A small-diameter graphene and its preparation method and application, and a PET composite material and its preparation method

Abstract

The present invention provides a small-diameter graphene, a preparation method and application thereof, and a PET composite material and a preparation method thereof, relating to the technical field of graphene materials. In the present invention, graphite, water, glass beads, 1-pyrenemethanol and methanol are mixed and subjected to sand grinding to obtain a graphene / glass bead mixed suspension; the glass beads have different particle sizes, and their particle sizes are 400-600 μm, 150-300 μm, 50-100 μm and 1-40 μm respectively; the graphene / glass bead mixed suspension is allowed to stand and settle to obtain an upper-layer graphene suspension; the graphene suspension is spray-dried to obtain a small-diameter graphene powder. The preparation method provided by the present invention can simply and efficiently prepare graphene with a complete structure and a small particle diameter. Applying the prepared small-diameter graphene to the PET composite material can significantly improve the mechanical properties and electrical conductivity of the PET material.

Description

Technical Field

[0001] The present invention relates to the technical field of graphene materials, and particularly to a small-diameter graphene and its preparation method and application, as well as a PET composite material and its preparation method. Background Art

[0002] Graphene is a two-dimensional carbon nanomaterial composed of a single layer of sp 2 hybridized carbon atoms in a hexagonal honeycomb lattice. The special microstructure of graphene endows it with excellent electrical conductivity, optical properties, ultra-high mechanical properties (Young's modulus of 1.01 TPa and tensile strength of 130 GPa), and excellent thermal conductivity. Therefore, it has broad application prospects in materials science, micro-nano processing, new energy, biomedicine, and drug delivery. At present, common preparation methods of graphene include mechanical exfoliation method, oxidation-reduction method, SiC epitaxial growth method, and chemical vapor deposition method. The preparation process of graphene is directly related to the quality, performance, and application of graphene. For example, graphene prepared by chemical vapor deposition method has thinner layers and a complete structure, and is mainly used in the preparation of high-end graphene films; the mechanical exfoliation method mainly prepares graphene with a layer size of 15 - 20 μm, and graphene that is too large or too small cannot be prepared. Small-diameter graphene (generally refers to graphene with a diameter ≤ 10 μm) is easier to disperse due to its smaller diameter and weaker π-π interaction between layers. For specific application scenarios, such as graphene / polymer masterbatch, graphene-modified fibers, conductive slurries for lithium batteries, etc., small-diameter graphene has more advantages. At present, methods for preparing small-diameter graphene have been reported.

[0003] Chinese Patent CN201910728286.8 discloses a preparation method of small-diameter graphene, including: mixing an alkaline solution dispersed with graphite powder with a soluble salt to obtain a mixed solution containing a grinding aid, and the grinding aid is in a supersaturated state in the mixed solution so that a part of the grinding aid precipitates and disperses in the mixed solution; stirring the mixed solution dispersed with graphite powder and solid particles precipitated from the grinding aid to obtain a graphene dispersion; washing and drying the graphene dispersion. This method uses a large amount of alkaline reagents, which causes great corrosion to the equipment. Later, the grinding aid needs to be removed after the reaction. The process is not only cumbersome but also generates a large amount of waste liquid, which is harmful to the environment and human health.

[0004] Chinese Patent CN201911302670.8 discloses a preparation method of small-diameter graphene powder. The graphene powder is obtained by jet peeling of graphite through a supercritical fluid slit. This method has high requirements for graphene preparation equipment and process control, high overall preparation cost, and low preparation efficiency.

[0005] Chinese Patent CN201811624417.X discloses a method for preparing small-sized single-layer graphene. This method conducts a high-degree oxidative exfoliation on microcrystalline graphite by introducing concentrated phosphoric acid and increasing the dosage of strong oxidant, and then combines purification, ultrasonic crushing, and thermal reduction to obtain small-sized single-layer graphene. This method uses strong oxidants and concentrated acids to prepare graphene oxide, which is then thermally reduced to graphene. It requires a large amount of acid, which is environmentally unfriendly. Improper control of the thermal reduction process easily causes defects in graphene, and the entire process has high energy consumption.

[0006] How to prepare graphene with a complete structure and a small sheet diameter through a simple and efficient method is the technical key for the large-scale application of this material in the future in fields such as chemical fiber, batteries, and plastic modification. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a small-diameter graphene, its preparation method and application, and a PET composite material and its preparation method. The preparation method provided by the present invention can simply and efficiently prepare graphene with a complete structure and a small sheet diameter.

[0008] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0009] The present invention provides a method for preparing small-diameter graphene, comprising the following steps:

[0010] Mix graphite, water, glass beads, 1-pyrenemethanol, and methanol and conduct sand grinding to obtain a graphene / glass bead mixed suspension; the glass beads include first glass beads, second glass beads, third glass beads, and fourth glass beads. The particle sizes of the first glass beads, second glass beads, third glass beads, and fourth glass beads are 400 - 600 μm, 150 - 300 μm, 50 - 100 μm, and 1 - 40 μm respectively, and the mass ratio of the first glass beads, second glass beads, third glass beads, and fourth glass beads is (1 - 2):(2 - 3):(4 - 16):(8 - 20);

[0011] Let the graphene / glass bead mixed suspension stand for sedimentation to obtain an upper-layer graphene suspension;

[0012] Spray-dry the graphene suspension to obtain small-diameter graphene powder.

[0013] Preferably, the graphite includes flake graphite and / or expanded graphite; the particle size of the graphite is 5000 mesh - 20000 mesh.

