A high temperature resistant alkoxyl-containing silicon-silane hybrid resin and a method of making the same

Abstract

The application provides a high-temperature-resistant alkoxyl-containing silicon-silane hybrid resin and a preparation method thereof. Specifically, the silicon-silane hybrid resin is prepared by a Grignard reagent method in three steps. The process flow is simple, the prepared novel silicon-silane hybrid resin introduces alkoxyl, and after curing, the novel silicon-silane hybrid resin has excellent high-temperature resistance, good mechanical properties and film-forming property.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials. Specifically, this invention relates to a high-temperature resistant alkoxy-containing silylene hybrid resin and its preparation method. Background Technology

[0002] The development of high-temperature resistant polymers is closely related to the needs of aerospace technology, and they can be used in many fields as thermal protection materials and structural-thermal integrated materials. Silynylene hybrid resins are a class of thermosetting materials whose main chain contains silicon, carbon-carbon triple bonds, and benzene rings. The abundant presence of carbon-carbon triple bonds in the main chain enables cross-linking to form a three-dimensional network structure during the curing reaction, resulting in outstanding heat resistance. Furthermore, this resin has good processability, with no small molecule release during the curing reaction, exhibiting excellent high-temperature resistance, ablation resistance, high ceramicity, low dielectric constant, and low dielectric loss. It can be widely used as a high-temperature resistant and insulating material in aerospace, nuclear power, and other fields.

[0003] Traditional silylene hybrid resins contain a large number of rigid groups such as benzene rings, resulting in highly brittle cured products. Japanese researchers Itoh et al. synthesized a silylene hybrid (MSP) resin with the structure -Si(R)HC≡C-Ar-C≡C- using condensation polymerization, which exhibits excellent heat resistance. However, the high brittleness of cured MSP resin and its poor bonding with fibers mean that while it possesses good heat resistance, it cannot simultaneously achieve good mechanical properties. This limits the practical applications of MSP resin, making it difficult to use in aerospace, high-temperature load-bearing components, and other fields.

[0004] Zhou Quan et al. from East China University of Science and Technology invented a method for preparing a carborane-modified hyperbranched polycarbosilane ceramic precursor (patent number CN 201711368871), which can effectively improve the high temperature resistance of the material. However, the raw materials for this material are expensive and difficult to obtain, which greatly limits the application of this material.

[0005] This invention employs the Grignard reagent method, reacting phenylacetylene with alkoxy polysiloxane to form an organic-inorganic hybrid system. This improves the high-temperature resistance of the siloxyacetylene hybrid resin while mitigating its shortcomings of low flexibility and high brittleness in cured products, thus meeting the requirements for next-generation high-temperature resistant materials. The characteristics of the phenylacetylene / alkoxy polysiloxane resin are as follows: Currently, there are no reports on phenylacetylene / alkoxy polysiloxane resins available domestically or internationally. Summary of the Invention

[0006] One object of the present invention is to provide a high-temperature resistant alkoxy-containing silylene hybrid resin and a method for preparing the same.

[0007] In a first aspect of the invention, a high-temperature resistant alkoxy-containing silylene hybrid resin is provided, the resin having the structure shown in Formula I:

[0008]

[0009] Where: n is a positive integer from 1 to 100, and each R1 is independently C 1-10 Alkyl group, each R2 is independently a hydroxyl group, C 1-10 Alkyl or phenyl;

[0010] The number-average molecular weight of the alkoxy-containing silylene hybrid resin is 2000-15000.

[0011] In another preferred embodiment, each R1 is independently C. 1-6 Alkyl group, each R2 is independently a hydroxyl group, C 1-6 Alkyl or phenyl.

[0012] In another preferred embodiment, n is a positive integer from 10 to 80; more preferably, it is a positive integer from 20 to 70.

[0013] In a second aspect of the present invention, a method for preparing the high-temperature resistant alkoxy-containing silylene hybrid resin described in the first aspect of the present invention is provided, comprising the following steps:

[0014] In an inert solvent, phenylethynyl magnesium bromide reacts with an alkoxy-containing polysiloxane to obtain the high-temperature resistant alkoxy-containing silylethynyl hybrid resin described in the first aspect of this invention.

