Liquid silicone rubber composition and preparation method thereof

Abstract

The invention relates to a liquid silicone rubber composition and a preparation method thereof. According to the composition, the modified liquid silicone rubber, the graphene filler and the tert-butyl peroxybenzoate cross-linking agent are introduced, and a proper catalyst (such as titanium fluoride) and a proper plasticizer (such as dioctyl phthalate) are combined, so that the mechanical property, the heat conductivity and the self-repairing capability of the liquid silicone rubber are effectively improved. In the preparation process, graphene is used as a filler to enhance the thermal conductivity and tensile strength of the material, and the cross-linking reaction improves the structural stability and durability of the material. The composition has excellent high temperature resistance, chemical resistance and excellent self-repairing characteristic, and can provide reliable moisture-proof and insulation protection in the fields of electrical equipment, automobiles, medical treatment and the like. Experimental results show that the original performance of the liquid silicone rubber material can be recovered through heat treatment after the liquid silicone rubber material is damaged for multiple times, and the liquid silicone rubber material shows relatively high repair efficiency. The liquid silicone rubber composition provided by the invention has a wide application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of liquid silicone rubber, in particular to a liquid silicone rubber composition and a preparation method thereof. Background Art

[0002] With the growing demand for high-performance materials in modern industry, liquid silicone rubber (LSR), as a polymer material with excellent comprehensive performance, has been widely used in many fields such as automobiles, electronics, and medical treatment. The excellent performance of liquid silicone rubber is mainly due to its good elasticity, high temperature resistance, weather resistance, chemical stability, and biocompatibility. With the continuous improvement of production technology and the expansion of application fields, the performance of liquid silicone rubber has been gradually optimized, especially in terms of processability, molding accuracy, wear resistance, and self-healing performance, which have become the focus of research and development. At present, the modification methods of liquid silicone rubber mainly include physical methods and chemical methods. The former usually involves the addition of fillers, such as silicon dioxide (SiO2), carbon nanotubes, etc.; the latter focuses on the design of molecular structure, and the material is usually modified by crosslinking, copolymerization, functionalization, etc. Through these means, the mechanical properties, thermal stability, and working environment range of liquid silicone rubber have been further improved.

[0003] However, existing liquid silicone rubber compositions often have stress concentration problems under high-load applications, which can easily lead to local damage or rupture, especially under dynamic loads, long-term use or high-temperature environments, where the performance of the material decreases significantly. To solve this problem, researchers have tried to improve the mechanical properties of the material by introducing core-shell nanoparticles. Core-shell nanoparticles use their heterogeneous structure to enable the material to effectively disperse stress when subjected to external forces, thereby enhancing its tensile strength and toughness. However, although the addition of nanoparticles can improve the mechanical properties, existing technologies have not been able to effectively solve the problem of uniform stress distribution, nor have they been able to achieve the self-repair function of the material after damage occurs. At the same time, the self-repairing ability of liquid silicone rubber materials has not been fully utilized and developed. Most studies focus on improving the durability of the material by increasing the degree of crosslinking or introducing a network structure of polymer chains, but these methods usually sacrifice the flexibility and processability of the material, and have low repair efficiency, and have not been widely promoted in practical applications. Summary of the invention

[0004] Although the addition of nanoparticles can improve mechanical properties, existing technologies have not yet effectively solved the problem of uniform stress distribution, nor have they been able to achieve the self-repair function of the material after damage occurs. At the same time, the self-repairing ability of liquid silicone rubber materials has not been fully utilized and developed. Most studies focus on improving the durability of the material by increasing the degree of cross-linking or introducing a network structure of polymer chains, but these methods usually sacrifice the flexibility and processability of the material, and the repair efficiency is low, and they have not been widely promoted in practical applications.

