Silicone rubber modified by polydopamine modified silicon dioxide nanoparticles as well as preparation method and application of silicone rubber

Abstract

The invention belongs to the technical field of silicone rubber, and particularly relates to polydopamine modified silicon dioxide nanoparticle modified silicone rubber and a preparation method and application thereof.According to the silicone rubber, polydopamine modified silicon dioxide nanoparticles are introduced for modification, and under the condition that catalysis of a toxic or heavy metal catalyst is not needed, the silicon dioxide nanoparticles can be prepared into silicon dioxide nanoparticles; the silicon rubber is synthesized in a green cross-linking system, and the polydopamine modified silicon dioxide nanoparticles have double effects of cross-linking and enhancement, so that the polydopamine modified silicon dioxide nanoparticle modified silicon rubber provided by the invention is relatively good in tensile strength, Young modulus, solvent resistance, thermal weight loss and the like; therefore, the technical problem that the performance of the existing green cross-linking system synthesized silicone rubber is relatively low is solved.

Description

Technical Field

[0001] The present application belongs to the technical field of silicone rubber, and in particular to silicone rubber modified with polydopamine-modified silica nanoparticles, and a preparation method and application thereof. Background Art

[0002] The preparation process of traditional room temperature vulcanized silicone rubber is that polydimethylsiloxane is catalyzed by platinum catalysts, organic tin catalysts and other catalysts to form chemical bonds between polydimethylsiloxane molecular chains to form a polymer silicone rubber with a three-dimensional network structure.

[0003] Silicone rubber has shown broad application prospects in many fields such as sealants, electronics, automobiles and medical devices due to its excellent high and low temperature resistance, corrosion resistance, thermal stability, biocompatibility and low surface energy, and the demand for silicone rubber is growing. However, most of the catalysts used in the preparation of traditional silicone rubber are toxic (or heavy metal) substances, which may cause environmental pollution during use and pose potential harm to the health of organisms. Driven by the concept of green chemistry, researchers have actively explored and developed a series of catalyst-free green cross-linking systems, such as the introduction of borate, azide-alkyne cycloaddition, dynamic covalent and coordination bonds. Among them, amino-functionalized polydimethylsiloxane is often used to construct a catalyst-free reaction system due to its commercial availability and high reactivity, but the silicone rubber synthesized by the catalyst-free green cross-linking system has poor mechanical properties, which greatly limits its wide application in the industrial field. With the growing demand for green and environmentally friendly high-performance materials, the performance optimization of silicone rubber materials synthesized by the catalyst-free green cross-linking system has become a research hotspot. How to achieve catalyst-free cross-linking of silicone rubber and enhance its mechanical properties at the same time has become a key issue to be solved in the field of materials science. Summary of the invention

[0004] In view of this, the present application provides silicone rubber modified with polydopamine-modified silica nanoparticles, and a preparation method and application thereof, in order to solve the technical problem of low performance of existing green cross-linking system synthetic silicone rubber.

[0005] In a first aspect, the present application provides silicone rubber modified with polydopamine-modified silica nanoparticles, wherein the raw materials include polydopamine-modified silica nanoparticles and amino-functionalized polydimethylsiloxane.

[0006] Preferably, calculated by weight, the composition comprises 1 to 10 parts by weight of polydopamine-modified silica nanoparticles and 10 to 20 parts by weight of amino-functionalized polydimethylsiloxane.

[0007] Preferably, the polydopamine-modified silica nanoparticles are selected from at least one of polydopamine-modified fumed silica nanoparticles, polydopamine-modified precipitated silica nanoparticles, polydopamine-modified sol-gel silica nanoparticles, and polydopamine-modified microemulsion silica nanoparticles.

[0008] Preferably, the amino-functionalized polydimethylsiloxane is selected from amino-terminated polydimethylsiloxane and / or side-chain amino polydimethylsiloxane.

