CN110283318B - Method for improving thermal stability of low-viscosity silicone oil by using silazane and metal oxide - Google Patents

Method for improving thermal stability of low-viscosity silicone oil by using silazane and metal oxide Download PDF

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CN110283318B
CN110283318B CN201811599380.XA CN201811599380A CN110283318B CN 110283318 B CN110283318 B CN 110283318B CN 201811599380 A CN201811599380 A CN 201811599380A CN 110283318 B CN110283318 B CN 110283318B
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silicone oil
metal oxide
low
temperature
viscosity
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CN110283318A (en
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伍川
荣瑞
张超
董红
瞿志荣
郭世平
苏锦华
苏丽
吕叶红
薛启浩
蒋攀
栾文耕
张伟伟
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Hangzhou Normal University
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/38—Polysiloxanes modified by chemical after-treatment
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/38—Polysiloxanes modified by chemical after-treatment
    • C08G77/382—Polysiloxanes modified by chemical after-treatment containing atoms other than carbon, hydrogen, oxygen or silicon
    • C08G77/388—Polysiloxanes modified by chemical after-treatment containing atoms other than carbon, hydrogen, oxygen or silicon containing nitrogen

Abstract

The invention relates to the field of organic chemistry, and provides a method for improving the thermal stability of low-viscosity silicone oil by using silazane and metal oxide in order to solve the problems that the existing silicone oil cannot be used at a high temperature and a low use temperature in an oxygen-free and aerobic environment. Under the protection of inert atmosphere and at a certain temperature, the metal oxide or the mixture thereof which is subjected to vacuum drying treatment is utilized to carry out heat treatment on the low-viscosity silicone oil, and the low-viscosity silicone oil which is subjected to metal oxide treatment is obtained after operations such as filtration, reduced pressure and low boiling removal; and further treating the low-viscosity silicone oil treated by the metal oxide by hexamethyldisilazane to obtain hexamethyldisilazane and modified silicone oil treated by the metal oxide. The thermal decomposition temperature of the prepared modified silicone oil in oxygen and air is obviously improved, and the method has the advantages of simple operation condition, simple steps and high yield of the modified silicone oil, and is very suitable for large-scale production.

Description

Method for improving thermal stability of low-viscosity silicone oil by using silazane and metal oxide
Technical Field
The invention relates to the field of organic chemistry, in particular to a method for improving the thermal stability of low-viscosity silicone oil by utilizing silazane and metal oxide.
Background
The silicone oil is a linear polysiloxane which is composed of repeated Si-O-Si chain links and keeps a liquid state at room temperature, and if organic functional groups connected to Si atoms are methyl, the silicone oil is called dimethyl silicone oil, and the chemical structural formula of the silicone oil is shown as a formula (I):
Figure BDA0001922004830000011
wherein Me represents methyl group, and x represents polymerization degree of polysiloxane.
When part of dimethylsiloxy units (-Me) in the polydimethylsiloxane molecule2The SiO-) is substituted by methyl phenyl silica chain link (-MePhSiO-) to obtain linear poly (dimethyl-methylphenyl) siloxane copolymer, called methyl phenyl silicone oil, the chemical structural formula of which is shown as formula (II):
Figure BDA0001922004830000012
in which Me represents methyl, Ph represents phenyl, X1And X2Respectively represent the degree of polymerization of dimethylsiloxy units and methylphenylsiloxy units.
With degree of polymerization X in the linear polydimethylsiloxane molecule or with degree of polymerization X of dimethylsiloxy units in the linear poly (dimethyl-methylphenyl) siloxane copolymer molecule1And degree of polymerization X of methylphenylsiloxy units2The viscosity of the silicone oil gradually increases.Silicone oils of different viscosities are used in various fields of the national economy, for example, silicone oils of high viscosity are used as base polymers for silicone greases, silicone creams, mold release agents, and silicone oils of low viscosity are used in the personal care industry such as cosmetics, hair shampoos, lipsticks, hand creams, etc. Compared with other synthetic polymers, the silicone oil has the characteristics of excellent high and low temperature resistance, low viscosity-temperature coefficient, low surface tension, physiological inertia, good chemical stability, good electrical insulation, weather resistance, hydrophobicity and the like, and can be used for a long time at the temperature of minus 50-200 ℃; in addition, the silicone oil has excellent physical characteristics, can be directly used for damp-proof insulation, damping, shock absorption, defoaming, lubrication, polishing and the like, is widely used as insulation lubrication, shock absorption, oil dust prevention, dielectric fluid and heat carrier, and is used as defoaming, mold release agent, paint and daily chemical additive.