[0005] The present application provides a method for preparing a liquid silicone rubber composition, comprising the following preparation steps: step S1. adding a modified liquid silicone rubber matrix material and a plasticizer into a mixing container, and stirring them evenly using a high shear stirrer; step S2. after the modified liquid silicone rubber matrix material and the plasticizer are evenly mixed, adding core-shell nanoparticles, fillers and catalysts in sequence, and stirring them using a high-speed stirrer; step S3. adding a crosslinking agent into the above mixture, stirring the mixture evenly again to ensure that the crosslinking agent is fully dispersed, placing the mixture into a heating device, setting the temperature to 150° C., and performing a crosslinking reaction for 60 minutes.

[0006] It should be noted that in step S1, the modified liquid silicone rubber matrix material and the plasticizer are added to a mixing container and stirred using a high shear agitator. Due to its good fluidity and adaptability, the addition of the plasticizer can reduce the viscosity of the silicone rubber and improve its processing performance; in step S2, the core-shell nanoparticles, fillers and catalysts are sequentially added to the mixture of the modified liquid silicone rubber matrix material and the plasticizer, and fully stirred with a high-speed agitator. The core-shell structure of the core-shell nanoparticles makes the liquid silicone rubber material have good mechanical properties and self-healing properties. The addition of fillers helps to enhance the thermal conductivity, mechanical strength, wear resistance and other properties of the material, while the role of the catalyst is to accelerate the subsequent cross-linking reaction, ensure the efficient cross-linking process, and improve the structural stability of the silicone rubber; in step S3, the cross-linking agent is added to the above mixture, and it is ensured that the cross-linking agent is fully dispersed in the entire system. The role of the cross-linking agent is to form a cross-linked structure between the polymer chains, thereby enhancing the mechanical properties, thermal stability and chemical stability of the silicone rubber. In this step, the temperature is set to 150°C for cross-linking reaction, and the cross-linking reaction time is 60 minutes to ensure that the cross-linking reaction is complete and a three-dimensional cross-linked structure is formed. The control of temperature and time is to promote the smooth progress of the cross-linking reaction, while avoiding excessive reaction that leads to a decrease in material performance. At this time, the cross-linking reaction will make the network structure of silicone rubber more stable, giving it excellent weather resistance, elasticity and high temperature resistance.

[0007] As a preferred technical solution for a method for preparing a liquid silicone rubber composition, the plasticizer is dioctyl phthalate.

[0008] It should be noted that dioctyl phthalate, as a plasticizer, can effectively reduce the viscosity of liquid silicone rubber, increase its fluidity, and improve its mechanical properties, making the material more flexible at low temperatures.

[0009] As a preferred technical solution for a method for preparing a liquid silicone rubber composition, the filler is graphene.

[0010] It should be noted that using graphene as a filler in a liquid silicone rubber composition can significantly improve the mechanical properties and thermal conductivity of the material, and can also improve the self-healing ability.

[0011] As a preferred technical solution for a method for preparing a liquid silicone rubber composition, the catalyst is titanium fluoride.

[0012] It should be noted that titanium fluoride, as a catalyst, mainly enhances the overall performance of liquid silicone rubber by promoting the cross-linking reaction in silicone rubber, increasing the cross-linking rate, improving thermal stability and chemical resistance, etc.

[0013] As a preferred technical solution for a method for preparing a liquid silicone rubber composition, the crosslinking agent is tert-butyl perbenzoate.

[0014] It should be noted that tert-butyl perbenzoate (TBPB) is a free radical initiator, which decomposes under the action of heat to generate free radicals. The generation of free radicals can initiate the crosslinking reaction in the liquid silicone rubber.

[0015] As a preferred technical solution for preparing a liquid silicone rubber composition, the method for preparing a modified liquid silicone rubber matrix material comprises the following technical steps: slowly dropping methyltrichlorosilane into PDMS (polydimethylsiloxane), controlling the temperature at 40-60°C, and stirring the reaction for 2-4 hours.