[0009] The second aspect of the present application provides a preparation method of polydopamine-modified silica nanoparticle-modified silicone rubber, which can prepare the polydopamine-modified silica nanoparticle-modified silicone rubber described in the first aspect, including the following steps:

[0010] Step S1: Add silica nanoparticles and dopamine to an alkaline buffer solution, mix evenly, and carry out a self-polymerization reaction to obtain a suspension containing polydopamine-modified silica nanoparticles;

[0011] Step S2: Carry out solid-liquid separation, washing, and drying on the suspension containing polydopamine-modified silica nanoparticles in sequence to obtain polydopamine-modified silica nanoparticles;

[0012] Step S3: Add the polydopamine-modified silica nanoparticles and amino-functionalized polydimethylsiloxane to an organic solvent, mix evenly, and carry out a prepolymerization reaction to obtain a silicone rubber prepolymer;

[0013] Step S4: Carry out a cross-linking and curing reaction on the silicone rubber prepolymer to obtain polydopamine-modified silica nanoparticle-modified silicone rubber.

[0014] Preferably, in step S1, the alkaline buffer solution is selected from at least one of carbonate buffer solutions, bicarbonate buffer solutions, hydrogen phosphate buffer solutions, and disodium hydrogen phosphate buffer solutions.

[0015] Preferably, in step S1, the pH of the alkaline buffer solution is 7.5 - 12.

[0016] Preferably, in step S1, the process of mixing evenly and carrying out the self-polymerization reaction is: mix evenly and carry out the self-polymerization reaction for 4 - 12 h under magnetic stirring.

[0017] Preferably, in step S2, the method of solid-liquid separation is at least one of centrifugation, suction filtration, and gravity sedimentation;

[0018] The method of washing is to wash with an alkaline buffer solution 1 - 10 times;

[0019] The method of drying is to dry at 80 - 120 °C for 6 - 24 h.

[0020] Preferably, in step S3, the organic solvent is selected from at least one of n-hexane, pentane, and heptane.

[0021] Preferably, in step S3, the prepolymerization reaction is carried out at room temperature at a rotation speed of 100 - 400 rpm for 4 - 8 h, and then at 50 - 70 °C at a rotation speed of 400 - 600 rpm for 1 - 5 h.

[0022] Preferably, in step S4, the crosslinking and curing reaction is carried out in a polytetrafluoroethylene mold at room temperature for 3 - 10 days.

[0023] The third aspect of the present application provides the application of polydopamine-modified silica nanoparticle-modified silicone rubber in the fields of sealants, electronics, automobiles, or medical devices.

[0024] Compared with the prior art, the polydopamine-modified silica nanoparticle-modified silicone rubber, preparation method, and application provided by the present application have at least the following beneficial effects:

[0025] 1. For the polydopamine-modified silica nanoparticle-modified silicone rubber provided by the present application, the polydopamine-modified silica nanoparticles have dual functions of crosslinking and strengthening, significantly improving various properties of the silicone rubber such as mechanical properties and thermal properties.

[0026] 2. For the polydopamine-modified silica nanoparticle-modified silicone rubber provided by the present application, the selection of fumed silica nanoparticles enables more polydopamine modification on the surface, which is beneficial to further improving the properties of the silicone rubber.

[0027] 3. In the preparation method of the polydopamine-modified silica nanoparticle-modified silicone rubber provided by the present application, by controlling the type of buffer solution and process conditions such as the stirring speed during the preparation process, the properties of the silicone rubber are further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0029] Figure 1 It is a schematic diagram for preparing polydopamine-modified silica nanoparticles in the preparation method of polydopamine-modified silica nanoparticle-modified silicone rubber provided by the embodiment of the present application;

[0030] Figure 2Schematic diagram of the reaction between polydopamine-modified silica nanoparticles and amino-functionalized polydimethylsiloxane in the preparation method of polydopamine-modified silica nanoparticle-modified silicone rubber provided by the embodiments of the present application;

[0031] Figure 3 Flow schematic diagram of the preparation method of polydopamine-modified silica nanoparticle-modified silicone rubber provided by the embodiments of the present application. Detailed implementation manners

[0032] The present application provides polydopamine-modified silica nanoparticle-modified silicone rubber, its preparation method and application, which are used to solve the technical problem of the low performance of silicone rubber synthesized by the existing green crosslinking system.

