High-efficiency multi-element polysiloxane modified silica powder and preparation method thereof

Abstract

The invention relates to the technical field of surface modification of inorganic non-metallic materials, and discloses efficient multi-element polysiloxane modified silica powder and a preparation method thereof.The preparation method comprises the following steps that silica powder is subjected to ball milling, then a modifier is added for grinding, the temperature is increased to a preset temperature for a heat preservation reaction, and modified silica powder is obtained; wherein the mass of the modifier is 0.1%-1% of the mass of the silica powder, and the modifier comprises octa (phenyldimethoxysilyl) polyhedral oligomeric silsesquioxane. The modified silica powder has excellent dispersity, mechanical property and heat resistance in a high-molecular polymer system, and meanwhile, the modified silica powder has multiple active sites and can be further subjected to cross-linking reaction with a high-molecular polymer, so that the mechanical property of the material is improved.

Description

Technical Field

[0001] The invention relates to the technical field of surface modification of inorganic non-metallic materials, and in particular to a high-efficiency polysiloxane-modified silicon micropowder and a preparation method thereof. Background Art

[0002] Polyhedral oligomeric silsesquioxane (POSS) is a class of compounds with the structural formula RSiO 3 / 2 Siloxane compounds, R can be hydrogen atoms, alkyl, aryl, alkenyl and other organic groups, with low dielectric constant, high heat resistance, high mechanical strength, excellent optoelectronic properties and multiple functionalities, and are used in many fields. POSS is called cage-shaped silsesquioxane because of its cage-like shape. The size of the cage structure is above 1.5nm. From the perspective of molecular structure, the hexahedral core composed of Si-O-Si is nanomolecular size, generally called nanocore structure, and the 8 Rs are called functional arms. Different functional groups are grafted to give it different properties, so POSS with different structures can be obtained, thereby obtaining materials with different properties.

[0003] Silicon micropowder is used as a functional filler in the preparation of polymer composite materials due to its excellent high thermal stability, mechanical properties, low expansion coefficient, low cost and other characteristics. It is mainly used in epoxy molding compounds, copper clad laminates, rubber products and coatings. Because the surface of silicon micropowder is rich in hydroxyl groups, it shows polarity and hydrophilicity, and has poor compatibility with non-polar polymers. Therefore, silicon micropowder often needs surface modification before it can show good application performance in polymer material systems. However, in the prior art of surface modification of silicon dioxide micropowder, epoxy modifiers or silane coupling agents are commonly used for modification. The above-mentioned modification method will cause the thermal expansion coefficient of silicon micropowder to become larger, which will affect the dispersibility and fluidity of silicon micropowder in polymer material systems. Therefore, the present application provides a silicon micropowder modified with POSS to solve the above problems. Summary of the invention

[0004] Based on the above, the purpose of the present invention is to provide a high-efficiency polysiloxane-modified silicon micropowder and a preparation method thereof, which maintains the low expansion coefficient characteristics of the silicon micropowder and is applied in a high molecular polymer material system.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing high-efficiency polysiloxane-modified silicon micropowder comprises the following steps:

[0007] Firstly, the silicon micropowder is ball-milled, then a modifier is added for grinding, and the temperature is raised to a preset temperature for heat preservation reaction to obtain modified silicon micropowder;

[0008] The mass of the modifier is 0.1% to 1% of the mass of the silicon powder;

[0009] The modifier includes octa(phenyldimethoxysilyl) cage-shaped silsesquioxane.

[0010] As a preferred embodiment of a method for preparing a highly efficient polysiloxane-modified silicon micropowder, the structural formula of the octa(phenyldimethoxysilyl) cage-shaped silsesquioxane is:

[0011]

[0012] As a preferred solution for the preparation of a highly efficient multi-polysiloxane modified silicon micropowder, the preparation method of the octa(phenyldimethoxysilyl) cage-type silsesquioxane is as follows: octa(tetramethylammonium) cage-type silsesquioxane (cas: 69667-29-4) and phenyldimethoxychlorosilane are added to a solubilizing solvent in a molar ratio of 1:(8-10), and the reaction time is 12-72 hours at a temperature of -10°C to 100°C;

[0013] The dissolution aid solvent includes one or more of toluene, methanol, ethanol, n-hexane, cyclohexane, xylene, and acetone.

[0014] As a preferred solution for the preparation method of highly efficient multi-polysiloxane modified silicon micropowder, the ball milling temperature of the silicon micropowder is 80-100° C., and the ball milling time is 5-30 min.

[0015] As a preferred solution for the preparation method of highly efficient polysiloxane-modified silicon micropowder, during the grinding process, the preset temperature is 120-150° C., and the heat preservation reaction time is 10-30 minutes.

