CN1709928A - Siloxane containing aryne resin - Google Patents

Abstract

The invention relates to a kind of arylenealkyne resin containing siloxanes. The said resin makes diethynylene benzene (DEB) and silicon alkyl chloride as raw materials, firstly make use of the reaction of magnesium and alkyl bromide to produce Grignard reagent, then react with DEB to produce alkyne Grignard reagent; then react with silicon alkyl chloride, finally hydrolyze and condense in alkaline water liquor, or extend chain with siloxanes chloride, to form a kind of arylenealkyne resin containing siloxanes of new-style structure. The resin designed and synthesized by the invention has good processing property, and can be solidified into crosslinked resin of good thermostability under heat, light or radiative condition. Besides it has good machine capability, electric insulation capability and ceramic performance. So it can be used as the base material of high performance compound material resin, insulation material, the ceramic precursors and so on, and also has wide application prospect in such high technology fields as spaceflight, aviation, navigation and so on.

Description

Siloxane containing aryne resin

technical field

The present invention relates to a thermosetting resin, in particular to a silicone-containing aryne resin.

Background technique

Alkyne-containing resin (especially aryne resin) is a kind of heat-resistant resin developed and used in recent years. It does not need solvent during the molding process, and no small molecules escape during the curing process. It can be molded under normal or low pressure. The pyrolysis temperature of the cured resin is above 500°C, and the pyrolysis carbonization rate is as high as 80-86%. 50-60% of the currently used phenolic resin composite material, and has a compact structure and excellent ablation resistance. However, the rigidity of the cured resin is too high, resulting in unsatisfactory mechanical properties. Therefore, the modification of alkyne-containing resins (especially aryne resins) has become a research hotspot.

In the 1980s, Naval Research Laboratory TMKeller and others began to study high-temperature-resistant organosiloxane-based unsaturated resins, such as introducing alkyl alkynes into the main chain of ≡Si-O-Si≡-based polymers. Polymer-{-≡-≡-Si(Me) ₂ -[-O-Si(Me) ₂ -] _n } _x [(a) DYSon and TMKeller, Macromolecules 1995, 28, 399; (b) G. Burillo , Polym.Bull.1986, 16, 257; (c) DRParnell, J.Polym.Sci.Polym.Chem.Ed.1973, 11, 1107.], its relative average molecular weight is about 10,000. This type of polymer can be cured at 289-315°C. After curing, the polymer begins to degrade at 400°C in an air atmosphere. The residual rate is 60% at 1000°C, and 74% when there is a protective atmosphere. In addition, they have done a lot of related modification work, but the final performance of the material has not been significantly improved [(a) LJHenderson and TMKeller, Macromolecules 1994, 27, 1660; (b) D.Bucca, TMKeller , J.Polym.Sci.Part A: Polym.Chem.1999, 37, 4356; (c) DYSon, TMKeller, J.Polym.Sci.Part A: Polym.Chem.1995, 33, 2969; (d) RASundar, TMKeller, J.Polym.Sci.Part A: Polym.Chem.1997, 35, 2387; (e) D.Bucca, TMKeller, J.Polym.Sci.Part A: Polym.Chem.1997, 35, 1033; (f ) D. Bucca, TM Keller, Polym. Prepr. 1995, 36, 114.]. Du Zuodong of Shandong University and others tried to synthesize phenylethynyl dimethylchlorosilane by Grignard reagent method, butyl lithium method and metal sodium method respectively, and then synthesized the compound PhC≡C-Si(Me) ₂ -O- Si(Me) ₂ -C≡CPh [Chen Jianhua, Du Zuodong, Organic Chemistry of Silicon, in "Silicon chemistry", Ed by ERCorey, JYCorey and PPGaspar, Halsted Press (John Wiley & Sons): Oxford, 1988, Chapter 10, p105 .], and its structure was characterized accordingly. However, this resin is not suitable as a material, because the curing and crosslinking reaction temperature of the resin with phenylacetylene as the terminal group is very high, and it is not easy to process and shape; in addition, even if the resin is cured and crosslinked at a very high temperature, the The properties of the resulting material were also poor.

