Preparation method of a modified silicone rubber elastomer

Abstract

The present invention relates to the technical field of silicone rubber, and discloses a preparation method of a modified silicone rubber elastomer. The modified silicone rubber elastomer comprises 100 parts by weight of methyl vinyl silicone rubber, 5 - 25 parts by weight of organosilicon-grafted microcrystalline cellulose, 12 - 20 parts by weight of silica, 1.7 - 2.4 parts by weight of vulcanizing agent, 2.6 - 4.2 parts by weight of crosslinking agent, 1.5 - 2 parts by weight of auxiliary agent, and 1.2 - 1.6 parts by weight of antioxidant; the organosilicon-grafted microcrystalline cellulose contains a siloxane structure and has good compatibility with methyl vinyl silicone rubber. During the high-temperature vulcanization process, the alkenyl group of the organosilicon-grafted microcrystalline cellulose can undergo a crosslinking reaction with methyl vinyl silicone rubber and triallyl isocyanurate, enhancing the interfacial bonding strength between the microcrystalline cellulose and methyl vinyl silicone rubber, and enabling the silicone rubber elastomer to exhibit higher tensile properties, hardness, and tear strength.

Description

Technical Field

[0001] The present invention relates to the technical field of silicone rubber, and specifically to a preparation method of a modified silicone rubber elastomer. Background Art

[0002] Silicone rubber elastomers have good elasticity, heat resistance, aging resistance, and solvent resistance, and are widely used in toughening agents, impact modifiers, electronics, aerospace and other fields. Improving the mechanical strength of silicone rubber elastomers can expand their practical application fields. Cellulose is rich in reserves, inexpensive, easy to obtain, environmentally friendly, and has high mechanical strength, making it an excellent reinforcing filler. It is widely used in polymer materials such as plastics and rubbers. Patent CN113755014B discloses using silicone rubber and butyl rubber as base rubbers and cellulose as the loading matrix for antibacterial nanoparticles, improving the antibacterial properties of the bacterial materials. However, this cellulose does not improve the mechanical properties such as the tensile strength of the rubber material.

[0003] Functionalizing cellulose to expand its practical applications in elastomeric materials such as rubbers is a research hotspot. The paper "Preparation and Properties of Nanocellulose-Polypyrrole / Natural Rubber Flexible Conductive Elastomers" discloses that polypyrrole is in-situ polymerized in cellulose nanofibrils and then uniformly dispersed into the natural rubber elastic matrix to obtain a highly flexible natural rubber conductive elastomer. The present invention aims to conduct a grafting reaction on cellulose microcrystals to obtain cellulose microcrystals containing siloxane and alkenyl groups, improving the mechanical properties of silicone rubber elastomers. Summary of the Invention

[0004] The technical problem solved by the present invention is: to provide a modified silicone rubber elastomer with mechanical properties.

[0005] The technical solution of the present invention is: a preparation method of a modified silicone rubber elastomer, including 100 parts by weight of methyl vinyl silicone rubber, 5 - 25 parts by weight of organosilicon-grafted cellulose microcrystals, 12 - 20 parts by weight of silica, 1.7 - 2.4 parts by weight of vulcanizing agent, 2.6 - 4.2 parts by weight of crosslinking agent, 1.5 - 2 parts by weight of additives, and 1.2 - 1.6 parts by weight of anti-aging agent.

[0006] The preparation method of the modified silicone rubber elastomer includes:

[0007] Step A: Add pyridine, cellulose microcrystals to N,N-dimethylformamide, stir, introduce nitrogen, add bis(3,3'-formyl chloride-5,5'-vinylphenoxy)dimethylsilane, and stir and react at 40 - 65 °C for 36 - 48 h. Pour the solution into water, perform suction filtration, and wash successively with water, ethanol, and dichloromethane, then dry to obtain organosilicon-grafted cellulose microcrystals.

[0008] Step B: Add methyl vinyl silicone rubber, silicone-grafted microcrystalline cellulose, fumed silica, additives, and anti-aging agents into an open mill for the first mixing, then add vulcanizing agents and crosslinking agents for the second mixing. Finally, vulcanize the material in a flat vulcanizer, discharge the material, and obtain the modified silicone rubber elastomer.

