scale in industrial production like the chemical foaming method. Summary of the Invention

[0005] The purpose of this invention is to provide an organosilicon foam prepared using a water-in-oil Pickering emulsion as a template. This foam exhibits excellent mechanical properties and solves the problems of poor tensile properties, short service life, emulsifier residue, and easy collapse of pore structure in organosilicon foams prepared by existing emulsion template methods.

[0006] The silicone foam provided by this invention is obtained by thermosetting a water-in-oil type high internal phase Pickering emulsion;

[0007] The mass composition of the water-in-oil type high internal phase Pickering emulsion is as follows:

[0008]

[0009] Preferably, the organosilicon prepolymer is a vinyl polysiloxane or a hydrogen-containing polysiloxane, and curing is achieved by an addition reaction between vinyl silane and hydrogen silane initiated by a Pt catalyst. Peroxide crosslinking type and condensation reaction type organosilicon prepolymers cannot be used. The strength and toughness of the cured organosilicon can be adjusted by the degree of crosslinking of the organosilicon prepolymer. The organosilicon prepolymer of the present invention does not limit its degree of crosslinking.

[0010] The viscosity range of the organosilicon prepolymer is 10 mPa·s to 50000 mPa·s, preferably 100 mPa·s to 30000 mPa·s, such as Dow Corning SYLGARD 184 and EcoFlex 00-30. RG 01.

[0011] Preferably, the amount of the amphiphilic inorganic nanoparticles added is 0.5 to 4 parts, more preferably 0.5 to 5 parts, 0.5 to 2 parts, or 0.5 to 3 parts;

[0012] The molar ratio of hydrophilic groups to hydrophobic groups on the surface of the amphiphilic inorganic nanoparticles is 0.7–1.5:1;

[0013] The hydrophilic group is at least one of hydroxyl and amino groups;

[0014] The hydrophobic group is an alkylsiloxy group; preferably, the alkylsiloxy group is at least one of trimethylsiloxy, dimethyldisiloxy, octyldimethylsiloxy, hexadecyldimethylsiloxy, and octadecyldimethylsiloxy.

[0015] The surface area (BET method) of the amphiphilic inorganic nanoparticles is in the range of 50 m². 2 / g~350m 2 / g, preferably 120m 2 / g~300m 2 / g;

[0016] The amphiphilic inorganic nanoparticles described in this invention are not specifically limited to the type of particulate matter and can be selected from fumed silica, fumed titanium dioxide, etc.

[0017] The amphiphilic inorganic nanoparticles described in this invention are preferably amphiphilic fumed silica, such as... H15 H2O H30, AEROSIL R805.

[0018] The lipophilic solvent is a solvent that has good solubility with the organosilicon prepolymer and does not affect the curing of the organosilicon prepolymer, and is selected from at least one of toluene, cyclohexane, octamethyltetrasiloxane and hexamethyldisiloxane.

[0019] Preferably, the amount of the lipophilic solvent added is 50-100 parts, more preferably 50-100 parts, 50-60 parts, or 50-80 parts.

[0020] The dispersed phase is water, or an aqueous solution containing an alcohol or other aqueous solvent;

[0021] The dispersed phase contains a water-soluble substance; the water-soluble substance is a water-soluble drug, a water-soluble salt, or a combination thereof.

[0022] Preferably, the amount of the dispersed phase added is 400-800 parts, more preferably 400-700 parts, 400-500 parts, or 400-600 parts;

[0023] The water-in-oil type high internal phase Pickering emulsion of the present invention can be prepared according to the following method:

[0024] The organosilicon prepolymer, the lipophilic solvent, and the amphiphilic inorganic nanoparticles are mixed uniformly to obtain an oil phase. Then, the dispersed phase is added dropwise to the oil phase under stirring at a certain speed to obtain a water-in-oil emulsion with excellent stability. The stirring speed is 50-500 rpm, preferably 70-300 rpm.

[0025] The order of oil phase mixing is as follows:

[0026] When the viscosity of the selected organosilicon prepolymer is less than 10000 mPa·s, the organosilicon prepolymer and the amphiphilic inorganic nanoparticles are first mixed evenly, and then mixed evenly with the oleophilic solvent; when the viscosity of the selected organosilicon prepolymer is greater than 10000 mPa·s, the organosilicon prepolymer and the oleophilic solvent are first mixed evenly, and then mixed evenly with the amphiphilic inorganic nanoparticles.

