Hyperbranched organic silicon modified high-strength polyether type ablation-resistant elastomer and preparation method thereof

Abstract

The invention discloses a hyperbranched organic silicon modified high-strength polyether type ablation-resistant elastomer and a preparation method thereof. The elastomer comprises a component A and a component B, wherein the mass percentage ratio of the component A to the component B is (10-90%): (90-10%); the component A mainly comprises the following raw materials: hyperbranched organic silicon resin and a catalyst; the raw material of the component B mainly comprises silane-terminated polyether; and the component A and the component B can also comprise a filler. The organosilicone elastomer can be obtained by mixing, stirring and curing the silane-terminated polyether and the hyperbranched organosilicone resin in proportion. According to the elastomer disclosed by the invention, the hyperbranched organic silicon resin is used as a hard segment, and the silane-terminated polyether is used as a soft segment, so that the elastomer shows excellent high-temperature resistance, ablation resistance, strong adhesive force, excellent tear strength, excellent tensile strength and good elongation at break; the preparation method is simple, low in cost and suitable for large-scale application.

Description

Technical Field

[0001] The invention relates to an elastomer and a preparation method thereof, in particular to a hyperbranched organosilicon-modified high-strength polyether-type ablation-resistant elastomer and a preparation method thereof. Background Art

[0002] The particularity of the siloxane bond performance makes the thermodynamic properties of silicone materials present unique properties. Compared with the same series of carbon-based polymers, silicone polymers usually have better flexibility and ductility. At the same time, the bond energy of the silicon-oxygen bond in silicone polymers is as high as 443kJ / mol, so silicone polymers also have excellent heat resistance, and they have become the most widely used resin matrix in ablative thermal protection coatings. Among the many silicone polymers, silicone elastomers are a new type of silicone elastomer material, which are usually composed of linear polysiloxanes and bulk silicone resins. Its special bulk structure with alternating soft and hard segments gives it excellent heat resistance, ablation resistance and mechanical properties. In summary, silicone elastomers, as the resin matrix of ablative thermal protection coatings, have broad application prospects due to their convenient construction and excellent performance.

[0003] However, the inherent defects of silicone elastomers have always limited their application in the field of ablative thermal protection. First, the lack of intermolecular forces in silicone polymers leads to poor mechanical properties, especially the tear resistance and tensile properties are difficult to meet actual needs. Secondly, silicone polymers usually have a high viscosity, which makes it difficult to construct them in practice. A large amount of solvent needs to be added for dilution to improve the defect of difficult construction. Finally, due to the low surface energy, lack of carbon-based segments, and poor ablation thermal efficiency of traditional silicone polymers, they still have problems such as low surface adhesion, poor thermal protection effect, and high back temperature in actual applications. These defects have restricted the further development of silicone polymers in the field of ablative thermal protection materials and limited their application scenarios.

[0004] In response to the above problems, patent CN117402586A uses petroleum ether as solvent and ethyl orthosilicate as surface treatment agent to treat the bonded surface, so as to achieve the preparation of silicone rubber heat-resistant coating with stable bonding under high and low temperature environments, and improve the bonding strength between the primer and the silicone rubber heat-resistant coating. However, the introduction of surface treatment agent will increase the construction process of silicone heat-resistant coating and extend the construction time of silicone heat-resistant coating. At the same time, the introduction of solvent also further increases the environmental pressure, further increases the construction difficulty of thermal protection coating for large parts, and further limits the application of silicone heat-resistant coating. Patent CN117844374A introduces MQ resin powder as a hard segment structure in traditional silicone rubber heat-resistant coating, thereby modifying a matrix with low cost, excellent thermal stability, and high ablation heat protection efficiency, and improving the shear resistance of heat-resistant coating. However, the introduction of powdered silicone resin greatly increases the viscosity of silicone heat-resistant coating, resulting in such heat-resistant coating having problems such as high construction difficulty and high equipment failure rate in spraying construction. At the same time, the introduction of MQ resin will also lead to problems such as reduced elongation at break of the material and decreased flexibility of the coating, making it difficult to become an optimal solution to improve traditional silicone materials.

[0005] In summary, the current research on the modification of silicone materials in terms of heat protection and bonding properties is relatively simple. It is still a huge challenge to simultaneously improve the mechanical properties, adhesion and thermal protection properties of silicone heat protection materials without increasing the complexity of construction. Summary of the invention

[0006] Purpose of the invention: The purpose of the present invention is to provide a hyperbranched silicone modified high-strength polyether ablation-resistant elastomer with excellent adhesion and ablation resistance and temperature resistance;

[0007] The second object of the present invention is to provide a method for preparing the above-mentioned hyperbranched silicone-modified high-strength polyether-type ablation-resistant elastomer.

[0008] Technical solution: The hyperbranched silicone modified high-strength polyether ablation-resistant elastomer of the present invention comprises component A and component B, wherein the mass percentage of component A and component B is 10-90%:90-10%;

[0009] The A component includes the following raw materials in parts by weight: hyperbranched silicone resin: 100-25 parts; catalyst: 0-5 parts, excluding 0; flame retardant filler: 0-70 parts; ablation resistant filler: 0-70 parts; reinforcing filler: 0-70 parts;

[0010] The B component comprises the following raw materials in parts by weight: 100 to 25 parts of silane-terminated polyether; 0 to 5 parts of catalyst; 0 to 70 parts of flame-retardant filler; 0 to 70 parts of ablation-resistant filler; and 0 to 70 parts of reinforcing filler.

