CN115725170A - Polymer compound and preparation method and application thereof - Google Patents

Abstract

The invention relates to a polymer compound and a preparation method and application thereof, wherein the polymer compound comprises the following components in parts by weight: 100 parts of polymer powder, 0.1-3 parts of nano-particles A and 0.05-1.5 parts of nano-particles B; wherein the particle size of the nanoparticle A is smaller than that of the nanoparticle B; the mass ratio of the nano-particles A to the nano-particles B is (1-9): 1. The small-particle-size and large-particle-size nano particles adopted by the invention are compounded in a specific ratio, and the small-particle-size and large-particle-size nano particles and the nano particles are used as a flowing agent of polymer powder under the synergistic effect, so that the polymer compound has excellent fluidity, permeability and high-temperature stability.

Description

Polymer compound and preparation method and application thereof

Technical Field

The invention relates to the technical field of high molecular materials, in particular to a polymer compound and a preparation method and application thereof.

Background

A polymeric material refers to a high molecular weight compound consisting of many identical, simple structural units repeatedly linked by covalent bonds. The polymer powder is a fine chemical with certain particle size and distribution and certain particle morphology prepared by a chemical method or a physical method. The polymer powder is widely applied to the fields of powder coating, 3D printing, cosmetics, additives, medicines and the like.

Although the polymer powder can be prepared by a chemical synthesis method, such as suspension polymerization or emulsion polymerization, the preparation process is complicated, the types of polymers are limited, and most of the polymers can only be used for preparing styrene polymers or acrylic acid (ester) polymers. At present, the main means for obtaining the polymer powder is still a mechanical crushing mode, and the method has the advantages of simple process and continuous production, but the prepared particles have disordered shapes and wider particle size distribution.

The two methods are common methods for preparing polymer powders, but the powders prepared by these two methods have irregular shapes and poor flowability, and good flowability is critical for the application of polymer powders. The current methods for improving the flowability of polymer powders are mainly methods of reducing the interfacial force of particles (e.g. adding flow aids or coating polymers) and reducing the rolling resistance (e.g. modifying the particles, such as spherical shape, of polymers). In addition, since the polymer has limited temperature resistance, the powder flowability is reduced significantly when the use temperature is increased, limiting the application range. In the first method, the flow aid mixing process may be carried out in any suitable mixing apparatus, including a fluid bed, and one or more of a variety of rotating drums or mixers equipped with rotating shafts.

CN1102954C discloses a process for the preparation of a granular detergent composition which comprises the step of adding to the granular detergent powder particles a powdered flow aid of percarbonate having a mean particle size in the range of 250 to 900 micrometers and a partially hydrated crystalline sodium aluminosilicate.

CN109929242A discloses a nylon polymer powder heat absorbing material and a preparation method thereof, wherein the preparation method comprises the following steps: adding a nylon raw material, a molecular weight regulator and deionized water into a polymerization kettle, adding a heat medium after the pressure in the kettle is relieved to normal pressure, stirring, drawing wires and cutting to obtain nylon heat medium granules; adding the nylon thermal medium granules into a post-polycondensation barrel, heating, vacuumizing and stirring to obtain nylon thermal medium polycondensation granules; polycondensation granules of a nylon thermal medium are prepared into a nylon thermal medium powder material by adopting a cryogenic grinding process; adding 20 parts of nylon thermal medium powder material and 0.1-2 parts of carbon black into a stirring barrel for high-speed stirring to prepare a nylon carbon black mixed powder material; adding the nylon carbon black mixed powder material, the flow additive and 80 parts of the nylon thermal medium powder material into a powder mixing barrel, stirring at a high speed, and then sieving to obtain the nylon polymer powder heat absorbing material. The method disclosed by the method enables the nylon polymer powder to be applied to sintering of the optical fiber laser, and the surface quality and the mechanical property of a workpiece are good.

CN108727814A discloses a composite nylon powder material for selective laser sintering and a preparation method thereof, wherein the disclosed composite nylon powder material comprises the following components by weight: 30-70 parts of nylon resin powder; 30-50 parts of hollow glass beads; 0-20 parts of glass fiber; 0.2-2 parts of a coupling agent; 0.1-1.5 parts of a flow aid; 0.2-2 parts of antioxidant. The modified glass fiber and the hollow glass bead are added into the nylon resin powder, compared with the simple addition of the glass fiber, the nylon composite powder added with the hollow glass bead and the glass fiber has better flowability, the powder spreading effect is better, the strength modulus of a sintered part is higher, and the nylon composite material of the hollow glass bead and the glass fiber expands the application field of nylon.

