Silica surface modification method, modified silica and applications
By modifying silica powder to form an annular polymer lubricating layer on the surface, the flowability and stability issues of the encapsulation material are solved, and the modified silica is well dispersed and has low hygroscopicity in the resin matrix, thereby improving the performance of the encapsulation material.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHENZHEN INST OF ADVANCED ELECTRONICS MATERIALS
- Filing Date
- 2023-08-30
- Publication Date
- 2026-05-15
AI Technical Summary
In existing technologies, silica surface modification methods result in poor flowability, high viscosity, high moisture absorption of packaging materials, and poor stability of modified micropowders, making them difficult to apply in the field of electronic packaging.
A cyclic polymer modifier was chemically grafted onto the surface of silica micropowder after vacuum heating treatment to form an impermeable cyclic polymer lubricating layer. The modification was completed by high-temperature and high-speed stirring to form modified silica with reduced thermal expansion coefficient, reduced viscosity and moisture absorption.
It improves the dispersion stability of modified silica in the resin matrix, reduces the moisture absorption rate, has better flowability and viscosity, enhances the stability of modified particles, and reduces the interaction between particles and resin.
Smart Images
Figure CN117229652B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of material modification technology, and in particular to a method for modifying the surface of silica and modified silica. Background Technology
[0002] Driven by the demand for smaller, faster, and lighter electronic devices, flip-chip packaging technology, with its advantages of better heat dissipation, small size, high throughput, and low profile, has become the most attractive packaging method for chip-level packaging. Due to the significant mismatch in thermal expansion coefficients between the chip and the substrate, solder joints subjected to enormous thermomechanical stress are prone to failure during thermal cycling. Therefore, a curable resin material is typically filled between the chip and the substrate to effectively distribute the thermal stress on the solder joints and further improve the reliability of the electronic package. Research shows that applying silica filler to the underfill adhesive can effectively improve the resin's thermal expansion coefficient and thermal stability. In capillary underfill processes, the silica needs to be surface-modified to achieve good flowability and viscosity of the underfill adhesive to ensure complete filling of the chip package. Generally, the viscosity of underfill adhesives is determined by the viscosity of the polymer and the interactions between fillers and between fillers themselves. The high silica filler ratios used to achieve good thermal conductivity and coefficient of thermal expansion in underfill adhesives often result in excessively high viscosity and poor flowability. Therefore, it is necessary to optimize the surface chemical structure of modified silica fillers to allow a larger proportion of filler to be incorporated into the resin without excessively reducing flowability, thus achieving a better balance between the properties of the underfill adhesive. Furthermore, complete grafting of surface silanol groups is often difficult to achieve during silica modification. Residual silanol groups on the modified silica surface easily combine with water molecules in the environment, affecting the chemical state of the modified silica surface and causing the underfill adhesive to have excessively high hygroscopicity, thus hindering its application in electronic packaging.
[0003] Currently, surface modification of silica micropowder using small-molecule silane coupling agents with different functional groups improves the coefficient of thermal expansion of the encapsulation material. However, higher grafting and filling rates lead to increased viscosity, poorer flowability, and higher moisture absorption in the encapsulation material. The modified silica micropowder also exhibits poor stability and is prone to agglomeration. Surface modification of silica micropowder using polymer long-chain grafting improves the stability of the encapsulation material and reduces moisture absorption. However, the interaction between polymer segments increases the viscosity of the encapsulation material and reduces its flowability. Summary of the Invention
[0004] Therefore, it is necessary to provide a silica surface modification method and modified silica with better flowability to address the technical defects of poor flowability of existing packaging materials.
[0005] To solve the above problems, this application adopts the following technical solution:
[0006] One of the objectives of this application is to provide a method for modifying the surface of silica, comprising the following steps:
[0007] Vacuum heating treatment of silica micro powder;
[0008] A cyclic polymer modifier was sprayed onto the surface of the treated silica micropowder at room temperature.
[0009] The silica micro powder was stirred under high temperature conditions to form cyclic polymer-modified silica micro powder.