[0027] The mixing method of the oil phase is as follows: the lipophilic solvent and the organosilicon prepolymer are preferably mixed by mechanical stirring, with a stirring speed preferably of 200-800 rpm, more preferably 250-500 rpm; the amphiphilic inorganic nanoparticles and the organosilicon prepolymer are preferably mixed by centrifugal mixing, with a centrifugal speed preferably of 500-2000 rpm, more preferably 1000-2000 rpm.

[0028] The mixing of the oil phase is preferably carried out at low temperature to avoid polymerization of the organosilicon prepolymer during the mixing process. The mixing temperature is preferably 5 to 30°C, and more preferably 10 to 25°C.

[0029] The water-in-oil type high internal phase Pickering emulsion is added into a mold, sealed, and then thermo-cured. After demolding, the cured product is obtained, and then water and oleophilic solvents are removed to obtain the final product.

[0030] The thermosetting temperature is 35–80°C, and the time is 2–24 hours;

[0031] The thermosetting process also includes a step of removing water and the oleophilic solvent. This can be done by high-temperature and atmospheric-pressure drying, high-temperature and vacuum drying, freeze drying, or by repeatedly mechanically pressing the cured material until the deformation is 60% to remove most of the dispersed phase, followed by high-temperature and atmospheric-pressure drying to remove the remaining water and oleophilic solvent. The drying temperature is 100-150°C.

[0032] This invention relates to a water-in-oil Pickering emulsion, which uses amphiphilic solid nanoparticles as emulsifiers. Compared to small-molecule surfactants, these nanoparticles require a smaller dosage, stabilize the high internal phase, and result in extremely high emulsion stability. The water droplets in the emulsion are distributed in a multi-level pattern, serving as templates for cell formation and achieving a multi-level dispersed pore structure in the silicone foam. This multi-level pore structure significantly improves the mechanical properties of the silicone foam. Furthermore, the amphiphilic inorganic nanoparticles are embedded on the surface of the silicone foam pores. Therefore, the silicone foam of this invention exhibits excellent mechanical properties. Attached Figure Description

[0033] Figure 1 The compression stress-strain curves of the organosilicon foam prepared in Example 1 of this invention under 80% strain for ten compression cycles.

[0034] Figure 2 The tensile stress-strain curve of the silicone foam prepared in Example 1 of this invention.

[0035] Figure 3 The image is a scanning electron microscope (SEM) image of the organosilicon foam prepared in Example 1 of this invention. Detailed Implementation

[0036] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0037] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0038] Example 1

[0039] By weight, the water-in-oil Pickering emulsion in this embodiment consists of the following components:

[0040] 100 parts of Dow Corning SYLGARD 184 silicone prepolymer, fumed silica H30 (surface area 270-330m²) 2 / g, containing 0.5 parts of 50mol% silanol groups and 50mol% dimethyldisiloxy groups on the surface, 55 parts of hexamethyldisiloxane, and 500 parts of 1wt% NaCl aqueous solution.

[0041] Mix components A and B of the SYLGARD184 silicone prepolymer mechanically at a ratio of 10:1.5 until homogeneous, then... H30 was added to the SYLGARD184 silicone prepolymer and mixed for 2 minutes at 2000 rpm using a Thinky centrifugal mixer. Then, hexamethyldisiloxane was added to the resulting mixture and mechanically stirred until homogeneous to obtain the oil phase. The oil phase was then mechanically stirred at 100 rpm at room temperature while simultaneously adding 1 wt% NaCl aqueous solution dropwise to the oil phase to obtain a stable water-in-oil Pickering silicone emulsion.

[0042] After the above emulsion is put into the mold and sealed, it is placed in an 80°C oven for constant temperature curing for 4 hours. After natural cooling, most of the 1wt% NaCl aqueous solution is repeatedly mechanically extruded out. Then, it is placed in a 120°C oven for constant temperature for 30 minutes to obtain organosilicon foam.