[0016] It should be noted that in this reaction, the chlorine atoms of methyltrichlorosilane can react with the siloxy groups (Si-OH) on the surface of PDMS, thereby grafting the methyl groups onto the molecular chains of PDMS through silicon-oxygen bonds, and indirectly changing the interface properties between PDMS and the filler through the silane bridging structure, thereby improving the compatibility and dispersibility of the filler in the PDMS matrix.

[0017] As a preferred technical scheme for the preparation of a liquid silicone rubber composition, the preparation method of the core-shell nanoparticles includes the following technical steps: first, dispersing silica particles in ethanol, wherein the concentration of silica in the ethanol is 5 mg / mL, adding polystyrene monomers and benzoyl peroxide initiator, and allowing polystyrene molecules to form a polystyrene shell on the surface of silica at 70-80°C. After the reaction is completed, removing excess monomers and solvents by precipitation, washing and drying, and obtaining silica core / polystyrene shell composite nanoparticles.

[0018] It should be noted that the silica (SiO2) particles are dispersed in ethanol. Ethanol as a solvent has good dispersibility and can effectively disperse the silica particles in the liquid to avoid aggregation between particles. Polystyrene (PS) monomers are added, and the styrene monomers will undergo free radical polymerization under the action of temperature and initiator. Benzoyl peroxide decomposes at a temperature of 70-80°C to generate benzoyl radicals (C6H5CO·), which can initiate the polymerization reaction of styrene monomers. The polymerization reaction is a chain reaction. Styrene molecules are attacked by free radicals and new monomers are gradually added to the polymerization chain to form polystyrene long-chain polymers. Through this reaction process, the polystyrene shell continuously grows on the surface of the silica particles, and finally forms composite nanoparticles of silica core / polystyrene shell.

[0019] In addition, the liquid silicone rubber composition prepared by the above preparation method of the present invention includes, by mass fraction: 60 to 90 parts of modified liquid silicone rubber matrix material, 1 to 5 parts of plasticizer, 5 to 8 parts of core-shell nanoparticles, 0.1 to 0.6 parts of cross-linking agent, 1 to 4 parts of filler and 0.05 to 0.09 parts of catalyst.

[0020] It should be noted that the polystyrene shell softens and flows when heated, the liquid silicone rubber matrix material can provide self-healing function, and the siloxane bonds (Si-O-Si) in its molecular chain can self-repair by reorganization of dynamic silicon oxygen bonds when damaged. The plasticizer weakens the interaction force between silicone rubber segments through intermolecular interactions, thereby enhancing the flexibility of the material. The core-shell nanoparticles not only increase their mechanical properties, but also the polystyrene shell grafted on the core-shell nanoparticles provides a flow environment under heating, which enhances the flexibility and dynamics of the grafted methyl groups on the liquid silicone rubber material, so that the siloxane chains can quickly adjust and form new bonds after contact; under the action of the catalyst, the molecular chains in the liquid silicone rubber are promoted to cross-link to form a network structure, thereby enhancing the mechanical strength, thermal stability and aging resistance of the material. The addition of fillers can enhance the mechanical properties, wear resistance and thermal conductivity of the liquid silicone rubber.

[0021] The liquid silicone rubber composition of the present invention and the preparation method thereof have significant beneficial effects. By introducing core-shell nanoparticles, graphene fillers and precisely controlled cross-linking reactions, the liquid silicone rubber of the present invention not only has excellent mechanical properties, thermal conductivity and self-repairing ability, but also can show good high temperature resistance, chemical resistance and efficient repair function in practical applications. In particular, by optimizing the material formula, the addition of graphene effectively improves the thermal conductivity and mechanical properties, while the core-shell nanoparticles enhance the self-repairing ability, so that the material can restore its original performance through simple heat treatment after being damaged, thereby significantly improving the long-term stability and reliability of the material. These improvements make the liquid silicone rubber of the present invention have broad application prospects in the fields of electrical equipment, automobiles, medical treatment, etc. DETAILED DESCRIPTION

[0022] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0023] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0024] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0025] Preparation Example

[0026] Preparation Example 1

[0027] The preparation method of the core-shell nanoparticles comprises the following technical steps: firstly, dispersing silicon dioxide particles in ethanol, wherein the concentration of silicon dioxide in the ethanol is 5 mg / mL, adding polystyrene monomers and benzoyl peroxide initiator, and allowing polystyrene molecules to form a polystyrene shell on the surface of silicon dioxide at 70-80° C., and after the reaction is completed, removing excess monomers and solvents through precipitation, washing and drying to obtain composite nanoparticles of silicon dioxide core / polystyrene shell.