Contents of the invention

The present invention designs and synthesizes a silicone-containing aryne resin based on molecular structure design. In the resin of the present invention, it contains aryl acetylene groups, which can undergo polymerization reaction under the action of heat, radiation or light to form highly cross-linked polymers; and the presence of siloxane segments also endows The polymer has good flexibility and high temperature ceramic performance. Therefore, this type of polymer has excellent heat resistance and weather resistance after curing and crosslinking, and can undergo ceramicization reaction at high temperature (800-1800° C.) to form a silicon-containing ceramic material.

The aryne resin containing siloxane in the present invention has a structure as shown in formula (1).

(1) In the formula: R ₁ is C ₆ H ₅ ; R ₂ is C ₆ H ₅ or CH ₃ ; k=0~3, n=0~3.

The method for preparing the aryne resin containing siloxane of the present invention comprises the steps:

1) Preparation of Bromoethane Grignard Reagent and Diethynylphenyl Grignard Reagent

The synthesis reaction is as follows:

(2)

(3)

(4)

Bromoethane Grignard reagent synthesis:

Add bromoethane solution in tetrahydrofuran (THF) suspension containing magnesium powder dropwise, the molar ratio of bromoethane to magnesium powder is 1.0:1.0～1.5 (preferably 1.0:1.1～1.3); control solution bromoethane With a concentration of 3-5mol/L THF, add a small amount of iodine crystals to initiate the reaction, and control the reaction at 0-30°C. After the dropwise addition, heat to 60-66°C and react for 2 hours to obtain bromoethane Grignard reagent [Formula (2 ) shown compound]. The whole preparation process is carried out under the protection of inert gas (chemically stable gas, such as: nitrogen, helium or argon, etc.).

Synthesis of Diethynylphenyl Grignard Reagent:

Under stirring and cooling in an ice bath, in tetrahydrofuran solution (concentration 3 ~5mol/L THF) was added dropwise with the bromoethane Grignard reagent synthesized above. After dropping, react at 60-66° C. for 2 hours to obtain the compound represented by formula (3) or formula (4).

Wherein: the molar ratio of bromoethane and diethynylbenzene is 1.00～2.50: 1.00 (preferably 1.05～2.00: 1.00), and the whole preparation process is in an inert gas (chemically stable gas, such as: nitrogen, helium or argon) etc.) under protection.

2) Synthesis of aryne resin containing siloxane

Firstly, react the tetrahydrofuran solution of diphenyldichlorosilane with the diethynylbenzene Grignard reagent [compound represented by formula (3) or/and formula (4)] prepared in step 1) at 60-66°C for 2 Hours, different compounds can be obtained. Wherein the molar ratio of diethynylphenyl Grignard reagent to diphenyldichlorosilane is 1.00:1.00～2.50 (preferably 1.00:1.05～1.60), and the THF solution concentration of diphenyldichlorosilane is controlled at 3～5mol/L THF, the whole reaction process is carried out under the protection of inert gas (chemically stable gas, such as: nitrogen, helium or argon, etc.). Then the obtained compound is hydrolyzed with a sodium hydroxide or potassium hydroxide aqueous solution with a concentration of 0.5-1.25N to obtain a hydrolyzate, and the hydrolyzate is condensed at 70-80°C for 2-3 hours or in a mixed solvent composed of tetrahydrofuran and pyridine Reaction with dimethyldichlorosilane or diphenyldichlorosilane or dichloropolysiloxane, its dosage (moles) will be 1/2 of the above-mentioned diphenyldichlorosilane used, after the reaction finishes, use Extract with toluene, then wash the organic toluene layer with deionized water until neutral, and evaporate the solvent to obtain the target compound [its structure is shown in formula (1)].

Among the raw materials and reagents involved in the above preparation method, all are commercially available except diethynylbenzene. The diethynylbenzene mentioned in the present invention refers to 1,3-diethynylbenzene or 1,4-diethynylbenzene or their mixtures. For the preparation method, refer to British Patent GB1313524, US Patents US 4,997,991 and US 4,120,909.

The siloxane-containing aryne resin designed and synthesized by the present invention has the following characteristics:

1) The process performance is good, soluble in many common solvents, and easy to apply; the resin is easy to cure, the curing temperature is low and the heat release is also low; 2) the acetylene group can be cured under the action of heat, radiation, or even light. 3) No small molecules are released when the resin is cured; 4) The structure and molecular size of the synthesized resin can be controlled by molecular design; 5) The cured resin has good Excellent mechanical properties and excellent chemical resistance; 6) The cured resin can undergo ceramic reaction.