[0043] The density of the silicone foam prepared in this embodiment is 280 mg / cm³. 3 The stress-strain curves for ten compression cycles under 80% deformation are shown below. Figure 1 As shown, after ten compression cycles, the maximum stress retention rate was 92%, and the strain loss rate was 5.3%; the tensile stress-strain curve is shown below. Figure 2 As shown, the tensile strength is 390 kPa and the elongation at break is 122%; the scanning electron microscope image is as follows. Figure 3 The maximum pore size is less than 100 micrometers.

[0044] Example 2

[0045] By weight, the water-in-oil Pickering silicone emulsion in this embodiment consists of the following components:

[0046] 100 parts of Dow Corning SYLGARD 184 silicone prepolymer, fumed silica H15 (surface area of ​​120m²) 2 / g, containing 2 parts of 50mol% silanol groups and 50mol% dimethyldisiloxy groups on the surface, 60 parts of hexamethyldisiloxane, and 600 parts of 1wt% NaCl aqueous solution.

[0047] Mix components A and B of the SYLGARD184 silicone prepolymer by mechanical stirring at a ratio of 10:1 until homogeneous, then... H15 was added to the SYLGARD184 silicone prepolymer and mixed for 2 minutes at 2000 rpm using a Thinky centrifugal mixer to remove bubbles. Toluene was then added to the mixture, and the mixture was mechanically stirred until homogeneous to obtain the oil phase. The mixture was then mechanically stirred at 100 rpm at room temperature. While stirring, 1 wt% NaCl aqueous solution was added dropwise to the oil phase mixture to obtain a stable water-in-oil Pickering silicone emulsion.

[0048] After the above emulsion is put into a sealed mold, it is placed in an oven at 60°C for 8 hours to cure. After natural cooling, most of the 1wt% NaCl aqueous solution is squeezed out. Then, it is placed in an oven at 120°C for 30 minutes to obtain silicone foam.

[0049] The density of the silicone foam prepared in this embodiment is 262 mg / cm³. 3 After ten compression cycles at 80% deformation, the maximum stress retention rate is 89%, and the strain loss rate is 6.2%; the tensile strength is 370 kPa, and the elongation at break is 103%; the maximum pore size is less than 100 micrometers.

[0050] Example 3

[0051] By weight, the water-in-oil Pickering silicone emulsion in this embodiment consists of the following components:

[0052] 100 parts of Dow Corning SYLGARD 184 silicone prepolymer, fumed silica H2O (surface area 170m²) 2 / g, containing 2 parts of 50mol% silanol groups and 50mol% dimethyldisiloxy groups on the surface, 60 parts of hexamethyldisiloxane, and 500 parts of 2wt% CaCl2 aqueous solution.

[0053] Mix components A and B of the SYLGARD184 silicone prepolymer mechanically at a ratio of 10:1.5 until homogeneous, then... H2O was added to SYLGARD184 silicone prepolymer and mixed for 2 minutes at 2000 rpm using a Thinky centrifugal mixer to remove bubbles. Then, hexamethyldisiloxane was added to the resulting mixture and mechanically stirred until homogeneous to obtain the oil phase. The mixture was then mechanically stirred at 100 rpm at room temperature while simultaneously adding CaCl2 aqueous solution dropwise to the oil phase mixture to obtain a stable water-in-oil Pickering silicone emulsion.

[0054] After the above emulsion is poured into a sealed mold, it is placed in a 40°C oven for constant temperature curing for 12 hours. After natural cooling, most of the CaCl2 aqueous solution is squeezed out, and then it is kept at a constant temperature of 120°C for 30 minutes to obtain silicone foam.

[0055] The density of the silicone foam prepared in this embodiment is 292 mg / cm³. 3 After ten compression cycles at 80% deformation, the maximum stress retention rate is 90%, and the strain loss rate is 5.9%; the tensile strength is 382 kPa, and the elongation at break is 112%; the maximum pore size is less than 100 micrometers.

[0056] Example 4

[0057] By weight, the water-in-oil Pickering silicone emulsion in this embodiment consists of the following components:

[0058] 100 parts of RG 01 type silicone prepolymer, and AEROSIL R805 fumed silica (surface area 150m²). 2 / g, containing 48mol% silanol groups, 52mol% octyldimethylsiloxy groups (5 parts), 80 parts octamethyltetrasiloxane, and 700 parts 1wt% potassium chloride aqueous solution.