[0010] In some embodiments, in the step of vacuum heating the silica micropowder, the heating temperature is 180-200 degrees Celsius and the heating time is 3 hours.
[0011] In some embodiments, the cyclic polymer modifier is prepared as follows in the step of spraying the cyclic polymer modifier onto the surface of the treated silica micropowder at room temperature:
[0012] A silane coupling agent is added to a methanol solution of the polymer, and the mixture is stirred at 40-80°C for 10-24 hours to obtain the cyclic polymer modifier.
[0013] The molar mass ratio of the polymer to the silane coupling agent is 1:2, 1:3, or 1:4.
[0014] In some embodiments, in the step of adding a silane coupling agent to a methanol solution of the polymer and stirring at 40-80°C for 10-24 hours to obtain the cyclic polymer modifier, the polymer is one or a mixture of several polymers with functional groups on both sides, and the end-capping functional groups may be amino, carbon-carbon double bonds, ester groups, or mercapto groups.
[0015] In some embodiments, in the step of adding a silane coupling agent to a methanol solution of the polymer and stirring at 40-80°C for 10-24 hours to obtain the cyclic polymer modifier, the polymer is other polymers whose monomers contain benzene rings or six-membered rings.
[0016] In some embodiments, in the step of adding a silane coupling agent to a methanol solution of the polymer and stirring at 40-80°C for 10-24 hours to obtain the cyclic polymer modifier, the silane coupling agent is any coupling agent with an alkoxy group at one end and the other end capable of reacting with the end functional group of the polymer. For example, (3-glycidylpropoxy)trimethoxysilane.
[0017] In some embodiments, in the step of adding a silane coupling agent to a methanol solution of the polymer and stirring at 40-80°C for 10-24 hours to obtain the cyclic polymer modifier, the silane coupling agent includes trimethoxymercaptopropylsilane or trimethoxypropenylsilane.
[0018] In some embodiments, the step of stirring the above-mentioned silica micro powder under high temperature conditions to form cyclic polymer modified silica micro powder specifically includes the following steps: stirring the above-mentioned silica micro powder at a high speed of 300-700 rpm for 30-60 minutes at 100-120 degrees Celsius to obtain modified silica micro powder.
[0019] The second objective of this application is to provide a modified silica, which is prepared by the aforementioned silica surface modification method.
[0020] The third objective of this application is to provide an application of the modified silica described above in encapsulation materials.
[0021] The present application adopts the above technical solution, and its beneficial effects are as follows:
[0022] The silica surface modification method and modified silica provided in this application involve adding a synthesized cyclic polymer modifier to vacuum-heat-pretreated silica micropowder via spray. Chemical grafting is then completed under high temperature and high-speed stirring, forming an impermeable, rigid annular polymer lubricating layer on the silica surface. This results in polymer-modified silica micropowder with reduced thermal expansion coefficient, lower viscosity and moisture absorption, and improved stability. Compared to grafted linear polymer chains, the physicochemical properties of the annular polymer brush are significantly altered due to its annular topology. This change is fundamentally due to the smoothness of the cyclic polymer surface and the formation of the impermeable layer. The siloxane ends anchored to the silica surface reduce the degrees of freedom of the cyclic polymer chains, forming an impermeable layer to reduce the interaction between silica particles and the external environment. Compared with small molecule modifiers, cyclic polymer chains can more completely coat the surface of silica, improve the dispersion stability of modified silica in the resin matrix, reduce moisture absorption, and the polymer brush with low friction characteristics weakens the interaction between modified particles and between modified particles and resin, resulting in better flowability and viscosity. Attached Figure Description
[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 A flowchart illustrating the steps of the silica surface modification method provided in this application embodiment.
[0025] Figure 2 This is a schematic diagram illustrating the preparation principle of the cyclic polymer modifier provided in the embodiments of this application. Detailed Implementation
[0026] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.
[0027] In the description of this application, it should be understood that the terms "upper", "lower", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0029] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments.
[0030] Please see Figure 1 The following is a flowchart of the steps of the silica surface modification method provided in this embodiment, including steps S110 to S130. The specific implementation of each step is described in detail below.
