Modified tetraphenylacetylene silane resin prepolymer and preparation method thereof

Abstract

The invention discloses a modified tetraphenylacetylene silane resin prepolymer and a preparation method thereof. Specifically, the invention discloses a modified tetraphenylacetylene silane resin prepolymer which is of a three-dimensional network structure and has a repeated structural unit shown in the specification. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the field of organic synthetic polymer materials, and in particular relates to a modified tetraphenylethynylsilane resin prepolymer and a preparation method thereof. Background Art

[0002] With the rapid development of aerospace technology in recent years, the scientific and technological needs in the field of high-speed aircraft have put forward higher requirements for polymer materials. Pure polymer organic materials can no longer meet today's complex application requirements. Organic-inorganic hybrid technology provides a new way for the design, preparation and application of high-performance polymer materials. Organic-inorganic hybrid materials prepared by introducing inorganic elements into polymer structures have superior performance.

[0003] At present, the most typical silanylene resin is a silanylene resin containing a silicon-hydrogen bond. The resin has good processing properties, no by-products are generated during the curing reaction, and it exhibits excellent properties such as high temperature resistance, low dielectric constant and high-temperature ceramicization. It can be used in the fields of high heat resistance, ablation resistance, wave transmission and ceramic materials. Silanylene resins can usually self-cure at high temperatures, forming a -C=CC=C- structure through a silane addition reaction or a naphthalene ring structure through a Diels-Alder reaction. Silanylene resins can be prepared into high-performance composite materials with glass fibers, which have good thermal and dielectric properties. However, due to their high curing temperature, they usually need to be carried out under conditions above 350°C, and complete curing requires a high temperature of more than 400°C. There are many restrictions on the molding process and application scenarios, and the energy consumption is relatively high. Pure silanylene hybrid resins are difficult to meet the requirements of contemporary molding and processing, so other methods are needed to further reduce their curing temperature and energy consumption.

[0004] In view of this, there is an urgent need in the art to develop silane resins with lower curing temperatures and excellent physical properties. Summary of the invention

[0005] An object of the present invention is to provide a modified tetraphenylethynylsilane resin prepolymer having a low curing temperature and excellent physical properties.

[0006] In the first aspect of the present invention, a modified tetraphenylethynylsilane resin prepolymer is provided, wherein the prepolymer is made of tetraphenylethynylsilane and Sydney ketone; the prepolymer is a three-dimensional network structure and has a repeating structural unit as shown below:

[0007]

[0008] Wherein, R represents phenyl,

[0009] Silicon atoms The connection structure indicating this site is omitted, and this site is a structure produced by the reaction of the phenylethynyl group or the alkynyl group in the phenylethynyl group with the five-membered heterocyclic part in Sydney ketone.

[0010] In another preferred embodiment, the number average molecular weight Mn of the prepolymer is 4000-6000; and / or the weight average molecular weight Mw is 7000-9000.

[0011] In another preferred embodiment, the number average molecular weight Mn of the prepolymer is 5000-6000; and / or the weight average molecular weight Mw is 8000-9000.

[0012] In another preferred embodiment, the number average molecular weight Mn of the prepolymer is 5235; and / or the weight average molecular weight Mw is 8907.

[0013] In the second aspect of the present invention, there is provided a method for preparing the modified tetraphenylethynylsilane resin prepolymer according to the first aspect of the present invention, comprising the following steps:

[0014] Sydney ketone reacts with tetraphenylethynylsilane in an organic polar solvent to obtain the modified tetraphenylethynylsilane resin prepolymer.

[0015] In another preferred embodiment, the reaction temperature is 120-180°C; preferably 140-180°C; more preferably 160-180°C.

[0016] In another preferred embodiment, the reaction time is 2 to 12 hours; preferably 4 to 8 hours.

[0017] In another preferred embodiment, the Sydney ketone has a structure selected from the following group:

[0018]

[0019] In another preferred embodiment, the molar ratio of tetraphenylethynylsilane to sydney ketone is 1:(1.5-2.5), preferably 1:2.

[0020] In another preferred embodiment, the organic polar solvent is selected from the following group: N,N-dimethylformamide, N-methylpyrrolidone, N,N-dimethylacetamide, or a combination thereof; preferably N-methylpyrrolidone.