[0011] Wherein, the structural formula of the hyperbranched silicone resin is:

[0012]

[0013] Wherein, R is one or more combinations of methyl, phenyl, vinyl, chloromethyl, glycidyl ether propyl, and R' is methyl. As a hard segment component, the hyperbranched silicone resin improves the temperature resistance and ablation resistance of the material on the one hand, and as a cross-linking site, it increases the cross-linking degree of the material system, thereby improving the mechanical properties of the material.

[0014] Preferably, R of the hyperbranched silicone resin is phenyl, R′ is methyl, and its structural formula is:

[0015]

[0016] This type of hyperbranched silicone resin is combined with a silane-terminated polyether and cured under the catalysis of a catalyst to obtain a silicone elastomer with high strength and high flexibility.

[0017] Preferably, R of the hyperbranched silicone resin is vinyl, R′ is methyl, and its structural formula is:

[0018]

[0019] This type of hyperbranched silicone resin is combined with a silane-terminated polyether and cured under the catalysis of a catalyst to obtain a silicone elastomer with high hardness, high strength and high ablation resistance.

[0020] The preparation steps of the hyperbranched silicone resin are as follows: mixing a coupling agent containing an R or R' functional group in the structural formula and a solvent, then adding water and a hydrochloric acid solution to react, and removing by-products after the reaction to obtain a hyperbranched silicone resin.

[0021] Preferably, a coupling agent containing R or R' functional group in the structural formula and a solvent are placed in a three-necked flask equipped with a condenser, a constant pressure dropping funnel and a thermometer, mixed evenly, and then deionized water and a hydrochloric acid solution are added dropwise, and after the dropwise addition is completed, the mixture is refluxed at 20°C to 120°C for 4h to 24h. After the reaction is completed, stirring is stopped, and by-products are removed by rotary evaporation at 20°C to 80°C to obtain a hyperbranched silicone resin. The concentration of the hydrochloric acid solution is 36.5%.

[0022] Preferably, the coupling agent is phenyltrimethoxysilane and methyltrimethoxysilane, or phenyltrimethoxysilane and methyloxysilane, or methyltrimethoxysilane, or vinyltrimethoxysilane and methyltrimethoxysilane, or chloromethyltrimethoxysilane and methyltrimethoxysilane.

[0023] Preferably, the solvent is one or more of acetone, ethanol, methanol, tetrahydrofuran, ethyl acetate, dichloromethane, chloroform, and toluene. More preferably, the solvent is ethanol.

[0024] Wherein, the structural formula of the silane-terminated polyether is:

[0025]

[0026] Wherein, R is one of methyl, ethyl, and isopropyl, and R' is one of carbon-carbon bond (CC) and carbamate bond (-NHCOO-).

[0027] The preparation steps of the silane-terminated polyether are as follows: mixing high molecular weight polyether, catalyst and terminal hydrogen-containing or terminal isocyanate silane coupling agent containing R or R' functional group in the structural formula for reaction, and removing impurities after the reaction to obtain the polyether.

[0028] Preferably, the reaction temperature is 20°C to 150°C, and the reaction time is 2h to 10h.

[0029] Preferably, the molar ratio of the high molecular weight polyether to the coupling agent is 1:(2-3); and the added amount of the catalyst is 0.05wt%-5wt%.

[0030] Preferably, the high molecular weight polyether is at least one of hydroxyl-terminated polyethylene oxide, hydroxyl-terminated polypropylene oxide, vinyl-terminated polyethylene oxide, and vinyl-terminated polypropylene oxide; the molecular weight of the high molecular weight polyether is 1000 to 100000; more preferably, the high molecular weight polyether is a hydroxyl-terminated polypropylene oxide-ethylene oxide mixture with a molecular weight of more than 10000.

[0031] Preferably, the catalyst is at least one of organic tin catalysts such as stannous octoate, dibutyltin dilaurate, dioctyltin dilaurate, or at least one of titanate catalysts such as tetrabutyl titanate and tetraethyl titanate. The function of the catalyst is to reduce the activation energy of the material reaction, lower the curing temperature, and increase the curing rate of the material.

[0032] Preferably, the coupling agent is isocyanate propyltrimethoxysilane, and its preparation reaction equation is:

[0033]

[0034] This type of silane-terminated polyether has better compatibility, excellent adhesion and tear resistance with hyperbranched silicone resin, and is cured with the hyperbranched silicone resin under catalyst to obtain a silicone elastomer with high strength, high adhesion, tear resistance and ablation resistance.

[0035] The raw materials of the hyperbranched silicone-modified high-strength polyether-type ablation-resistant elastomer further include at least one of a reinforcing filler, a flame-retardant filler and an ablation-resistant filler.

[0036] Preferably, the reinforcing filler is at least one of titanium dioxide, heavy calcium carbonate, fumed silica, light calcium carbonate, nano calcium carbonate, silicon micropowder, carbon black, and iron red. The reinforcing filler is used to improve the mechanical properties of the material, and can also reduce the volume shrinkage of the material during curing and improve the dimensional stability.

[0037] Preferably, the flame retardant filler is at least one of aluminum hypophosphite, decabromodiphenylethane, antimony trioxide, aluminum hydroxide, red phosphorus, ammonium polyphosphate, and magnesium hydroxide; the ablation resistant filler is at least one of hollow glass microspheres, mica powder, kaolin powder, zirconium oxide powder, talcum powder, and chopped glass fiber powder. The flame retardant and ablation resistant fillers are used to improve the flame retardant properties of the material, and can further improve the high temperature residual carbon rate of the material and enhance its ablation resistance.