[0059] Will Components A and B of RG 01 silicone prepolymer were mechanically mixed at a ratio of 10:1 until homogeneous, and then AEROSIL R805 was added. In the RG 01 silicone prepolymer, the mixture was stirred at 2000 rpm for 2 minutes using a Thinky centrifugal mixer to remove bubbles. Then, octamethyltetrasiloxane was added to the resulting mixture and mechanically stirred until homogeneous to obtain an oil phase. Then, the mixture was mechanically stirred at 100 rpm at room temperature, and 1 wt% potassium chloride aqueous solution was added dropwise to the oil phase mixture while mechanically stirring to obtain a stable water-in-oil Pickering silicone emulsion.

[0060] After the above emulsion is poured into a sealed mold, it is placed in an 80°C oven for constant temperature curing for 4 hours. After natural cooling, most of the potassium chloride aqueous solution is squeezed out, and then it is kept at a constant temperature of 120°C for 30 minutes to obtain silicone foam.

[0061] The density of the silicone foam prepared in this embodiment is 182 mg / cm³. 3 After ten compression cycles at 80% deformation, the maximum stress retention rate is 91%, and the strain loss rate is 6.1%; the tensile strength is 316 kPa, and the elongation at break is 108%; the maximum pore size is less than 100 micrometers.

[0062] Example 5

[0063] By weight, the water-in-oil Pickering silicone emulsion in this embodiment consists of the following components:

[0064] 100 parts of EcoFlex 00-30 silicone prepolymer, and AEROSIL R805 fumed silica (surface area 150m²). 2 / g, containing 3 parts of 48mol% silanol groups and 52mol% octyldimethylsiloxy groups on the surface, 100 parts of toluene, and 400 parts of 2wt% potassium chloride aqueous solution.

[0065] Components A and B of EcoFlex 00-30 silicone prepolymer were mechanically mixed at a 1:1 ratio until homogeneous. Then, AEROSIL R805 was added to the EcoFlex 00-30 silicone prepolymer and mixed for 2 minutes at 2000 rpm using a Thinky centrifugal mixer. Toluene was then added to the resulting mixture and mechanically stirred until homogeneous to obtain the oil phase. The mixture was then mechanically stirred at 100 rpm at room temperature while simultaneously adding potassium chloride aqueous solution dropwise to the oil phase mixture to obtain a stable water-in-oil Pickering silicone emulsion.

[0066] After the above emulsion is poured into a sealed mold, it is placed in a 50°C oven for constant temperature curing for 10 hours. After natural cooling, it is placed in a 150°C oven for constant temperature curing for 30 minutes to obtain silicone foam.

[0067] The density of the silicone foam prepared in this embodiment is 372 mg / cm³. 3 After ten compression cycles at 80% deformation, the maximum stress retention rate was 87%, and the strain loss rate was 7.2%; the tensile strength was 576 kPa, and the elongation at break was 138%; the maximum pore size was less than 100 micrometers.

[0068] Example 6

[0069] By weight, the water-in-oil Pickering emulsion in this embodiment consists of the following components:

[0070] 100 parts of Dow Corning SYLGARD 184 silicone prepolymer, fumed silica H30 (surface area 270-330m²) 2 / g, containing 0.5 parts of 50mol% silanol groups and 50mol% dimethyldisiloxy groups on the surface, 55 parts of hexamethyldisiloxane, and 600 parts of vancomycin hydrochloride aqueous solution (vancomycin hydrochloride concentration is 1μg / ml).

[0071] Mix components A and B of the SYLGARD184 silicone prepolymer by mechanical stirring at a ratio of 10:1 until homogeneous, then... H30 was added to SYLGARD184 silicone prepolymer and mixed for 2 minutes at 2000 rpm using a Thinky centrifugal mixer. Then, hexamethyldisiloxane was added to the resulting mixture and mechanically stirred until homogeneous to obtain an oil phase. The oil phase was then mechanically stirred at 100 rpm at room temperature while simultaneously adding vancomycin hydrochloride aqueous solution dropwise to the oil phase to obtain a stable water-in-oil Pickering silicone emulsion.