[0009] Preferably, the vulcanizing agent is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, the crosslinking agent is triallyl isocyanurate, the additive is stearic acid, and the anti-aging agent is N-phenyl-2-naphthylamine.

[0010] Preferably, in step A, the mass ratio of microcrystalline cellulose to bis(3,3'-formyl chloride-5,5'-vinylphenoxy)dimethylsilane is 100:(15 - 80).

[0011] Preferably, the preparation method of bis(3,3'-formyl chloride-5,5'-vinylphenoxy)dimethylsilane includes:

[0012] (1) Under an ice bath, add methyl 3-bromo-5-hydroxybenzoate, pyridine, and dichlorodimethylsilane with a molar ratio of (2 - 2.2):(2 - 2.4):1 to toluene, react at 20 - 35 °C for 4 - 8 h, concentrate the solution under reduced pressure, wash successively with water and petroleum ether. Add the product to methanol, then add an aqueous sodium hydroxide solution, heat to 70 - 85 °C, carry out a condensation reflux reaction for 3 - 5 h, neutralize with a hydrochloric acid solution, add dichloromethane for extraction and separation. Dry the organic phase with anhydrous sodium sulfate, filter, concentrate the filtrate under reduced pressure, and recrystallize the product with ethanol to obtain intermediate 1.

[0013] (2) Add intermediate 1, vinylboronic acid pinacol ester, 1,1'-bis(diphenylphosphino)ferrocene dichloropalladium, and N,N-diisopropylethylamine with a molar ratio of 1:(2 - 2.4):(0.08 - 0.09):(3.4 - 4) to toluene. Under a nitrogen atmosphere, heat to 80 - 90 °C and react for 5 - 8 h. Concentrate under reduced pressure, wash successively with petroleum ether and acetone, and recrystallize the product with dichloromethane to obtain intermediate 2.

[0014] (3) Add intermediate 2 to thionyl chloride with a molar ratio of (12 - 18):1, heat to 60 - 70 °C, carry out a condensation reflux reaction for 3 - 4 h, concentrate under reduced pressure, wash with petroleum ether, dry, and obtain bis(3,3'-formyl chloride-5,5'-vinylphenoxy)dimethylsilane. The reaction formula is as follows:

[0015]

[0016] Preferably, in step B, during mixing, the roll temperature of the open mill is 45 - 55 °C, the roll gap is 1 - 2 mm, the first mixing time is 5 - 8 min, and the second mixing time is 2 - 3 min.

[0017] Preferably, in step B, during vulcanization, the temperature of the flat vulcanizer is 165 - 175 °C, the time is 20 - 30 min, and the pressure is 10 - 15 MPa.

[0018] The technical effect of the present invention is that: using methyl 3 - bromo - 5 - hydroxybenzoate, dichlorodimethylsilane, vinylboronic acid pinacol ester, and thionyl chloride as reactants, bis(3,3'-formyl chloride - 5,5'-vinylphenoxy)dimethylsilane is prepared. It contains an acyl chloride group and reacts with the hydroxyl groups of microcrystalline cellulose to obtain organosilicon - grafted microcrystalline cellulose. Thus, siloxane groups and alkenyl groups are introduced into the molecular chain of microcrystalline cellulose.

[0019] The present invention uses methyl vinyl silicone rubber as the base rubber of the silicone rubber elastomer and organosilicon - grafted microcrystalline cellulose as the modifier. It contains a siloxane structure and has structural similarity with methyl vinyl silicone rubber, thereby improving the compatibility between the two. A homogeneous compatible system can be formed, and the problem of phase separation and interface defects caused by interface incompatibility between the two will not occur. It is beneficial for microcrystalline cellulose to improve the mechanical properties of the silicone rubber elastomer.