[0021] In another preferred embodiment, the mass ratio of the tetraphenylethynylsilane to the organic polar solvent is 1:(15-20).

[0022] In another preferred embodiment, the method comprises:

[0023] Under the protection of inert gas, tetraphenylethynylsilane and sydney ketone are dissolved in an organic polar solvent in a molar ratio of 1:(1.5-2.5), and reacted at 120-180° C. for 2-12 hours to obtain the modified tetraphenylethynylsilane resin prepolymer.

[0024] In another preferred embodiment, the reaction is carried out with stirring.

[0025] In another preferred embodiment, the reaction further comprises: after the reaction is completed, cooling to room temperature (15-35° C.), adding a precipitant to the reaction solution to precipitate a solid, which is a modified tetraphenylethynylsilane resin prepolymer.

[0026] In another preferred embodiment, the precipitant is water, a C1-C6 alcohol solvent, or a combination thereof; preferably, it is one or more of water, methanol, and ethanol; more preferably, it is methanol.

[0027] In another preferred embodiment, the method further comprises post-treatment: filtering the precipitated solid, washing, and drying.

[0028] In another preferred embodiment, the washing refers to washing with water and / or ethanol.

[0029] In another preferred embodiment, the number of washing is multiple times (eg, 2, 3, or 4 times).

[0030] In the third aspect of the present invention, a cured product of the modified tetraphenylvinyl silane resin prepolymer described in the first aspect of the present invention is provided, wherein the cured product is obtained by curing the modified tetraphenylvinyl silane resin prepolymer described in the first aspect of the present invention.

[0031] In another preferred embodiment, the curing is temperature gradient curing.

[0032] In another preferred embodiment, the temperature gradient curing is 200°C / 2h+220°C / 2h+250°C / 2h+280°C / 5h.

[0033] In another preferred embodiment, the temperature gradient curing is 200°C / 2h+220°C / 2h+250°C / 2h+300°C / 5h.

[0034] In another preferred embodiment, the T of the solidified material under nitrogen atmosphere is d5 is 400-458℃; T d5 405-445℃;

[0035] Preferably, the T of the solidified material under nitrogen atmosphere is d5 is 437-458℃; T d5 It is 439-445℃.

[0036] In another preferred embodiment, the retention rate of the silicene hybrid resin of the cured product at 1000° C. in a nitrogen atmosphere is 55-73%; the retention rate of the silicene hybrid resin in an air atmosphere is 15-46%;

[0037] Preferably, the retention rate of the silicene hybrid resin of the cured product at 1000° C. in a nitrogen atmosphere is 69-73%; and the retention rate of the silicene hybrid resin in an air atmosphere is 38-46%.

[0038] In a fourth aspect of the present invention, a product is provided, wherein the product comprises a cured product of the modified tetraphenylethynylsilane resin prepolymer described in the first aspect of the present invention.

[0039] In another preferred embodiment, in the product, the proportion of the cured product of the modified tetraphenylethynylsilane resin prepolymer described in the first aspect of the present invention is ≥1%; preferably ≥10%, ≥20%, ≥30%, ≥40%, ≥50%, ≥60%, ≥70%, ≥80%, ≥90%, ≥95%, ≥99%.

[0040] It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described below (such as embodiments) can be combined with each other to form a new or preferred technical solution. Due to space limitations, they will not be described one by one here. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 shows the infrared spectrum of tetraphenylethynylsilane;

[0042] Figure 2 The H NMR spectrum of tetraphenylethynylsilane is shown;

[0043] Figure 3 The infrared spectrum of 3,3'-(1,4-phenyl)disydone is shown;

[0044] Figure 4 The H NMR spectrum of 3,3'-(1,4-phenyl)disydone is shown;

[0045] Figure 5 The infrared spectrum of the modified tetraphenylacetylene silicone resin is shown;

[0046] Figure 6 GPC of modified tetraphenylethynylsilane resin prepolymer is shown;

[0047] Figure 7 The DSC spectra of tetraphenylethynylsilane before and after prepolymerization are shown. DETAILED DESCRIPTION

[0048] After extensive and in-depth research, the inventors introduced Sydney ketone into the structure of silane for the first time, and obtained a modified tetraphenylethynylsilane resin prepolymer with a curing temperature below 280°C. Specifically, the present invention prepares a silane resin prepolymer containing a heterocyclic structure by cycloaddition reaction of Sydney ketone and tetraphenylethynylsilane resin, thereby greatly reducing the curing temperature and energy consumption and improving the processing performance. Based on this, the inventors completed the present invention.