[0016] As a preferred solution of a method for preparing a highly efficient polysiloxane-modified silicon micropowder, the silicon micropowder comprises one of angular silicon micropowder and spherical silicon micropowder.

[0017] As a preferred solution for the preparation method of highly efficient polysiloxane-modified silicon micropowder, the particle size of the silicon micropowder is 0.2 to 5 um.

[0018] A high-efficiency polysiloxane-modified silicon micropowder is prepared by any of the above-mentioned preparation methods.

[0019] The beneficial effects of the present invention are:

[0020] The invention provides a high-efficiency multi-polysiloxane modified silicon micropowder and a preparation method thereof. Octa(phenyldimethoxysilyl) cage-shaped silsesquioxane is used to perform surface modification on silicon micropowder, and the heat resistance of silicon micropowder is further improved by introducing phenyl groups. The low expansion coefficient characteristic of silicon micropowder is maintained by a nano-core structure of POSS, and the dispersibility and fluidity of silicon micropowder in a high molecular polymer material system are improved. The functional arms of POSS are used to provide multiple active sites, and on the one hand, silicon micropowder is completely grafted and coated for modification, and its dispersibility in a high molecular polymer material system is improved. On the other hand, the multiple active sites on the surface of the modified silicon micropowder can participate in the chemical crosslinking reaction of the high molecular polymer system, and its mechanical properties are improved.

[0021] Since the surface of silicon micropowder contains a large number of hydroxyl groups, the hydroxyl groups on the surface of the modified silicon micropowder are largely consumed, which significantly improves the dispersibility, mechanical properties and heat resistance of the modified silicon micropowder in the polymer system. In addition, the present invention adopts ball milling dry modification technology to make the modified silicon micropowder uniform in particle size and good in modification effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0023] Figure 1 The electron microscope images of the silicon micropowder provided by the present invention are as follows: (a) angular silicon micropowder before modification, (b) angular silicon micropowder after modification, (c) spherical silicon micropowder before modification, and (d) spherical silicon micropowder after modification.

[0024] Figure 2 It is the structural formula of octa(phenyldimethoxysilyl) cage-shaped silsesquioxane;

[0025] Figure 3 It is the structural formula of octamethylammonium cage-type silsesquioxane. DETAILED DESCRIPTION

[0026] For ease of understanding of the present invention, the present invention will be described more fully below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. Unless otherwise defined, all technical and scientific terms used in the present invention belong to the technical field of the present invention.

[0027] The embodiment of the present invention provides a high-efficiency multi-polysiloxane modified silicon micropowder and a preparation method thereof, the preparation method comprising the following steps: firstly heating the silicon micropowder to 80-100° C. and ball milling for 5-30 min, then adding octa(phenyldimethoxysilyl) cage-shaped silsesquioxane for grinding, and heating to 120-150° C. for heat preservation reaction for 10-30 min to obtain modified silicon micropowder;

[0028] Specifically, the mass of the modifier is 0.1% to 1% of the mass of the silicon micropowder, and the particle size of the silicon micropowder is 0.2 to 5 um.

[0029] Specifically, silicon micropowder includes angular silicon micropowder and spherical silicon micropowder. Angular silicon micropowder is mostly used in low-end material systems, mainly in the coating field, with lower cost; spherical silicon micropowder is used in copper clad laminates, epoxy molding compounds and rubber fields. The spherical morphology is conducive to slowing down heat transfer during heating, and the reinforcement and viscosity reduction properties are better.

[0030] Specifically, the synthesis method of octa(phenyldimethoxysilyl) cage-type silsesquioxane is a functional group conversion method, and the synthesis process is: using octa-tetramethylammonium cage-type silsesquioxane (the structural schematic diagram of octa-tetramethylammonium cage-type silsesquioxane is as shown in Figure 3 As shown) and phenyldimethoxychlorosilane are added to a dissolving solvent in a molar ratio of 1: (8-10), and the reaction time is 12-72 hours at a temperature of -10°C to 100°C; the dissolving solvent includes one or more of toluene, methanol, ethanol, n-hexane, cyclohexane, xylene, acetone, etc.

[0031] The present invention will be further described below by means of specific examples.

[0032] Example 1

[0033] 100g of angular silicon micropowder with an average particle size of 2um was added to a ball mill, and the temperature was raised to 100°C for ball milling for 10 minutes. Then 0.5g of octa(phenyldimethoxysilyl) cage-shaped silsesquioxane modifier was added, and the temperature was raised to 120°C for insulation reaction for 10 minutes to obtain modified silicon micropowder;

[0034] Take 30g of modified silicon micropowder and disperse it into 100g of epoxy resin system containing amino curing agent, disperse it in a homogenizer for 5 minutes, and use a digital viscometer to test the viscosity of the epoxy resin coating. Then, the dispersed epoxy resin coating is ultrasonically degassed, and dumbbell-shaped test strips are prepared by inverting. After curing, the tensile properties of the body are tested with a universal electronic tensile testing machine. The tensile strength, elongation at break and flexural strength test standards are GB / T 528-2009, and the viscosity test standard is GB / T 10247-2008.