[0020] The present invention uses 2,5 - dimethyl - 2,5 - bis(tert - butylperoxy)hexane as the vulcanizing agent. During high - temperature vulcanization, the alkenyl groups of organosilicon - grafted microcrystalline cellulose can cross - link with methyl vinyl silicone rubber and triallyl isocyanurate, enhancing the interfacial bonding strength between microcrystalline cellulose and methyl vinyl silicone rubber. Microcrystalline cellulose forms a rigid chemical cross - link network in methyl vinyl silicone rubber, increasing the cross - link density of the silicone rubber elastomer, enhancing the mechanical properties of the silicone rubber, and showing higher tensile properties, hardness, and tear strength. Detailed implementation mode

[0021] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0022] Example 1

[0023] (1), Under an ice bath, add 22 mmol of methyl 3-bromo-5-hydroxybenzoate (CAS No. 192810-12-1), 20 mmol of pyridine, and 10 mmol of dichlorodimethylsilane (CAS No. 75-78-5) to 20 mL of toluene, and react at 20 °C for 8 h. After the reaction, concentrate the solution under reduced pressure, wash it successively with water and petroleum ether. Add the product to 60 mL of methanol, then add 60 mL of an aqueous sodium hydroxide solution with a molar concentration of 4 mol / L, heat to 85 °C, and reflux for 3 h. Add hydrochloric acid solution for neutralization, add dichloromethane for extraction and separation. Dry the organic phase with anhydrous sodium sulfate, filter, and concentrate the filtrate under reduced pressure. Recrystallize the product with ethanol to obtain Intermediate 1.

[0024] (2), Add 5 mmol of Intermediate 1, 10 mmol of vinylboronic acid pinacol ester (CAS No. 75927-49-0), 0.4 mmol of 1,1'-bis(diphenylphosphino)ferrocene dichloropalladium (CAS No. 72287-26-4), and 20 mmol of N,N-diisopropylethylamine to 70 mL of toluene. Under a nitrogen atmosphere, heat to 90 °C and react for 5 h. Concentrate under reduced pressure, wash successively with petroleum ether and acetone. Recrystallize the product with dichloromethane to obtain Intermediate 2.

[0025] (3), Add 5 mmol of Intermediate 2 to 90 mmol of thionyl chloride, heat to 70 °C, and reflux for 4 h. Concentrate under reduced pressure, wash with petroleum ether, and dry to obtain bis(3,3'-formyl chloride-5,5'-vinylphenoxy)dimethylsilane.

[0026] Example 2

[0027] (1), Under an ice bath, add 20 mmol of methyl 3-bromo-5-hydroxybenzoate, 20 mmol of pyridine, and 10 mmol of dichlorodimethylsilane to 15 mL of toluene, and react at 35 °C for 4 h. After the reaction, concentrate the solution under reduced pressure, wash it successively with water and petroleum ether. Add the product to 80 mL of methanol, then add 80 mL of an aqueous sodium hydroxide solution with a molar concentration of 4 mol / L, heat to 70 °C, and reflux for 5 h. Add hydrochloric acid solution for neutralization, add dichloromethane for extraction and separation. Dry the organic phase with anhydrous sodium sulfate, filter, and concentrate the filtrate under reduced pressure. Recrystallize the product with ethanol to obtain Intermediate 1.

[0028] (2) Add 5 mmol of intermediate 1, 12 mmol of vinylboronic acid pinacol ester, 0.45 mmol of 1,1'-bis(diphenylphosphino)ferrocene dichloropalladium, and 17 mmol of N,N-diisopropylethylamine to 80 mL of toluene. Under a nitrogen atmosphere, heat to 80 °C and react for 8 h. Concentrate under reduced pressure and wash successively with petroleum ether and acetone. Recrystallize the product from dichloromethane to obtain intermediate 2.

[0029] (3) Add 5 mmol of intermediate 2 to 90 mmol of thionyl chloride. Heat to 60 °C and reflux with condensation for 3 h. Concentrate under reduced pressure, wash with petroleum ether, and dry to obtain bis(3,3'-formyl chloride-5,5'-vinylphenoxy)dimethylsilane.

[0030] Example 3

[0031] (1) Add 120 mL of pyridine and 20 g of microcrystalline cellulose to 200 mL of N,N-dimethylformamide. Stir and then introduce nitrogen. Add 3 g of bis(3,3'-formyl chloride-5,5'-vinylphenoxy)dimethylsilane (prepared according to the method of Example 1). Stir and react at 45 °C for 36 h. Pour the solution into water, filter by suction, and wash successively with water, ethanol, and dichloromethane. Dry to obtain organosilicon-grafted microcrystalline cellulose.