[0038] The preparation method of the above-mentioned hyperbranched silicone modified high-strength polyether type ablation-resistant elastomer comprises the following steps:

[0039] (1) adding a catalyst to a hyperbranched silicone resin and stirring to obtain a component A;

[0040] (2) using silane-terminated polyether as component B;

[0041] (3) The raw materials of component A and component B are uniformly mixed and cured to obtain the hyperbranched silicone modified polyether elastomer.

[0042] In actual use, for the convenience of use and sales, the catalyst and the hyperbranched silicone resin are uniformly mixed by a mechanical stirring device to form component A, and the reinforcing filler, the flame retardant and ablation resistant filler and the silane-terminated polyether are uniformly mixed by a three-roll mill device to form component B for packaging. When it is necessary to obtain a silicone elastomer, the A and B components are uniformly mixed and cured under certain conditions to obtain a hyperbranched silicone modified polyether elastomer.

[0043] Preferably, the curing condition is curing at room temperature for 7 days or curing at 80° C. for 24 hours.

[0044] The above-mentioned hyperbranched silicone modified high-strength polyether-type ablation-resistant elastomer is used in the field of high temperature resistance and ablation resistance.

[0045] Principle of the invention: The present invention provides a new idea for the preparation of high-strength ablation-resistant elastomers, using hyperbranched silicone resin as a hard segment and silane-terminated polyether as a soft segment, and the two are co-cured under a catalyst to obtain a silicone elastomer. Thanks to the advantages of Si-O-Si bonds in thermal properties, as well as the larger intramolecular free volume, lower viscosity and good solubility of hyperbranched silicone polymers, hyperbranched silicone polymers are introduced into the preparation of silicone elastomers, which improves viscosity controllability, mechanical properties, ablation resistance and temperature resistance. At the same time, thanks to the strong intermolecular force and segment entanglement ability of the COC bond in the high molecular weight silane-terminated polyether, silane-terminated polyether is introduced into the preparation of silicone elastomers, which improves the tear resistance, bonding performance and mechanical properties of the material system. The silicone elastomer obtained by copolymerization of the two has the advantages of both, fundamentally solving the problems of poor mechanical properties, poor heat resistance and low adhesion of traditional silicone polymers. At the same time, by freely adjusting the content of hard segments and soft segments, a new type of high-strength ablation-resistant silicone elastomer with different characteristics such as anti-ablation, high adhesion, and strong mechanical properties can be prepared.

[0046] Beneficial effects: Compared with the prior art, the present invention achieves the following significant effects:

[0047] (1) The present invention introduces a silane-terminated polyether with excellent flexibility and adhesion as a soft segment, and introduces a hyperbranched silicone resin with excellent heat resistance, anti-ablation and heat resistance as a hard segment, thereby realizing a silicone elastomer with excellent adhesion and anti-ablation and heat resistance. The silicone elastomer of the present invention combines the advantages of hyperbranched silicone and silane-terminated polyether, and has excellent anti-ablation, adhesion, mechanical properties and heat resistance.

[0048] (2) The present invention can freely adjust the mechanical properties, heat resistance, adhesion, high and low temperature resistance and other performance requirements of the material system according to the actual usage scenario by changing the weight proportions of the hyperbranched silicone component and the silane-terminated polyether component in the material system. The formula is highly flexible, further expanding the application prospects of silicone polymers.

[0049] (3) The present invention provides a method for preparing a high-performance, low-cost silicone elastomer. The method has a simple process, few side reactions, and is easy to mass produce. Compared with the traditional method of improving the adhesion and anti-ablation properties of silicone polymers, this preparation method greatly improves the heat protection efficiency and mechanical properties of the silicone polymer system without increasing the construction process and construction difficulty, and can meet the application requirements in special scenarios.

[0050] (4) The elastomer of the present invention has a simple preparation process and low production cost, and has broad application space in the fields of aerospace, military industry and national defense, automobile industry, biology, electronics, and medicine. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a physical picture of the silicone elastomer obtained in Example 1;

[0052] Figure 2 This is a test diagram of the mechanical properties of the silicone elastomer obtained in Example 1;

[0053] Figure 3 This is a test diagram of the mechanical properties of the silicone elastomer obtained in Example 2;

[0054] Figure 4 This is a test diagram of thermal stability of the silicone elastomer obtained in Example 2;

[0055] Figure 5 This is a mechanical properties test diagram of the product obtained in Comparative Example 1;

[0056] Figure 6 This is a mechanical properties test diagram of the product obtained in Comparative Example 2;

[0057] Figure 7 This is a thermal stability performance test diagram of the product obtained in Comparative Example 3;

[0058] Figure 8 This is a schematic diagram of the heat resistance performance assessment of the silicone elastomer obtained in Example 3;

[0059] Fig. 9 This is a test diagram of the anti-ablation performance of the silicone elastomer obtained in Example 4;

[0060] Fig.10 This is a test chart of the heat protection performance of the silicone elastomer obtained in Example 5. DETAILED DESCRIPTION

[0061] The present invention is described in further detail below.