However, when the temperature exceeds 175 ℃, polysiloxane molecules undergo a degradation reaction, and the degradation reaction of polysiloxane molecules is accelerated along with the increase of the temperature, so that the service life of the silicone oil at high temperature is shortened or the silicone oil cannot be used for a long time at the temperature of 250 ℃ or above. In an oxygen-free environment, the degradation reaction products of polysiloxane molecules are micromolecular cyclosiloxanes such as hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6) and the like, and the mechanism of the degradation reaction products mainly derives from the 'button type' degradation of the main chain of the polysiloxane molecules; in an aerobic environment, the organic functional group of the polysiloxane molecule side chain is oxidized to generate a free radical, the generated free radical further attacks other organic functional groups of the polysiloxane molecule side chain, and the polysiloxane is crosslinked while generating small molecular compounds such as alkane, aldehyde, ketone, acid and the like, so that the viscosity of the silicone oil is increased until finally a three-dimensional reticular gel is gradually formed, and the silicone oil loses the fluidity.
In order to improve the thermo-oxidative stability of silicone oils, US patent US4193885 discloses a method of adding to the silicone oil suitable amounts of compounds containing Ti, Zr, Hf which can be mixed with the silicone oil in the form of organo-siloxy derivatives of Ti, Zr, Hf; or mixing proper amount of organic derivatives of Ti, Zr and Hf with silicone oil, and heating to decompose the added organic derivatives; or mixing excessive Ti, Zr and Hf compounds with silicone oil to form the heat stable additive, and diluting the additive with additional silicone oil to obtain Ti, Zr and Hf compounds with proper concentration. The thermal stability of the silicone oil can be further improved by mixing the silicone oil containing Ti, Zr and Hf with a small amount of a compound containing Si-H. The heat-stable silicone oil disclosed by the invention is particularly suitable for being used as an organic heat carrier in an oxygen-free and water-free environment.
The silicone oil is not only used for heat transfer media in water-free and oxygen-free environments such as closed heating or cooling pipeline systems, but also widely used for heat transfer media in open systems such as chemistry, chemical engineering, pharmacy and polymer synthesis processing. Compared with an anhydrous and anaerobic environment, the silicone oil in an open system is more prone to cross-linking, gelation and curing at high temperature due to the fact that organic functional groups of molecular side chains are attacked by free radicals, so that the silicone oil loses fluidity, heat cannot be transferred, cross-linked products are heated and oxidized, smoke is generated, and even fire hazards are caused.
Although the technical solution disclosed in US patent 4193885 can effectively improve the thermal stability of silicone oil in an anhydrous and oxygen-free closed system, the technical solution uses expensive organic derivatives of Zr and Hf, resulting in increased cost; on the other hand, the solution disclosed in this patent is not suitable for improving the thermal performance of silicone oil in an aerobic, open system.
Disclosure of Invention
Compared with untreated silicon oil, the method for improving the thermal stability of the low-viscosity silicon oil by utilizing silazane and metal oxide obviously improves the thermal performance of the silicon oil prepared by the method in an anaerobic environment and an aerobic environment, and has the characteristics of low energy consumption, small environmental pollution, safety, environmental protection, high yield, easy solid-liquid separation, simple process and equipment, low production cost and the like.
The invention is realized by the following technical scheme: a method of improving the thermal stability of low viscosity silicone oils comprising the steps of:
(1) adding low-viscosity silicone oil and metal oxide into a reaction vessel under the protection of inert gas, stirring, and then heating up from room temperature for reaction to obtain a solid-liquid mixture;
the low-viscosity silicone oil is selected from dimethyl silicone oil or methyl phenyl silicone oil;
a low-viscosity silicone oil having a viscosity of 500mPa.s or less at 20 ℃, preferably 200mPa.s or less at 20 ℃; more preferably, the viscosity (20 ℃) of the low-viscosity silicone oil is less than or equal to 100 mPa.s.
The metal oxide is selected from ZnO and Al2O3、MgO、MnO2、CeO2The amount of the metal oxide is 0.5-15% of the mass of the low-viscosity silicone oil. Preferably, the metal oxide is selected from ZnO or CeO2When the metal oxide is selected from ZnO and CeO2In the presence of ZnO and CeO2The mass ratio of (A) to (B) is 0.01-1: 1, and the dosage of the metal oxide is 1-10% of the mass of the silicone oil.