In summary, the resin described in the present invention can be made into a material with excellent heat resistance, ablation resistance, and insulation through self-polymerization or copolymerization with other resins, and has broad application prospects in the fields of aviation and aerospace. .

Detailed ways

Be that the present invention is further described by example below, and its purpose is to better understand content of the present invention. Therefore, the examples given do not limit the protection scope of the present invention.

Embodiment 1

Soak the magnesium powder with 5% dilute hydrochloric acid for 2-3 minutes, and then filter with suction; then wash with deionized water three times, and filter with suction; wash with absolute ethanol for three times, and filter with suction; finally wash with petroleum ether for three times, and filter with suction After drying, the magnesium powder that can be used can be obtained. The 500ml four-necked round-bottomed flask equipped with constant pressure funnel, spherical condenser, ventilation tube/thermometer and stirrer was evacuated and filled with nitrogen, and replaced like this three times; under nitrogen protection, 3.0g (0.12 mol) magnesium powder and a small amount of iodine crystals, and then add 30ml of tetrahydrofuran (treated with sodium metal to remove water and oxygen), and stir evenly. Add 10.9g (0.10mol) bromoethane and 30ml tetrahydrofuran (THF, dried over sodium metal) mixed solution into the constant pressure funnel, start to drop bromoethane/THF mixed solution, stir rapidly, about 1/5 of the mixed liquid After continuously dropping into the flask, the reaction is exothermic, and then the remaining mixed solution is added dropwise at a rate of about 1/2 drop/second, while cooling with ice water. It can be seen that the reaction system changes from the original light brown yellow to iron gray, and gradually becomes turbid. After the dropwise addition, react under heating in an oil bath at 60-66°C for 2 hours to obtain the Grignard reagent of ethyl bromide.

Add 30ml of tetrahydrofuran and 0.095mol of 1,3-diethynylbenzene into a four-neck round-bottomed flask equipped with a constant pressure funnel, a spherical condenser, a vent tube/thermometer and a stirrer, and the bromoethane Grignard reagent prepared above Transfer to a constant pressure funnel under the protection of nitrogen, add dropwise under the conditions of stirring and cooling in an ice-water bath, and react under heating in an oil bath at 60-66°C for 2 hours to obtain the diethynylbenzene Grignard reagent.

Add 30ml of tetrahydrofuran and 24.03 grams (0.095mol) of diphenyldichlorosilane into a 500ml four-necked flask, and add the above-prepared diethynylbenzene Grignard reagent dropwise under nitrogen protection. The reaction was carried out under heating in an oil bath for 2 hours. After the reaction was completed, an aqueous potassium hydroxide solution with a certain concentration of 1.25N was added dropwise to the flask under cooling in an ice-water bath, and the hydrolysis reaction was carried out at a temperature of 75° C. in an oil bath for 2 hours. Then add toluene 30ml for extraction and separation, and wash with deionized water until neutral, remove the solvent with a rotary evaporator to obtain a reddish-brown liquid resin (its structure is shown in formula (5)), the productive rate is 55.4%, and the viscosity at normal temperature Below 400cp.

The infrared spectrum of the resin was measured by coating film method: Si-O-Si absorption peak appeared at 1085cm ^-1 , and acetylene triple bond and acetylene hydrogen absorption peaks appeared at 3291cm ^-1 and 2159cm ^-1 .

Example 2

The 500ml four-neck round-bottomed flask equipped with a 100ml constant pressure funnel, spherical condenser, vent tube/thermometer and stirrer was vacuumized and filled with nitrogen, and replaced like this three times; under nitrogen protection, 3.0g ( 0.12mol) of magnesium powder and a small amount of iodine crystals treated (same as in Example 1), and then 30ml of tetrahydrofuran (dried over sodium metal) was added, and stirred evenly. Add 0.10 mol ethyl bromide and 30 ml tetrahydrofuran (THF, treated with sodium metal to remove water and oxygen) mixture into the constant pressure funnel, start adding bromide/THF mixture dropwise to the flask, and stir rapidly, during which you can see The reaction system changed from light brownish yellow to iron gray, and gradually became turbid. After the dropwise addition, react under heating in an oil bath at 60-66°C for 2 hours to obtain the Grignard reagent of ethyl bromide.