[0062] Example 1

[0063] (1) The preparation steps of silane-terminated polyether are as follows: under nitrogen protection, 1 mol of hydroxy-terminated polyethylene oxide with a molecular weight of 10,000, 2 mol of isocyanate propyl trimethoxy silane, and 2 wt% of dibutyltin disilicate are added into a three-necked flask. The mixture is heated until slight reflux occurs, and the by-products are collected by distillation. The mixture is then slowly heated to 120° C. for reaction for 6 h, cooled to 80° C., and unreacted isocyanate propyl trimethoxy silane is removed by vacuum at -0.1 MPa using an oil pump to obtain a light yellow transparent silane-terminated polyether.

[0064] (1) The preparation steps of the hyperbranched silicone resin are as follows: 0.5 mol of phenyltrimethoxysilane and 0.5 mol of methyltrimethoxysilane and 150 g of methanol are weighed respectively, and placed in a three-necked flask equipped with a condenser, a constant pressure dropping funnel and a thermometer, and mixed evenly, and then 1.3 mol of deionized water and 5 ml of 36.5% hydrochloric acid are added dropwise. After the addition is completed, the mixture is refluxed at 120° C. for 4 h. After the reaction is completed, stirring is stopped, and by-products are removed by rotary evaporation at 50° C. to obtain a phenylmethyl hyperbranched silicone resin.

[0065] (3) The preparation method of the hyperbranched silicone modified high-strength polyether type ablation-resistant elastomer is as follows:

[0066] S1: 39.5 g of hyperbranched silicone resin and 0.5 g of dibutyltin disilicate were mixed and stirred for 30 min to obtain component A;

[0067] S2: 100 g of silane-terminated polyether as component B;

[0068] S3: Mix component A and component B and stir them thoroughly;

[0069] S4: The mixed material is injected into a mold and cured at room temperature for 14 days to finally produce a high-strength silicone elastomer.

[0070] The actual picture of the organosilicon elastomer obtained in this example is as follows Figure 1 shown. Figure 2 The test results of the mechanical properties of the prepared high-strength silicone elastomer show that the tensile strength of the prepared high-strength silicone elastomer is as high as 6.1 MPa, and the elongation at break is close to 320%, showing extremely excellent mechanical properties without adding reinforcing fillers.

[0071] Example 2

[0072] (1) The preparation steps of silane-terminated polyether are as follows: under nitrogen protection, 1 mol of vinyl-terminated polypropylene oxide with a molecular weight of 8000, 2 mol of trimethoxysilane, and 0.1 wt% of Karstedt catalyst are added into a three-necked flask, and then the temperature is slowly raised to 80° C. for reaction for 2 h, and then the temperature is slowly raised to 120° C. for reaction for 2 h, and then the temperature is lowered to 80° C., and unreacted trimethoxysilane is removed by vacuum at -0.1 MPa using an oil pump to obtain a light yellow transparent silane-terminated polyether.

[0073] (2) The preparation steps of hyperbranched silicone resin are as follows: 0.5 mol of phenyltrimethoxysilane and 0.5 mol of vinyltrimethoxysilane and 150 g of ethanol are weighed respectively, and placed in a three-necked flask equipped with a condenser, a constant pressure dropping funnel and a thermometer, and mixed evenly, and then 1.5 mol of deionized water and 5 ml of 36.5% hydrochloric acid are added dropwise. After the addition is completed, the mixture is refluxed at 70°C for 24 h. After the reaction is completed, stirring is stopped, and by-products are removed by rotary evaporation at 80°C to obtain vinylcyclohexyl hyperbranched silicone resin.

[0074] (3) The preparation method of the hyperbranched silicone modified high-strength polyether type ablation-resistant elastomer is as follows:

[0075] S1: 45 g of hyperbranched silicone resin and 5 g of dibutyltin diosilicate were mixed and stirred for 30 min to obtain component A;

[0076] S2: 100 g of silane-terminated polyether as component B;

[0077] S3: Mix component A and component B and stir them thoroughly;

[0078] S4: The mixed material is injected into a mold and cured at room temperature for 14 days to finally produce a high-strength and heat-resistant silicone elastomer.

[0079] Figure 3 , Figure 4 The mechanical properties and thermal stability test diagrams of the high-strength and heat-resistant silicone elastomer are shown in order. It can be seen that the tensile strength of the high-strength and heat-resistant silicone elastomer without filler addition reaches 4.8MPa, and the elongation at break exceeds 230%. At the same time, its 5% decomposition temperature exceeds 335℃, the residual carbon rate at 1000℃ exceeds 43%, and the maximum thermal decomposition rate is only 0.8% / ℃, showing excellent thermal stability and mechanical properties.

[0080] Example 3

[0081] (1) The preparation steps of silane-terminated polyether are as follows: under nitrogen protection, 1 mol of a vinyl-terminated polypropylene oxide-ethylene oxide mixture with a molecular weight of 10,000, 2.2 mol of trimethoxysilane, and 0.5 wt% of a Karstedt catalyst are added into a three-necked flask, and then the temperature is slowly raised to 80° C. for reaction for 2 h, and then the temperature is slowly raised to 120° C. for reaction for 2 h, and then the temperature is lowered to 80° C., and unreacted trimethoxysilane is removed by vacuum at -0.1 MPa using an oil pump to obtain a light yellow transparent silane-terminated polyether.

