CN107857994A - Nylon composite material and preparation method thereof - Google Patents

Abstract

The invention provides a nylon composite material and a preparation method thereof. The raw materials for the preparation of the nylon composite material include nylon 6 and fluorocarbon materials. The nylon composite material prepared by the preparation method of the invention not only improves the dispersibility of the system, but also The mechanical properties of the material are improved, and the mechanical, friction resistance, heat resistance, self-cleaning, electrical insulation, water repellency and other properties of nylon composite materials are effectively improved.

Description

A kind of nylon composite material and preparation method thereof

technical field

The invention belongs to the field of composite materials, and relates to a nylon composite material and a preparation method thereof.

Background technique

Nylon (Nylon) is a term for polyamide fibers, which can be made into long or short fibers. Nylon is the trade name of polyamide fiber, also known as nylon, and its English name is Polyamide (referred to as PA). Its basic composition is aliphatic polyamide linked by amide bonds [NHCO]. Commonly used nylon can be divided into two categories: one is polyhexamethylene adipate obtained by polycondensation of hexamethylenediamine and adipic acid, and the chemical structure formula of its long-chain molecule is The other is obtained by polycondensation or ring-opening polymerization of caprolactam, and the chemical structural formula of its long-chain molecules is: PA has good comprehensive properties, including mechanical properties, heat resistance, wear resistance, chemical resistance and self-lubricating properties, and low friction coefficient, certain flame retardancy, easy processing, suitable for glass fiber and Other fillers are used to enhance and modify, improve performance and expand application range. It is mainly used in synthetic fibers to replace metals such as steel, iron, and copper. It is an important engineering plastic; it can also be used as raw materials for various medical and knitwear.

The modification of nylon is based on nylon, adding substances that can change its physical properties to change the various properties of nylon. Modification methods include copolymerization modification, blending modification and other methods. Through such a conventional method, the mechanical properties, wear resistance, corrosion resistance, and molding process of nylon are relatively good, while the mechanical properties, self-cleaning properties, heat resistance, water absorption and other properties need to be improved. However, most of the additives in the modified nylon prepared by conventional modification methods are not well dispersed, which limits the addition ratio of additives and the performance of nylon composite materials; at this time, it is necessary to add dispersants, solvents, etc. to enhance the dispersion of nylon , mechanical properties, etc., but the addition of dispersant has caused problems such as complicated preparation process and increased production cost.

Fluorinated graphite, also known as polyfluorocarbon or fluorinated carbon, is a new type of carbon material with excellent performance and unique quality. It has excellent lubricity, good solvent resistance, good weather resistance, non-toxic, non-flammable, non-corrosive, and stable chemical properties. It is an excellent high-energy electrode material, insulating material, waterproof material, and lubricating material.

CN107189418A discloses a toughened nylon 6 and its preparation method. The toughened nylon 6 is prepared by blending nylon 6 and a toughening agent phosphate compound, but this material only solves the problem of unstable mechanical properties, and cannot improve Dispersion of the material as a whole; CN102344676A discloses glass fiber reinforced nylon 6, including nylon 6: 50.5-95%, alkali-free glass fiber: 4.5-55.5%, trichloroethane: 2.6-35%, heat stabilizer: 0.1 -3.0%, glass fiber treatment agent: 0.1-3.0%, other additives: 1.3-5.5%, which solves the problem of the two-phase interface combination of glass fiber and nylon 6, improves the surface finish of the product, and makes the finished product durable Wear resistance, although this method improves the wear resistance, it does not improve the dispersion, mechanical properties, water absorption and other properties of the system, which has certain defects.

Therefore, it is necessary to develop a nylon composite material with various excellent properties to solve some problems existing in the current materials.

Contents of the invention

Aiming at the deficiencies of the prior art, the object of the present invention is to provide a nylon composite material and a preparation method thereof.

To achieve this purpose of the invention, the present invention adopts the following technical solutions:

In one aspect, the present invention provides a nylon composite material, wherein the raw materials for the preparation of the nylon composite material include nylon 6 and graphite fluoride.

In the present invention, the fluorocarbon material is introduced into the nylon system, and the fluorocarbon bond in the fluorocarbon material can react with the amide bond in the nylon composite material under the high temperature environment during mixing to form a crosslinked structure and bring about a change in properties , without adding other additives such as solubilizer, the nylon composite material with high performance is prepared by mixing and injection molding, which not only improves the dispersion of the system, but also improves the mechanical properties of the material, and effectively improves the performance of the nylon composite material. Mechanical, friction resistance, heat resistance, self-cleaning, electrical insulation, water repellency and other properties.