Preferably, the metal oxide needs to be dried before use, the drying temperature is 105-160 ℃, and the drying time is 1-12 hours; more preferably, the drying temperature of the metal oxide before use is 110-150 ℃, and the drying time is 2-10 h. The drying is preferably vacuum drying with an absolute pressure of 10-5～3000Pa。
The reaction temperature of the mixture composed of the low-viscosity silicone oil and the metal oxide is 140-400 ℃, and the reaction time is 1-24 hours; preferably, the reaction temperature of the mixture of the low-viscosity silicone oil and the metal oxide is 200-350 ℃, and the reaction time is 6-20 h.
(2) Then cooling to room temperature, closing the inert gas, carrying out reduced pressure filtration on the solid-liquid mixture, collecting filtrate, transferring the filtrate to a reduction reaction kettle, carrying out low-boiling-point substance removal operation under the protection of the inert gas and stirring, cooling to room temperature after completion, closing the inert gas and stirring to obtain modified silicone oil treated by metal oxide;
(3) adding modified silicone oil treated by metal oxide into a reaction kettle, preserving heat, dropwise adding hexamethyldisilazane into the modified silicone oil under the protection of inert gas, and maintaining the reaction after dropwise adding;
the mass ratio of the hexamethyldisilazane to the modified silicone oil treated with the metal oxide is 0.01-0.30: 1, and preferably, the mass ratio of the hexamethyldisilazane to the silicone oil treated with the metal oxide is 0.03-0.20: 1.
The reaction temperature of the hexamethyldisilazane and the modified silicone oil treated by the metal oxide is-20-50 ℃, and preferably, the reaction temperature of the hexamethyldisilazane and the silicone oil treated by the metal oxide is 0-35 ℃.
The dropping time of the hexamethyldisilazane is 0.5-12 h, and the reaction maintaining time is 1-15 h, preferably, the dropping time of the hexamethyldisilazane is 1.0-10 h, and the reaction maintaining time is 2-12 h;
(4) and transferring the reaction mixture to a reduction reaction kettle, carrying out reduction operation under the protection of inert gas and stirring, cooling to room temperature, closing the inert gas and stirring to obtain the modified silicone oil treated by silazane and metal oxide.
The low-boiling-point substance removal operation temperature is 180-300 ℃, the holding time is 1-24 h, and the absolute pressure is 10-53000Pa, preferably 190-260 ℃ of low boiling point removal operation temperature, 2-16 h of holding time and 10 of pressure (absolute pressure)-32000Pa, which is used for removing residual small molecular compounds in the reaction product.
The inert gas is selected from argon or nitrogen; preferably, the inert gas is selected from nitrogen, having a purity greater than or equal to 99.9%.
Under the protection of inert atmosphere and a certain temperature, the low-viscosity dimethyl silicone oil or methyl phenyl silicone oil is subjected to heat treatment by using metal oxide or a mixture thereof, and after operations such as filtration, reduced pressure and low boiling removal and the like, the low-viscosity silicone oil treated by the metal oxide is obtained; and then further treating the low-viscosity silicone oil treated by the metal oxide by hexamethyldisilazane, and removing low-molecular compounds under the protection of inert gas to obtain hexamethyldisilazane and modified silicone oil treated by the metal oxide, so that the thermal stability of the low-viscosity silicone oil in an oxygen-free environment and an aerobic environment is improved.
Compared with the prior art, the invention has the beneficial effects that:
(1) the operation condition is simple, the steps are simple, and the yield is high;
(2) the modified silicone oil treated by hexamethyldisilazane and metal oxide has low decomposition rate in air and nitrogen, and has good thermal stability.
Detailed Description
The present invention is further illustrated by the following examples, which are not intended to limit the scope of the invention, and the starting materials used in the examples are commercially available or can be prepared by conventional methods.
Example 1
150g of a commercially available dimethylsilicone fluid having a viscosity (20 ℃) of 500mPa.s was charged into a 250mL three-necked flask equipped with a reflux condenser, mechanical stirring and a thermometer, 5g of ZnO powder subjected to vacuum drying at 130 ℃ for 9 hours was then added, and after introducing a slight amount of nitrogen gas (purity 99.9%) from a bottom-inserted tube, stirring was turned on, the temperature was gradually raised from room temperature to 280 ℃ and maintained at 280 ℃ for 14 hours. After cooling to room temperature, the nitrogen and stirring were turned off, the mixture in the three-necked flask was filtered under reduced pressure, and the filtrate was collected.