[0082] (2) The preparation steps of hyperbranched silicone resin are as follows: weigh 1.0 mol of methyltrimethoxysilane and 150 g of ethyl acetate, put them into a three-necked flask equipped with a condenser, a constant pressure dropping funnel and a thermometer, mix them evenly, then add 1 mol of deionized water and 10 ml of 36.5% hydrochloric acid dropwise, after the addition is completed, reflux at 70°C for 6 h. After the reaction is completed, stop stirring, and remove by-products by rotary evaporation at 60°C to obtain methyl hyperbranched silicone resin.

[0083] (3) The preparation method of the hyperbranched silicone modified high-strength polyether type ablation-resistant elastomer is as follows:

[0084] S1: 20 g of hyperbranched silicone resin and 2 g of dibutyltin diosilicate were mixed and stirred for 30 min to obtain component A;

[0085] S2: 80 g of silane-terminated polyether as component B;

[0086] S3: Mix component A and component B and stir them thoroughly;

[0087] S4: The mixed material is injected into a mold and cured at room temperature for 14 days to finally produce a heat-resistant silicone elastomer.

[0088] Figure 8 This is the temperature resistance test diagram of the prepared elastomer. It can be seen from the figure that the prepared heat-resistant silicone elastomer still maintains the integrity of its morphology after aging at 120°C for 12 hours. Compared with the complete liquefaction and decomposition of ordinary silane-terminated polyether, the heat resistance is significantly improved, proving that the introduction of hyperbranched silicone resin as a cross-linking site greatly improves the heat resistance of the material system.

[0089] Example 4

[0090] (1) The preparation steps of silane-terminated polyether are as follows: under nitrogen protection, 1 mol of vinyl-terminated polypropylene oxide with a molecular weight of 10,000, 2.5 mol of trimethoxysilane, and 1 wt% of Karstedt catalyst are added into a three-necked flask, and then the temperature is slowly raised to 80° C. for reaction for 4 h, and then the temperature is slowly raised to 150° C. for reaction for 2 h, and then the temperature is lowered to 80° C., and unreacted trimethoxysilane is removed by vacuum at -0.1 MPa using an oil pump to obtain a light yellow transparent silane-terminated polyether.

[0091] (2) The preparation steps of hyperbranched silicone resin are as follows: 0.5 mol of vinyl trimethoxysilane and 0.5 mol of methyl trimethoxysilane and 150 g of tetrahydrofuran are weighed respectively, and placed in a three-necked flask equipped with a condenser, a constant pressure dropping funnel and a thermometer, and mixed evenly, and then 2 mol of deionized water and 1.5 ml of 36.5% hydrochloric acid are added dropwise. After the addition is completed, the mixture is refluxed at 100° C. for 4 h. After the reaction is completed, stirring is stopped, and by-products are removed by rotary evaporation at 80° C. to obtain vinyl methyl hyperbranched silicone resin.

[0092] (3) The preparation method of the hyperbranched silicone modified high-strength polyether type ablation-resistant elastomer is as follows:

[0093] S1: 49.5 g of hyperbranched silicone resin and 0.5 g of dibutyltin disilicate were mixed and stirred for 30 min to obtain component A;

[0094] S2: 40 g of silane-terminated polyether and 20 g of fumed silica were stirred for 2 h using a three-roll mill as component B;

[0095] S3: Mix component A and component B and stir them thoroughly;

[0096] S4: The mixed material is injected into a mold and cured at room temperature for 10 days to finally obtain an ablation-resistant silicone elastomer.

[0097] Fig. 9 The ablation resistance test diagram of the prepared ablation-resistant elastomer shows that the prepared ablation-resistant silicone elastomer still maintains the integrity of its overall shape after being placed in a muffle furnace at 800°C for 5 minutes, while the pure hyperbranched silicone resin and pure silane-terminated polyether in comparison both show thermal oxidative decomposition. This proves that the constructed silicone elastomer has excellent ablation resistance.

[0098] Example 5

[0099] (1) The preparation steps of silane-terminated polyether are as follows: under nitrogen protection, 1 mol of vinyl-terminated polyethylene oxide with a molecular weight of 8000, 3 mol of trimethoxysilane, and 0.5 wt% of Karstedt catalyst are added into a three-necked flask, and then the temperature is slowly raised to 80° C. for reaction for 4 h, and then the temperature is slowly raised to 120° C. for reaction for 4 h, and then the temperature is lowered to 60° C., and unreacted trimethoxysilane is removed by vacuum at -0.1 MPa using an oil pump to obtain a light yellow transparent silane-terminated polyether.

[0100] (2) The preparation steps of hyperbranched silicone resin are as follows: 0.5 mol of vinyl trimethoxysilane and 0.5 mol of methyl trimethoxysilane and 150 g of acetone are weighed respectively, and placed in a three-necked flask equipped with a condenser, a constant pressure dropping funnel and a thermometer, and mixed evenly, and then 1.1 mol of deionized water and 1 ml of 36.5% hydrochloric acid are added dropwise. After the addition is completed, the mixture is refluxed at 150° C. for 2 h. After the reaction is completed, stirring is stopped, and by-products are removed by rotary evaporation at 60° C. to obtain methyl hyperbranched silicone resin.

[0101] (3) The preparation method of the hyperbranched silicone modified high-strength polyether type ablation-resistant elastomer is as follows:

[0102] S1: 39.5 g of hyperbranched silicone resin and 0.5 g of dibutyltin disilicate were mixed and stirred for 30 min to obtain component A;

[0103] S2: 50 g of silane-terminated polyether, 10 g of aluminum hydroxide, 10 g of aluminum hypophosphite, 10 g of hollow glass microspheres, 10 g of silica powder, and 10 g of kaolin were stirred for 2 h using a three-roll mill as component B;

[0104] S3: Mix component A and component B and stir them thoroughly;

[0105] S4: The mixed material is injected into a mold and cured at 100° C. for 48 hours to finally obtain a heat-resistant and ablation-resistant silicone elastomer.