[0028] Preparation Example 2

[0029] The preparation method of the modified liquid silicone rubber matrix material comprises the following technical steps: slowly dropping methyltrichlorosilane into PDMS, controlling the temperature at 40-60° C., and stirring the reaction for 2-4 hours.

[0030] Example

[0031] Example 1

[0032] Example 1 provides a liquid silicone rubber composition and a preparation method thereof, wherein the liquid silicone rubber composition includes, by mass fraction: 60 parts of a modified liquid silicone rubber matrix material (Preparation Example 2), 3 parts of a plasticizer (dioctyl phthalate), 5 parts of core-shell nanoparticles (Preparation Example 1), 0.6 parts of a cross-linking agent (tert-butyl perbenzoate), 1 part of a filler (graphene), and 0.06 parts of a catalyst (titanium fluoride).

[0033] The preparation method of the silicone rubber composition comprises the following preparation steps:

[0034] Step S1. Add the modified liquid silicone rubber matrix material (Preparation Example 2) and the plasticizer into a mixing container and stir evenly using a high shear stirrer;

[0035] Step S2. After the modified liquid silicone rubber matrix material and dioctyl phthalate are evenly mixed, core-shell nanoparticles (Preparation Example 1), graphene and titanium fluoride are added in sequence, and stirred using a high-speed stirrer;

[0036] Step S3. Add tert-butyl perbenzoate to the above mixture, stir the mixture again to ensure that the cross-linking agent is fully dispersed, place the mixture in a heating device, set the temperature to 150° C., and perform a cross-linking reaction for 60 minutes.

[0037] Example 2

[0038] Example 2 provides a liquid silicone rubber composition and a preparation method thereof, wherein the liquid silicone rubber composition includes, by mass fraction: 90 parts of a modified liquid silicone rubber matrix material (Preparation Example 2), 1 part of a plasticizer (dioctyl phthalate), 7 parts of core-shell nanoparticles (Preparation Example 1), 0.5 parts of a cross-linking agent (tert-butyl perbenzoate), 4 parts of a filler (graphene), and 0.09 parts of a catalyst (titanium fluoride).

[0039] The preparation method of the silicone rubber composition comprises the following preparation steps:

[0040] Step S1. Add the modified liquid silicone rubber matrix material (Preparation Example 2) and the plasticizer into a mixing container and stir evenly using a high shear stirrer;

[0041] Step S2. After the modified liquid silicone rubber matrix material and dioctyl phthalate are evenly mixed, core-shell nanoparticles (Preparation Example 1), graphene and titanium fluoride are added in sequence, and stirred using a high-speed stirrer;

[0042] Step S3. Add tert-butyl perbenzoate to the above mixture, stir the mixture again to ensure that the cross-linking agent is fully dispersed, place the mixture in a heating device, set the temperature to 150° C., and perform a cross-linking reaction for 60 minutes.

[0043] Example 3

[0044] Example 3 provides a liquid silicone rubber composition and a preparation method thereof, wherein the liquid silicone rubber composition includes, by mass fraction: 80 parts of a modified liquid silicone rubber matrix material (Preparation Example 2), 5 parts of a plasticizer (dioctyl phthalate), 8 parts of core-shell nanoparticles (Preparation Example 1), 0.3 parts of a cross-linking agent (tert-butyl perbenzoate), 2 parts of a filler (graphene), and 0.05 parts of a catalyst (titanium fluoride).

