Device and method for preparing nanofiller vertical alignment film material

Abstract

The invention relates to the technical field of vertical orientation of a nanofiller in a base material, and particularly discloses a device and a method for preparing a nanofiller vertical orientation film material. The device comprises a rotating motor, a forming mold part and a magnetic field part, wherein the forming mold part is used for adding and placing a material for preparing the nanofiller vertical alignment film material and forming the material; the rotating motor is connected with the forming die part and provides outward centrifugal force in the radial direction of the forming die part; the magnetic field component provides inward magnetic field force in the radial direction of the forming die component. Directional arrangement of materials in a forming mold part is adjusted under the dual action of a magnetic field and a centrifugal force field, and solidification of the vertical orientation structure of the nanofiller in the film material is achieved. The device and the preparation method provided by the invention are simple, convenient, efficient and wide in application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparing vertically oriented nano-fillers in a substrate, and particularly relates to an apparatus and a method for preparing a vertically oriented film material of nano-fillers. Background Art

[0002] Thermal interface materials (TIMs) are materials used to improve heat transfer in electronic devices. Polymer-based thermal interface nanocomposites have attracted much attention in the field of heat conduction due to their easy processing and low interfacial thermal resistance with chips and heat sinks, and have great application prospects. To achieve the goals of low cost, high performance, and maintaining the flexibility and interfacial compatibility of the polymer materials in the thermal interface materials themselves, it is often necessary for nano-fillers to form a percolation network along a specific direction during the preparation process, build a heat conduction path at a low loading amount, and the effect of enhancing the thermal conductivity also largely depends on the ability to control the orientation of nano-fillers in the polymer matrix material. Existing methods such as chemical vapor deposition (CVD), ice templating arrangement, etc. require relatively precise control of the preparation conditions and are difficult to prepare on a large scale; while the external field control of a single electric field, magnetic field, or shear force field has great difficulties in the orientation of most nano-fillers, especially in the vertical direction, due to the excellent flexibility of most nano-fillers themselves and the increased orientation freedom of two-dimensional nano-fillers compared to one-dimensional nano-fillers. Therefore, simply and quickly achieving the vertical alignment of nano-fillers in the composite material remains a challenge. Summary of the Invention

[0003] The object of the present invention is to provide an apparatus and a method for preparing a vertically oriented film material of nano-fillers. By designing the dual action of a magnetic field and a centrifugal force field, the directional arrangement of nano-fillers is adjusted; after the nano-fillers are oriented, they are fixed by the slow curing of the polymer matrix, and at the same time, they act as the polymer part of the matrix of the composite material.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] The first aspect of the present invention is to provide an apparatus for preparing a vertically oriented film material of nano-fillers, the apparatus comprising a rotating motor, a forming die component, and a magnetic field component.

[0006] The forming die component is used to add and place the materials for preparing the vertically oriented film material of nano-fillers and form the materials.

[0007] The rotating motor is connected to the forming die component to provide a centrifugal force radially outward along the forming die component.

[0008] The magnetic field component provides a magnetic force radially inward along the forming die component.

[0009] Adjust the directional arrangement of the magnetic nano-fillers in the molding die component under the dual action of a magnetic field and a centrifugal force field to achieve vertical orientation.

[0010] Furthermore, the molding die component includes a cylinder with one end closed and the other end open.

[0011] Furthermore, the rotating shaft of the rotating motor is fixedly connected to the closed end of the cylinder.

[0012] Furthermore, one end of the magnetic field component passes through the open end of the cylinder and is suspended inside the cylinder.

[0013] Furthermore, the magnetic field component is a columnar magnet with a radial magnetic induction intensity of 3000 - 5000 Gs.

[0014] Furthermore, the other end of the magnetic field component is fixed to a bracket.

[0015] Furthermore, the bracket is an adjustable lifting bracket.

[0016] The second aspect of the present invention is to provide a method for preparing a film material with vertically oriented nano-fillers using the above device, including the following steps:

[0017] S1. Disperse the magnetic nano-filler powder in a specified polymer matrix, stir for a preset time to achieve stable dispersion of the filler in the matrix, add a curing agent, and then introduce it into the molding die component;

[0018] S2. Before the polymer matrix cures, install the molding die component on the rotating motor, start the rotating motor and adjust it to the corresponding speed. Wait until the polymer matrix in the molding die component is evenly distributed on the inner wall of the die under the action of centrifugal force and gravity, and then place the magnetic field component along the axial direction of the die.