At present, the improvement of the fluidity of the polymer is limited by adopting a mode of reducing the acting force of particle interfaces and reducing the rolling resistance, so that the development of a polymer material with excellent fluidity is very important.

Disclosure of Invention

In view of the disadvantages of the prior art, it is an object of the present invention to provide a polymer composite having excellent flowability, permeability and high temperature stability, and a method for preparing the same and use thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a polymer composite, which comprises the following components in parts by weight: 100 parts of polymer powder, 0.1-3 parts of nano-particles A and 0.05-1.5 parts of nano-particles B;

wherein the particle size of the nanoparticle A is smaller than that of the nanoparticle B;

the mass ratio of the nanoparticles A to the nanoparticles B is (1-9): 1, wherein 1-9 can be 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5 and the like.

According to the polymer composite, the nano-particles A and the nano-particles B in a specific mass ratio are used as the flowing agents of the polymer powder, and the nano-particles A and the nano-particles B are coated on the polymer powder under the synergistic effect, so that the surface of the particles is reduced, the friction force and the acting force are reduced, and the fluidity, the permeability and the stability at high temperature of the polymer powder are improved.

The weight portion of the nano-particles A is 0.1-3 parts, such as 0.2 part, 0.5 part, 0.8 part, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts and the like.

The weight part of the nanoparticles B is 0.05-1.5 parts, such as 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, 1 part, 1.1 part, 1.2 part, 1.3 part, 1.4 part and the like.

Preferably, the mass ratio of the nanoparticles A and the nanoparticles B is (1.5-4): 1, wherein 1.5-4 can be 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 3.8, etc.

The mass ratio of the nanoparticles A and the nanoparticles B in the present invention is preferably (1.5-4): 1, and the polymer composite obtained in this mass ratio range is more excellent in fluidity and high-temperature stability.

Preferably, the particle size of the nanoparticles a is 5-50nm, such as 6nm, 8nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 42nm, 45nm, 48nm, etc., preferably 5-30nm.

The particle size of the nanoparticle A is preferably 5-30nm, because the small-sized nanoparticles can form a denser coating on the surface of the polymer, thereby reducing the acting force among particles.

Preferably, the particle size of the nanoparticles B is 50-600nm, such as 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, etc., preferably 50-300nm.

The particle size of the nanoparticle B of the present invention is preferably 50 to 300nm because the nanoparticles having a larger particle size form rolling friction and barrier effects on the polymer surface, reducing interparticle forces.

Preferably, the polymer powder has a median particle diameter of 5 to 500. Mu.m, for example 10 μm, 50 μm, 100. Mu.m, 150. Mu.m, 200. Mu.m, 250. Mu.m, 300. Mu.m, 350. Mu.m, 400. Mu.m, 450. Mu.m, etc., preferably 10 to 300. Mu.m, more preferably 50 to 150. Mu.m.

Preferably, the polymer powder comprises a thermoplastic polymer powder and/or a thermosetting polymer powder.

Preferably, the polymer powder comprises a thermoplastic polymer powder.

Preferably, the thermoplastic polymer powder comprises any one of, or a combination of at least two of, a thermoplastic elastomer, a polyamide, a polyolefin, a polymethacrylate, a polycarbonate, or a polystyrene, wherein typical but non-limiting combinations include: combinations of thermoplastic elastomers and polyamides, combinations of polyolefins, polymethacrylates, and polycarbonates, combinations of polyamides, polyolefins, polymethacrylates, polycarbonates, and polystyrenes, and the like.

Preferably, the nanoparticles a comprise any one or a combination of at least two of nanosilica, nanosilica or nanosilica, wherein typical but non-limiting combinations include: the combination of nano-silicon dioxide and nano-titanium dioxide, the combination of nano-titanium dioxide and nano-silicon carbide, the combination of nano-silicon dioxide, nano-titanium dioxide and nano-silicon carbide, and the like.