[0031] Step S110: Vacuum heat treatment of silica micro powder.
[0032] Specifically, the silica micro powder is preheated in a vacuum at 180-200 degrees Celsius for 3 hours.
[0033] Step S120: Spray the cyclic polymer modifier onto the surface of the treated silica micropowder at room temperature.
[0034] In some embodiments, the step of spraying a cyclic polymer modifier onto the surface of the treated silica micropowder at room temperature is described below:
[0035] A silane coupling agent is added to a methanol solution of the polymer, and the mixture is stirred at 40-80°C for 10-24 hours to obtain the cyclic polymer modifier; wherein the molar mass ratio of the polymer to the silane coupling agent is 1:2, 1:3, or 1:4.
[0036] Please see Figure 2 This is a schematic diagram illustrating the preparation principle of the cyclic polymer modifier provided in this embodiment.
[0037] In this embodiment, the polymer is one or a mixture of several polymers with functional groups on both sides, and the end-capping functional groups may be amino, carbon-carbon double bonds, ester groups, or mercapto groups.
[0038] In this embodiment, the polymer is another polymer containing a benzene ring or a six-membered ring in the monomer.
[0039] For example, the polymers mentioned above can be bis(3-aminopropyl)-terminated polydimethyldiphenylsiloxane, bis(3-aminopropyl)-terminated polyterephthalic acid, bis(3-aminopropyl)-terminated polybisphenol A carbonate, or bis(3-aminopropyl)-terminated polycyclohexyl methacrylate.
[0040] In this embodiment, the silane coupling agent is any coupling agent with an alkoxy group at one end and the other end capable of reacting with the functional group of the polymer terminal group. For example, (3-glycidylpropoxy)trimethoxysilane. In this embodiment, the silane coupling agent includes trimethoxymercaptopropylsilane or trimethoxypropenesilane.
[0041] In this embodiment, the molecular structure of the cyclic polymer modifier is as follows:
[0042]
[0043] It is understandable that the physicochemical properties of cyclic polymers are significantly altered compared to grafted linear polymer chains due to their cyclic topology. This change is fundamentally caused by the smoothness of the cyclic polymer surface and the formation of an impermeable layer. The siloxane ends anchored to the silica surface reduce the degrees of freedom of the cyclic polymer chains, forming an impermeable layer to reduce the interaction between silica particles and the external environment. Compared to small-molecule modifiers, cyclic polymer chains are more capable of completely coating the silica surface, improving the dispersion stability of modified silica in the resin matrix, reducing moisture absorption, and the low-friction polymer brush weakens the interaction between modified particles and between modified particles and the resin, resulting in better flowability and viscosity.
[0044] Step S130: Stir the above silica micro powder under high temperature conditions to form cyclic polymer modified silica micro powder.
[0045] In this embodiment, the following steps are specifically included: stirring the above-mentioned silica micro powder at a high speed of 300-700 rpm for 30-60 minutes at 100-120 degrees Celsius to obtain modified silica micro powder.
[0046] The silica surface modification method and modified silica provided in this application involve adding a synthesized cyclic polymer modifier to vacuum-heat-pretreated silica micropowder via spray. Chemical grafting is then completed under high temperature and high-speed stirring, forming an impermeable, rigid annular polymer lubricating layer on the silica surface. This results in polymer-modified silica micropowder with reduced thermal expansion coefficient, lower viscosity and moisture absorption, and improved stability. Compared to grafted linear polymer chains, the physicochemical properties of the annular polymer brush are significantly altered due to its annular topology. This change is fundamentally due to the smoothness of the cyclic polymer surface and the formation of the impermeable layer. The siloxane ends anchored to the silica surface reduce the degrees of freedom of the cyclic polymer chains, forming an impermeable layer to reduce the interaction between silica particles and the external environment. Compared with small molecule modifiers, cyclic polymer chains can more completely coat the surface of silica, improve the dispersion stability of modified silica in the resin matrix, reduce moisture absorption, and the polymer brush with low friction characteristics weakens the interaction between modified particles and between modified particles and resin, resulting in better flowability and viscosity.