[0033] Next, the technical solutions of the present application will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0034] In view of the defect that the performance of silicone rubber synthesized by the current catalyst-free green crosslinking system is poor, the present application provides polydopamine-modified silica nanoparticle-modified silicone rubber. The raw materials of the polydopamine-modified silica nanoparticle-modified silicone rubber provided by the present application include polydopamine-modified silica nanoparticles and amino-functionalized polydimethylsiloxane.

[0035] In the silicone rubber provided by the present application, polydopamine-modified silica nanoparticles are used as one of the raw materials. After the silica nanoparticles are modified by polydopamine, the surface contains rich active groups, which can react with the amino groups on the amino-functionalized polydimethylsiloxane under mild conditions, such as Michael addition and Schiff base reaction, so as to realize the crosslinking and curing of silicone rubber polymer without catalyst. The polydopamine-modified silica nanoparticles are incorporated into the three-dimensional crosslinking network of the silicone rubber polymer, and its mechanism is as Figure 1-2 shown; after being modified by polydopamine, the silica nanoparticles as inorganic nano-fillers can be better dispersed in the silicone rubber polymer, enhancing the performance of the silicone rubber polymer. Therefore, the polydopamine-modified silica nanoparticles in the present application play a dual role of crosslinking and strengthening; when the silicone rubber is subjected to external force, the stress can be effectively transmitted through the crosslinking network, and the silica nanoparticles limit the movement of the silicone rubber molecular chains, thereby improving the mechanical properties such as the tensile strength, hardness and Young's modulus of the silicone rubber. At the same time, the thermal stability and solvent resistance of the silicone rubber are also improved, enhancing the performance of the silicone rubber and overcoming the defect that the performance of silicone rubber synthesized by the current catalyst-free green crosslinking system is poor.

[0036] As a preferred technical solution, the polydopamine-modified silica nanoparticles can be selected from polydopamine-modified fumed silica nanoparticles, polydopamine-modified precipitated silica nanoparticles, polydopamine-modified sol-gel method silica nanoparticles, polydopamine-modified microemulsion method silica nanoparticles, etc.; among them, a large number of silanol groups exist on the surface of the fumed silica nanoparticles, which have high chemical activity and are easily modified by dopamine. Therefore, in this application, polydopamine-modified fumed silica nanoparticles are further preferred.

[0037] As a preferred technical solution, the amino-functionalized polydimethylsiloxane can be obtained by reacting aminopropylmethylsilane with dimethylsiloxane at a molar ratio of 1:13.8, and the amino mole fraction is 6.76%; it can be selected from amino-terminated polydimethylsiloxane, side-chain amino polydimethylsiloxane, etc.; both amino-terminated polydimethylsiloxane and side-chain amino polydimethylsiloxane contain amino groups and can react with the polydopamine-modified silica nanoparticles, improving the properties of the silicone rubber.

[0038] Correspondingly, this application also provides a preparation method of a silicone rubber modified with polydopamine-modified silica nanoparticles. The preparation method includes mixing silica nanoparticles and dopamine in an alkaline buffer solution evenly for self-polymerization reaction to obtain a suspension containing polydopamine-modified silica nanoparticles; in a weakly alkaline environment, dopamine (DA) can undergo self-polymerization, and the generated polydopamine binds to the surface of the fumed silica nanoparticles SiO2 (Silicon dioxide) through covalent bonds and hydrogen bonds and other interactions to form polydopamine-modified silica nanoparticles SiO2@PDA (Silicon dioxide decorated with Polydopamine); subsequently, the polydopamine-modified silica nanoparticles and amino-functionalized polydimethylsiloxane PDMAS (Amino-functionalized polydimethylsiloxanes) are added to an organic solvent and mixed evenly for prepolymerization reaction to obtain a partially crosslinked silicone rubber prepolymer, and then added to a mold and crosslinked and cured at room temperature to obtain a silicone rubber modified with polydopamine-modified silica nanoparticles.