Preferably, the nanoparticles B comprise any one or a combination of at least two of nano-silica, nano-titania, nano-silicon carbide, nano-alumina, talc, magnesium stearate or magnesium oxide, wherein typical but non-limiting combinations include: the combination of nano silicon dioxide and nano titanium dioxide, the combination of nano titanium dioxide, nano silicon carbide and nano aluminum oxide, and the combination of nano aluminum oxide, talcum powder, magnesium stearate and magnesium oxide.

In a second aspect, the present invention provides a method for preparing the polymer composite of the first aspect, the method comprising the steps of:

and stirring and mixing the polymer powder and the nano-particles A for the first time, stirring and mixing the mixed raw materials and the nano-particles B for the second time, and screening to obtain the polymer compound.

In the process of preparing the polymer composite, the polymer powder is preferentially mixed with the nano-particles A with smaller particle size, so that the polymer powder can be coated on the surface of the particles in a better compact manner, while the nano-particles B with larger particle size influence the coverage of the nano-particles with smaller particle size on the surface of the polymer powder if the nano-particles B are mixed firstly.

Preferably, the time for the first stirring and mixing is 1-15min, such as 2min, 3min, 4min, 5min, 6min, 7min, 8min, 9min, 10min, 11min, 12min, 13min, 14min, etc., preferably 1-3min.

Preferably, the second stirring and mixing time is 1-6min, such as 1.5min, 2min, 2.5min, 3min, 3.5min, 4min, 4.5min, 5min, 5.5min, etc., preferably 1-2min.

The stirring and mixing of the invention is continuous stirring and mixing, and the mixing time is not enough, so that the polymer powder and the nano particles can not be uniformly mixed; too long a mixing time may result in loss and intercalation of the nanoparticles, thereby losing the effect of the composite nanoparticles.

Preferably, the sieving is performed by a sieve.

Preferably, the mesh number of the screen is 50 to 300 mesh, such as 60 mesh, 80 mesh, 100 mesh, 120 mesh, 140 mesh, 160 mesh, 180 mesh, 200 mesh, 220 mesh, 240 mesh, 260 mesh, and the like. The mesh number of the screen is 50-300 meshes, and the particle size of particles passing through the screen is 30-500 meshes.

As a preferred technical scheme, the preparation method comprises the following steps:

and stirring and mixing the polymer powder and the nano-particles A for the first time for 1-15min, stirring and mixing the mixed raw materials and the nano-particles B for the second time for 1-6min, and finally screening by using a screen with the mesh number of 50-300 to obtain the polymer compound.

In a third aspect, the present invention provides a use of the polymer composite of the first aspect in powder coating or 3D printing.

Compared with the prior art, the invention has the following beneficial effects:

the small-particle-size and large-particle-size nano particles adopted by the invention are compounded in a specific ratio, and the small-particle-size and large-particle-size nano particles and the nano particles are used as a flowing agent of polymer powder under the synergistic effect, so that the polymer compound has excellent fluidity, permeability and high-temperature stability. Taking the polymer powder as thermoplastic polyurethane as an example, the SE flow energy of the polymer composite is below 7.75mJ/g, the FRI is below 1.35, and the permeability is above 4.11 mbar.

Drawings

FIG. 1 is a scanning electron micrograph of a polymer composite according to example 1;

FIG. 2 is a scanning electron micrograph of a polymer composite according to example 1 heated at 100 ℃;

FIG. 3 is a scanning electron micrograph of a polymer composite according to example 2;

FIG. 4 is a scanning electron micrograph of a polymer composite according to example 2 heated at 135 ℃;

FIG. 5 is a scanning electron micrograph of a polymer composite according to example 3;

FIG. 6 is a scanning electron micrograph of a polymer composite according to example 4;

FIG. 7 is a scanning electron micrograph of a polymer composite according to example 6;

FIG. 8 is a scanning electron micrograph of a polymer composite according to example 8;

FIG. 9 is a scanning electron micrograph of a polymer composite according to comparative example 1;

FIG. 10 is a scanning electron micrograph of a polymer composite described in comparative example 1 after heating at 100 ℃;

FIG. 11 is a scanning electron micrograph of a polymer composite according to comparative example 2.