Transferring the collected filtrate to a device for removing low-boiling-point substances, introducing a trace amount of nitrogen (with the purity of 99.9 percent) for bubbling, and ensuring that the absolute pressure of the system reaches 10-3When Pa, gradually raising the temperature from room temperature to 250 ℃, and maintaining the temperature at 250 ℃ for 15h to remove low-boiling substances in the filtrate. And after the temperature of the kettle liquid is reduced to room temperature, stopping stirring, increasing the flow of nitrogen in the bottom inserting pipe, and after the pressure reduction and reduction system is recovered to normal pressure, collecting the kettle liquid to obtain the ZnO-treated low-viscosity dimethyl silicone oil.
Transferring 100g of prepared ZnO-treated low-viscosity dimethyl silicone oil into another three-neck flask with a stirring and reflux condensing device, reducing the temperature of the material to 0 ℃ under the protection of nitrogen, dropwise adding 3g of hexamethyldisilazane into the three-neck flask through a constant-pressure dropping funnel at a constant speed for 1h,after the addition, the temperature was maintained at 0 ℃ for 6 hours. After the pressure is restored to be constant, the materials in the kettle are transferred to another device for removing low-boiling-point substances, and a trace amount of nitrogen (with the purity of 99.9%) is introduced for bubbling until the system absolute pressure reaches 10-3And Pa, gradually raising the temperature from room temperature to 200 ℃, and maintaining the temperature at 200 ℃ for 2h to remove low-boiling substances in the filtrate. And after the temperature of the kettle liquid is reduced to room temperature, stopping stirring, increasing the flow of nitrogen in the bottom inserting pipe, and after the pressure reduction and reduction system is recovered to normal pressure, collecting the kettle liquid to obtain 95.1g of low-viscosity dimethyl silicone oil treated by hexamethyldisilazane and ZnO.
Thermogravimetric (TGA) experiments in air and nitrogen atmosphere were carried out on untreated low-viscosity dimethylsilicone oil and low-viscosity dimethylsilicone oil treated with hexamethyldisilazane and ZnO prepared in example 1 respectively by using Discovery TGA of TA company of America, the test temperature range was 40-800 ℃, the temperature rise rate was 10K/min, the flow rates of air and nitrogen were both 30mL/min, and the relative weight loss of each sample was 10% (Td)10)、20％(Td20) And 50% (Td)50) The corresponding temperatures are shown in table 1.
Example 2
150g of a commercially available methylphenyl silicone oil having a viscosity (20 ℃) of 20mPa.s and a phenyl content of 7 mol% was charged into a 250mL three-necked flask equipped with a reflux condenser, mechanical stirring and a thermometer, 10g of ZnO powder subjected to vacuum drying at 110 ℃ for 7 hours was then added, after introducing a slight amount of nitrogen gas (purity 99.9%) from a bottom-inserted tube, stirring was started, and the temperature was gradually raised from room temperature to 350 ℃ and maintained at 350 ℃ for 8 hours. After cooling to room temperature, the nitrogen and stirring were turned off, the mixture in the three-necked flask was filtered under reduced pressure, and the filtrate was collected.
Transferring the collected filtrate to a low-boiling-point substance removal device, introducing a trace amount of argon gas for bubbling, gradually raising the temperature from room temperature to 240 ℃ when the absolute pressure of the system reaches 1525Pa, and maintaining the temperature at 240 ℃ for 8 hours to remove the low-boiling-point substances in the filtrate. And after the temperature of the kettle liquid is reduced to room temperature, closing stirring, increasing the flow of argon in the bottom inserting pipe, and after the pressure reduction and reduction system is recovered to normal pressure, collecting the kettle liquid to obtain the ZnO-treated low-viscosity methyl phenyl silicone oil.
100g of the prepared ZnO-treated low-viscosity methylphenyl silicone oil was transferred to another three-neck flask with stirring and reflux condenser, after the temperature of the material was reduced to 20 ℃ under the protection of nitrogen (purity 99.9%), 8g of hexamethyldisilazane was added dropwise to the three-neck flask via a constant-pressure dropping funnel at a constant speed for 2h, and after the dropwise addition was completed, the mixture was maintained at 20 ℃ for 12 h. After the pressure is restored to be constant, the materials in the kettle are transferred to another low-boiling-point substance removing device, a small amount of argon is introduced for bubbling, when the absolute pressure of the system reaches 1525Pa, the temperature is gradually increased from room temperature to 230 ℃, and the temperature is maintained at 230 ℃ for 4 hours to remove the low-boiling-point substances in the filtrate. And after the temperature of the kettle liquid is reduced to room temperature, stopping stirring, increasing the flow of argon in the bottom inserting pipe, and after the pressure reduction and reduction system is recovered to normal pressure, collecting the kettle liquid to obtain 93.8g of low-viscosity methyl phenyl silicone oil treated by hexamethyldisilazane and ZnO.