[0047] The technical solutions described above in this application will be explained in detail below with reference to specific embodiments.
[0048] Example 1 (Comparative Example):
[0049] 1) Preheat 1 kg of silica micro powder with an average particle size of 500 nanometers in a vacuum at 180-200 degrees Celsius for 3 hours;
[0050] 2) Spray 2% by weight of γ-glycidoxypropyltrimethoxysilane onto silica micropowder at room temperature.
[0051] 3) Stir at 115 degrees Celsius and 600 rpm for 60 minutes to obtain epoxy-modified silica micro powder;
[0052] 4) Add 60% by weight of epoxy-modified silica micro powder to bisphenol A epoxy resin, mix evenly and degas in a mixer at 2000 rpm and under vacuum conditions, and test the room temperature viscosity (shear rate 50 / sec) with a rheometer.
[0053] 5) Add 60% by weight of epoxy-modified silica micro powder to bisphenol A epoxy resin containing curing agent, mix evenly and degas in a mixer at 2000 rpm and under vacuum, cure at 160 degrees Celsius for 2 hours to prepare cured samples, test the coefficient of thermal expansion on TMA, test the elastic modulus on DMA, put the cured sample into a reaction vessel containing deionized water and cook at 120 degrees Celsius for 24 hours to test the moisture absorption rate.
[0054] Example 2 (Comparative Example):
[0055] 1) Add 2.5g of mono(3-aminopropyl)-terminated polydimethyldiphenylsiloxane with a molecular weight of 1000g / mol to 50ml of anhydrous methanol solution, and add 0.59g of (3-glycidylpropoxy)trimethoxysilane. Stir at 50℃ for 12 hours to obtain a cyclic polymer modifier. Then, heat at 70℃ for 1h to evaporate and remove the residual methanol solvent in the solution.
[0056] 2) Preheat 1 kg of silica micro powder with an average particle size of 500 nanometers in a vacuum at 180-200 degrees Celsius for 3 hours;
[0057] 3) Spray 2% by weight of the cyclic polymer modifier onto the silica micro powder at room temperature.
[0058] 4) Stir at 115 degrees Celsius and 600 rpm for 60 minutes to obtain cyclic polymer-modified silica micro powder;
[0059] 5) Add 60% by weight of modified silica micro powder to bisphenol A epoxy resin, mix evenly and degas in a mixer at 2000 rpm and under vacuum conditions, and test the room temperature viscosity (shear rate 50 / sec) with a rheometer.
[0060] 6) Add 60% by weight of epoxy-modified silica micro powder to bisphenol A epoxy resin containing curing agent, mix evenly and degas in a mixer at 2000 rpm and under vacuum conditions, cure at 160 degrees Celsius for 2 hours to prepare cured samples, test the coefficient of thermal expansion on TMA, and put the cured sample into a reaction vessel containing deionized water and cook at 120 degrees Celsius for 24 hours to test the moisture absorption rate.
[0061] Example 3:
[0062] 1) Add 2.5g of bis(3-aminopropyl)-terminated polydimethyldiphenylsiloxane with a molecular weight of 1000g / mol to 50ml of anhydrous methanol solution, and add 1.18g of (3-glycidylpropoxy)trimethoxysilane. Stir at 40℃ for 10 hours to obtain a cyclic polymer modifier. Then, heat at 70℃ for 1 hour to evaporate and remove the residual methanol solvent in the solution.
[0063] 2) Preheat 1 kg of silica micro powder with an average particle size of 500 nanometers in a vacuum at 180 degrees Celsius for 3 hours;
[0064] 3) Spray 2% by weight of the cyclic polymer modifier onto the silica micro powder at room temperature.
[0065] 4) Stir at 300 rpm for 60 minutes at 100 degrees Celsius to obtain cyclic polymer-modified silica micro powder;
[0066] 5) Add 60% by weight of modified silica micro powder to bisphenol A epoxy resin, mix evenly and degas in a mixer at 2000 rpm and under vacuum conditions, and test the room temperature viscosity (shear rate 50 / sec) with a rheometer.