[0015] In another preferred embodiment, the method has one or more of the following features:

[0016] (i) The equivalent ratio of the phenylethynyl magnesium bromide to the alkoxy group in the alkoxy-containing polysiloxane is 1:(2-3);

[0017] (ii) The reaction temperature is 60±5℃ after the addition is complete;

[0018] (iii) The reaction time is 2-5 hours.

[0019] In another preferred embodiment, the method further includes a post-treatment, wherein the post-treatment is to cool to room temperature, add an acidic solution dropwise, separate the layers, concentrate under reduced pressure, and obtain the high-temperature resistant alkoxy-containing silylene hybrid resin of claim 1.

[0020] In another preferred embodiment, the acidic solution is a dilute hydrochloric acid solution; more preferably, it is a 5 wt% dilute hydrochloric acid solution.

[0021] In another preferred embodiment, the method for preparing phenylacetylene-based magnesium bromide includes the following steps:

[0022] (1) In an inert solvent, in the presence of a catalyst, bromoethane reacts with magnesium to produce ethyl magnesium bromide;

[0023] (2) In an inert solvent, the ethyl magnesium bromide reacts with phenylacetylene to generate phenylacetyl magnesium bromide.

[0024] In another preferred embodiment, the catalyst is iodine.

[0025] In another preferred embodiment, each step of the reaction is carried out under a dry, inert atmosphere.

[0026] In another preferred embodiment, the alkoxy-containing polysiloxane has the structure described in Formula II:

[0027]

[0028] Where: n is a positive integer from 1 to 100, and each R1 is independently C 1-10 Alkyl group, each R2 is independently a hydroxyl group, C 1-10 Alkyl or phenyl; and the molecular weight of the polysiloxane is 300-900.

[0029] In another preferred embodiment, the alkoxy-containing polysiloxane is selected from the group consisting of: methoxyhydroxy polysiloxane, methoxymethyl polysiloxane, ethoxyhydroxy polysiloxane, or combinations thereof.

[0030] In another preferred embodiment, step (1) has one or more of the following features:

[0031] (i) The molar ratio of bromoethane to magnesium is 1:(1.2-1.5);

[0032] (ii) The inert solvent is selected from the group consisting of C2-C6 ether solvents, C2-C6 ketone solvents, or combinations thereof;

[0033] (iii) The reaction temperature is 60±5℃;

[0034] (iv) The reaction time is 1.5-3 hours.

[0035] In another preferred embodiment, the inert solvent is selected from the group consisting of tetrahydrofuran, diethyl ether, or combinations thereof.

[0036] In another preferred embodiment, step (2) has one or more of the following features:

[0037] (i) The molar ratio of ethyl magnesium bromide to phenylacetylene is (2-3):1;

[0038] (ii) The reaction temperature is 60±5℃;

[0039] (iii) Reaction time: 1-3 hours.

[0040] In another preferred embodiment, the following steps are included:

[0041] (a) Under the protection of a dry, inert gas, a mixed solution a of bromoethane and an inert solvent is slowly added dropwise to a container containing iodine and magnesium. The temperature is controlled at 25±5℃ during the dropwise addition. After the dropwise addition is completed, the temperature is raised to react and the first mixture is obtained.

[0042] (b) Under the protection of a dry, inert gas, a mixed solution b of phenylacetylene and an inert solvent was added dropwise to the first mixture cooled to room temperature. The temperature was controlled at 25±5℃ during the dropwise addition. After the dropwise addition was completed, the temperature was raised to react and a second mixture was obtained.

[0043] (c) Under the protection of dry, inert gas, a mixed solution c of alkoxy-containing polysiloxane and inert solvent is added dropwise to the second mixture cooled to room temperature. The temperature is controlled at 25±5℃ during the dropwise addition. After the dropwise addition is completed, the temperature is raised to react. After post-treatment, the alkoxy-containing silyl yne hybrid resin is obtained.