Add 30ml tetrahydrofuran and 0.0713mol diethynylbenzene (1,3-diethynylbenzene and 1,4-di ethynylbenzene mixture), the bromoethane Grignard reagent prepared above was transferred to a constant pressure funnel under nitrogen protection, and added dropwise under stirring and cooling in an ice-water bath. The reaction was carried out for 2 hours under heating in an oil bath to obtain the diethynylphenyl Grignard reagent.

Add 30ml of tetrahydrofuran and 0.095mol of diphenyldichlorosilane into a 500ml four-neck flask, add the above-prepared diethynylbenzene Grignard reagent dropwise under the protection of nitrogen, and heat it in an oil bath at 60-66°C React for 2 hours. After the reaction was completed, a certain concentration of 1.25N potassium hydroxide aqueous solution was added dropwise to the flask under cooling in an ice-water bath, and then hydrolyzed for 2 hours at a temperature of 75° C. in an oil bath. Then add about 30ml of toluene for extraction and separation, take the organic layer and wash with deionized water until neutral, remove the solvent with a rotary evaporator to obtain a reddish-brown liquid resin (its structure is shown in formula (6)), and the yield is 73.5 %. The relative molecular weight of the resin measured by GPC is 1169, and the viscosity at room temperature is 490cp.

The infrared spectrum of the resin was measured by coating method: Si-O-Si absorption peak at 1085cm ^-1 , alkyne absorption peak at 2159cm ^-1 , and alkyne hydrogen absorption peak at 3291cm ^-1 .

Example Three

Vacuumize a 500ml four-necked round-bottomed flask equipped with a 100ml constant pressure funnel, spherical condenser, vent tube/thermometer and stirrer, then fill it with nitrogen to dehumidify and deoxygenate, and add 0.12mol of magnesium powder to the four-necked flask under nitrogen protection and a small amount of iodine crystals, and then add 30ml of tetrahydrofuran (dried over sodium metal), and stir evenly. Add 0.10 mol of bromoethane and 30 ml of tetrahydrofuran mixture dropwise through a constant pressure funnel, and cool with an ice-water bath while dropping. During the period, it can be seen that the reaction system changes from the original light brown yellow to iron gray, and gradually becomes turbid. After the dropwise addition, react under heating in an oil bath at 60-66°C for 2 hours to obtain the Grignard reagent of ethyl bromide.

Add 30ml of tetrahydrofuran and 0.0633mol of 1,3-diethynylbenzene in a four-neck round-bottomed flask equipped with a constant pressure funnel, a spherical condenser, a vent tube/thermometer, and a stirrer, and the bromoethane Grignard reagent prepared above Transfer it to a constant pressure funnel under the protection of nitrogen, and drop it into the flask under stirring and cooling in an ice bath. After the drop is completed, react for 2 hours under heating in an oil bath at 60-66°C to obtain the diethynylphenyl Grignard reagent .

Add 30ml of tetrahydrofuran and 0.095mol of diphenyldichlorosilane into a 500ml four-neck flask, add the above-prepared diethynylbenzene Grignard reagent dropwise under the protection of nitrogen, and heat it in an oil bath at 60-66°C React for 2 hours. After the reaction was completed, a certain concentration of 1.25N potassium hydroxide aqueous solution was added dropwise to the flask under cooling in an ice bath, and then hydrolyzed at a temperature of 75° C. in an oil bath for 2 hours. Then add about 30ml of toluene for extraction and separation, and wash with deionized water until neutral, and remove the solvent with a rotary evaporator to obtain a reddish-brown liquid resin (its structure is shown in formula (7)), with a yield of 57.9%. The viscosity is about 500cp.

Infrared spectroscopic analysis of the resin was measured by coating film method: Si-O-Si absorption peak at 1082cm ^-1 , alkyne absorption peak at 2160cm ^-1 , and alkyne hydrogen absorption peak at 3294cm ^-1 .

Embodiment 4

Vacuumize a 500ml four-necked round-bottomed flask equipped with a 100ml constant pressure funnel, spherical condenser, vent tube/thermometer and stirrer, then fill it with nitrogen to dehumidify and deoxygenate, and add 0.12mol of magnesium powder to the four-necked flask under nitrogen protection and a few iodine crystals, then add 30ml of tetrahydrofuran (dried over sodium metal), and stir well. Add 0.10 mol of bromoethane and 30 ml of tetrahydrofuran mixture dropwise through a constant pressure funnel, and cool with an ice-water bath while dropping. During this period, it can be seen that the reaction system changes from the original light brown yellow to iron gray, and gradually becomes turbid. After the dropwise addition, react under heating in an oil bath at 60-66°C for 2 hours to obtain the Grignard reagent of ethyl bromide.