[0032] (2) Add 100 g of methyl vinyl silicone rubber, 5 g of organosilicon-grafted microcrystalline cellulose, 12 g of silica, 1.8 g of the additive stearic acid, and 1.6 g of the antioxidant N-phenyl-2-naphthylamine to an open mill. The roll temperature is 45 °C and the roll gap is 2 mm. Conduct the first mixing for 5 min, then add 2.4 g of the vulcanizing agent 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and 4.2 g of the crosslinking agent triallyl isocyanurate, and conduct the second mixing for 3 min. Finally, vulcanize the material in a flat vulcanizer for 30 min at a temperature of 165 °C and a pressure of 10 MPa. Discharge to obtain the modified silicone rubber elastomer.

[0033] Example 4

[0034] (1) Add 120 mL of pyridine and 20 g of microcrystalline cellulose to 200 mL of N,N-dimethylformamide. Stir and then introduce nitrogen. Add 8 g of bis(3,3'-formyl chloride-5,5'-vinylphenoxy)dimethylsilane (prepared according to the method of Example 1). Stir and react at 65 °C for 36 h. Pour the solution into water, filter by suction, and wash successively with water, ethanol, and dichloromethane. Dry to obtain organosilicon-grafted microcrystalline cellulose.

[0035] (2) Add 100 g of methyl vinyl silicone rubber, 12 g of silicone-grafted microcrystalline cellulose, 20 g of fumed silica, 1.5 g of stearic acid as an additive, and 1.2 g of antioxidant N-phenyl-2-naphthylamine to an open mill. The roll temperature is 55 °C, the roll gap is 2 mm, and primary mixing is carried out for 6 min. Then add 2.4 g of vulcanizing agent 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and 3.3 g of crosslinking agent triallyl isocyanurate, and carry out secondary mixing for 3 min. Finally, vulcanize the material in a flat vulcanizer for 30 min at a temperature of 170 °C and a pressure of 15 MPa, and discharge to obtain a modified silicone rubber elastomer.

[0036] Example 5

[0037] (1) Add 140 mL of pyridine and 20 g of microcrystalline cellulose to 200 mL of N,N-dimethylformamide. After stirring, introduce nitrogen, and add 12 g of bis(3,3'-formyl chloride-5,5'-vinylphenoxy)dimethylsilane (prepared according to the method of Example 1). Stir and react at 40 °C for 48 h. Pour the solution into water, filter by suction, and wash successively with water, ethanol, and dichloromethane, and then dry to obtain silicone-grafted microcrystalline cellulose.

[0038] (2) Add 100 g of methyl vinyl silicone rubber, 18 g of silicone-grafted microcrystalline cellulose, 15 g of fumed silica, 1.8 g of stearic acid as an additive, and 1.3 g of antioxidant N-phenyl-2-naphthylamine to an open mill. The roll temperature is 45 °C, the roll gap is 2 mm, and primary mixing is carried out for 8 min. Then add 1.7 g of vulcanizing agent 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and 3.8 g of crosslinking agent triallyl isocyanurate, and carry out secondary mixing for 2 min. Finally, vulcanize the material in a flat vulcanizer for 20 min at a temperature of 175 °C and a pressure of 10 MPa, and discharge to obtain a modified silicone rubber elastomer.

[0039] Example 6

[0040] (1) Add 140 mL of pyridine and 20 g of microcrystalline cellulose to 200 mL of N,N-dimethylformamide. After stirring, introduce nitrogen, and add 16 g of bis(3,3'-formyl chloride-5,5'-vinylphenoxy)dimethylsilane (prepared according to the method of Example 1). Stir and react at 60 °C for 48 h. Pour the solution into water, filter by suction, and wash successively with water, ethanol, and dichloromethane, and then dry to obtain silicone-grafted microcrystalline cellulose.