Detailed Description

For the purpose of facilitating an understanding of the present invention, the present invention will now be described by way of examples. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

Example 1

This example provides a polymer composite, which is composed of the following components in parts by weight: 100 parts of polymer powder, 0.3 part of nanoparticle a and 0.13 part of nanoparticle B;

the polymer powder: the thermoplastic polyurethane after cryogenic grinding has the median particle diameter of 65 mu m and the hardness of ShoreA 90, and the raw materials are purchased from Wanhua chemical group GmbH with the brand of WHT-1490IV;

and (3) nanoparticles A: nano silicon dioxide with the particle size of 12nm;

and (3) nanoparticles B: nanometer silicon dioxide with particle size of 50nm.

The preparation method of the polymer composite comprises the following steps:

mixing the polymer powder and the nano-particles A for the first time for 2min, then mixing the mixed raw materials with the nano-particles B for the second time for 1min, and finally sieving by using a 50-mesh sieve to obtain the polymer compound.

Example 2

This example provides a polymer composite, which is composed of the following components in parts by weight: 100 parts of polymer powder, 0.5 part of nanoparticle a and 0.33 part of nanoparticle B;

the polymer powder: the polypropylene after cryogenic grinding has a median particle size of 50 μm, and the raw material is purchased from Wanhua chemical group Limited company and has a mark number of WANFAB GP1000;

the nano-particles A: nano silicon carbide with the particle size of 5nm;

and (3) nanoparticles B: nanometer alumina with particle size of 80nm.

The preparation method of the polymer composite comprises the following steps:

and mixing the polymer powder and the nano-particles A for 3min for the first time, mixing the mixed raw materials with the nano-particles B for 2min for the second time, and finally sieving by using a 70-mesh sieve to obtain the polymer compound.

Example 3

This example provides a polymer composite, which is composed of the following components in parts by weight: 100 parts of polymer powder, 3 parts of nanoparticle A and 0.75 part of nanoparticle B;

the polymer powder: the phenolic resin after cryogenic grinding has the median particle size of 5 mu m and the raw material brand of 2123;

and (3) nanoparticles A: nano titanium dioxide with the particle size of 5nm;

and (3) nanoparticles B: the grain size of the nanometer silicon carbide is 50nm.

The preparation method of the polymer composite comprises the following steps:

mixing the polymer powder and the nano-particles A for the first time for 15min, then mixing the mixed raw materials and the nano-particles B for the second time for 6min, and finally screening by using a 300-mesh screen to obtain the polymer compound.

Example 4

This example provides a polymer composite, which is composed of the following components in parts by weight: 100 parts of polymer powder, 0.2 part of nanoparticles a and 0.06 part of nanoparticles B;

the polymer powder: the thermoplastic polyurethane after cryogenic grinding has the median particle size of 500 mu m and the hardness of ShoreA 90, and the raw material is purchased from Wanhua chemical group Limited company and has the brand number of WHT-1490IV;

the nano-particles A: nano silicon dioxide with the particle size of 50nm;

and (3) nanoparticles B: talcum powder with particle diameter of 600nm.

The preparation method of the polymer composite comprises the following steps:

mixing the polymer powder and the nano-particles A for the first time for 1min, then mixing the mixed raw materials and the nano-particles B for the second time for 1min, and finally sieving by using a 50-mesh sieve to obtain the polymer compound.

Example 5

This example provides a polymer composite, which is composed of the following components in parts by weight: 100 parts of polymer powder, 0.1 part of nanoparticle a and 0.05 part of nanoparticle B;

the polymer powder: the thermoplastic polyurethane after cryogenic grinding has the median particle diameter of 150 mu m and the hardness of ShoreA 90, and the raw materials are purchased from Wanhua chemical group GmbH with the brand of WHT-1490IV;

and (3) nanoparticles A: nano titanium dioxide with the particle size of 30nm;

and (3) nanoparticles B: talcum powder with particle size of 300nm.

The preparation method of the polymer composite comprises the following steps:

mixing the polymer powder and the nano-particles A for the first time for 1min, then mixing the mixed raw materials and the nano-particles B for the second time for 2min, and finally screening by using a 60-mesh screen to obtain the polymer compound.

Example 6

This example provides a polymer composite, which is composed of the following components in parts by weight: 100 parts of polymer powder, 2 parts of nanoparticles a and 0.75 part of nanoparticles B;

the polymer powder: the thermoplastic polyurethane after cryogenic grinding has the median particle size of 10 mu m and the hardness of ShoreA 90, and the raw material is purchased from Wanhua chemical group Limited company and has the brand number of WHT-1490IV;

and (3) nanoparticles A: nano silicon carbide with the particle size of 5nm;

and (3) nanoparticles B: nanometer silicon dioxide with particle size of 50nm.