[0039] Preferably, in the method for preparing the silicone rubber provided in the present application, in order not to affect the progress of the reaction, alkaline buffer solutions such as carbonate buffer solution, bicarbonate buffer solution, hydrogen phosphate buffer solution, and disodium hydrogen phosphate buffer solution should be preferably selected, such as sodium carbonate buffer solution, sodium bicarbonate buffer solution, sodium hydrogen phosphate buffer solution, disodium hydrogen phosphate buffer solution, etc.; Tris buffer solution and other alkaline buffer solutions (tris(hydroxymethyl)aminomethane) should not be selected.

[0040] Preferably, in the method for preparing the silicone rubber provided in the present application, in order to reduce possible nanoparticle aggregation and promote better coating and modification of fumed silica nanoparticles by polydopamine, the fumed silica nanoparticles and dopamine should be mixed evenly under magnetic stirring for self-polymerization reaction; correspondingly, when the polydopamine-modified silica nanoparticles and amino-functionalized polydimethylsiloxane are subjected to a prepolymerization reaction, they should also be mixed evenly at a certain rotation speed for the prepolymerization reaction. After the silicone rubber prepolymer has a certain viscosity and stabilizes the nanoparticles, it is then poured into a mold for room temperature crosslinking and curing.

[0041] The polydopamine-modified silica nanoparticle-modified silicone rubber provided in the present application will be specifically described below in conjunction with examples and experimental examples.

[0042] Example 1

[0043] This example provides a method for preparing a polydopamine-modified silica nanoparticle-modified silicone rubber, as Figure 1-3 shown; the preparation method includes steps of preparing polydopamine-modified silica nanoparticles, post-treatment, prepolymerization reaction, and room temperature crosslinking and curing.

[0044] The steps of preparing polydopamine-modified silica nanoparticles are as Figure 1 shown, including: accurately weighing 10 g of fumed silica nanoparticles and adding them to 100 mL of sodium carbonate buffer solution with a pH of 8.5; weighing 3 g of dopamine according to the requirement that the addition ratio of dopamine to silica nanoparticles is 3:10, and then using a magnetic stirrer to stir at a speed of 400 rpm for 6 h, so that dopamine undergoes self-polymerization and coats and modifies the surface of the silica nanoparticles in a weakly alkaline environment, obtaining a suspension containing polydopamine-modified silica nanoparticles.

[0045] The steps of post-treatment include: centrifuging the reaction suspension at a speed of 8000 rpm for 15 min, then washing it 3 times with sodium carbonate buffer solution with a pH of 8.5, putting the washed product into an oven, and drying it at 100 °C for 12 h to obtain dry polydopamine-modified silica nanoparticle powder.

[0046] The steps of the prepolymerization reaction are as follows Figure 2 shown as follows: Weigh 10 g of amino-functionalized polydimethylsiloxane PDMAS, dissolve it in 10 ml of n-hexane, and fully mix it under magnetic stirring to obtain a PDMAS solution; subsequently, according to the proportion that the content of polydopamine-modified silica nanoparticles SiO2@PDA is 10%, weigh 1.15 g of SiO2@PDA and add it to the above PDMAS solution; next, stir at room temperature for 6 h with a rotation speed set at 300 rpm to make the reactants fully contact and react for prepolymerization reaction, and then continue to stir at 60 °C for 3 h with the rotation speed increased to 500 rpm to overcome the resistance caused by the increase in viscosity and ensure that the reactants are evenly mixed, obtaining a silicone rubber prepolymer.

[0047] The steps of room-temperature crosslinking and curing include: Pour the silicone rubber prepolymer obtained from the prepolymerization reaction into a polytetrafluoroethylene (PTFE) mold and cure it at room temperature for 7 days to obtain a silicone rubber modified with polydopamine-modified silica nanoparticles, and the doping amount of SiO2@PDA in the silicone rubber is about 10%.