[0041] (2) Add 100 g of methyl vinyl silicone rubber, 25 g of silicone-grafted microcrystalline cellulose, 12 g of fumed silica, 1.5 g of stearic acid as an additive, and 1.2 g of N-phenyl-2-naphthylamine as an antioxidant to an open mill. The roll temperature is 45 °C, the roll gap is 2 mm, and primary mixing is carried out for 5 min. Then add 2 g of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane as a vulcanizing agent and 2.6 g of triallyl isocyanurate as a crosslinking agent, and carry out secondary mixing for 3 min. Finally, vulcanize the material in a flat vulcanizer for 30 min at a temperature of 175 °C and a pressure of 10 MPa, and discharge to obtain a modified silicone rubber elastomer.

[0042] Comparative Example 1

[0043] (1) Add 100 g of methyl vinyl silicone rubber, 12 g of fumed silica, 1.8 g of stearic acid as an additive, and 1.6 g of N-phenyl-2-naphthylamine as an antioxidant to an open mill. The roll temperature is 45 °C, the roll gap is 2 mm, and primary mixing is carried out for 5 min. Then add 2.4 g of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane as a vulcanizing agent and 4.2 g of triallyl isocyanurate as a crosslinking agent, and carry out secondary mixing for 3 min. Finally, vulcanize the material in a flat vulcanizer for 30 min at a temperature of 165 °C and a pressure of 10 MPa, and discharge to obtain a modified silicone rubber elastomer.

[0044] Comparative Example 2

[0045] (2) Add 100 g of methyl vinyl silicone rubber, 5 g of microcrystalline cellulose, 12 g of fumed silica, 1.8 g of stearic acid as an additive, and 1.6 g of N-phenyl-2-naphthylamine as an antioxidant to an open mill. The roll temperature is 45 °C, the roll gap is 2 mm, and primary mixing is carried out for 5 min. Then add 2.4 g of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane as a vulcanizing agent and 4.2 g of triallyl isocyanurate as a crosslinking agent, and carry out secondary mixing for 3 min. Finally, vulcanize the material in a flat vulcanizer for 30 min at a temperature of 165 °C and a pressure of 10 MPa, and discharge to obtain a modified silicone rubber elastomer.

[0046] Comparative Example 3

[0047] (1) Add 5 mmol of intermediate 1 (prepared according to the method of Example 1) to 90 mmol of thionyl chloride, heat to 70 °C, carry out reflux reaction for 4 h, concentrate under reduced pressure, wash with petroleum ether, and dry to obtain bis(3,3'-formyl chloride-5,5'-bromo)dimethylsilane. The structural formula is

[0048] (2) Add 120 mL of pyridine and 20 g of microcrystalline cellulose to 200 mL of N,N-dimethylformamide. After stirring, introduce nitrogen gas, add 3 g of bis(3,3'-formyl chloride-5,5'-bromo)dimethylsilane, and stir and react at 45 °C for 36 h. Pour the solution into water, perform suction filtration, wash successively with water, ethanol, and dichloromethane, and dry to obtain organosilicon-grafted microcrystalline cellulose.

[0049] (3) Add 100 g of methyl vinyl silicone rubber, 5 g of organosilicon-grafted microcrystalline cellulose, 12 g of white carbon black, 1.8 g of the auxiliary agent stearic acid, and 1.6 g of the antioxidant N-phenyl-2-naphthylamine to an open mill. The roll temperature is 45 °C and the roll gap is 2 mm. Conduct the first mixing for 5 min, then add 2.4 g of the vulcanizing agent 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and 4.2 g of the crosslinking agent triallyl isocyanurate, and conduct the second mixing for 3 min. Finally, vulcanize the material in a flat vulcanizer for 30 min at a temperature of 165 °C and a pressure of 10 MPa, and discharge to obtain a modified silicone rubber elastomer.

[0050] Comparative Example 4

[0051] (1) Add 120 mL of pyridine and 20 g of microcrystalline cellulose to 200 mL of N,N-dimethylformamide. After stirring, introduce nitrogen gas, add 3 g of acryloyl chloride, and stir and react at 45 °C for 36 h. Pour the solution into water, perform suction filtration, wash successively with water, ethanol, and dichloromethane, and dry to obtain acrylate-based microcrystalline cellulose.