[0044] In a third aspect of the invention, a cured product of the silylene hybrid resin described in the first aspect of the invention is provided, the cured product being obtained by curing the high-temperature resistant alkoxy-containing silylene hybrid resin described in the first aspect of the invention.

[0045] In another preferred embodiment, the curing refers to temperature gradient curing.

[0046] In another preferred embodiment, the temperature gradient refers to 200℃ / 2h-250℃ / 2h-300℃ / 4h-350℃ / 4h.

[0047] In another preferred embodiment, the solidified material is subjected to a nitrogen atmosphere at a T d5 The temperature is 626-650℃; the temperature in air is T d5 The temperature is 524-550℃.

[0048] In another preferred embodiment, the cured product has a silane hybrid resin content of 87-90% under a nitrogen atmosphere and 18-22% under an air atmosphere at 1000°C.

[0049] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Detailed Implementation

[0050] Through long-term and in-depth research, the inventors have developed for the first time an alkoxy-containing silane-yne ​​hybrid resin. This invention employs the Grignard reagent method, involving a three-step reaction. Step 1: Bromoethane reacts with magnesium shavings under the catalysis of iodine to generate ethyl magnesium bromide; Step 2: Ethyl magnesium bromide reacts with phenylacetylene to generate phenylacetylene-based magnesium bromide; Step 3: Phenylacetylene-based magnesium bromide reacts with an alkoxy-containing polysiloxane, followed by post-treatment to obtain the final high-temperature resistant silane-yne ​​hybrid resin. This invention features a simple process flow, and the novel silane-yne ​​hybrid resin, by introducing alkoxy groups, exhibits excellent high-temperature resistance, good mechanical properties, and film-forming properties after curing, showing promising application prospects in aerospace, silicone coatings, and other fields. Based on this, this invention was completed.

[0051] the term

[0052] As used in this article, the term "room temperature" refers to 0-40°C, preferably 15-35°C.

[0053] As used herein, the term "alkyl" refers to a straight-chain, branched, or cyclic alkyl group, preferably a C1-10 alkyl group, more preferably a C1-6 alkyl group. In this invention, the alkyl group also includes groups in which one or more H atoms on the alkyl group are substituted by substituents selected from the group consisting of halogens, substituted or unsubstituted phenyl groups, and unsubstituted or substituted C1-6 alkyl groups. It should be understood that the term also includes C3-10 substituted or unsubstituted cycloalkyl groups.

[0054] This invention addresses the drawback of high brittleness after curing in current silylene hybrid resins by designing and synthesizing a class of silylene hybrid resins with excellent high-temperature resistance and mechanical properties, starting from molecular structure design. This resin contains a large number of carbon-carbon triple bonds and alkoxy groups, which can undergo polymerization reactions under the influence of heat, light, radiation, and other energies to form a cross-linked network polymer. The presence of silicon (Si) significantly improves the polymer's temperature resistance, ablation resistance, and oxidation resistance. The alkoxy groups can mitigate the high brittleness of the cured resin and enhance the polymer's mechanical properties.

[0055] Preparation method of high temperature resistant alkoxy-containing silyl yne hybrid resin

[0056] A high-temperature resistant alkoxy-containing silylene hybrid resin, comprising the following steps:

[0057] The first step of the reaction: bromoethane reacts with magnesium in the presence of iodine to produce ethyl magnesium bromide.

[0058] The invention is characterized by the following: the molar ratio of bromoethane to magnesium is 1:(1.2-1.5); the temperature is controlled at 25±5℃ during the slow droplet addition of the bromoethane solution; the reaction temperature is 60±5℃ after the droplet addition is completed; and the reaction time is 1.5-3 hours.

[0059] The second step of the reaction involves the reaction of ethyl magnesium bromide with phenylacetylene to produce phenylacetylene-based magnesium bromide. The molar ratio of ethyl magnesium bromide to phenylacetylene is (2-3):1. The temperature during the dropwise addition of the phenylacetylene solution is 25±5℃, the reaction temperature is 60±5℃, and the reaction time is 1-3 hours after the dropwise addition is completed.