[0106] Fig.10 This is the open flame ablation test diagram of the prepared ablation-resistant elastomer. It can be seen from the figure that the prepared ablation-resistant silicone elastomer exhibits excellent heat resistance under 1000℃ alcohol burner ablation. The back temperature is only 95℃ after 5 minutes of ablation, and the back temperature does not exceed 250℃ after 30 minutes of ablation. At the same time, the overall shape of the elastomer remains intact after 30 minutes of ablation, without obvious cracking or breakage. It shows excellent ablation and heat resistance capabilities.

[0107] Example 6

[0108] (1) The preparation steps of silane-terminated polyether are as follows: under nitrogen protection, 1 mol of a hydroxy-terminated polypropylene oxide-ethylene oxide mixture with a molecular weight of 10,000, 2.2 mol of isocyanate propyltrimethoxysilane, and 5 wt% of a dibutyltin diisocyanate catalyst are added into a three-necked flask; then the temperature is slowly raised to 80° C. for reaction for 6 h, then the temperature is slowly raised to 120° C. for reaction for 4 h, then the temperature is lowered to 80° C., and unreacted trimethoxysilane is removed in vacuo at -0.1 MPa using an oil pump to obtain a light yellow transparent silane-terminated polyether.

[0109] (2) The preparation steps of hyperbranched silicone resin are as follows: 0.5 mol of phenyltrimethoxysilane and 0.5 mol of methyltrimethoxysilane and 150 g of dichloromethane are weighed respectively, and placed in a three-necked flask equipped with a condenser, a constant pressure dropping funnel and a thermometer, and mixed evenly, and then 1.3 mol of deionized water and 3 ml of 36.5% hydrochloric acid are added dropwise. After the addition is completed, reflux treatment is carried out at 70° C. for 12 h. After the reaction is completed, stirring is stopped, and by-products are removed by rotary evaporation at 60° C. to obtain phenyl hyperbranched silicone resin.

[0110] (3) The preparation method of the hyperbranched silicone modified polyether elastomer is as follows:

[0111] S1: 39.5 g of hyperbranched silicone resin and 0.5 g of dibutyltin disilicate were mixed and stirred for 30 min to obtain component A;

[0112] S2: 30 g of silane-terminated polyether, 10 g of ammonium polyphosphate, 10 g of red phosphorus, 10 g of decabromodiphenylethane, 10 g of antimony trioxide, 10 g of heavy calcium carbonate, 10 g of nano calcium carbonate and 10 g of talcum powder were stirred for 2 h using a three-roll mill as component B;

[0113] S3: Mix component A and component B and stir them thoroughly;

[0114] S4: The mixed material is injected into a mold and cured at 100° C. for 48 hours to finally produce a solvent-resistant, flame-retardant, high-strength silicone elastomer.

[0115] Example 7

[0116] (1) The preparation steps of silane-terminated polyether are as follows: under nitrogen protection, 1 mol of hydroxy-terminated polypropylene oxide with a molecular weight of 10,000, 2.2 mol of isocyanate propyltrimethoxysilane, and 5 wt% of dibutyltin diisocyanate catalyst are added into a three-necked flask; then the temperature is slowly raised to 80° C. for reaction for 6 h, then the temperature is slowly raised to 120° C. for reaction for 4 h, then the temperature is lowered to 80° C., and unreacted trimethoxysilane is removed in vacuo at -0.1 MPa using an oil pump to obtain a light yellow transparent silane-terminated polyether.

[0117] (2) The preparation steps of the hyperbranched silicone resin are as follows: 0.5 mol of chloromethyltrimethoxysilane and 0.5 mol of methyltrimethoxysilane and 150 g of chloroform are weighed respectively, and placed in a three-necked flask equipped with a condenser, a constant pressure dropping funnel and a thermometer, and mixed evenly, and then 1.3 mol of deionized water and 3 ml of 36.5% hydrochloric acid are added dropwise. After the addition is completed, the mixture is refluxed at 70° C. for 6 h. After the reaction is completed, stirring is stopped, and by-products are removed by rotary evaporation at 60° C. to obtain a flame retardant hyperbranched silicone resin.

[0118] (3) The preparation method of the hyperbranched silicone modified polyether elastomer is as follows:

[0119] S1: 39.5 g of hyperbranched silicone resin and 0.5 g of dibutyltin disilicate were mixed and stirred for 30 min to obtain component A;

[0120] S2: 40 g of silane-terminated polyether, 10 g of zirconium oxide, 10 g of aluminum hypophosphite, 10 g of light calcium carbonate, and 10 g of titanium dioxide were stirred for 2 h using a three-roll mill as component B;

[0121] S3: Mix component A and component B and stir them thoroughly;

[0122] S4: The mixed material is injected into a mold and cured at 100° C. for 48 hours to finally produce a flame-retardant high-strength silicone elastomer.