[0035] Example 2

[0036] 100g of spherical silicon micropowder with an average particle size of 0.2um was added to a ball mill, and the temperature was raised to 90°C for ball milling for 30 minutes. Then 1.0g of octa(phenyldimethoxysilyl) cage-shaped silsesquioxane modifier was added, and the temperature was raised to 135°C for 20 minutes to obtain modified silicon micropowder;

[0037] Take 40g of modified silicon micropowder and disperse it into 100g of silicone rubber heat protection material system containing crosslinking agent, disperse it in a dynamic mixer for 15min, add 50g of butyl acetate diluent and disperse it for 10min, then use a digital viscometer to test the viscosity of silicone rubber heat protection coating, then spray the dispersed silicone rubber heat protection coating to prepare samples, cut it into dumbbell-shaped test strips after curing, and use a universal electronic tensile machine to test the tensile properties of the body. Among them, the relevant performance test standards are consistent with those in Example 1.

[0038] Example 3

[0039] 100g of spherical silicon powder with an average particle size of 5um was added to a ball mill, and the temperature was raised to 80°C for ball milling for 5min. Then 0.1g of octa(phenyldimethoxysilyl) cage-shaped silsesquioxane modifier was added, and the temperature was raised to 150°C for insulation reaction for 30min, and the modified silicon powder was obtained;

[0040] Take 40g of modified silicon micropowder and disperse it into 100g of silicone rubber heat protection material system containing crosslinking agent, disperse it in a dynamic mixer for 15min, add 50g of toluene diluent and disperse it for 10min, then use a digital viscometer to test the viscosity of silicone rubber heat protection coating, then spray the dispersed silicone rubber heat protection coating to prepare samples, cut it into dumbbell-shaped test strips after curing, and use a universal electronic tensile machine to test the tensile properties of the body. Among them, the relevant performance test standards are consistent with those in Example 1.

[0041] In order to further illustrate the key points of this patent, a comparative case is added for illustration.

[0042] Comparative Example 1

[0043] 100g of angular silicon micropowder with an average particle size of 2um was added to the ball mill, and the temperature was raised to 100℃ for ball milling for 10min. Then the temperature was raised to 120℃ for insulation reaction for 10min, and the ground silicon micropowder was obtained;

[0044] Take 30g of the above-mentioned ground silicon micropowder and disperse it into 100g of the epoxy resin system containing the amino curing agent, disperse it in a homogenizer for 5 minutes, and use a digital viscometer to test the viscosity of the epoxy resin coating. Then, the dispersed epoxy resin coating is ultrasonically degassed, and a dumbbell-shaped test strip is prepared by inverting. After curing, the tensile properties of the body are tested with a universal electronic tensile testing machine, wherein the tensile strength, elongation at break and flexural strength test standards are GB / T 528-2009, and the viscosity test standard is GB / T10247-2008.

[0045] Comparative Example 2

[0046] 100g of spherical silicon micropowder with an average particle size of 0.2um was added to the ball mill, and the temperature was raised to 90℃ for ball milling for 30min. Then the temperature was raised to 135℃ for 20min of heat preservation, and the ground silicon micropowder was obtained;

[0047] Take 40g of the above-mentioned ground silicon powder and disperse it into 100g of the silicone rubber heat protection material system containing a crosslinker, disperse it in a dynamic mixer for 15min, add 50g of butyl acetate diluent and disperse it for 10min, then use a digital viscometer to test the viscosity of the silicone rubber heat protection coating, then spray the dispersed silicone rubber heat protection coating to prepare samples, cut it into dumbbell-shaped test strips after curing, and use a universal electronic tensile machine to test the tensile properties of the body. Among them, the relevant performance test standards are consistent with those in Example 1.

[0048] Comparative Example 3

[0049] 100g of spherical silicon micropowder with an average particle size of 5um was added to the ball mill, and the temperature was raised to 80℃ for ball milling for 5min. Then the temperature was raised to 150℃ for 30min of heat preservation, and the ground silicon micropowder was obtained;

[0050] Take 40g of the above-mentioned ground silicon powder and disperse it into 100g of the silicone rubber heat protection material system containing a crosslinker, disperse it in a dynamic mixer for 15min, add 50g of toluene diluent and disperse it for 10min, then use a digital viscometer to test the viscosity of the silicone rubber heat protection coating, then spray the dispersed silicone rubber heat protection coating to prepare samples, cut it into dumbbell-shaped test strips after curing, and use a universal electronic tensile machine to test the tensile properties of the body. Among them, the relevant performance test standards are consistent with those in Example 1.