[0019] Furthermore, the polymer matrix includes any one of thermoplastic polymers, photo-curable polymers, or chemically cross-linked solid polymers.

[0020] Furthermore, the magnetic nano-fillers are magnetic nano-particles or are prepared from the magnetic nano-particles, and the magnetic nano-particles include any one or more of graphene, diamond, boron nitride, MXene, thermally conductive ceramics, hydrotalcite, magnetite, and Co.

[0021] Compared with the prior art, the beneficial effects brought by the technical solution provided by the present invention are:

[0022] (1) The device provided by the present invention includes a rotating motor, a forming die component, and a magnetic field component. The forming die component is used to add and place the materials for preparing the vertically oriented film material of nano-fillers and form the materials. The rotating motor is connected to the forming die component to provide a centrifugal force radially outward along the forming die component. The magnetic field component provides a magnetic force radially inward along the forming die component. During the process, the nano-fillers are affected by inertial centrifugal force, magnetic force, and fluid resistance: when the cylinder speed is low, there is no relative movement between the nano-fillers and the matrix. As the speed increases, the centrifugal force increases, and the nano-fillers start to move relatively outward. The magnetic torque makes the flakes tend to be distributed radially, and the resistance torque tends to turn the flakes towards the velocity direction, strengthening the radial distribution effect of the magnetic torque. Thus, the directional arrangement of the nano-filler materials in the forming die component is adjusted under the dual action of the magnetic field and the centrifugal force field, and the vertically oriented structure of the nano-fillers in the film material is solidified.

[0023] (2) The method provided by the present invention is simple, efficient, and has broad application prospects. Description of the Drawings

[0024] Figure 1 is a schematic structural diagram of a device for preparing a vertically oriented film material of nano-fillers provided by the present invention;

[0025] Figure 2 is a scanned cross-sectional view of the film material prepared in Example 2;

[0026] Figure 3 is a scanned cross-sectional view of the composite material prepared in Comparative Example 1 under a single centrifugal force field;

[0027] Figure 4 is a scanned cross-sectional view of the composite material prepared in Comparative Example 1 under a single magnetic force. Detailed Embodiments

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the following further describes in detail the specific embodiments of the present invention with reference to specific examples and drawings. For those not specified in the examples regarding specific test methods, instrument equipment, or conditions, they are all carried out according to the techniques or conditions described in the literature in this field or according to the product specifications. For the reagents or instruments not specified for the manufacturers, they are all conventional products that can be obtained through commercial purchase.

[0029] Example 1

[0030] This example provides a device for preparing a vertically oriented film material of nano-fillers.

[0031] Reference Figure 1Schematic structural diagram of an apparatus for preparing a vertically oriented film material of nano-fillers provided by the present invention, mainly composed of a rotating motor 1, a forming die component 2, and a magnetic field component 3. The forming die component 2 is fixed on the rotating motor 1, and the magnetic field component 3 is fixed at the position of the cylindrical axis of the forming die component 2 by an adjustable lifting bracket 4.

[0032] It should be noted that the magnetic field component 3 provides a magnetic field force inward along the radial direction of the cylinder, the rotating motor 1 provides a centrifugal force acting outward along the radial direction, and the forming die component 2 provides a substrate for polymer forming. As the polymer matrix cures, a structure in which the nano-fillers are oriented along the axial direction of the cylinder is formed. After removing the film and cutting it along the axial direction, a rectangular film is obtained, and the nano-fillers in it are oriented in the vertical direction to form a film material.

[0033] In some embodiments, the forming die component 2 includes a cylinder 21 with one end closed and the other end open. The cylindrical forming die is a key device for forming a film-like composite material. The cylindrical forming die is fixed on the motor, and the motor can rotate the cylindrical die and drive the slurry of the composite material in the barrel to rotate. Under the action of adjustable centrifugal force, the polymer substrate in the slurry is uniformly and densely formed into a film, and under the action of shear force, an external field is provided for the formation of the filler orientation structure.