The preparation method of the polymer composite comprises the following steps:

mixing the polymer powder and the nano-particles A for the first time for 1.5min, then mixing the mixed raw materials and the nano-particles B for the second time for 1min, and finally screening by using a 300-mesh screen to obtain the polymer compound.

Example 7

This example provides a polymer composite, which is composed of the following components in parts by weight: 100 parts of polymer powder, 2 parts of nanoparticles a and 0.5 part of nanoparticles B;

the polymer powder: the thermoplastic polyurethane after cryogenic grinding has the median particle size of 300 mu m and the hardness of ShoreA 90, and the raw materials are purchased from Wanhua chemical group Limited company and have the brand number of WHT-1490IV;

the nano-particles A:1 part of nano silicon dioxide with the grain diameter of 35nm,1 part of nano titanium dioxide with the grain diameter of 35nm;

and (3) nanoparticles B:0.25 part of nano silicon carbide with the grain diameter of 150nm,0.25 part of nano aluminum oxide with the grain diameter of 150nm.

The preparation method of the polymer composite comprises the following steps:

mixing the polymer powder and the nano-particles A for the first time for 2min, then mixing the mixed raw materials and the nano-particles B for the second time for 2min, and finally screening by using a 50-mesh screen to obtain the polymer compound.

Example 8

This example provides a polymer composite, which is composed of the following components in parts by weight: 100 parts of polymer powder, 1 part of nanoparticles a and 0.3 part of nanoparticles B;

the polymer powder: the polypropylene after the cryogenic grinding has the median particle size of 80 μm, and the raw material is purchased from Wanhua chemical group GmbH with the trade mark of WANFAB GP1000;

and (3) nanoparticles A:0.5 part of nano silicon dioxide with the grain diameter of 15nm,0.5 part of nano silicon carbide with the grain diameter of 15nm;

and (3) nanoparticles B:0.15 part of nano silicon carbide with the grain diameter of 100nm,0.15 part of nano silicon dioxide with the grain diameter of 100nm.

The preparation method of the polymer composite comprises the following steps:

mixing the polymer powder and the nano-particles A for the first time for 2min, then mixing the mixed raw materials and the nano-particles B for the second time for 3min, and finally screening by using a 60-mesh screen to obtain the polymer compound.

Examples 9 to 12

Examples 9 to 12 differ from example 1 in that the mass ratio of nanoparticles a to nanoparticles B was different, the total mass of nanoparticles a to nanoparticles B was 0.6 parts;

in examples 9 to 12, the mass ratios of nanoparticles a to nanoparticles B were 9 (example 9), 1 (example 10), 4.

Examples 13 to 16

Examples 13 to 16 differ from example 1 in that the particle diameters of nanoparticles A were 5nm (example 13), 50nm (example 14), 3nm (example 15) and 60nm (example 16), respectively, and the rest was the same as in example 1.

Examples 17 to 19

Examples 17 to 19 differ from example 1 in that the particle diameters of nanoparticles B were 600nm (example 17), 30nm (example 18) and 700nm (example 19), respectively, and the rest was the same as in example 1.

Comparative example 1

The comparative example provides a polymer composite consisting of, in parts by weight: 100 parts of polymer powder and 0.5 part of small-particle-size nano-particles;

the polymer powder: the thermoplastic polyurethane after cryogenic grinding has the median particle size of 60 mu m and the hardness of ShoreA 90, and the raw materials are purchased from Wanhua chemical group Limited company and have the brand number of WHT-1490IV;

small particle size nanoparticles: nanometer silicon dioxide with particle size of 15nm.

The preparation method of the polymer composite comprises the following steps:

and mixing the polymer powder and the small-particle-size nanoparticles for 2min, and screening by using a 50-mesh screen to obtain the polymer composite.

Comparative example 2

The present comparative example provides a polymer composite consisting of, in parts by weight: 100 parts of polymer powder and 0.7 part of large-particle-size nanoparticles;

the polymer powder: the thermoplastic polyurethane after cryogenic grinding has the median particle diameter of 80 mu m and the hardness of ShoreA 90, and the raw materials are purchased from Wanhua chemical group GmbH with the brand of WHT-1490IV;

large-particle-size nanoparticles: nano silicon dioxide with the particle size of 100nm.