[0060] The third step involves reacting phenylacetylene-based magnesium bromide with an alkoxy-containing polysiloxane, followed by post-treatment to obtain the final silylene hybrid resin, phenylacetylene / alkoxy polysiloxane resin, with the following structural formula:

[0061]

[0062] Where: n is a positive integer from 1 to 100, and each R1 is independently C 1-10 Alkyl group, each R2 is independently a hydroxyl group, C 1-10 Alkyl or phenyl.

[0063] The molar ratio of phenylethynyl magnesium bromide to alkoxy groups in alkoxy-containing polysiloxanes is 1:(2-3). The temperature is controlled at 25±5℃ during the dropwise addition of the alkoxy polysiloxane solution. After the dropwise addition is complete, the reaction temperature is 60±5℃ and the reaction time is 2-5 hours.

[0064] The process of this invention is simple, and the novel silylene hybrid resin prepared by the invention introduces alkoxy and carbon-carbon triple bonds. After curing, it has excellent high-temperature resistance, good mechanical properties and film-forming properties. It can be used to prepare high-performance composite materials, high-temperature resistant resin coatings, etc., and has good application prospects in aerospace, nuclear power, organosilicon coatings and other fields.

[0065] Compared with the prior art, the main advantages of the present invention are as follows:

[0066] (1) At room temperature, the high-temperature resistant alkoxy-containing silylene hybrid resin of the present invention is an orange-yellow liquid with good solubility in low-boiling-point and low-polarity solvents.

[0067] (2) The preparation process of the high-temperature resistant alkoxy-containing silylene hybrid resin of the present invention is simple, and it is cured by condensation reaction under the action of heat, light or chemical action;

[0068] (3) The alkoxy-containing silylene hybrid resin of the present invention has excellent high temperature resistance, good processability and film-forming properties.

[0069] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. Percentages and parts are by weight unless otherwise stated.

[0070] Example 1

[0071] Under dry, high-purity nitrogen protection, 4.90 g of magnesium shavings and 0.10 g of iodine were added to a 500 ml four-necked flask (dry, high-purity nitrogen protection). A solution of 22.70 g of bromoethane and 42 g of tetrahydrofuran was added dropwise using a constant pressure funnel. The temperature was controlled at 25 °C during the dropwise addition. After the dropwise addition was completed, the temperature was raised to 63 °C and the reaction was carried out for 2 hours.

[0072] After the solution cooled, 20.40 g of phenylacetylene was mixed with 33 g of tetrahydrofuran solution and added dropwise together, with the temperature controlled at 25 °C during the process. After the addition was completed, the temperature was raised to 63 °C and the reaction was carried out for 2 hours.

[0073] After the solution was cooled, 64.80 g of methoxyhydroxy polysiloxane was mixed with 142.50 g of tetrahydrofuran and added dropwise slowly, while controlling the solution temperature at 25 °C. Then the temperature was raised to 63 °C and the reaction was allowed to proceed for 2 hours.

[0074] After the reactant solution cooled to room temperature, 120g of 5% dilute hydrochloric acid solution was added dropwise, and the mixture was stirred thoroughly until the solution separated into layers. After standing, the upper oil phase was washed with water until neutral, dried to remove water, and then subjected to vacuum distillation to remove all solvent, yielding the desired product.

[0075] A portion of the product was placed in a ceramic crucible and cured in a muffle furnace according to the following stepped heating program: 200℃ / 2h-250℃ / 2h-300℃ / 4h-350℃ / 4h. After the muffle furnace cooled to room temperature, the cured product was obtained.

[0076] FTIR: 2873cm -1 (-OCH3), 2962cm -1 (Si-C), 2163cm -1 (-C≡C-), 1061cm -1 (Si-O-Si).

[0077] DSC: Curing exothermic peak 366℃.

[0078] TGA: The thermal decomposition temperature (T) of the alkoxy-containing silylene hybrid resin cured product of the present invention under air and nitrogen. d5 The mass retention rates at 526.6℃ and 626.1℃ and 1000℃ were 21.5% and 88.0%, respectively.