[0049] the term

[0050] As used herein, the term "room temperature" refers to 0-40°C, preferably 15-35°C.

[0051] Sydney Ketone

[0052] Sydney ketone is a mesoionic compound with 1,3-dipole properties, which can undergo dipolar cycloaddition reactions with unsaturated compounds such as alkenes and alkynes. Sydney ketone compounds are five-membered heterocyclic compounds composed of O(1)-N(2)-N(3)C(4)-C(5), which belong to the non-benzene aromatic family. The charge distribution of each atom on the compound ring is quite special and cannot be represented by a single covalent structural formula, making its reaction unique.

[0053] Specifically, the Sydney ketone catalyst provided by the present invention has the structure shown below:

[0054]

[0055] Modified tetraphenylethynylsilane resin prepolymer and preparation method thereof

[0056] The curing of most silane resins relies on the self-curing reaction of triple bonds, and the structure is uncertain. The steric hindrance of the acetylene group in the structure is extremely large. However, by adding Sydney ketone, a new heterocyclic structure can be introduced, the structure is precise, and the curing temperature is greatly reduced, and the cross-linking degree is increased. Based on this, the inventors designed and developed a method for preparing a low-temperature cured modified silane resin prepolymer. The obtained cured product has good heat resistance, which provides convenience for the preparation of high-performance composite materials.

[0057] Tetraphenylethynylsilane resin

[0058] Specifically, the present invention reacts difunctional Sydney ketone with tetraphenylethynylsilane resin to prepare a low-temperature curing resin. Through the cycloaddition reaction, a heterocyclic structure is formed, which greatly reduces the curing temperature and energy consumption required for the complete curing of the resin, and the prepolymer is suitable for a variety of molding processes.

[0059] The modified tetraphenylethynylsilane resin prepolymer of the present invention has

[0060]

[0061] Specifically, the present invention provides a method for preparing the modified tetraphenylethynylsilane resin prepolymer, comprising the following steps:

[0062] In an inert atmosphere, in an organic polar solvent, sydney ketone and tetraphenylethynyl silane resin react at 120-180°C for 2-12 hours; after the reaction is completed, the reaction solution is cooled to room temperature, and the reaction solution is added to a precipitant, and the product precipitates, thereby obtaining a prepolymer of a low-temperature curing modified silylene resin.

[0063] In the present invention, sydney ketone and tetraphenylethynylsilane resin can react at any temperature between 120-180°C to obtain a prepolymer, for example, 120°C, 130°C, 140°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, etc.

[0064] In the present invention, the inert gas used is not particularly limited and can be any inert gas commonly used in the art, such as nitrogen, argon, and the like.

[0065] In the present invention, the reaction time is not particularly limited and can be any time between 2 and 12 hours for the reaction to occur; for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0066] In the present invention, the post-treatment of the reaction is a conventional post-treatment step, including: collecting solids by filtration, (multiple) washing, (vacuum) drying, etc.

[0067] In the present invention, the organic polar solvent refers to a solvent molecule having polar bonds, which is a polar molecule, so that these molecules have electrical polarity. The organic polar solvents suitable for the present invention include amide solvents, pyrrolidone solvents, etc.; for example: N, N-dimethylformamide, N-methylpyrrolidone, N, N-dimethylacetamide, etc.

[0068] In the present invention, the precipitant refers to a liquid that precipitates the prepolymer from the solution, for example, water or an alcohol solvent.

[0069] In one embodiment, the phenyl groups on the tetraphenylethynylsilane resin in the reaction may be optionally substituted by a group selected from the group consisting of halogen, cyano, amino, hydroxyl, C1-C3 alkyl, halogenated C1-C3 alkyl, C1-C3 hydroxyalkyl.

[0070] The melting point of tetraphenylethynylsilane is relatively high, and it cannot be completely cured at 400°C. The melting point of the modified tetraphenylethynylsilane resin is significantly reduced, and it can be completely cured at a lower temperature subsequently without the need for high-temperature post-treatment.