[0072] After the above emulsion is poured into a mold and sealed, it is placed in a 37°C oven for constant temperature curing for 20 hours. After natural cooling, it is placed in a 120°C oven for constant temperature curing for 30 minutes to obtain silicone foam.

[0073] The density of the silicone foam prepared in this embodiment is 273 mg / cm³. 3 After ten compression cycles at 80% deformation, the maximum stress retention rate was 92%, and the strain loss rate was 6.7%; the tensile strength was 437 kPa, and the elongation at break was 109%; the maximum pore size was less than 100 micrometers.

[0074] The above results show that the silicone foam provided by the present invention has small pore size and excellent mechanical properties.

[0075] Comparative Example 1

[0076] By weight, the water-in-oil Pickering silicone emulsion in this embodiment consists of the following components:

[0077] 100 parts of Dow Corning SYLGARD 184 silicone prepolymer, 2 parts of Span 80, 50 parts of hexamethyldisiloxane, and 250 parts of 1wt% NaCl aqueous solution.

[0078] Components A and B of the SYLGARD184 silicone prepolymer were mechanically mixed at a ratio of 10:1 until homogeneous. Span 80 was then added to the SYLGARD184 mixture, and the mixture was stirred for 2 minutes at 2000 rpm using a Thinky centrifugal mixer to remove bubbles. Hexamethyldisiloxane was then added to the resulting mixture, and the mixture was mechanically stirred until homogeneous to obtain the oil phase. The oil phase was then mechanically stirred at 100 rpm at room temperature. Simultaneously, 1 wt% NaCl aqueous solution was added dropwise to the oil phase mixture to obtain a stable water-in-oil silicone emulsion.

[0079] After the above emulsion is put into a sealed mold, it is placed in an 80°C oven for constant temperature curing for 4 hours. The cured material is dried by high temperature and normal pressure drying, high temperature and reduced pressure drying, freeze drying, or repeated mechanical extrusion of the cured material to remove the dispersed phase. The pore structure of the cured material collapses.

Claims

1. An organosilicon foam obtained by thermosetting a water-in-oil type high internal phase Pickering emulsion; The mass composition of the water-in-oil type high internal phase Pickering emulsion is as follows: 100 parts of organosilicon prepolymer; 0.1-5 parts of amphiphilic inorganic nanoparticles; 10-100 parts of lipophilic solvent; Dispersed phase: 100-1000 parts; The mole ratio of the hydrophilic group and the hydrophobic group on the surface of the amphiphilic inorganic nanoparticles is 0.7-1.5:1, and the surface area is 50 m 2 / g-350 m 2 / g; The hydrophilic group is at least one of hydroxyl and amino groups; The hydrophobic group is an alkylsiloxy group, which is at least one of trimethylsiloxy, dimethyldisiloxy, octyldimethylsiloxy, hexadecyldimethylsiloxy, and octadecyldimethylsiloxy.

2. The silicone foam according to claim 1, characterized in that: The organosilicon prepolymer is a vinyl polysiloxane and a hydrogen-containing polysiloxane; The viscosity of the organosilicon prepolymer is 10 mPa·s to 50000 mPa·s.

3. The silicone foam according to claim 1 or 2, characterized in that: The lipophilic solvent is a solvent that has good solubility with the organosilicon prepolymer and does not affect the curing of the organosilicon prepolymer, and is selected from at least one of toluene, cyclohexane, octamethylcyclotetrasiloxane and hexamethyldisiloxane.

4. The silicone foam according to claim 1 or 2, characterized in that: The dispersed phase is water, or an aqueous solution containing an alcohol-based solvent; The dispersed phase contains a water-soluble substance; the water-soluble substance is a water-soluble drug, a water-soluble salt, or a combination thereof.

5. The silicone foam according to claim 1 or 2, characterized in that: The thermosetting temperature is 35~80℃, and the time is 2~24 hours.

6. The silicone foam according to claim 1 or 2, characterized in that: The thermosetting process further includes the step of removing the dispersed phase and the oleophilic solvent.

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