The preparation method of the polymer composite comprises the following steps:

and mixing the polymer powder and the large-particle-size nanoparticles for 3min, and screening by using a 80-mesh screen to obtain the polymer composite.

Comparative examples 3 to 4

Comparative examples 3 to 4 are different from example 1 in that the mass ratio of nanoparticles a to nanoparticles B is different, and the total mass of nanoparticles a to nanoparticles B is 0.6 parts;

in comparative examples 3 to 4, the mass ratio of nanoparticles a to nanoparticles B was 10.

And (3) performance testing:

the polymer composites described in examples 1-19 and comparative examples 1-4 were tested as follows:

(1) Flow property: fully drying a sample, measuring by using a Furimann FT4 powder rheometer, starting test software, selecting a required test method of 'stability and variable flow rate' to test fluidity, wherein the test result comprises flow activation energy, the 'permaability' test air permeability of 1-15 kPa, and the test result comprises a pressure drop of 1-15 kPa, and finally performing data processing;

(2) Bulk density: measuring with a Baite BT-1000 powder comprehensive characteristic tester, cleaning a density container, keeping the inside dry, adjusting the density container to be horizontal, opening the powder comprehensive characteristic tester, and loading a loose density container of 100m, wherein the distance between a funnel opening and the upper edge of a density cup is 40 mm;

weighing 100g of a powder sample, pouring the powder sample into a funnel above a tester, and blocking a feed opening of the funnel;

quickly opening a feed opening of the funnel, enabling the sample in the funnel to vertically fall into the density container in a natural state, scraping the redundant sample at the top of the density cup by using a scoop, tapping the density cup to fix the sample, and recording the mass M1 of the powder in the container and the bulk density rho (g/cm) ³ )＝M1/100；。

The test was performed several times, ensuring the repeatability of the results, the test results are summarized in table 1.

TABLE 1

The data in the table 1 are analyzed, and it can be seen that, taking the polymer powder as thermoplastic polyurethane as an example, the SE flow energy of the polymer composite is below 7.75mJ/g, the FRI is below 1.35, and the permeability is above 4.11 mbar; the air permeability and pressure drop of the polymer composite are obviously higher, the powder is more tightly stacked, the gaps among particles are less, the result is consistent with the result of the bulk density, the BFE flow energy is the powder comprehensively representing the bulk density and the powder cohesion property, the bulk density is high, the cohesion property is high, the higher the energy required by the blade of the powder rheometer is to push, and the BFE also shows an increasing trend. Therefore, the polymer composite of the present invention has excellent fluidity and permeability.

As can be seen from the analysis of comparative examples 1-2 and example 1, although the bulk density in comparative example 2 is relatively large due to the selection of the large-particle-diameter powder, since the bulk density is not as sensitive to the flowability as much as the influence on the particle diameter, it can be inferred that comparative examples 1-2 are still inferior in performance to example 1, demonstrating that the use of the synergistic combination of nanoparticles a and nanoparticles B can serve as a flow agent for polymer powder to form a polymer composite having excellent flowability and high-temperature stability.

As is clear from the analysis of comparative examples 3-4 and examples 9-10, comparative examples 3-4 do not perform as well as examples 9-10, demonstrating that the mass ratio of nanoparticles A to nanoparticles B is better than that of the polymer composites obtained in the range of (1-9): 1.

As can be seen from the analysis of examples 9-12, examples 9-10 do not perform as well as examples 11-12, demonstrating that the preferred mass ratio of nanoparticles A to nanoparticles B (1.5-4): 1 gives polymer composites with better performance.

Analysis of examples 13-16 reveals that examples 15-16 do not perform as well as examples 13-14, demonstrating that the particle size of nanoparticle A is in the range of 5-50nm to better cooperate with nanoparticle B to improve the performance of the polymer composite.

As can be seen from the analysis of examples 17-19 and example 1, examples 18-19 are inferior to examples 1 and 17, and it is demonstrated that the particle size of nanoparticle B is in the range of 50-600nm to better enhance the performance of the polymer composite in cooperation with nanoparticle A.