[0052] (2) Add 100 g of methyl vinyl silicone rubber, 5 g of acrylate-based microcrystalline cellulose, 12 g of white carbon black, 1.8 g of the auxiliary agent stearic acid, and 1.6 g of the antioxidant N-phenyl-2-naphthylamine to an open mill. The roll temperature is 45 °C and the roll gap is 2 mm. Conduct the first mixing for 5 min, then add 2.4 g of the vulcanizing agent 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and 4.2 g of the crosslinking agent triallyl isocyanurate, and conduct the second mixing for 3 min. Finally, vulcanize the material in a flat vulcanizer for 30 min at a temperature of 165 °C and a pressure of 10 MPa, and discharge to obtain a modified silicone rubber elastomer.

[0053] The tensile properties were tested according to the method of GB / T 528-2009. The tear strength was tested according to the method of GB / T 529-2008. The hardness was tested according to the method of GB / T 531.1-2008. The results are shown in Table 1.

[0054]

[0055] After testing, compared with Comparative Example 1, in the silicone rubber elastomers of Examples 3-6, organosilicon-grafted cellulose microcrystals are added. After the grafting reaction of the cellulose microcrystals, a siloxane structure is introduced into the molecular chain, which has a structural similarity with methyl vinyl silicone rubber, thereby improving the compatibility between the cellulose microcrystals and methyl vinyl silicone rubber, and a homogeneous compatible system can be formed. There will be no problem of phase separation and formation of interfacial defects due to interfacial incompatibility between the two. And the organosilicon-grafted cellulose microcrystals contain alkenyl groups. Under the action of the vulcanizing agent 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, its alkenyl groups can crosslink with methyl vinyl silicone rubber and triallyl isocyanurate, further enhancing the interfacial bonding strength between the cellulose microcrystals and methyl vinyl silicone rubber. The cellulose microcrystals form a rigid chemical crosslinking network in the methyl vinyl silicone rubber, increasing the crosslinking density of the silicone rubber elastomer, enhancing the mechanical properties of the silicone rubber, and showing higher tensile properties, hardness and tear strength.

[0056] Ordinary cellulose microcrystals are added to the silicone rubber elastomer of Comparative Example 2. The compatibility between it and methyl vinyl silicone rubber is poor, the interface between the two is incompatible, and phase separation is likely to occur to form interfacial defects, which will affect the mechanical properties of the silicone rubber elastomer.

[0057] In Comparative Example 3, bis(3,3'-formyl chloride-5,5'-bromo)dimethylsilane was reacted with cellulose microcrystals. The obtained organosilicon-grafted cellulose microcrystals contain a siloxane structure and have good compatibility with methyl vinyl silicone rubber. The cellulose microcrystals can play a reinforcing role and improve the mechanical properties of the silicone rubber elastomer. However, the organosilicon-grafted cellulose microcrystals do not contain alkenyl groups and cannot crosslink with methyl vinyl silicone rubber, and do not form a rigid chemical crosslinking network in the silicone rubber. The improvement effect on the mechanical properties of the silicone rubber elastomer is lower than that of each example.

[0058] In Comparative Example 4, acryloyl chloride was reacted with cellulose microcrystals. The obtained acrylate-based cellulose microcrystals contain alkenyl groups and can crosslink with methyl vinyl silicone rubber to form a rigid chemical crosslinking network, which is beneficial to improving the mechanical properties of the silicone rubber elastomer. However, the acrylate-based cellulose microcrystals do not contain a siloxane structure, and the compatibility with methyl vinyl silicone rubber is not good. The strengthening effect on the silicone rubber elastomer is lower than that of each example.