Preferably, the mass percentage of the nylon 6 in the nylon composite material is 75-99.9%, such as 75%, 80%, 85%, 90%, 95%, 98% or 99.9%.

Preferably, the mass percentage of the fluorinated graphite in the nylon composite material is 0.1-25%, such as 0.1%, 1%, 5%, 10%, 15%, 20% or 25%.

Preferably, the fluorocarbon material is one or a combination of at least two of fluorinated graphite, fluorinated graphene, fluorinated carbon nanotubes, fluorinated fullerenes, fluorinated carbon black or fluorinated pitch.

On the other hand, the present invention provides a kind of preparation method of nylon composite material, and described preparation method comprises the steps:

(1) Nylon 6 is dried, and then mixed with a fluorocarbon material to obtain a product;

(2) The nylon composite material is obtained by crushing, drying and injection molding the product described in step (1).

Preferably, the drying temperature in step (1) is 50-70°C, for example, 50°C, 55°C, 60°C, 65°C or 70°C.

Preferably, the drying time in step (1) is 10-48 hours, for example, it can be 10 hours, 20 hours, 30 hours, 40 hours or 48 hours.

In the present invention, the nylon 6 is dried to remove moisture in the nylon 6, so that the subsequent mixing effect is better.

Preferably, the mixing in step (1) is performed in a rheometer.

Preferably, the rotational speed of the rheometer is 40-80 rpm, for example, 40 rpm, 50 rpm, 60 rpm, 70 rpm or 80 rpm.

Preferably, the kneading temperature in step (1) is 220-250°C, for example, 220°C, 230°C, 240°C or 250°C.

Preferably, the kneading time in step (1) is 12-17 minutes, such as 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes or 17 minutes.

In the present invention, the kneaded product is pulverized into granules suitable for injection molding.

Preferably, the drying temperature in step (2) is 50-70°C, for example, 50°C, 55°C, 60°C, 65°C or 70°C.

Preferably, the drying time in step (2) is 10-13 hours, such as 10 hours, 11 hours, 12 hours or 13 hours.

In the present invention, the crushed particles are dried before injection molding, and the water is removed again, which is beneficial for subsequent injection molding into nylon composite materials meeting the national standard.

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

The present invention introduces the fluorocarbon material into the nylon system. The fluorocarbon bond of the fluorocarbon material can react with the amide bond in the nylon composite material under the high temperature environment during mixing to form a cross-linked structure, which brings about a change in properties. In the case of other additives such as solubilizers, high-performance nylon composite materials are obtained through mixing and injection molding, which not only improves the dispersion of the system, but also improves the mechanical properties of the material, effectively improving the mechanical and friction resistance of nylon composite materials. , heat resistance, self-cleaning, electrical insulation, water repellency and other properties.

Description of drawings

Fig. 1A is a scanning electron microscope image of a liquid nitrogen brittle section of a nylon composite material containing 0.5% graphite fluoride prepared in Example 2 of the present invention.

Fig. 1B is a scanning electron microscope image of the liquid nitrogen brittle section of the nylon composite material containing 5% graphite fluoride prepared in Example 4 of the present invention.

Fig. 1C is a scanning electron microscope image of the liquid nitrogen brittle section of the nylon composite material containing 15% graphite fluoride prepared in Example 7 of the present invention.

Fig. 2 is a columnar analysis diagram of the elastic modulus of the nylon composite material prepared in Examples 1-9 of the present invention.

Fig. 3 is a dynamic thermomechanical analysis diagram of Example 5, Example 6, Example 7, Example 9 and pure nylon 6 of the present invention.

Fig. 4A is an analysis diagram of the water absorption of Example 5, Example 6, Example 7, Example 9 of the present invention and pure nylon 6 at different times.

Fig. 4B is an analysis diagram of percentage weight gain after water absorption of Example 5, Example 6, Example 7, Example 9 of the present invention and pure nylon 6 in a water environment for 250 hours.

Detailed ways

The technical solutions of the present invention will be further described below through specific embodiments. It should be clear to those skilled in the art that the embodiments are only for helping to understand the present invention, and should not be regarded as specific limitations on the present invention.