[0067] 6) Add 60% by weight of epoxy-modified silica micro powder to bisphenol A epoxy resin containing curing agent, mix evenly and degas in a mixer at 2000 rpm and under vacuum conditions, cure at 160 degrees Celsius for 2 hours to prepare cured samples, test the coefficient of thermal expansion on TMA, and put the cured sample into a reaction vessel containing deionized water and cook at 120 degrees Celsius for 24 hours to test the moisture absorption rate.
[0068] Example 4:
[0069] 2.5 g of bis(3-aminopropyl)-terminated polyterephthalic acid with a molecular weight of 1000 g / mol was added to 50 ml of anhydrous methanol solution, and 1.18 g of (3-glycidylpropoxy)trimethoxysilane was added. The mixture was stirred at 40 °C for 12 hours to obtain a cyclic polymer modifier. Subsequently, the residual methanol solvent in the solution was removed by heating and evaporating at 70 °C for 1 hour. 2) 1 kg of silica micropowder with an average particle size of 500 nm was preheated in a vacuum at 200 °C for 3 hours.
[0070] 3) Spray 2% by weight of the cyclic polymer modifier onto the silica micro powder at room temperature.
[0071] 4) Stir at 115 degrees Celsius and 600 rpm for 40 minutes to obtain cyclic polymer-modified silica micro powder;
[0072] 5) Add 60% by weight of modified silica micro powder to bisphenol A epoxy resin, mix evenly and degas in a mixer at 2000 rpm and under vacuum conditions, and test the room temperature viscosity (shear rate 50 / sec) with a rheometer.
[0073] 6) Add 60% by weight of epoxy-modified silica micro powder to bisphenol A epoxy resin containing curing agent, mix evenly and degas in a mixer at 2000 rpm and under vacuum conditions, cure at 160 degrees Celsius for 2 hours to prepare cured samples, test the coefficient of thermal expansion on TMA, and put the cured sample into a reaction vessel containing deionized water and cook at 120 degrees Celsius for 24 hours to test the moisture absorption rate.
[0074] Example 5:
[0075] 1) Add 2.5g of bis(3-aminopropyl)-terminated polybisphenol A carbonate with a molecular weight of 3000g / mol to 50ml of anhydrous methanol solution, and add 0.39g of (3-glycidylpropoxy)trimethoxysilane. Stir at 50℃ for 12 hours to obtain a cyclic polymer modifier. Then, heat at 70℃ for 1h to evaporate and remove the residual methanol solvent in the solution.
[0076] 2) Preheat 1 kg of silica micro powder with an average particle size of 500 nanometers in a vacuum at 180-200 degrees Celsius for 3 hours;
[0077] 3) Spray 2% by weight of the cyclic polymer modifier onto the silica micro powder at room temperature.
[0078] 4) Stir at 700 rpm for 30 minutes at 120 degrees Celsius to obtain cyclic polymer-modified silica micro powder;
[0079] 5) Add 60% by weight of modified silica micro powder to bisphenol A epoxy resin, mix evenly and degas in a mixer at 2000 rpm and under vacuum conditions, and test the room temperature viscosity (shear rate 50 / sec) with a rheometer.
[0080] 6) Add 60% by weight of epoxy-modified silica micro powder to bisphenol A epoxy resin containing curing agent, mix evenly and degas in a mixer at 2000 rpm and under vacuum conditions, cure at 160 degrees Celsius for 2 hours to prepare cured samples, test the coefficient of thermal expansion on TMA, and put the cured sample into a reaction vessel containing deionized water and cook at 120 degrees Celsius for 24 hours to test the moisture absorption rate.
[0081] Example 6:
[0082] 1) Add 2.5g of bis(3-aminopropyl)-terminated polycyclohexyl methacrylate with a molecular weight of 3000g / mol to 50ml of anhydrous methanol solution, and add 0.39g of (3-glycidylpropoxy)trimethoxysilane. Stir at 50℃ for 12 hours to obtain a cyclic polymer modifier. Then, heat at 70℃ for 1h to evaporate and remove the residual methanol solvent in the solution.