[0048] Example 2

[0049] This example provides a preparation method of a silicone rubber modified with polydopamine-modified silica nanoparticles. The preparation method includes the steps of preparing polydopamine-modified silica nanoparticles, post-treatment, prepolymerization reaction, and room-temperature crosslinking and curing.

[0050] The steps of preparing polydopamine-modified silica nanoparticles include: Accurately weigh 10 g of fumed silica nanoparticles and add them to 100 mL of sodium carbonate buffer solution with pH = 8.5; according to the requirement that the addition ratio of dopamine to silica nanoparticles is 3:10, weigh 3 g of dopamine and add it to the above solution, and then use a magnetic stirrer to stir at a rotation speed of 400 rpm for 6 h to make dopamine self-polymerize and coat and modify on the surface of silica nanoparticles in a weakly alkaline environment, obtaining a suspension containing polydopamine-modified silica nanoparticles.

[0051] The steps of post-treatment include: Centrifuge the reacted suspension at a rotation speed of 8000 rpm for 15 min, then wash it 3 times with sodium carbonate buffer solution with pH = 8.5, put the washed product into an oven, and dry it at 100 °C for 12 h to obtain dry polydopamine-modified silica nanoparticle powder.

[0052] The steps of the prepolymerization reaction include: weighing 10 g of amino-functionalized polydimethylsiloxane PDMAS, dissolving it in 10 ml of n-hexane, and fully mixing it under magnetic stirring to obtain a PDMAS solution; subsequently, weighing 4.29 g of SiO2@PDA according to the proportion of 30% of the content of polydopamine-modified silica nanoparticles SiO2@PDA, and adding it to the above PDMAS solution; next, stirring at room temperature for 6 h with a rotation speed set at 300 rpm to allow the reactants to fully contact and react for the prepolymerization reaction, and then continuing to stir at 60 °C for 3 h with the rotation speed increased to 500 rpm to overcome the resistance caused by the increased viscosity and ensure uniform mixing of the reactants, thus obtaining a silicone rubber prepolymer.

[0053] The steps of room-temperature crosslinking and curing include: pouring the silicone rubber prepolymer obtained from the prepolymerization reaction into a polytetrafluoroethylene (PTFE) mold and curing it at room temperature for 7 days to obtain a silicone rubber modified with polydopamine-modified silica nanoparticles, and the doping amount of SiO2@PDA in the silicone rubber is about 30%.

[0054] Example 3

[0055] This example provides a preparation method of a silicone rubber modified with polydopamine-modified silica nanoparticles. The preparation method includes the steps of preparing polydopamine-modified silica nanoparticles, post-treatment, prepolymerization reaction, and room-temperature crosslinking and curing.

[0056] The steps of preparing polydopamine-modified silica nanoparticles include: accurately weighing 10 g of fumed silica nanoparticles and adding them to 100 mL of sodium carbonate buffer solution with a pH of 8.5; weighing 3 g of dopamine according to the requirement of the addition ratio of dopamine to silica nanoparticles of 3:10, and adding it to the above solution. Subsequently, using a magnetic stirrer to stir at a rotation speed of 400 rpm for 6 h, so that dopamine undergoes self-polymerization and coats and modifies the surface of the silica nanoparticles in a weakly alkaline environment, obtaining a suspension containing polydopamine-modified silica nanoparticles.

[0057] The steps of post-treatment include: centrifuging the reacted suspension at a rotation speed of 8000 rpm for 15 min, then washing it 3 times with sodium carbonate buffer solution with a pH of 8.5, putting the washed product into an oven, and drying it at 100 °C for 12 h to obtain dry polydopamine-modified silica nanoparticle powder.