Add 30ml of tetrahydrofuran and 0.095mol of 1,3-diethynylbenzene into a four-neck round-bottomed flask equipped with a constant pressure funnel, a spherical condenser, a vent tube/thermometer and a stirrer, and the bromoethane Grignard reagent prepared above Transfer it to a constant pressure funnel under the protection of nitrogen, and drop it into the flask under stirring and cooling in an ice bath. After the drop is completed, react for 2 hours under heating in an oil bath at 60-66°C to obtain the diethynylphenyl Grignard reagent .

Add 30ml of tetrahydrofuran and 0.095mol of diphenyldichlorosilane into a 500ml four-neck flask, add the above-prepared diethynylbenzene Grignard reagent dropwise under the protection of nitrogen, and heat it in an oil bath at 60-66°C React for 2 hours. After the reaction is over, add a certain amount of 0.5N sodium hydroxide aqueous solution dropwise to the flask under cooling in an ice bath. After reacting for 2 hours at room temperature, add about 30ml of toluene to extract and separate, and wash with deionized water until neutral. ,dry. Then dissolve and dilute with 20ml THF, add dropwise a mixture of 0.048mol dichlorodimethylsilane (or bis-(dichlorodimethylsiloxy) dimethylsilane) and 20ml pyridine, and react at 75°C oil bath temperature After 3 to 4 hours, wash with water, add a small amount of 10ml toluene to extract the organic phase, continue to wash with deionized water until neutral, and evaporate the solvent after drying to obtain an orange-yellow viscous liquid resin (its structure is shown in formula (8)), The yield is about 70%.

The infrared spectrum of the resin is measured by the coating method: near 2900cm ^-1 , the hydrocarbon CH stretching vibration-absorption peak on _CH3 appears; the vibration absorption peak of the alkyne triple bond exists at 2158cm ^-1 ; and it appears at 1076cm ^-1 The characteristic absorption peak of -Si-O-Si-.

Example 5

The resin obtained by Example 1～Example 4 can be miscible in acetone, THF, toluene, chloroform, methylene dichloride, carbon tetrachloride, dimethylsulfoxide, dimethylformamide, dimethylacetamide, N -Solvents such as methylpyrrolidone, ethyl acetate, ether, toluene, etc., insoluble in non-polar solvents such as n-hexane, petroleum ether, etc. The resin can be cured above 200°C.

The resin obtained in Example 2 is cured in an oven at 130°C/1hr+150°C/1hr+180°C/2.5h+200°C/2hr+250°C/2hr and then post-treated at 300°C/2hr+350°C/2hr , to obtain a dense and hard brown cured product, the thermal stability of the cured resin is excellent, the initial thermal decomposition temperature is measured by TGA analysis (10°C/min), and its initial thermal decomposition temperature is above 400°C, and the residual rate under nitrogen atmosphere at 800°C is 81.9 %; The residual rate in the air is 29.0%. The cured resin is raised to 400°C at a heating rate of 5-10°C/min, and then raised to 1300°C. It is kept for 5-12 hours under anaerobic or low-oxygen conditions, and the white substance of the sintered product, that is, the cured resin produces ceramics at high temperatures. reaction.

It can be seen that siloxane-containing aryne resin is a new type of heat-resistant resin matrix with great potential. It has good processing performance and can be used as a precursor for advanced composite material resin matrix, high-performance insulating materials and advanced ceramic materials.

Claims (5)

1, a kind of aryne resin containing siloxane, its structure is as shown in the following formula:

In the formula: R ₁ is C ₆ H ₅ ; R ₂ is C ₆ H ₅ or CH ₃ ; k=0~3, n=0~3. 2. The aryne resin according to claim 1, wherein n=0, k=0. 3. The aryne resin according to claim 1, wherein n=1, k=0. 4. The aryne resin according to claim 1, wherein n=0, k=1. 5. The aryne resin according to claim 1, wherein R ₂ is CH ₃ , n=0, k=3.