[0045] The preparation method of the silicone rubber composition comprises the following preparation steps:

[0046] Step S1. Add the modified liquid silicone rubber matrix material (Preparation Example 2) and the plasticizer into a mixing container and stir evenly using a high shear stirrer;

[0047] Step S2. After the modified liquid silicone rubber matrix material and dioctyl phthalate are evenly mixed, core-shell nanoparticles (Preparation Example 1), graphene and titanium fluoride are added in sequence, and stirred using a high-speed stirrer;

[0048] Step S3. Add tert-butyl perbenzoate to the above mixture, stir the mixture again to ensure that the cross-linking agent is fully dispersed, place the mixture in a heating device, set the temperature to 150° C., and perform a cross-linking reaction for 60 minutes.

[0049] Example 4

[0050] Example 4 provides a liquid silicone rubber composition and a preparation method thereof, wherein the liquid silicone rubber composition includes, by mass fraction: 60 parts of a modified liquid silicone rubber matrix material (Preparation Example 2), 3 parts of a plasticizer (dioctyl phthalate), 5 parts of core-shell nanoparticles (Preparation Example 1), 0.1 parts of a cross-linking agent (tert-butyl perbenzoate), 2 parts of a filler (graphene), and 0.05 parts of a catalyst (titanium fluoride).

[0051] The preparation method of the silicone rubber composition comprises the following preparation steps:

[0052] Step S1. Add the modified liquid silicone rubber matrix material (Preparation Example 2) and the plasticizer into a mixing container and stir evenly using a high shear stirrer;

[0053] Step S2. After the modified liquid silicone rubber matrix material and dioctyl phthalate are evenly mixed, core-shell nanoparticles (Preparation Example 1), graphene and titanium fluoride are added in sequence, and stirred using a high-speed stirrer;

[0054] Step S3. Add tert-butyl perbenzoate to the above mixture, stir the mixture again to ensure that the cross-linking agent is fully dispersed, place the mixture in a heating device, set the temperature to 150° C., and perform a cross-linking reaction for 60 minutes.

[0055] Example 5

[0056] Example 5 provides a liquid silicone rubber composition and a preparation method thereof, wherein the liquid silicone rubber composition includes, by mass fraction: 80 parts of a modified liquid silicone rubber matrix material (Preparation Example 2), 4 parts of a plasticizer (dioctyl phthalate), 8 parts of core-shell nanoparticles (Preparation Example 1), 0.5 parts of a cross-linking agent (tert-butyl perbenzoate), 1 part of a filler (graphene), and 0.08 parts of a catalyst (titanium fluoride).

[0057] The preparation method of the silicone rubber composition comprises the following preparation steps:

[0058] Step S1. Add the modified liquid silicone rubber matrix material (Preparation Example 2) and the plasticizer into a mixing container and stir evenly using a high shear stirrer;

[0059] Step S2. After the modified liquid silicone rubber matrix material and dioctyl phthalate are evenly mixed, core-shell nanoparticles (Preparation Example 1), graphene and titanium fluoride are added in sequence, and stirred using a high-speed stirrer;

[0060] Step S3. Add tert-butyl perbenzoate to the above mixture, stir the mixture again to ensure that the cross-linking agent is fully dispersed, place the mixture in a heating device, set the temperature to 150° C., and perform a cross-linking reaction for 60 minutes.

[0061] Examples 6 to 12

[0062] The difference between Examples 6 to 12 is that the amount of filler added is different from that of Example 5, as shown in Table 1 below.

[0063] Table 1

[0064]

[0065]

[0066] Comparison Example

[0067] Comparative Example 1

[0068] The difference between the comparative example 1 and the example 1 is that the unmodified liquid silicone rubber matrix material is replaced with an equal amount of modified liquid silicone rubber matrix material.