Thermogravimetric (TGA) experiments in air and nitrogen atmosphere were carried out on untreated low-viscosity methylphenyl silicone oil and low-viscosity methylphenyl silicone oil treated with hexamethyldisilazane and ZnO prepared in example 2 respectively by using Discovery TGA of TA company of USA, the test temperature range was 40-800 ℃, the temperature rise rate was 10K/min, the flow rates of air and nitrogen were 30mL/min, and the relative weight loss of each sample was 10% (Td)10)、20％(Td20) And 50% (Td)50) The corresponding temperatures are shown in table 1.
Example 3
150g of a commercial dimethylsilicone fluid having a viscosity (20 ℃) of 50mPa.s was placed in a 250mL three-necked flask equipped with a reflux condenser, mechanical stirring and thermometer, and then 4g of ZnO powder subjected to vacuum drying at 150 ℃ for 2 hours and 10g of CeO subjected to vacuum drying at 150 ℃ for 4 hours were added2After introducing a trace amount of nitrogen (purity 99.9%) through the bottom-inserted tube, the powder was stirred, gradually warmed from room temperature to 220 ℃ and maintained at 220 ℃ for 10 hours. After cooling to room temperature, the nitrogen and stirring were turned off, the mixture in the three-necked flask was filtered under reduced pressure, and the filtrate was collected.
Transferring the collected filtrate to a low-boiling-point substance removal device, introducing a trace amount of nitrogen (with the purity of 99.9%) for bubbling, gradually raising the temperature from room temperature to 220 ℃ when the absolute pressure of the system reaches 10Pa, and maintaining the temperature at 220 ℃ for 10 hours to remove low-boiling-point substances in the filtrate. To-be-stirred tank liquorCooling to room temperature, closing stirring, increasing nitrogen flow in the bottom inserting tube, collecting kettle liquid after the reduced pressure reduction system returns to normal pressure to obtain ZnO and CeO2Treated low viscosity dimethylsilicone fluids.
100g of prepared ZnO and CeO2The treated low-viscosity dimethyl silicone oil is transferred into another three-neck flask with a stirring and reflux condensing device, 20g of hexamethyldisilazane is dropwise added into the three-neck flask at a constant speed for 10h through a constant-pressure dropping funnel after the temperature of the materials is maintained at 30 ℃ under the protection of nitrogen (the purity is 99.9%), and the temperature is maintained for 7h at 30 ℃ after the dropwise addition. After the pressure is restored to be constant, the materials in the kettle are transferred to another device for removing low-boiling-point substances, and a trace amount of nitrogen (with the purity of 99.9%) is introduced for bubbling until the system absolute pressure reaches 10-3When Pa, gradually raising the temperature from room temperature to 220 ℃, and maintaining the temperature at 220 ℃ for 6h to remove low-boiling substances in the filtrate. After the temperature of the kettle liquid is reduced to room temperature, the stirring is closed, the nitrogen flow in the bottom inserting pipe is increased, after the pressure reduction and reduction system is recovered to the normal pressure, the kettle liquid is collected, and 87.9g of the kettle liquid is obtained after hexamethyldisilazane, ZnO and CeO are added2Treated low viscosity dimethylsilicone fluids.
Hexamethyldisilazane and ZnO and CeO obtained in example 3 were applied to untreated low-viscosity dimethylsilicone oil by Discovery TGA of TA of USA2Performing Thermogravimetric (TGA) experiments on the treated low-viscosity dimethylsilicone oil in air and nitrogen atmosphere, wherein the testing temperature range is 40-800 ℃, the heating rate is 10K/min, the flow rates of air and nitrogen are both 30mL/min, and the relative weight loss of each sample is 10% (Td)10)、20％(Td20) And 50% (Td)50) The corresponding temperatures are shown in table 1.
Example 4
150g of a commercial dimethylsilicone fluid having a viscosity (20 ℃) of 10mPa.s were placed in a 250mL three-necked flask with reflux condenser, mechanical stirring and thermometer, and 20g of Al treated with vacuum drying at 140 ℃ for 5h were added2O3After introducing a trace amount of nitrogen (purity 99.9%) into the powder through a dip tube, the mixture was stirred and gradually warmed from room temperature to 250 ℃ and maintained at 250 ℃ for 18 hours. After cooling to room temperature, the nitrogen and the stirring are turned off, and the flask is placed in a three-neck flaskThe mixture was filtered under reduced pressure and the filtrate was collected.