[0071] The prepolymerization temperature of the modified tetraphenylethynylsilane resin prepolymer obtained by the method of the present invention is lower than 200° C., while the curing temperature of acetylene silane in the art is usually higher than 350° C., and the curing temperature of the modified prepolymer of the present invention is lower than 300° C. The modification method of the present invention is significantly lower than the prepolymerization temperature, realizes low-temperature curing, reduces energy consumption, and the cured product obtained by curing has a precise structure, high yield, simple processing technology, and low curing temperature, and can be widely used in the fields of electronics, aerospace, high-performance composite materials, etc.

[0072] Compared with the prior art, the main advantages of the present invention include:

[0073] (1) The present invention is the first to use Sydney ketone to modify silane resin.

[0074] (2) The silane resin prepolymer modified by sydney ketone of the present invention has lower prepolymerization temperature and curing temperature, and the curing temperature is lower than 300° C., thereby reducing energy consumption.

[0075] (3) The present invention provides a method for preparing a novel low-temperature curing modified silane resin prepolymer. Compared with the traditional curing temperature of silane resin above 400°C, the prepolymer of the present invention breaks through the high steric hindrance of the internal acetylene group in tetraphenylethynylsilane, can be cured and molded at a lower temperature, reduces energy consumption, and is suitable for various molding processes, which is conducive to the preparation of various high-performance composite materials.

[0076] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples without specifying specific conditions are usually based on conventional conditions or the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are calculated by weight.

[0077] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein can be applied to the methods of the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only.

[0078] Example 1

[0079]

[0080] (1) 0.864 g of tetraphenylethynylsilane, 0.984 g of 3,3'-(1,4-phenyl)dimethylpyrrolidone, and 15 ml of N-methylpyrrolidone were added to a dry four-necked flask, heated to 170°C under nitrogen protection, and reacted for 4 hours under high-speed stirring. After the reaction was completed, the flask was cooled to room temperature.

[0081] (2) The product solution obtained in step (1) was poured into 200 ml of H2O, and a large amount of dark brown precipitate appeared. The precipitate was filtered and washed with deionized water and ethanol solution for several times, and dried to obtain a yellow solid, i.e., a low-temperature modified silylene resin prepolymer.

[0082] (3) After grinding the prepolymer in step (2), a small amount of THF was dissolved and coated on an aluminum plate, and heated in an oven at 50° C. for 30 min until the solvent was completely evaporated.

[0083] (4) Curing the sample obtained in step (3) in a muffle furnace by stepwise heating at 200°C / 2h+220°C / 2h+250°C / 2h+280°C / 5h, and cooling the muffle furnace to room temperature to obtain a cured product of the low-temperature curing modified silylene resin.

[0084] The cured product was subjected to TGA test in a nitrogen atmosphere and an air atmosphere at a heating rate of 10°C / min.

[0085] With the same formula and reaction temperature, the prepolymerization time was changed to prepare multiple solid samples. The thermal decomposition temperature (T d5 ) and 1000℃ mass retention rates are shown in the following table:

[0086]

[0087] Example 2

[0088] (1) 0.864 g of tetraphenylethynylsilane, 1.13 g of 3,3'-(1,4-phenyl)dimethylpyrrolidone, and 15 ml of N-methylpyrrolidone were added to a dry four-necked flask, heated to 180°C under nitrogen protection, and reacted for 2 h under high-speed stirring. After the reaction was completed, the flask was cooled to room temperature.

[0089] (2) The product solution obtained in step (1) was poured into 200 ml of ethanol, and a large amount of black precipitate appeared. The precipitate was filtered, and the filter residue was washed with deionized water and methanol for multiple times, and dried to obtain a dark yellow solid, i.e., the low-temperature modified silylene resin prepolymer.

[0090] (3) After grinding the prepolymer in step (2), a certain amount of THF was dissolved and coated on an aluminum plate, and heated in an oven at 50° C. for 30 min until the solvent was completely evaporated. The coating step was repeated three times.

[0091] (4) Curing the sample obtained in step (3) in a muffle furnace by stepwise heating at 200°C / 2h+220°C / 2h+250°C / 2h+300°C / 5h, and cooling the muffle furnace to room temperature to obtain a cured product of the low-temperature curing modified silylene resin.