[0079] Example 2

[0080] Under dry, high-purity nitrogen protection, 4.90 g of magnesium shavings and 0.10 g of iodine were added to a 500 ml four-necked flask (dry, high-purity nitrogen protection). A solution of 22.70 g of bromoethane and 42 g of tetrahydrofuran was added dropwise using a constant pressure funnel. The temperature was controlled at 25 °C during the dropwise addition. After the dropwise addition was completed, the temperature was raised to 63 °C and the reaction was carried out for 2 hours.

[0081] After the solution cooled, 20.40 g of phenylacetylene was mixed with 33 g of tetrahydrofuran solution and added dropwise together, with the temperature controlled at 25 °C during the process. After the addition was completed, the temperature was raised to 63 °C and the reaction was carried out for 2 hours.

[0082] After the solution was cooled, 45g of methoxymethyl polysiloxane and 82.50g of tetrahydrofuran solution were slowly added dropwise while the temperature was controlled at 25℃. Then the temperature was raised to 63℃ and the reaction was allowed to proceed for 2 hours.

[0083] After the reactant solution cooled to room temperature, 120g of 5% dilute hydrochloric acid solution was added dropwise, and the mixture was stirred thoroughly until the solution separated into layers. After standing, the upper oil phase was washed with water until neutral, dried to remove water, and the solvent was removed by vacuum distillation to obtain the desired product. A portion of the product was placed in a ceramic crucible and cured in a muffle furnace according to the following stepped heating program: 200℃ / 2h - 250℃ / 2h - 300℃ / 4h - 350℃ / 4h. After the muffle furnace cooled to room temperature, the cured product was obtained.

[0084] FTIR: 2874cm -1 (-OCH3), 2963cm -1 (Si-C), 2163cm -1 (-C≡C-), 1261cm -1 (Si-CH3), 1060cm -1 (Si-O-Si).

[0085] DSC: Curing exothermic peak 370℃.

[0086] TGA: The thermal decomposition temperature (T) of the alkoxy-containing silylene hybrid resin cured product of the present invention under air and nitrogen. d5 The mass retention rates at 524.1℃ and 629.6℃ were 21.29% and 87.66% at 1000℃, respectively.

[0087] Example 3

[0088] Under dry, high-purity nitrogen protection, 4.90 g of magnesium shavings and 0.10 g of iodine were added to a 500 ml four-necked flask (dry, high-purity nitrogen protection). A solution of 22.70 g of bromoethane and 42 g of tetrahydrofuran was added dropwise using a constant pressure funnel. The temperature was controlled at 25 °C during the dropwise addition. After the dropwise addition was completed, the temperature was raised to 63 °C and the reaction was carried out for 2 hours.

[0089] After the solution cooled, 20.40 g of phenylacetylene was mixed with 33 g of tetrahydrofuran solution and added dropwise together, with the temperature controlled at 25 °C during the process. After the addition was completed, the temperature was raised to 63 °C and the reaction was carried out for 2 hours.

[0090] After the solution was cooled, 64.80 g of ethoxyhydroxy polysiloxane and 142.50 g of tetrahydrofuran solution were slowly added dropwise while the temperature was controlled at 25 °C. Then the temperature was raised to 63 °C and the reaction was allowed to proceed for 2 hours.

[0091] After the reactant solution cooled to room temperature, 120g of 5% dilute hydrochloric acid solution was added dropwise, and the mixture was stirred thoroughly until the solution separated into layers. After standing, the upper oil phase was washed with water until neutral, dried to remove water, and the solvent was removed by vacuum distillation to obtain the desired product. A portion of the product was placed in a ceramic crucible and cured in a muffle furnace according to the following stepped heating program: 200℃ / 2h - 250℃ / 2h - 300℃ / 4h - 350℃ / 4h. After the muffle furnace cooled to room temperature, the cured product was obtained.

[0092] TGA: The thermal decomposition temperature (T) of the alkoxy-containing silylene hybrid resin cured product of the present invention under air and nitrogen. d5 The mass retention rates at 529.5℃ and 640.1℃ and 1000℃ were 18.99% and 88.78%, respectively.