[0069] Comparative Example 2

[0070] The difference between the comparative example 2 and the example 1 is that the same amount of silicon dioxide particles are replaced with core-shell nanoparticles.

[0071] Comparative Example 3

[0072] The difference between the comparative example 3 and the example 1 is that the graphene is replaced by an equal amount of modified liquid silicone rubber matrix material.

[0073] Performance testing

[0074] 1. Viscosity value test: According to GB / T 265-1988 "Method for determination of kinematic viscosity and calculation of dynamic viscosity of petroleum products", the viscosity of the mixed liquid silicone rubber composition is tested;

[0075] 2. Thermal conductivity test: Test the cured silicone in accordance with GB / T 30031-2013 "Laser flash method for determination of thermal conductivity and thermal diffusivity of plastics".

[0076] 3. Tensile strength test: Test the cured silicone in accordance with GB / T 1040.3-2006 "Determination of tensile properties of plastics Part 3: Test conditions for films and sheets".

[0077] 4. Repair efficiency: Prepare 10 standard tensile specimens, pre-stretch to 50% strain and cut, heat at 80℃ for 2 hours after the fracture surfaces are in contact, retest the tensile strength, and calculate the repair efficiency.

[0078]

[0079] Complex efficiency;

[0080] Table 2

[0081]

[0082] It can be seen from Examples 1 to 4 and Table 2 that the viscosity of the mixed phase prepared in Examples 1 to 4 is 745 mPa·s to 812 mPa·s, and the thermal conductivity, tensile strength and repair efficiency of the cured liquid rubber material are 1.80 W / m·K to 2.25 W / m·K, 1.63±0.23 MPa to 2.51±0.41 MPa and 83% to 87%, respectively.

[0083] Combining Examples 5 to 12 and Table 2, it can be seen that as the amount of graphene added gradually increases, the viscosity of the mixed phase shows a trend of continuous increase, gradually increasing from 769 mPa·s (Example 5) to 921 mPa·s (Example 12), and the thermal conductivity also continues to increase, from 1.84 W / m·K (Example 5) to 2.56 W / m·K (Example 12), and the tensile strength first increases to Example 9 (2.14 ± 0.45 MPa) and then decreases to Example 12 (1.74 ± 0.38 MPa). The repair efficiency also increases to Example 8 (88%) and then decreases to Example 12 (74%). The viscosity gradually increases mainly because graphene is a two-dimensional sheet-structured nanomaterial. When it is added to the liquid silicone rubber matrix, it will have a strong interaction with the matrix material (such as modified liquid silicone rubber). This interaction increases the internal friction of the system, which reduces the fluidity of the mixture, which is manifested as a gradual increase in viscosity. The thermal conductivity gradually increases mainly because graphene has extremely high thermal conductivity (about 5000W / m·K). When its content gradually increases, a denser and more effective heat conduction network will be formed in the material. This network promotes the rapid transfer of thermal energy, thereby increasing the overall thermal conductivity from 1.84W / m·K to 2.56W / m·K. The reason why the tensile strength increases first and then decreases is mainly because the lower graphene content may play a reinforcing role, and the tensile strength is improved by good interface bonding with the matrix material. However, when the graphene content increases further, excessive fillers may cause agglomeration, destroying the continuity and uniformity of the material. This agglomeration reduces the effective stress transfer between the matrix and the filler, resulting in a decrease in tensile strength. The reason why the repair efficiency increases first and then decreases is that an appropriate amount of graphene can effectively improve the structural stability of the matrix, reduce the breakage of molecular chains during damage, and enhance the crack healing ability, thereby promoting the improvement of the repair efficiency. A high concentration of graphene may affect the flexibility of the silicone rubber matrix and the fluidity of the self-healing process. Excessive addition of graphene may increase the overall rigidity of the material, limit the self-healing ability of the material when damaged, and cause the repair efficiency to decrease instead.