[0059] The above examples are only used to illustrate the technical concept and characteristics of the present invention. The purpose is to enable those familiar with this technology to understand the content of the present invention and implement it accordingly. It cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a modified silicone rubber elastomer, characterized in that: The modified silicone rubber elastomer comprises 100 parts by weight of methyl vinyl silicone rubber, 5-25 parts by weight of organosilicon grafted cellulose microcrystals, 12-20 parts by weight of white carbon black, 1.7-2.4 parts by weight of a vulcanizing agent, 2.6-4.2 parts by weight of a crosslinking agent, 1.5-2 parts by weight of an auxiliary agent, and 1.2-1.6 parts by weight of an antioxidant; The preparation method of the modified silicone rubber elastomer comprises: Step A, adding pyridine and cellulose microcrystals to N,N-dimethylformamide, introducing nitrogen after stirring, adding bis(3,3'-formyl chloride-5,5'-vinylphenoxy)dimethylsilane, stirring and reacting at 40-65° C. for 36-48 hours, pouring the solution into water, filtering, washing, and drying to obtain organosilicon-grafted cellulose microcrystals; Step B, adding methyl vinyl silicone rubber, organosilicon grafted cellulose microcrystals, white carbon black, additives, and antioxidants into an open mill for primary mixing, then adding a vulcanizing agent and a crosslinking agent for secondary mixing, and finally vulcanizing the materials in a flat vulcanizer, discharging the materials, and obtaining a modified silicone rubber elastomer.

2. The method for preparing the modified silicone rubber elastomer according to claim 1, characterized in that: The vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, the crosslinking agent is triallyl isocyanurate, the auxiliary agent is stearic acid, and the antioxidant is N-phenyl-2-naphthylamine.

3. The method for preparing the modified silicone rubber elastomer according to claim 1, characterized in that: In the step A, the mass ratio of cellulose microcrystals to bis(3,3'-carbonyl chloride-5,5'-vinylphenoxy)dimethylsilane is 100:(15-80).

4. The method for preparing a modified silicone rubber elastomer according to claim 1, characterized in that: The preparation method of the bis(3,3'-formyl chloride-5,5'-vinylphenoxy)dimethylsilane comprises: (1) In an ice bath, add methyl 3-bromo-5-hydroxybenzoate, pyridine, and dichlorodimethylsilane to toluene, and react at 20-35° C. for 4-8 hours. After the reaction, concentrate the solution under reduced pressure, wash, add the product to methanol, then add sodium hydroxide aqueous solution, heat to 70-85° C., condense and reflux for 3-5 hours, add hydrochloric acid solution to neutralize, add dichloromethane, extract and separate, and recrystallize to obtain intermediate 1; (2) Add intermediate 1, vinylboronic acid pinacol ester, 1,1'-bis(diphenylphosphino)ferrocenepalladium dichloride, and N,N-diisopropylethylamine to toluene, heat to 80-90° C. in a nitrogen atmosphere, react for 5-8 hours, concentrate under reduced pressure, wash, and recrystallize to obtain intermediate 2; (3) Add intermediate 2 to thionyl chloride, heat to 60-70° C., condense and reflux for 3-4 hours, concentrate under reduced pressure, wash, and dry to obtain bis(3,3'-formyl chloride-5,5'-vinylphenoxy)dimethylsilane.

5. The method for preparing the modified silicone rubber elastomer according to claim 4, characterized in that: In the above (1), the molar ratio of methyl 3-bromo-5-hydroxybenzoate, pyridine and dichlorodimethylsilane is (2-2.2):(2-2.4):

1.

6. The method for preparing the modified silicone rubber elastomer according to claim 4, characterized in that: In the above (2), the molar ratio of intermediate 1, vinylboronic acid pinacol ester, 1,1'-bis(diphenylphosphino)ferrocenepalladium dichloride, and N,N-diisopropylethylamine is 1:(2-2.4):(0.08-0.09):(3.4-4).

7. The method for preparing a modified silicone rubber elastomer according to claim 4, characterized in that: In the above (3), the molar ratio of thionyl chloride to intermediate 2 is (12-18):

1.

8. The method for preparing a modified silicone rubber elastomer according to claim 1, characterized in that: In the step B, during mixing, the roller temperature of the open mixer is 45-55° C., the roller distance is 1-2 mm, the first mixing time is 5-8 min, and the second mixing time is 2-3 min.

9. The method for preparing a modified silicone rubber elastomer according to claim 1, characterized in that: In the step B, the temperature of the flat vulcanizing press during vulcanization is 165-175° C., the time is 20-30 min, and the pressure is 10-15 MPa.

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