Example 1

The graphite fluoride mass fraction is a nylon composite material of 3%, and the specific preparation method is as follows:

(1) Nylon 6 was dried at 60°C for 12 hours, then mixed with fluorinated graphite in a rheometer, and mixed at 240°C and 50 rpm for 15 minutes to obtain the product;

(2) The product described in step (1) was pulverized, dried at 60°C for 12 hours, and injected to obtain a nylon composite material with a mass of 3% graphite fluoride.

Example 2

The graphite fluoride mass fraction is a nylon composite material of 0.5%, and the specific preparation method is as follows:

(1) Nylon 6 was dried at 50°C for 13 hours, then mixed with fluorinated graphite in a rheometer, and mixed at 220°C and 80 rpm for 12 minutes to obtain the product;

(2) The product described in the step (1) was pulverized, dried at 50°C for 13 hours, and injected to obtain a nylon composite material with a mass of 0.5% graphite fluoride.

The prepared nylon composite material was subjected to scanning electron microscope analysis of the liquid nitrogen brittle section, as shown in Figure 1A, on the cross-sectional surface of the nylon composite material, we can see well-dispersed fluorocarbon material particles, and there are many other particles on the surface. The folds in the center indicate that the fluorocarbon material acts as a stress dispersion point, which improves the mechanical properties of the nylon composite.

Example 3

The graphite fluoride mass fraction is a nylon composite material of 1%, and the specific preparation method is as follows:

(1) Dry nylon 6 at 70°C for 10 hours, then mix it with fluorinated graphite in a rheometer, and knead at 250°C and 40 rpm for 17 minutes to obtain the product;

(2) The product described in step (1) was pulverized, dried at 70° C. for 10 hours, and injected to obtain a nylon composite material with 1% graphite fluoride mass.

Example 4

The graphite fluoride mass fraction is the nylon composite material of 5%, and the specific preparation method is as follows:

(1) Nylon 6 was dried at 62°C for 12 hours, then mixed with fluorinated graphite in a rheometer, and mixed at 230°C and 50 rpm for 13 minutes to obtain the product;

(2) The product described in step (1) was pulverized, dried at 60° C. for 12 hours, and injected to obtain a nylon composite material with a mass of 5% graphite fluoride.

The prepared nylon composite material was subjected to scanning electron microscope analysis of the liquid nitrogen brittle section, as shown in Figure 1B, on the cross-sectional surface of the nylon composite material, we can see well-dispersed fluorocarbon material particles, which improves the nylon composite material. Mechanical behavior.

Example 5

The graphite fluoride mass fraction is a nylon composite material with a mass fraction of 7%, and the specific preparation method is as follows:

(1) Nylon 6 was dried at 60°C for 12 hours, then mixed with fluorinated graphite in a rheometer, and mixed at 240°C and 50 rpm for 15 minutes to obtain the product;

(2) The product described in step (1) was pulverized, dried at 60°C for 12 hours, and injected to obtain a nylon composite material with a mass of 7% graphite fluoride.

Example 6

The graphite fluoride mass fraction is a nylon composite material of 10%, and the specific preparation method is as follows:

(1) Dry nylon 6 at 60°C for 30 hours, then mix it with fluorinated graphite in a rheometer, and knead at 240°C and 50 rpm for 15 minutes to obtain the product;

(2) The product described in step (1) was pulverized, dried at 60° C. for 12 hours, and injected to obtain a nylon composite material with 10% graphite fluoride mass.

Example 7

The graphite fluoride mass fraction is the nylon composite material of 15% (recorded as 15%-1), and the specific preparation method is as follows:

(1) Dry nylon 6 at 60°C for 48 hours, then mix it with fluorinated graphite in a rheometer, and knead at 240°C and 50 rpm for 15 minutes to obtain the product;

(2) The product described in step (1) was pulverized, dried at 60° C. for 12 hours, and injected to obtain a nylon composite material with a mass of fluorinated graphite of 15%.

The prepared nylon composite material was subjected to scanning electron microscope analysis of the liquid nitrogen brittle section, as shown in Figure 1C, on the cross-sectional surface of the nylon composite material, we can see well-dispersed fluorocarbon material particles, which improves the nylon composite material. Mechanical behavior.