[0034] In some embodiments, in order to make the curing time of the composite material forming adjustable, the forming die component 2 further includes a heating component 22. The heating component 22 provides a heat source inside the forming die component 2, and its structure is not limited. It can be arranged on the cylinder 21 of the forming die component 2, and a heating sensor is set to control the temperature inside the forming die component 2. It can also set the cylinder 21 as a sandwich layer and uniformly arrange the heating component 22 in the sandwich layer to provide a uniform temperature inside the forming die component 2.

[0035] In some embodiments, in order to improve the quality of the vertical orientation of the nano-fillers, the magnetic induction intensity of the magnetic field component 3 should be not less than 3000 Gs. The magnetic field component 3 can be a columnar magnet, and the material can be a neodymium magnet. The permanent magnet magnetic field generated by it is directed outward along the radial direction, the curved magnetic field is uniform, and the magnetic induction intensity and size can be adjusted according to needs. After the motor is started, a relatively rotating magnetic field is formed.

[0036] The present invention also provides a method for preparing a film material with vertically oriented nano-fillers by using this apparatus, which is as follows:

[0037] Step 1, disperse the magnetic nano-filler powder in a specified polymer matrix, stir for a predetermined time to achieve stable dispersion of the filler in the matrix, and add it to the mold after adding the curing agent;

[0038] Step 2, before the polymer matrix is cured, install the aforementioned forming mold on the motor, start the motor and adjust it to the corresponding speed. Wait until the polymer matrix in the mold is evenly distributed on the inner wall of the mold under the action of centrifugal force and gravity, and then place a columnar permanent magnet with uniform magnetic induction intensity along the axial direction of the mold.

[0039] The polymer substrate for preparing the composite film can be thermoplastic polymers (such as PP, PE, ABS, PA, PBAT, etc.), photo-curable polymers (such as PC, PMMA, PDMS, etc.) or chemically cross-linked solid polymers (such as epoxy resin, phenolic resin, PVA, etc.).

[0040] The magnetic nano-fillers for preparing the composite film can be zero-dimensional, one-dimensional, and two-dimensional nano (such as graphene, diamond boron nitride, MXene, thermally conductive ceramics, metal powders, hydrotalcite, etc.) composite thermally conductive fillers composite with magnetic nanoparticles, or separate magnetic one-dimensional and two-dimensional iron oxide nanoparticles, Co and other nanoparticles.

[0041] The following will specifically illustrate the device and method for preparing the nano-filler vertically oriented film material provided by the present invention through specific embodiments and drawings.

[0042] Example 2

[0043] This example provides a method for preparing a composite film material with vertically oriented nano-fillers.

[0044] Using the device provided in Example 1, disperse graphene filler powder with certain magnetic response performance in the silicone rubber matrix. The addition amount of graphene is 1 wt.%, and mechanically stir for 3 h to achieve stable dispersion of the filler in the matrix. Then add 4 wt.% curing agent (as the curing agent for room temperature vulcanized silicone rubber, Jinan Xingfeilong Chemical Co., Ltd.), stir evenly and add it into the forming mold parts.

[0045] Before the composite film is cured, install the forming mold parts filled with uncured composite materials on the rotating motor. The power of the motor is 100 W. Start the motor and adjust the speed to 500 rpm. Wait until the polymer matrix in the mold is evenly distributed on the inner wall of the mold under the action of centrifugal force and gravity, and then place a magnetic field part with a magnetic induction intensity of about 3500 Gs along the axial direction of the mold.

[0046] After the composite film is cured at room temperature for 3 h, take it out of the forming mold. At this time, the film is in a cylindrical shape, and the fillers are arranged along the radial direction of the cylinder. Cut the film along the axial direction to obtain a composite material with graphene arranged vertically. Its scanning cross-sectional view is as Figure 2 shown. The thermal conductivity of the obtained composite film in the vertical direction is 0.915 W / m·K, which is 5.71 times that of the pure silicone rubber sample (0.16 W / m·K).

[0047] Example 3

[0048] This embodiment provides a method for preparing a composite film material with vertically oriented nano-fillers.