The collected filtrate was transferred to a low boiling substance removal device, a trace amount of nitrogen (purity 99.9%) was bubbled, and when the system absolute pressure reached 0.01Pa, the temperature was gradually raised from room temperature to 230 ℃, and maintained at 230 ℃ for 3 hours to remove low boiling substances from the filtrate. After the temperature of the kettle liquid is reduced to room temperature, the stirring is closed, the flow of nitrogen in the bottom inserting pipe is increased, after the pressure reduction and reduction system is recovered to normal pressure, the kettle liquid is collected, and Al is obtained2O3Treated low viscosity dimethylsilicone fluids.
100g of prepared Al2O3And transferring the treated low-viscosity dimethyl silicone oil into another three-neck flask with a stirring and reflux condensing device, reducing the temperature of the material to 5 ℃ under the protection of nitrogen, dropwise adding 15g of hexamethyldisilazane into the three-neck flask through a constant-pressure dropping funnel at a constant speed for 8h, and maintaining the temperature at 5 ℃ for 3h after dropwise adding. After the pressure is returned to the constant pressure, the materials in the kettle are transferred to another low-boiling-point substance removing device, a small amount of nitrogen (with the purity of 99.9%) is introduced for bubbling, when the absolute pressure of the system reaches 0.01Pa, the temperature is gradually increased from room temperature to 240 ℃, and the temperature is maintained at 240 ℃ for 3 hours to remove the low-boiling-point substances in the filtrate. After the temperature of the kettle liquid is reduced to room temperature, the stirring is closed, the flow of nitrogen in the bottom inserting pipe is increased, after the pressure reduction and reduction system is recovered to the normal pressure, the kettle liquid is collected, and 96.8g of hexamethyldisilazane and Al are obtained2O3Treated low viscosity dimethylsilicone fluids.
Hexamethyldisilazane and Al from example 4 were applied to untreated low viscosity dimethylsilicone fluids using Discovery TGA from TA USA2O3Performing Thermogravimetric (TGA) experiments on the treated low-viscosity dimethylsilicone oil in air and nitrogen atmosphere, wherein the testing temperature range is 40-800 ℃, the heating rate is 10K/min, the flow rates of air and nitrogen are both 30mL/min, and the relative weight loss of each sample is 10% (Td)10)、20％(Td20) And 50% (Td)50) The corresponding temperatures are shown in table 1.
Example 5
150g of a commercially available methylphenyl silicone oil having a viscosity (20 ℃) of 100mPa.s and a phenyl content of 7 mol% was charged into a 250mL three-necked flask equipped with a reflux condenser, mechanical stirring and a thermometer, 2g of MgO powder which had been subjected to vacuum drying at 125 ℃ for 6 hours was then added, argon gas was introduced from a bottom-inserted tube, stirring was started, the temperature was gradually raised from room temperature to 200 ℃ and the mixture was maintained at 200 ℃ for 16 hours. After cooling to room temperature, the argon was turned off and stirring was carried out, and the mixture in the three-necked flask was subjected to reduced pressure filtration to collect the filtrate.
Transferring the collected filtrate to a low-boiling-point substance removing device, introducing a trace amount of argon gas for bubbling, gradually raising the temperature from room temperature to 210 ℃ when the absolute pressure of the system reaches 5Pa, and maintaining the temperature at 210 ℃ for 6 hours to remove the low-boiling-point substances in the filtrate. And after the temperature of the kettle liquid is reduced to room temperature, closing stirring, increasing the flow of argon in the bottom inserting pipe, and after the pressure reduction and reduction system is recovered to normal pressure, collecting the kettle liquid to obtain the MgO-treated low-viscosity methyl phenyl silicone oil.
100g of the prepared MgO-treated low-viscosity methylphenyl silicone oil was transferred to another three-neck flask with stirring and reflux condenser, the temperature of the material was reduced to 10 ℃ under the protection of nitrogen (purity 99.9%), 10g of hexamethyldisilazane was added dropwise to the three-neck flask via a constant-pressure dropping funnel at a constant speed for 6 hours, and after completion of the addition, the mixture was maintained at 10 ℃ for 8 hours. After the pressure is returned to the constant pressure, the materials in the kettle are transferred to another low-boiling-point substance removing device, a small amount of nitrogen (with the purity of 99.9%) is introduced for bubbling, when the absolute pressure of the system reaches 5Pa, the temperature is gradually increased from the room temperature to 210 ℃, and the temperature is maintained at 210 ℃ for 5 hours to remove the low-boiling-point substances in the filtrate. And after the temperature of the kettle liquid is reduced to room temperature, stopping stirring, increasing the flow of nitrogen in the bottom inserting pipe, and after the pressure reduction and reduction system is recovered to normal pressure, collecting the kettle liquid to obtain 92.6g of low-viscosity methyl phenyl silicone oil treated by hexamethyldisilazane and MgO.