[0123] Example 8

[0124] (1) The preparation steps of silane-terminated polyether are as follows: under nitrogen protection, 1 mol of a hydroxy-terminated polyethylene oxide-propylene oxide mixture with a molecular weight of 10,000, 2.2 mol of isocyanate propyltrimethoxysilane, and 5 wt% of a dibutyltin diisocyanate catalyst are added into a three-necked flask; then the temperature is slowly raised to 80° C. for reaction for 6 h, then the temperature is slowly raised to 120° C. for reaction for 4 h, then the temperature is lowered to 80° C., and unreacted trimethoxysilane is removed in vacuo at -0.1 MPa using an oil pump to obtain a light yellow transparent silane-terminated polyether.

[0125] (2) The preparation steps of the hyperbranched silicone resin are as follows: 0.5 mol of phenyltrimethoxysilane and 0.5 mol of methyltrimethoxysilane and 150 g of chloroform are weighed respectively, and placed in a three-necked flask equipped with a condenser, a constant pressure dropping funnel and a thermometer, and mixed evenly, and then 1.3 mol of deionized water and 3 ml of 36.5% hydrochloric acid are added dropwise. After the addition is completed, the mixture is refluxed at 70° C. for 12 h. After the reaction is completed, stirring is stopped, and by-products are removed by rotary evaporation at 60° C. to obtain a temperature-resistant self-ceramic hyperbranched silicone resin.

[0126] (3) The preparation method of the hyperbranched silicone modified polyether elastomer is as follows:

[0127] S1: 39.5 g of hyperbranched silicone resin and 0.5 g of dibutyltin disilicate were mixed and stirred for 30 min to obtain component A;

[0128] S2: 70 g of silane-terminated polyether, 10 g of iron oxide red, 10 g of carbon black, 5 g of chopped glass fiber powder, and 5 g of magnesium hydroxide were stirred for 2 h using a three-roll mill as component B;

[0129] S3: Mix component A and component B and stir them thoroughly;

[0130] S4: The mixed material is injected into a mold and cured at room temperature for 7 days to finally produce an aging-resistant and temperature-resistant silicone elastomer.

[0131] Comparative Example 1

[0132] The remaining steps of this comparative example are the same as those of Example 1, except that the phenylmethyl hyperbranched silicone resin is replaced with methyltrimethoxysilane. Figure 5 The results show that the tensile strength of the cured material is only 0.8 MPa, and the elongation at break is only 262%, which is significantly lower than that of Example 1. This proves that the introduction of hyperbranched silicone resin into the construction of a new silicone elastomer has excellent mechanical properties.

[0133] Comparative Example 2

[0134] The remaining steps of this comparative example are the same as those of Example 1, except that the silane-terminated polyether is replaced with 107 silicone rubber. Figure 6 The results show that the tensile strength of the cured material is 5.56 MPa, but the elongation at break is only 49%, which is significantly lower than that of Example 1, proving that the introduction of silane-terminated polyether into the construction of a new silicone elastomer has excellent flexibility.

[0135] Comparative Example 3

[0136] The remaining steps of this comparative example are the same as those of Example 2, except that the vinylmethyl hyperbranched silicone resin is replaced with vinyltrimethoxysilane. Figure 7 It shows that the 5% thermal decomposition temperature of the cured material is only 311°C, the maximum thermal decomposition rate is as high as 1.7% / °C, and the residual carbon rate at 1000°C is only 5.3%. Compared with Example 2, the thermal stability and ablation resistance are greatly reduced, which proves that the introduction of hyperbranched silicone resin into the construction of a new silicone elastomer has excellent temperature resistance and ablation resistance.

[0137] Comparative Example 4

[0138] The remaining steps of this comparative example are the same as those of Example 2, except that trimethoxysilane is replaced by dimethoxysilane in the preparation step of silane-terminated polyether. The results show that the tensile strength of the cured material is 0.56 MPa, and the elongation at break is 230%, which is significantly lower than that of the material in Example 2, proving that the use of a trifunctional silane coupling agent as a capping agent in the material is conducive to improving the crosslinking density of the material, thereby obtaining a new silicone elastomer with excellent mechanical properties.

[0139] Comparative Example 5

[0140] The remaining steps of this comparative example are the same as those of Example 1, with the only difference being that in the preparation step of the silane-terminated polyether, isocyanate propyl trimethoxy silane was replaced with glycidyl ether propyl trimethoxy silane. As a result, it was found that the material could not be cured normally, and only a semi-cured gel material could be obtained. It was proved that isocyanate propyl trimethoxy silicon has a high reactivity, and its application as a capping agent in the material is conducive to the successful modification of the material to obtain a new type of silicone elastomer with excellent mechanical properties. The glycidyl ether group has a low reaction activity, resulting in a low reaction conversion rate, and therefore has a more obvious effect on the material properties.

[0141] Comparative Example 6

[0142] The remaining steps of this comparative example are the same as those of Example 3, except that the 36.5% hydrochloric acid solution is replaced with ammonia water in the preparation step of the hyperbranched silicone resin. The result shows that the obtained hyperbranched silicone resin is in a semi-gel state, has high viscosity and no fluidity, and solidifies rapidly in the air, has poor processing performance, and has no practical application value. It is proved that the catalytic activity of the alkaline catalyst is high in the synthesis process of the hyperbranched silicone resin, and the obtained hyperbranched silicone resin has poor practicality and cannot be used normally in the material.