[0058] The steps of the prepolymerization reaction include: weighing 10 g of amino-functionalized polydimethylsiloxane PDMAS, dissolving it in 10 ml of n-hexane, and fully mixing it evenly under magnetic stirring to obtain a PDMAS solution; subsequently, weighing 6.70 g of SiO2@PDA according to the proportion of 40% of the content of polydopamine-modified silica nanoparticles SiO2@PDA, and adding it to the above PDMAS solution; next, stirring at room temperature for 6 h with a rotation speed set at 300 rpm to allow the reactants to fully contact and react for the prepolymerization reaction, and then continuing to stir at 60 °C for 3 h with the rotation speed increased to 500 rpm to overcome the resistance caused by the increased viscosity and ensure the uniform mixing of the reactants, thus obtaining a silicone rubber prepolymer.

[0059] The steps of room-temperature crosslinking and curing include: pouring the silicone rubber prepolymer obtained from the prepolymerization reaction into a polytetrafluoroethylene (PTFE) mold and curing it at room temperature for 7 days to obtain a silicone rubber modified with polydopamine-modified silica nanoparticles, and the doping amount of SiO2@PDA in the silicone rubber is about 40%.

[0060] Example 4

[0061] This example provides a preparation method of polydopamine-modified silicone rubber. As the first comparative example of Examples 1-3, the preparation method includes the steps of prepolymerization reaction and room-temperature crosslinking and curing.

[0062] The steps of the prepolymerization reaction include: weighing 10 g of amino-functionalized polydimethylsiloxane PDMAS, dissolving it in 10 ml of n-hexane, and fully mixing it evenly under magnetic stirring to obtain a PDMAS solution; subsequently, weighing 1.15 g of purchased polydopamine nanoparticles and adding them to the above PDMAS solution according to the proportion of 10% of the content of polydopamine nanoparticles PDA; next, stirring at room temperature for 6 h with a rotation speed set at 300 rpm to allow the reactants to fully contact and react for the prepolymerization reaction, and then continuing to stir at 60 °C for 3 h with the rotation speed increased to 500 rpm to overcome the resistance caused by the increased viscosity and ensure the uniform mixing of the reactants, thus obtaining a silicone rubber prepolymer.

[0063] The steps of room-temperature crosslinking and curing include: pouring the silicone rubber prepolymer obtained from the prepolymerization reaction into a polytetrafluoroethylene (PTFE) mold and curing it at room temperature for 7 days to obtain a silicone rubber modified with polydopamine nanoparticles.

[0064] Experimental example

[0065] In Experimental Example 1 of this application, the silicone rubbers provided in Examples 1-4 were subjected to performance tests; the performance tests included tensile strength, Young's modulus, solvent resistance, and thermogravimetric tests; the tensile strength test was carried out with reference to the national standard GB / T 528 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber", the Young's modulus test was carried out with reference to the national standard GB / T 528 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber", the solvent resistance test method: the silicone rubber was cut into thin slices with a size of 10×10 mm and a thickness of 1-2 mm, and the silicone rubber was immersed in toluene at room temperature for 500 min, and the thermogravimetric test was carried out with reference to the national standard GB / T14837.3 "Analysis of vulcanized and unvulcanized rubber components by thermogravimetry for rubbers and rubber products", and the test results are shown in Table 1.

[0066] Table 1: Performance test results of silicone rubber

[0067]

[0068] As can be seen from Table 1, the silicone rubbers prepared by directly using polydopamine nanoparticles to modify silicone rubber have poor performance in terms of tensile strength, Young's modulus, solvent resistance, and thermogravimetric loss; while the silicone rubbers modified with polydopamine-modified silica nanoparticles provided in Examples 1-3, due to the fact that the polydopamine-modified silica nanoparticles SiO2@PDA can be uniformly dispersed in the silicone rubber matrix, enhancing the crosslinking density and intermolecular interaction of the silicone rubber, the performance such as tensile strength, Young's modulus, solvent resistance, and thermogravimetric loss has been improved. This is because the polydopamine-modified silica nanoparticles uniformly dispersed in the silicone rubber play a dual role of crosslinking and strengthening. When the doping amount of SiO2@PDA is 10%,

[0069] the tensile strength of the silicone rubber reaches 1.55 MPa, the Young's modulus reaches 7.73 MPa, and at the same time, the thermogravimetric loss is only 10% at 438.9 °C and only 50% at 609.6 °C, with a high thermal decomposition temperature and good thermal stability; compared with the silicone rubber modified only with PDA, the performance such as tensile strength and Young's modulus is significantly improved; moreover, with the increase of the doping amount of SiO2@PDA, the performance such as tensile strength, Young's modulus, solvent resistance, and thermogravimetric loss of the silicone rubber can also be improved; when the doping amount of SiO2@PDA in the silicone rubber is 30%, its mechanical properties, thermal stability, and solvent resistance are stronger.