As can be seen from comparing fig. 1 and fig. 2, in fig. 1, nanoparticles B and nanoparticles a are uniformly distributed in the polymer powder matrix; after the polymer composite is heated at 100 ℃, the nano particles B and the nano particles A are still uniformly distributed in the polymer powder matrix, and loss and embedding phenomena do not occur, so that the polymer composite provided by the invention is proved to have excellent high-temperature stability. Similar results were obtained comparing fig. 3 and fig. 4.

Comparing fig. 9 and 10, it can be seen that the nanoparticles of a single type in fig. 9 are uniformly distributed in the polymer powder matrix, but after heating, the nanoparticles in fig. 10 are significantly embedded and lost, which affects the heat resistance and high temperature fluidity of the polymer composite.

Therefore, the polymer composite formed by compounding the nano-particles A and the nano-particles B in a specific ratio and mixing the polymer powder has excellent fluidity and high-temperature thermal stability.

As can be seen from the analysis of fig. 5 to 8, the polymer composites obtained by appropriately adjusting the particle sizes and kinds of nanoparticles a, B and polymer powders have excellent fluidity and high-temperature thermal stability, although the present invention does not give scanning electron microscopy images after high-temperature heating, it is presumed from the results of examples 1 to 2 and comparative example 1 that examples 3 to 4, 6 and 8 also have similar results, i.e., the polymer composites formed by mixing nanoparticles a and B in a specific ratio have excellent fluidity and high-temperature thermal stability; while the nanoparticles are uniformly distributed in fig. 11, it can also be predicted to have similar results as comparative example 1, i.e., nanoparticles of a single particle size species have limited improvement in the properties of the polymer powder, especially high temperature stability and flowability.

The applicant states that the present invention is illustrated in detail by the above examples, but the present invention is not limited to the above detailed methods, i.e. it is not meant that the present invention must rely on the above detailed methods for its implementation. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.

Claims (10)

1. The polymer composite is characterized by comprising the following components in parts by weight: 100 parts of polymer powder, 0.1-3 parts of nano-particles A and 0.05-1.5 parts of nano-particles B;

wherein the particle size of the nanoparticle A is smaller than that of the nanoparticle B;

the mass ratio of the nano-particles A to the nano-particles B is (1-9): 1.

2. The polymer composite according to claim 1, wherein the mass ratio of the nanoparticles A to the nanoparticles B is (1.5-4): 1.

3. The polymer composite according to claim 1 or 2, wherein the nanoparticles a have a particle size of 5-50nm;

preferably, the particle size of the nanoparticles B is 50 to 600nm.

4. The polymer composite according to any one of claims 1 to 3, wherein the polymer powder has a median particle diameter of 5 to 500 μm.

5. The polymer composite according to any of claims 1 to 4, wherein the polymer powder comprises a thermoplastic polymer powder and/or a thermosetting polymer powder;

preferably, the polymer powder comprises a thermoplastic polymer powder;

preferably, the thermoplastic polymer powder comprises any one of, or a combination of at least two of, a thermoplastic elastomer, a polyamide, a polyolefin, a polymethacrylate, a polycarbonate, or a polystyrene;

preferably, the nanoparticles a comprise any one of or a combination of at least two of nano-silica, nano-titania or nano-silicon carbide;

preferably, the nanoparticles B comprise any one of or a combination of at least two of nano-silica, nano-titania, nano-silicon carbide, nano-alumina, talc, magnesium stearate or magnesium oxide.

6. A method of preparing a polymer composite according to any one of claims 1 to 5, comprising the steps of:

and stirring and mixing the polymer powder and the nano-particles A for the first time, stirring and mixing the mixed raw materials and the nano-particles B for the second time, and screening to obtain the polymer compound.

7. The method according to claim 6, wherein the time for the first stirring and mixing is 1-15min;

preferably, the time for the second stirring and mixing is 1-6min.

8. The production method according to claim 6 or 7, wherein the sieving is performed by a screen;

preferably, the mesh number of the screen is 50-300 meshes.

9. The method according to any one of claims 6 to 8, characterized by comprising the steps of:

and stirring and mixing the polymer powder and the nano-particles A for the first time for 1-15min, stirring and mixing the mixed raw materials and the nano-particles B for the second time for 1-6min, and finally screening by using a screen with the mesh number of 50-300 to obtain the polymer compound.

10. Use of a polymer composite according to any one of claims 1 to 5 in powder coating or 3D printing.

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