[0049] Disperse hexagonal boron nitride filler powder with certain magnetic response performance in a polydimethylsiloxane matrix. The addition amount of hexagonal boron nitride is 1 wt.%, and stir for 3 h to achieve stable dispersion of the filler in the matrix. Subsequently, add 10 wt.% curing agent (as the curing agent for room temperature vulcanized silicone rubber, Jinan Xingfeilong Chemical Co., Ltd.), and after stirring evenly, add it into the molding die parts.

[0050] Before the composite film cures, install the molding die parts filled with uncured composite material on a rotating motor with a motor power of 100 W. Start the motor and adjust the rotation speed to 550 rpm. Wait until the polymer matrix in the die is evenly distributed on the inner wall of the die under the action of centrifugal force and gravity. Subsequently, place a magnetic field component with a magnetic induction intensity of about 3500 Gs along the axial direction of the die.

[0051] Adjust the temperature of the molding die to 60 °C. After the composite film cures for 1 h, take it out from the molding die. At this time, the film is in a cylindrical shape, and the fillers are arranged along the radial direction of the cylinder. Cut the film along the axial direction to obtain a composite material with hexagonal boron nitride arranged vertically. The thermal conductivity of the obtained composite film in the vertical direction is 0.456 W / m·K, which is 3.04 times that of the pure silicone rubber sample (0.15 W / m·K).

[0052] Comparative Example 1

[0053] It is basically the same as Example 1, except that only centrifugal force is applied to prepare the composite film material, and its scanning cross-sectional view is as Figure 3 shown.

[0054] Comparative Example 2

[0055] It is basically the same as Example 1, except that only magnetic field force is applied to prepare the composite film material, and its scanning cross-sectional view is as Figure 4 shown.

[0056] Without conflict, the above embodiments and the features in the embodiments in this article can be combined with each other.

[0057] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An apparatus for preparing a nanocomposite filler vertically oriented film material, characterized in that, The device includes a rotating motor (1), a forming die component (2), and a magnetic field component (3). The forming die component (2) is used to add and place the materials for preparing the vertically oriented film material of the nano filler and form the materials into a shape. The rotating motor (1) is connected to the forming die component (2) to provide a centrifugal force radially outward along the forming die component. The magnetic field component (3) provides a magnetic field force radially inward along the forming die component. Under the dual action of the magnetic field and the centrifugal force field, the directional arrangement of the magnetic nano filler in the forming die component (2) is adjusted to achieve vertical orientation.

2. The device according to claim 1, wherein The forming die component (2) includes a cylinder (21) and a heating component (22). One end of the cylinder (21) is closed and the other end is open. The heating component (22) provides a heat source for the inside of the forming die component (2).

3. The device according to claim 2, wherein, The rotating shaft of the rotating motor (1) is fixedly connected to the closed end of the cylinder (21).

4. The device according to claim 2, characterized in that, One end of the magnetic field component (3) passes through the open end of the cylinder (21) and is suspended inside the cylinder (21).

5. The device according to claim 4, characterized in that, The magnetic field component (3) is a columnar magnet, providing a radial magnetic induction intensity of 3000 - 5000 Gs.

6. The device according to claim 4, wherein, The other end of the magnetic field component (3) is fixed on a bracket (4).

7. The device according to claim 6, characterized in that, The bracket (4) is an adjustable lifting bracket.

8. A method for preparing a film material with vertically oriented nano-fillers by using the device according to any one of claims 1-7, characterized in that, It includes the following steps: S1. Disperse the magnetic nano filler in a specified polymer matrix, stir for a preset time to achieve stable dispersion of the filler in the matrix, and add it to the forming die component (2) after adding a curing agent. S2. Before the polymer matrix is cured, install the forming die component (2) on the rotating motor (1), start the rotating motor (1) and adjust it to the corresponding speed. Wait until the polymer matrix in the forming die component (2) is evenly distributed on the inner wall of the die under the action of centrifugal force and gravity, and then place the magnetic field component (3) along the axial direction of the die.

9. The method according to claim 8, wherein The polymer matrix includes any one of thermoplastic polymers, photo-curable polymers, or chemically cross-linked solid polymers.

10. The method according to claim 8, wherein The magnetic nano filler is magnetic nano particles or is prepared from the magnetic nano particles. The magnetic nano particles include any one or more of graphene, diamond, boron nitride, MXene, thermally conductive ceramics, hydrotalcite, iron tetroxide, and Co.

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