[0070] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A silicone rubber modified with polydopamine-modified silica nanoparticles, characterized in that, It includes polydopamine-modified silica nanoparticles and amino-functionalized polydimethylsiloxane.

2. A silicone rubber modified by polydopamine-modified silica nanoparticles according to claim 1, characterized in that, Calculated by mass parts, it includes 1 to 10 mass parts of polydopamine-modified silica nanoparticles and 10 to 20 mass parts of amino-functionalized polydimethylsiloxane.

3. A silicone rubber modified with polydopamine-modified silica nanoparticles according to claim 1, wherein, The polydopamine-modified silica nanoparticles are selected from at least one of polydopamine-modified fumed silica nanoparticles, polydopamine-modified precipitated silica nanoparticles, polydopamine-modified sol-gel method silica nanoparticles, and polydopamine-modified microemulsion method silica nanoparticles.

4. A silicone rubber modified by polydopamine-modified silica nanoparticles according to claim 1, wherein, The amino-functionalized polydimethylsiloxane is selected from amino-terminated polydimethylsiloxane and / or side-chain amino polydimethylsiloxane.

5. A method for preparing a silicone rubber modified by polydopamine-modified silica nanoparticles according to any one of claims 1-4, characterized in that, It includes the following steps: Step S1: Add silica nanoparticles and dopamine into an alkaline buffer solution, mix evenly and carry out a self-polymerization reaction to obtain a suspension containing polydopamine-modified silica nanoparticles. Step S2: Carry out solid-liquid separation, washing, and drying on the suspension containing polydopamine-modified silica nanoparticles in sequence to obtain polydopamine-modified silica nanoparticles. Step S3: Add polydopamine-modified silica nanoparticles and amino-functionalized polydimethylsiloxane into an organic solvent, mix evenly and carry out a prepolymerization reaction to obtain a silicone rubber prepolymer. Step S4: Carry out a crosslinking and curing reaction on the silicone rubber prepolymer to obtain a silicone rubber modified with polydopamine-modified silica nanoparticles.

6. The preparation method of a silicone rubber modified by polydopamine-modified silica nanoparticles according to claim 5, characterized in that, In step S1, the process of mixing evenly and carrying out the self-polymerization reaction is: mix evenly and carry out the self-polymerization reaction for 4 to 12 h under magnetic stirring.

7. The preparation method of a silicone rubber modified by polydopamine-modified silica nanoparticles according to claim 5, characterized in that, In step S2, the method of solid-liquid separation is at least one of centrifugation, suction filtration, and gravitational sedimentation. The method of washing is to wash with an alkaline buffer solution for 1 to 10 times. The method of drying is to dry at 80 to 120 °C for 6 to 24 h.

8. The preparation method of a silicone rubber modified by polydopamine-modified silica nanoparticles according to claim 5, characterized in that, In step S3, the process of the prepolymerization reaction is to react at a rotation speed of 100 to 400 rpm for 4 to 8 h at room temperature and react at a rotation speed of 400 to 600 rpm for 1 to 5 h at 50 to 70 °C.

9. The preparation method of a silicone rubber modified by polydopamine-modified silica nanoparticles according to claim 5, characterized in that, In step S4, the process of the crosslinking and curing reaction is to cure in a polytetrafluoroethylene mold for 3 to 10 days at room temperature.

10. Application of the silicone rubber modified with polydopamine-modified silica nanoparticles according to any one of claims 1-4 in the fields of sealants, electronics, automobiles, or medical devices.

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