[0093] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A method for preparing a high-temperature resistant alkoxy-containing silylene hybrid resin of formula (I), characterized in that, The method comprises the following steps: In an inert solvent, phenylacetylenyl magnesium bromide reacts with alkoxy-containing polysiloxane to obtain high-temperature-resistant alkoxy-containing silay hybrid resin shown in formula (I); wherein: n is a positive integer from 1 to 100, each R1is independently C 1-10 alkyl, each R2is independently hydroxy, C 1-10 alkyl, or phenyl; The alkoxy-containing silay hybrid resin has a number average molecular weight of 2,000-15,000. The alkoxy-containing polysiloxane has a structure shown in formula II: wherein: n is a positive integer from 1 to 100, each R1is independently C 1-10 alkyl, each R2is independently hydroxy, C 1-10 alkyl or phenyl; and the molecular weight of the polysiloxane is from 300 to 900; The equivalent ratio of phenylacetylenyl magnesium bromide to alkoxy in the alkoxy-containing polysiloxane is 1:(2-3); the reaction temperature after dropping is 60±5℃; and the reaction time is 2-5h.

2. The method of claim 1, wherein, each R1is independently C 1-6 alkyl, each R2is independently hydroxy, C 1-6 alkyl or phenyl.

3. The method of claim 1, wherein, n is a positive integer of 10-80.

4. The method of claim 1, wherein, n is a positive integer of 20-70.

5. The method of claim 1, wherein, The method further comprises post-treatment, wherein the post-treatment is cooling to room temperature, dropping an acidic solution, layering, and concentrating under reduced pressure to obtain the high-temperature-resistant alkoxy-containing silay hybrid resin of claim 1.

6. The method of claim 1, wherein, The method for preparing the phenylacetylenyl magnesium bromide comprises the following steps: (1) In an inert solvent, bromoethane reacts with magnesium in the presence of a catalyst to generate ethyl magnesium bromide; (2) In an inert solvent, the ethyl magnesium bromide reacts with phenylacetylene to generate phenylacetylenyl magnesium bromide.

7. The method of claim 1, wherein, The alkoxy-containing polysiloxane is selected from the group consisting of methoxyhydroxyl polysiloxane, methoxymethyl polysiloxane, ethoxyhydroxyl polysiloxane, or a combination thereof.

8. The method of claim 6, wherein, In step (1), one or more of the following features is present: (i) The molar ratio of bromoethane to magnesium is 1:(1.2-1.5); (ii) The inert solvent is selected from the group consisting of C2-C6 ether solvents, C2-C6 ketone solvents, or a combination thereof; (iii) The reaction temperature is 60±5℃; (iv) The reaction time is 1.5-3h.

9. The method of claim 6, wherein, In step (2), one or more of the following features is present: (i) The molar ratio of ethyl magnesium bromide to phenylacetylene is (2-3):1; (ii) The reaction temperature is 60±5℃; (iii) The reaction time is 1-3h.

10. The method of claim 1, wherein, The method comprises the following steps: (a) Under the protection of dry and inert gas, a mixed solution a of bromoethane and an inert solvent is slowly dropped into a container containing iodine and magnesium, the temperature is controlled at 25±5℃ during the dropping process, after the dropping is completed, the temperature is raised for reaction to obtain a first mixture; (b) Under the protection of dry and inert gas, a mixed solution b of phenylacetylene and an inert solvent is dropped into the first mixture cooled to room temperature, the temperature is controlled at 25±5℃ during the dropping process, after the dropping is completed, the temperature is raised for reaction to obtain a second mixture; (c) Under the protection of dry and inert gas, a mixed solution c of alkoxy-containing polysiloxane and an inert solvent is dropped into the second mixture cooled to room temperature, the temperature is controlled at 25±5℃ during the dropping process, after the dropping is completed, the temperature is raised for reaction, and after post-treatment, the alkoxy-containing silay hybrid resin is obtained.

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