[0092] The solidified product was subjected to TGA test in nitrogen atmosphere and air atmosphere at a heating rate of 10°C / min.

[0093] With the same formula and reaction temperature, a number of cured samples were prepared by changing the prepolymerization time. The thermal decomposition temperature (T d5 ) and 1000℃ mass retention rates are shown in the following table:

[0094]

[0095] Example 3

[0096] (1) 0.864 g of tetraphenylethynylsilane, 0.738 g of 3,3'-(1,4-phenyl)dimethylpyrrolidone, and 15 ml of N-methylpyrrolidone were added to a dry four-necked flask, heated to 160° C. under nitrogen protection, and reacted for 8 h under high-speed stirring. After the reaction was completed, the flask was cooled to room temperature.

[0097] (2) The product solution obtained in step (1) was poured into 200 ml of methanol, and a large amount of black precipitate appeared. The precipitate was filtered, and the filter residue was washed with deionized water and methanol for multiple times, and dried to obtain a brown solid, i.e., a low-temperature modified silylene resin prepolymer.

[0098] (3) After grinding the prepolymer in step (2), a small amount of DMF was dissolved and coated on an aluminum plate, and heated in an oven at 150° C. for 30 min until the solvent was completely evaporated.

[0099] (4) Curing the sample obtained in step (3) in a muffle furnace by stepwise heating at 200°C / 2h+220°C / 2h+250°C / 2h+280°C / 5h, and cooling the muffle furnace to room temperature to obtain a cured product of the low-temperature curing modified silylene resin.

[0100] The solidified product was subjected to TGA test in nitrogen atmosphere and air atmosphere at a heating rate of 10°C / min.

[0101] With the same formula and reaction temperature, the prepolymerization time was changed to prepare multiple solid samples. The thermal decomposition temperature (T d5 ) and 1000℃ mass retention rates are shown in the following table:

[0102]

[0103] All documents mentioned in the present invention are cited as references in this application, just as each document is cited as reference individually. In addition, it should be understood that after reading the above teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A modified tetraphenylethynylsilane resin prepolymer, characterized in that: The prepolymer is made of tetraphenylethynylsilane and sydney ketone as raw materials; the prepolymer is a three-dimensional network structure and has a repeating structural unit as shown below: Wherein, R represents phenyl, Silicon atoms The connection structure indicating this site is omitted, and this site is a structure produced by the reaction of the phenylethynyl group or the alkynyl group in the phenylethynyl group with the five-membered heterocyclic part in Sydney ketone.

2. The prepolymer according to claim 1, characterized in that The number average molecular weight Mn of the prepolymer is 4000-6000; and / or the weight average molecular weight Mw is 7000-9000.

3. A method for preparing the modified tetraphenylethynylsilane resin prepolymer according to claim 1, characterized in that: The steps include: Sydney ketone reacts with tetraphenylethynylsilane in an organic polar solvent to obtain the modified tetraphenylethynylsilane resin prepolymer.

4. The method according to claim 3, characterized in that The reaction temperature is 120-180°C, preferably 140-180°C, and more preferably 160-180°C.

5. The method according to claim 3, characterized in that The reaction time is 2 to 12 hours, preferably 4 to 8 hours.

6. The method according to claim 3, characterized in that The Sydney ketone has a structure selected from the group consisting of:

7. The method according to claim 3, characterized in that The molar ratio of tetraphenylethynylsilane to sydney ketone is 1:(1.5-2.5), preferably 1:

2.

8. The method according to claim 3, characterized in that The organic polar solvent is selected from the following group: N,N-dimethylformamide, N-methylpyrrolidone, N,N-dimethylacetamide, or a combination thereof; preferably N-methylpyrrolidone.

9. The method according to claim 3, characterized in that The method includes: Under the protection of inert gas, tetraphenylethynylsilane and sydney ketone are dissolved in an organic polar solvent in a molar ratio of 1:(1.5-2.5), and reacted at 120-180° C. for 2-12 hours to obtain the modified tetraphenylethynylsilane resin prepolymer.

10. A cured product of the modified tetraphenylethynylsilane resin prepolymer according to claim 1, characterized in that: The cured product is obtained by curing the modified tetraphenylethynylsilane resin prepolymer described in claim 1.

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