[0051] The angular silicon powder before modification and the angular silicon powder after modification used in the above Example 1, and the spherical silicon powder before modification and the angular silicon powder after spherical modification used in Example 2 were analyzed by scanning electron microscope. The electron microscope image is shown in Figure 1. Figure 1It can be seen that the morphology of silicon micropowder changes significantly after modification. The surface of angular silicon micropowder is smooth before modification, but becomes rough after modification by grafting and deposition of modifier. The surface of spherical silicon micropowder is rough before modification, but becomes smooth after modification by filling the pits with modifier. Figure 1 This indicates that the modification of the silica powder is complete, and the modifier gives the spherical silica powder and the angular silica powder good dispersibility and reactivity.

[0052] The performance data of Examples 1-3 and Comparative Examples 1-3 are shown in Table 1 after relevant performance tests:

[0053] Table 1 Summary of application performance of silicon micropowder

[0054] Experiment No. Tensile strength / MPa Elongation at break / % Coating viscosity / Pa·s Bending strength / MPa Example 1 97.3 6.4 8.2 180 Comparative Example 1 80.2 5.1 16.6 102 Example 2 3.6 130 0.67 / Comparative Example 2 2.2 80 2.3 / Example 3 2.5 68 0.36 / Comparative Example 3 2.1 35 1.7 /

[0055] It can be seen from the above data table that the use of modified silicon micropowder in polymer systems can greatly improve the dispersibility and fluidity of polymer systems. In Example 1 and Comparative Example 1, modified silicon micropowder is used in epoxy resin system, and the viscosity of the coating is reduced from 16.6Pa·s to 8.2Pa·s; in Example 2 and Comparative Example 2, and Example 3 and Comparative Example 3, modified silicon micropowder is used in silicone rubber composite material system. The viscosity of the coating is reduced from 2.3Pa·s to 0.67Pa·s and from 1.7Pa·s to 0.36Pa·s, respectively, and the viscosity reduction effect is significant. In addition, the epoxy resin system has a reinforcing effect before and after modification, and its tensile strength is increased from 80.2MPa to 97.3MPa, an increase of nearly 20%, and the bending strength is improved; and the silicone rubber composite material system is improved more significantly, by nearly 60%, because the multiple active sites on the surface of the modified silicon micropowder participate in the cross-linking reaction to increase the cross-linking density of the polymer system, thereby improving the mechanical properties.

[0056] The above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for preparing high-efficiency polysiloxane-modified silicon micropowder, characterized in that: The following steps are involved: Firstly, the silicon micropowder is ball-milled, then a modifier is added for grinding, and the temperature is raised to a preset temperature for heat preservation reaction to obtain modified silicon micropowder; The mass of the modifier is 0.1% to 1% of the mass of the silicon powder; The modifier includes octa(phenyldimethoxysilyl) cage-shaped silsesquioxane.

2. The method for preparing high-efficiency polysiloxane-modified silicon micropowder according to claim 1, characterized in that: The structural formula of the octa(phenyldimethoxysilyl) cage-shaped silsesquioxane is:

3. The method for preparing high-efficiency polysiloxane-modified silicon micropowder according to claim 2, characterized in that: The preparation method of the octa(phenyldimethoxysilyl) cage-type silsesquioxane is as follows: octa(phenyldimethoxysilyl) cage-type silsesquioxane and phenyldimethoxychlorosilane are added to a dissolving solvent in a molar ratio of 1:(8-10), and the reaction time is 12-72 hours at a temperature of -10°C to 100°C; The dissolution aid solvent includes one or more of toluene, methanol, ethanol, n-hexane, cyclohexane, xylene, and acetone.

4. The method for preparing high-efficiency polysiloxane-modified silicon micropowder according to claim 1, characterized in that: The ball milling temperature of the silicon micropowder is 80-100° C., and the ball milling time is 5-30 minutes.

5. The method for preparing high-efficiency polysiloxane-modified silicon micropowder according to claim 1, characterized in that: During the grinding process, the preset temperature is 120-150° C., and the heat preservation reaction time is 10-30 minutes.

6. The method for preparing high-efficiency polysiloxane-modified silicon micropowder according to claim 1, characterized in that: The silicon micropowder includes one of angular silicon micropowder and spherical silicon micropowder.

7. The method for preparing high-efficiency polysiloxane-modified silicon micropowder according to claim 1, characterized in that: The particle size of the silicon powder is 0.2-5 um.

8. A high-efficiency polysiloxane-modified silicon micropowder prepared by the preparation method according to any one of claims 1 to 7.

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