Thermogravimetric (TGA) experiments in air and nitrogen atmosphere were carried out on untreated low-viscosity methylphenyl silicone oil and low-viscosity methylphenyl silicone oil treated with hexamethyldisilazane and MgO prepared in example 5 respectively by using Discovery TGA of TA company of USA, the test temperature range was 40-800 ℃, the temperature rise rate was 10K/min, the flow rates of air and nitrogen were 30mL/min, and the relative weight loss of each sample was 10% (Td)10)、20％(Td20) And 50% (Td)50) Corresponding to temperature such asShown in table 1.
Example 6
200g of a commercially available dimethylsilicone oil having a viscosity (20 ℃) of 10mPa.s was charged into a 250mL three-necked flask equipped with a reflux condenser, mechanical stirring and a thermometer, and then 20g of the ZnO powder subjected to vacuum drying at 150 ℃ for 8 hours was added, and after introducing a trace amount of nitrogen gas (purity 99.9%) from a bottom-inserted tube, stirring was turned on, and the temperature was gradually raised from room temperature to 150 ℃ and maintained at 150 ℃ for 3 hours. After cooling to room temperature, the nitrogen and stirring were turned off, the mixture in the three-necked flask was filtered under reduced pressure, and the filtrate was collected.
Transferring the collected filtrate to a low-boiling-point substance removal device, introducing a trace amount of nitrogen (with the purity of 99.9%) for bubbling, gradually raising the temperature from room temperature to 200 ℃ when the absolute pressure of the system reaches 1Pa, and maintaining the temperature at 200 ℃ for 12 hours to remove low-boiling-point substances in the filtrate. And after the temperature of the kettle liquid is reduced to room temperature, stopping stirring, increasing the flow of nitrogen in the bottom inserting pipe, and after the pressure reduction and reduction system is recovered to normal pressure, collecting the kettle liquid to obtain the ZnO-treated low-viscosity dimethyl silicone oil.
150g of the prepared ZnO-treated low-viscosity dimethylsilicone oil was transferred to another three-neck flask with stirring and reflux condenser, the temperature of the material was reduced to 15 ℃ under nitrogen protection, 7.5g of hexamethyldisilazane was added dropwise to the three-neck flask via a constant pressure dropping funnel at a constant rate over 1 hour, and after the addition was completed, the temperature was maintained at 15 ℃ for 3 hours. After the pressure is restored to be constant, the materials in the kettle are transferred to another low-boiling-point substance removing device, a small amount of nitrogen (with the purity of 99.9%) is introduced for bubbling, when the absolute pressure of the system reaches 1Pa, the temperature is gradually increased from room temperature to 200 ℃, and the temperature is maintained at 200 ℃ for 8 hours to remove the low-boiling-point substances in the filtrate. And after the temperature of the kettle liquid is reduced to room temperature, stopping stirring, increasing the flow of nitrogen in the bottom inserting pipe, and after the pressure reduction and reduction system is recovered to normal pressure, collecting the kettle liquid to obtain 144g of low-viscosity dimethyl silicone oil treated by hexamethyldisilazane and ZnO.
Thermogravimetric (TGA) experiments in air and nitrogen atmosphere were carried out on untreated low viscosity dimethylsilicone oil and low viscosity dimethylsilicone oil treated with hexamethyldisilazane and ZnO prepared in example 6, respectively, using Discovery TGA of TA of USA, with test temperature ranging from 40 to 800 deg.CThe temperature rise rate is 10K/min, the flow rates of air and nitrogen are both 30mL/min, and the relative weight loss of each sample is 10% (Td)10)、20％(Td20) And 50% (Td)50) The corresponding temperatures are shown in table 1.