[0083] 2) Preheat 1 kg of silica micro powder with an average particle size of 500 nanometers in a vacuum at 180-200 degrees Celsius for 3 hours;
[0084] 3) Spray 2% by weight of the cyclic polymer modifier onto the silica micro powder at room temperature.
[0085] 4) Stir at 115 degrees Celsius and 600 rpm for 60 minutes to obtain cyclic polymer-modified silica micro powder;
[0086] 5) Add 60% by weight of modified silica micro powder to bisphenol A epoxy resin, mix evenly and degas in a mixer at 2000 rpm and under vacuum conditions, and test the room temperature viscosity (shear rate 50 / sec) with a rheometer.
[0087] 6) Add 60% by weight of epoxy-modified silica micro powder to bisphenol A epoxy resin containing curing agent, mix evenly and degas in a mixer at 2000 rpm and under vacuum conditions, cure at 160 degrees Celsius for 2 hours to prepare cured samples, test the coefficient of thermal expansion on TMA, and put the cured sample into a reaction vessel containing deionized water and cook at 120 degrees Celsius for 24 hours to test the moisture absorption rate.
[0088] Table 1 shows the room temperature viscosity, coefficient of thermal expansion, and moisture absorption of the cured samples from Examples 1-4.
[0089] Example Room temperature viscosity / Pa·s <![CDATA[Coefficient of thermal expansion / 10 -6 °C -1 > Moisture absorption rate Example 1 (Comparative Example) 202.2 32.5 0.94％ Example 2 (Comparative Example) 220.4 28.2 0.88％ Example 3 175.5 27.4 0.84％ Example 4 180.3 28.5 0.86％ Example 5 173.5 27.6 0.83％ Example 6 179.5 28.1 0.88％
[0090] As can be seen from the above embodiments, the silica surface modification method and modified silica provided in this application can more completely cover the silica surface with ring polymer chains, improve the dispersion stability of modified silica in the resin matrix, reduce the moisture absorption rate, and the polymer brush with low friction characteristics weakens the interaction between modified particles and between modified particles and resin, resulting in better flowability and viscosity.
[0091] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.
[0092] It is understood that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0093] The above are merely preferred embodiments of this application, and only specifically describe the technical principles of this application. These descriptions are only for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application, as well as other specific embodiments of this application that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of this application.
Claims
1. A method for modifying the surface of silica, characterized in that, Includes the following steps: Vacuum heating treatment of silica micro powder; A cyclic polymer modifier was sprayed onto the surface of the treated silica micropowder at room temperature. The above-mentioned silica micro powder was stirred under high temperature conditions to form cyclic polymer-modified silica micro powder; In the step of spraying a cyclic polymer modifier onto the surface of treated silica micropowder at room temperature, the cyclic polymer is prepared as follows: A silane coupling agent is added to a methanol solution of the polymer, and the mixture is stirred at 40-80°C for 10-24 hours to obtain the cyclic polymer modifier. Wherein, the molar mass ratio of the polymer to the silane coupling agent is 1:2, 1:3, or 1:4; The polymer is any one of bis(3-aminopropyl)-terminated polydimethyldiphenylsiloxane, bis(3-aminopropyl)-terminated polyterephthalic acid, bis(3-aminopropyl)-terminated polybisphenol A carbonate, and bis(3-aminopropyl)-terminated polycyclohexyl methacrylate. The silane coupling agent is (3-glycidylpropoxy)trimethoxysilane; The step of stirring the above-mentioned silica micro powder under high temperature conditions to form cyclic polymer modified silica micro powder specifically includes the following steps: stirring the above-mentioned silica micro powder at a high speed of 300-700 rpm for 30-60 minutes at 100-120 degrees Celsius to obtain modified silica micro powder.
2. The silica surface modification method as described in claim 1, characterized in that, In the step of vacuum heating treatment of silica micro powder, the heating temperature is 180-200 degrees Celsius.
3. A modified silica, characterized in that, It is prepared by the silica surface modification method according to any one of claims 1 to 2.
4. The application of the modified silica as described in claim 3 in encapsulation materials.