[0084] Combining Example 1, Comparative Example 1, Comparative Example 2 and Table 2, it can be seen that the viscosity, thermal conductivity, tensile strength and repair efficiency of Example 1 are improved relative to those of Comparative Example 1, and the unmodified liquid silicone rubber matrix material and the unmodified silica particles will cause the viscosity, thermal conductivity and tensile strength to deteriorate; in addition, the improvement in the repair efficiency of Example 1 relative to Comparative Examples 1 and 2 is mainly because the polystyrene shell grafted on the core-shell nanoparticles provides a flow environment under a heated environment, which enhances the flexibility and dynamics of the methyl groups grafted on the liquid silicone rubber material, so that the siloxane chains can quickly adjust and form new bonds after contact.

[0085] From Example 1, Comparative Example 3 and Table 2, it can be seen that the viscosity of the mixed phase prepared in Example 1 does not change much relative to that in Comparative Example 3, and the thermal conductivity, tensile strength and repair efficiency of the prepared liquid silicone rubber material are improved; the viscosity does not change much mainly because when the modified liquid silicone rubber matrix material replaces graphene, the modified matrix itself has good fluidity and low cohesion; the thermal conductivity, tensile strength and repair efficiency of the prepared liquid silicone rubber material are improved, mainly because graphene not only improves the thermal conductivity and tensile strength of liquid silicone rubber through its excellent thermal conductivity, strength and molecular network enhancement effect, but also improves the repair efficiency of the material through its own structural characteristics, so that the material exhibits stronger durability and self-healing ability under high temperature, mechanical stress or external damage.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a liquid silicone rubber composition, characterized in that: The method comprises the following preparation steps: Step S1. Add the modified liquid silicone rubber matrix material and the plasticizer into a mixing container and stir evenly using a high shear stirrer; Step S2. After the modified liquid silicone rubber matrix material and the plasticizer are evenly mixed, the core-shell nanoparticles, the filler and the catalyst are added in sequence and stirred using a high-speed stirrer; Step S3. Add a crosslinking agent to the above mixture, stir the mixture again to ensure that the crosslinking agent is fully dispersed, place the mixture in a heating device, set the temperature to 150° C., and perform a crosslinking reaction for 60 minutes.

2. The method for preparing the liquid silicone rubber composition according to claim 1, characterized in that: The plasticizer is dioctyl phthalate.

3. The method for preparing the liquid silicone rubber composition according to claim 1, characterized in that: The filler is graphene.

4. The method for preparing the liquid silicone rubber composition according to claim 1, characterized in that: The catalyst is titanium fluoride.

5. The method for preparing the liquid silicone rubber composition according to claim 1, characterized in that: The cross-linking agent is tert-butyl perbenzoate.

6. The method for preparing the liquid silicone rubber composition according to claim 1, characterized in that: The preparation method of the modified liquid silicone rubber matrix material comprises the following technical steps: slowly dropping methyltrichlorosilane into PDMS, controlling the temperature at 40-60° C., and stirring the reaction for 2-4 hours.

7. The method for preparing the liquid silicone rubber composition according to claim 1, characterized in that: The preparation method of the core-shell nanoparticles comprises the following technical steps: firstly, dispersing silicon dioxide particles in ethanol, wherein the concentration of silicon dioxide in the ethanol is 5 mg / mL, adding polystyrene monomers and benzoyl peroxide initiator, and allowing polystyrene molecules to form a polystyrene shell on the surface of silicon dioxide at 70-80° C., and after the reaction is completed, removing excess monomers and solvents through precipitation, washing and drying to obtain silicon dioxide core / polystyrene shell composite nanoparticles.

8. The liquid silicone rubber composition prepared by the preparation method according to claim 1, characterized in that: In terms of mass fraction, it includes: 60 to 90 parts of modified liquid silicone rubber matrix material, 1 to 5 parts of plasticizer, 5 to 8 parts of core-shell nanoparticles, 0.1 to 0.6 parts of cross-linking agent, 1 to 4 parts of filler and 0.05 to 0.09 parts of catalyst.

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