[0143] Comparative Example 7

[0144] The remaining steps of this comparative example are the same as those of Example 3, with the only difference being that in the step of preparing the hyperbranched silicone resin, the 36.5% concentration hydrochloric acid solution is replaced with acetic acid. It is found that when the obtained hyperbranched silicone resin is used as component A for the preparation of silicone elastomer, the tensile strength of the obtained material is only 1 MPa, and the elongation at break is only 100%, which is significantly lower than that of the material in Example 3. This proves that the catalytic activity is low when acetic acid is used as a catalyst, and the obtained hyperbranched silicone resin has a low degree of polymerization, resulting in a low degree of cross-linking of the material after curing, and poor material performance.

[0145] Comparative Example 8

[0146] The remaining steps of this comparative example are the same as those of Example 1, except that the addition amount of the hyperbranched silicone resin is adjusted to 5 g. As a result, it is found that the tensile strength of the obtained material is only 0.2 MPa, the elongation at break is only 50%, the 5% decomposition temperature is only 270°C, the residual carbon rate at 1000°C is only 6.5%, and the maximum thermal decomposition rate exceeds 3% / °C, which proves that the mechanical properties and temperature resistance of the material are significantly affected when the addition amount of the hyperbranched silicone is low.

[0147] Comparative Example 9

[0148] The remaining steps of this comparative example are the same as those of Example 1, with the only difference being that the silane-terminated polyether is adjusted to 5 g. It is found that the obtained material has a tensile strength of 8 MPa, but an elongation at break of only 8%, proving that when the amount of silane-terminated polyether added is low, the material exhibits hard plastic properties and loses its original excellent elasticity and toughness.

[0149] The performance comparison of different formulation systems of the above embodiments and comparative examples is shown in Table 1 below.

[0150] Table 1 Performance comparison of different formulation systems in various embodiments and comparative examples

[0151]

Claims

1. A hyperbranched silicone-modified high-strength polyether-type ablation-resistant elastomer, characterized in that: It comprises component A and component B, wherein the mass percentage of component A and component B is 10-90%:90-10%; The A component includes the following raw materials in parts by weight: hyperbranched silicone resin: 100-25 parts; catalyst: 0-5 parts, excluding 0; flame retardant filler: 0-70 parts; ablation resistant filler: 0-70 parts; reinforcing filler: 0-70 parts; The B component includes the following raw materials in parts by weight: 100 to 25 parts of silane-terminated polyether; Catalyst: 0-5 parts; flame retardant filler: 0-70 parts; ablation resistant filler: 0-70 parts; reinforcing filler: 0-70 parts.

2. The hyperbranched silicone-modified polyether high-strength ablation-resistant elastomer according to claim 1, characterized in that: The structural formula of the hyperbranched silicone resin is: Wherein, R is one or more combinations of methyl, phenyl, vinyl, chloromethyl, glycidyl ether propyl, and R' is methyl.

3. The hyperbranched silicone-modified polyether high-strength ablation-resistant elastomer according to claim 2, characterized in that: The preparation steps of the hyperbranched silicone resin are: mixing a coupling agent containing an R or R' functional group in the structural formula and a solvent, then adding water and a hydrochloric acid solution to react, and removing byproducts after the reaction is completed to obtain the hyperbranched silicone resin.

4. The hyperbranched silicone-modified polyether high-strength ablation-resistant elastomer according to claim 3, characterized in that: The coupling agent is phenyltrimethoxysilane and methyltrimethoxysilane, or phenyltrimethoxysilane and vinyltrimethoxysilane, or methyltrimethoxysilane, or vinyltrimethoxysilane and methyltrimethoxysilane, or chloromethyltrimethoxysilane and methyltrimethoxysilane.

5. The hyperbranched silicone-modified polyether elastomer according to claim 1, characterized in that: The structural formula of the silane-terminated polyether is: Wherein, R is one of methyl, ethyl, and isopropyl, and R' is one of carbon-carbon bond (CC) and carbamate bond (-NHCOO-).

6. The hyperbranched silicone-modified polyether elastomer according to claim 5, characterized in that: The preparation steps of the silane-terminated polyether are as follows: a high molecular weight polyether, a catalyst and a terminal hydrogen-containing or terminal isocyanate silane coupling agent containing the R or R' functional group in the structural formula are mixed and reacted, and impurities are removed after the reaction is completed to obtain the polyether.

7. The hyperbranched silicone-modified polyether elastomer according to claim 6, characterized in that: The molar ratio of the high molecular weight polyether to the coupling agent is 1:(2-3); the added amount of the catalyst is 0.05wt%-5wt%.

8. The hyperbranched silicone-modified polyether elastomer according to claim 6, characterized in that: The high molecular weight polyether is at least one of hydroxyl-terminated polyethylene oxide, hydroxyl-terminated polypropylene oxide, vinyl-terminated polyethylene oxide, and vinyl-terminated polypropylene oxide; the molecular weight of the high molecular weight polyether is 1,000 to 100,000.

9. The hyperbranched silicone-modified polyether high-strength ablation-resistant elastomer according to claim 6, characterized in that: The catalyst is at least one of stannous octoate, dibutyltin dilaurate, dioctyltin dilaurate, tetrabutyl titanate, and tetraethyl titanate.

10. A method for preparing the hyperbranched silicone modified high-strength polyether type ablation-resistant elastomer according to claim 1, characterized in that: The following steps are involved: (1) adding a catalyst to a hyperbranched silicone resin and stirring to obtain a component A; (2) using silane-terminated polyether as component B; (3) The raw materials of component A and component B are uniformly mixed and cured to obtain the hyperbranched silicone modified polyether elastomer.

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