Example 8

The graphite fluoride mass fraction is the nylon composite material of 15% (recorded as 15%-2), and the specific preparation method is as follows:

(1) Nylon 6 was dried at 60°C for 12 hours, then mixed with fluorinated graphite in a rheometer, and mixed at 240°C and 50 rpm for 15 minutes to obtain the product;

(2) The product described in step (1) was pulverized, dried at 60° C. for 12 hours, and injected to obtain a nylon composite material with a mass of fluorinated graphite of 15%.

Example 9

The graphite fluoride mass fraction is a nylon composite material of 20%, and the specific preparation method is as follows:

(1) Nylon 6 was dried at 60°C for 12 hours, then mixed with fluorinated graphite in a rheometer, and mixed at 240°C and 50 rpm for 15 minutes to obtain the product;

(2) The product described in step (1) was pulverized, dried at 60° C. for 12 hours, and injected to obtain a nylon composite material with a mass of fluorinated graphite of 20%.

Example 10

The nylon composite material whose mass fraction of fluorinated graphite is 0.1%, the specific preparation method is as follows:

(1) Nylon 6 was dried at 60°C for 12 hours, then mixed with fluorinated graphite in a rheometer, and mixed at 240°C and 50 rpm for 15 minutes to obtain the product;

(2) The product described in the step (1) was pulverized, dried at 60°C for 12 hours, and injected to obtain a nylon composite material with a mass of 0.1% graphite fluoride.

Example 11

The graphite fluoride mass fraction is a nylon composite material of 25%, and the specific preparation method is as follows:

(1) Nylon 6 was dried at 60°C for 12 hours, then mixed with fluorinated graphite in a rheometer, and mixed at 240°C and 50 rpm for 15 minutes to obtain the product;

(2) The product described in step (1) was pulverized, dried at 60° C. for 12 hours, and injected to obtain a nylon composite material with a mass of fluorinated graphite of 25%.

Example 12

The fluorinated graphene mass fraction is a nylon composite material of 3%, and the specific preparation method is as follows:

(1) Nylon 6 was dried at 60°C for 12 hours, then mixed with fluorinated graphene in a rheometer, and mixed at 240°C and 50 rpm for 15 minutes to obtain the product;

(2) The product described in step (1) was pulverized, dried at 60° C. for 12 hours, and injection-molded to obtain a nylon composite material with a mass of fluorinated graphene of 3%.

Example 13

A nylon composite material with a mass fraction of fluorinated carbon nanotubes of 3%, the specific preparation method is as follows:

(1) Nylon 6 was dried at 60°C for 12 hours, then mixed with fluorinated carbon nanotubes in a rheometer, and mixed at 240°C and 50 rpm for 15 minutes to obtain the product;

(2) The product described in step (1) was pulverized, dried at 60° C. for 12 hours, and injected to obtain a nylon composite material with a mass of fluorinated carbon nanotubes of 3%.

Example 14

The nylon composite material with a mass fraction of fluorinated asphalt of 3%, the specific preparation method is as follows:

(1) Dry nylon 6 at 60°C for 12 hours, then mix it with fluorinated pitch in a rheometer, and mix at 240°C and 50 rpm for 15 minutes to obtain the product;

(2) The product described in step (1) was pulverized, dried at 60° C. for 12 hours, and injected to obtain a nylon composite material with a mass of fluorinated pitch of 3%.

Comparative example 1

The difference between this comparative example and Example 1 is that the mass fraction of graphite fluoride in this comparative example is 30%, and the mass fraction of nylon 6 is 70%. The preparation method is the same as in Example 1.

Example 15

The nylon composite material prepared in Example 2, Example 3, Example 4, Example 6, Example 7 and pure nylon 6 material were tested for tribological properties, and the specific steps were as follows:

(1) Heat-treat the sample strip of the material (130°C, 1 hour), then soak it in acetone and ultrasonically clean it for 30 minutes to remove impurities on the surface, and then dry the sample strip in an oven;

(2) Polish the steel ring on the friction pair surface with 1200 mesh sandpaper for two minutes, and clean it with alcohol;

(3) Fix the sample strip for testing. The rotation speed is 100rpm, and the time is 2 hours;

(4) Record and calculate the friction coefficient, and the specific results are shown in Table 1 below.

Table 1

It can be seen from the results in the table that the friction coefficient of the nylon composite material added with graphite fluoride is reduced, and it has better friction resistance.