TABLE 1 comparison of thermal Properties of the Silicone oils obtained in examples 1 to 6
Figure BDA0001922004830000111

Claims (7)

1. A method for modifying silicone oil by treatment with a silazane and a metal oxide, characterized in that said method comprises the following steps:
(1) adding low-viscosity silicone oil and metal oxide into a reaction container under the protection of inert gas, stirring, and then heating from room temperature for reaction to obtain a solid-liquid mixture, wherein the using amount of the metal oxide is 0.5-15% of the mass of the low-viscosity silicone oil;
the low-viscosity silicone oil is selected from dimethyl silicone oil or methyl phenyl silicone oil, and the viscosity of the low-viscosity silicone oil is less than or equal to 500mPa.s at 20 ℃;
(2) cooling to room temperature, closing the inert gas, then carrying out reduced pressure filtration on the solid-liquid mixture, collecting filtrate, transferring the filtrate to a reduction reaction kettle, carrying out low-boiling-point substance removal operation under the protection of the inert gas and stirring, cooling to room temperature, closing the inert gas and stirring to obtain modified silicone oil treated by metal oxide;
(3) adding modified silicone oil treated by metal oxide into a reaction kettle for heat preservation, then dropwise adding hexamethyldisilazane into the modified silicone oil under the protection of inert gas, and maintaining the reaction after dropwise adding;
(4) transferring the reaction mixture to a reduction reaction kettle, carrying out reduction boiling substance removal operation under the protection of inert gas and stirring, cooling to room temperature, closing the inert gas and stirring to obtain modified silicone oil treated by silazane and metal oxide,
the low-boiling-point substance removal operation temperature in the step (2) and the step (4)The temperature is 180-300 ℃, the holding time is 1-24 h, and the absolute pressure is 10-5~3000 Pa。
2. Method according to claim 1, characterized in that said metal oxide is selected from ZnO, Al2O3、MgO、MnO2、CeO2One or more of them.
3. A method of modifying silicone oil with a silazane and a metal oxide according to claim 1, wherein the metal oxide is dried before use at a temperature of 105-160 ℃ for 1-12 hours.
4. The method for modifying silicone oil through treatment of silazane and metal oxide according to claim 1, wherein in step (1), the temperature is raised from room temperature to 140-400 ℃ and the reaction time is 1-24 hours.
5. The method for modifying silicone oil with silazane and metal oxide treatment according to claim 1, wherein the mass ratio of hexamethyldisilazane to modified silicone oil with metal oxide treatment in step (3) is 0.01 to 0.30: 1.
6. The method for modifying silicone oil by treatment with a silazane and a metal oxide according to claim 1, wherein the holding temperature of hexamethyldisilazane and the modified silicone oil treated with a metal oxide in step (3) is-20 to 50 ℃.
7. The method for modifying silicone oil through treatment of silazane and metal oxide according to claim 1, wherein hexamethyldisilazane is added dropwise for 0.5 to 12 hours in step (3), and the reaction is maintained for 1 to 15 hours.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105112010A (en) * 2015-09-15 2015-12-02 中国科学院化学研究所 Room-temperature curing adhesive based on silazane and modified silazane polymer and preparation method thereof
CN109096774A (en) * 2018-08-21 2018-12-28 镇江亿维硅材料科技有限公司 A kind of high-temperature-resisting silicon rubber rubber compound and preparation method thereof
CN110283318A (en) * 2018-12-26 2019-09-27 杭州师范大学 The method for improving silicone oil with low viscosity thermal stability using silazane and metal oxide
CN111253584A (en) * 2020-02-27 2020-06-09 西北大学 Preparation method of d-f heteronuclear bimetallic organic framework material based on single metal coordination polymer

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3916403B2 (en) * 2001-01-30 2007-05-16 株式会社スリーボンド Room temperature curable sealing material composition for automobiles
CN107936572B (en) * 2017-11-17 2019-10-18 华南理工大学 A kind of high transparency heat oxygen aging resistance add-on type liquid silicon rubber and preparation method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105112010A (en) * 2015-09-15 2015-12-02 中国科学院化学研究所 Room-temperature curing adhesive based on silazane and modified silazane polymer and preparation method thereof
CN109096774A (en) * 2018-08-21 2018-12-28 镇江亿维硅材料科技有限公司 A kind of high-temperature-resisting silicon rubber rubber compound and preparation method thereof
CN110283318A (en) * 2018-12-26 2019-09-27 杭州师范大学 The method for improving silicone oil with low viscosity thermal stability using silazane and metal oxide
CN111253584A (en) * 2020-02-27 2020-06-09 西北大学 Preparation method of d-f heteronuclear bimetallic organic framework material based on single metal coordination polymer

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
有机硅热载体的制备与性能研究;张超;《中国优秀硕士学位论文全文数据库工程科技Ⅰ辑》;20180515(第05期);第B016-128页 *
硅氮化合物在改进聚硅氧烷热稳定性中的作用;谢择民，等;《高分子学报》;19890228(第1期);第46-51页 *
耐高温有机硅粘接剂的研究新进展;杨志洲，等;《有机硅材料》;20101125;第24卷(第6期);第385-390页 *
金属化合物对硅橡胶耐热性能的影响;张玉环，等;《科技通报》;20090531;第25卷(第3期);第311-314页 *

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