Example 16

Mechanical Properties Test of Nylon Composites

Tensile tests were performed on the nylon composite materials prepared in Examples 1-9 and pure nylon 6, and the elastic modulus diagram was obtained. The specific results are shown in Figure 2, from which it can be concluded that the mechanical properties of nylon composites have been greatly improved.

Embodiment 5, embodiment 6, embodiment 7, embodiment 9 and pure nylon 6 are carried out thermomechanical performance analysis test (DMA), and specific result is as shown in Figure 3, it can be seen that the thermomechanical performance of nylon composite material has remarkable improved.

The mechanical properties of the nylon composite materials prepared in Examples 1-9 were compared with pure nylon 6 and Comparative Example 1, including elastic modulus, yield strength, and elongation. The specific results are shown in Table 2 below. The results show that the nylon 6 composite material prepared by adding 0.5% graphite fluoride exhibits good mechanical properties due to the good dispersion and bonding (no agglomeration) of graphite fluoride in the collective. At the same time, considering economic factors, adding 0.5% graphite fluoride is the best addition amount for mechanical properties. However, due to the difficulty of dispersion and compatibility, when the content of the fluorocarbon material added in the nylon composite material is greater than 25%, there are problems in the injection molding process of the nylon composite material. The range of fractions can optimize the performance of nylon composites; in addition, if the content of additives is too high, it will violate the original intention of preparing nylon composites.

Table 2

Water Absorption Performance Test of Nylon Composite Materials

Nylon 6 was investigated for its water absorption because it tends to absorb water, resulting in performance degradation. The prepared sample strips (tensile test sample specifications) were put into a vacuum oven and dried at a temperature of 110° C. for 24 hours to remove residual moisture, and then the weight of each sample strip was weighed as the original weight. The dried sample strips were placed in a constant temperature water bath at a temperature of 50°C. Take out the sample strip at regular intervals and wipe off the surface moisture for weighing and recording.

The nylon composite materials prepared in Example 1, Examples 3-9 and pure nylon 6 were tested for water absorption, and the specific results are shown in Figure 4A and Figure 4B.

From the results in the test chart, it can be concluded that the water absorption of the nylon composite material prepared by the present invention decreases with the increase of the mass fraction of the fluorocarbon material, which can improve the performance of the nylon composite material as a whole.

The applicant declares that the present invention illustrates a nylon composite material of the present invention and its preparation method through the above examples, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of selected raw materials in the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

Claims (10)

1. A nylon composite material, characterized in that, the raw materials for preparing the nylon composite material include nylon 6 and fluorocarbon material. 2. The nylon composite material according to claim 1, characterized in that, the mass percentage of the nylon 6 in the nylon composite material is 75-99.9%. 3. The nylon composite material according to claim 1 or 2, wherein the mass percentage of the fluorocarbon material in the nylon composite material is 0.1 to 25%; Preferably, the fluorocarbon material is one or a combination of at least two of fluorinated graphite, fluorinated graphene, fluorinated carbon nanotubes, fluorinated fullerenes, fluorinated carbon black or fluorinated pitch. 4. according to the preparation method of the described nylon composite material of any one of claim 1-3, it is characterized in that, described preparation method comprises the steps: (1) Nylon 6 is dried, and then mixed with a fluorocarbon material to obtain a product; (2) The nylon composite material is obtained by crushing, drying and injection molding the product described in step (1). 5. the preparation method of nylon composite material according to claim 4, is characterized in that, the drying temperature described in step (1) is 50～70 ℃; Preferably, the drying time in step (1) is 12-48 hours. 6. according to the preparation method of the described nylon composite material of claim 4 or 5, it is characterized in that, the mixing described in step (1) is carried out in rheometer; Preferably, the rotational speed of the rheometer is 40-80 rpm. 7. The preparation method of nylon composite material according to any one of claims 4-6, characterized in that, the mixing temperature in step (1) is 220-250°C. 8. The preparation method of nylon composite material according to any one of claims 4-7, characterized in that the mixing time in step (1) is 12-17 minutes. 9. The preparation method of nylon composite material according to any one of claims 4-8, characterized in that, the drying temperature in step (2) is 50-70°C. 10. The preparation method of the nylon composite material according to any one of claims 4-9, characterized in that, the drying time in step (2) is 10-13 hours.