[0014] Preferably, in terms of mass parts, the graphite, water, glass beads, and 1-pyrenemethanol are 5 - 30 parts, 60 - 100 parts, 10 - 30 parts, and 1 - 10 parts respectively.

[0015] Preferably, the rate of sanding is 300 - 1500 rpm, and the time is 2 - 6 h; the time of static sedimentation is 1 - 2 h.

[0016] The present invention provides small - diameter graphene prepared by the preparation method described in the above technical solution; the small - diameter graphene includes graphene sheets and 1 - pyrenemethanol compounded on the surface of the graphene sheets; the sheet diameter of the graphene sheets is 0.1 - 5 μm, and the thickness of the graphene sheets is 0.34 - 3.4 nm.

[0017] The present invention provides the application of the small - diameter graphene described in the above technical solution in PET composites.

[0018] The present invention provides a PET composite material, which comprises the following raw materials for preparation in parts by mass:

[0019]

[0020] The graphene is the small - diameter graphene described in the above technical solution.

[0021] Preferably, the chain extender includes one or more of 1,4 - butanediol, 1,6 - hexanediol, trimethylolpropane, N,N - dihydroxy(diisopropyl)aniline, and hydroquinone - bis(β - hydroxyethyl)ether; the antioxidant includes one or more of antioxidant 1010, antioxidant 168, antioxidant 1076, antioxidant 1098, and antioxidant 225.

[0022] The present invention provides the preparation method of the PET composite material described in the above technical solution, which comprises the following steps:

[0023] Mix the graphene, PET, chain extender, and antioxidant and perform twin - screw extrusion to obtain a PET composite material.

[0024] Preferably, the twin - screw extrusion includes successively arranged first extrusion temperature zone, second extrusion temperature zone, third extrusion temperature zone, fourth extrusion temperature zone, fifth extrusion temperature zone, sixth extrusion temperature zone, seventh extrusion temperature zone, eighth extrusion temperature zone, and ninth extrusion temperature zone; the temperatures of the first extrusion temperature zone, second extrusion temperature zone, third extrusion temperature zone, fourth extrusion temperature zone, fifth extrusion temperature zone, sixth extrusion temperature zone, seventh extrusion temperature zone, eighth extrusion temperature zone, and ninth extrusion temperature zone are 215 - 225 °C, 225 - 235 °C, 240 - 250 °C, 255 - 265 °C, 255 - 265 °C, 255 - 265 °C, 255 - 265 °C, 255 - 265 °C, and 250 - 260 °C respectively; the screw speed of the twin - screw extrusion is 220 - 320 rpm.

[0025] The present invention provides a method for preparing small-diameter graphene, comprising the following steps: mixing graphite, water, glass beads, 1-pyrenemethanol and methanol and performing sand milling to obtain a graphene / glass bead mixed suspension; the glass beads include a first glass bead, a second glass bead, a third glass bead and a fourth glass bead, the particle diameters of the first glass bead, the second glass bead, the third glass bead and the fourth glass bead are 400-600 μm, 150-300 μm, 50-100 μm and 1-40 μm respectively, and the mass ratio of the first glass bead, the second glass bead, the third glass bead and the fourth glass bead is (1-2):(2-3):(4-16):(8-20); allowing the graphene / glass bead mixed suspension to stand and settle to obtain an upper-layer graphene suspension; and spray-drying the graphene suspension to obtain small-diameter graphene powder. The present invention uses glass beads as a grinding aid, and significantly improves the exfoliation efficiency of sand milling on small-diameter graphite by reasonably proportioning glass beads with different particle diameters, can greatly reduce the preparation time of graphene, significantly improve the preparation efficiency, and after the sand milling is completed, the glass beads and graphene can be separated by physical sedimentation method, and the whole process is simple, efficient and environmentally friendly; in the process of preparing graphene in the present invention, the small molecule dispersant 1-pyrenemethanol is added to disperse graphene, the dispersion efficiency is high, it can prevent the re-stacking of small-diameter graphene after exfoliation, and the pyrene structure contained in 1-pyrenemethanol itself can be combined with graphene through π-π interaction, can repair the defects of small-diameter graphene, thereby improving the structural integrity of small-diameter graphene, and further improving the comprehensive performance of graphene. The preparation method provided by the present invention can simply and efficiently prepare graphene with complete structure and small diameter.

[0026] The present invention provides small-diameter graphene prepared by the preparation method described in the above technical solution; the small-diameter graphene includes graphene sheets and 1-pyrenemethanol compounded on the surface of the graphene sheets; the sheet diameter of the graphene sheets is 0.1-5 μm, and the thickness of the graphene sheets is 0.34-3.4 nm. The small-diameter graphene provided by the present invention has a smaller sheet diameter, thinner sheets and better structural integrity, so that it can have better redispersibility, mechanical strength and electrical conductivity; and the small molecule dispersant 1-pyrenemethanol is compounded on the graphene structure, so that the surface of the graphene has alcohol hydroxyl groups, and when compounding with the polymer matrix material polyester, the hydroxyl groups on its surface can react with the terminal carboxyl groups of the polyester, thereby enhancing the interfacial binding between the graphene and the polyester, which is beneficial to the dispersion of the graphene in the polymer matrix and the enhancement of the interfacial binding force. The small-diameter graphene provided by the present invention is applied to PET composite materials, and can significantly improve the mechanical properties and electrical conductivity of PET materials. Description of the Drawings

[0027] Figure 1SEM image of the small-diameter graphene prepared in Example 1;

[0028] Figure 2 Raman test spectrum of the graphene prepared in Example 1;

[0029] Figure 3 SEM image of the cross section of the graphene / PET composite prepared in Example 1. Detailed implementation manners

[0030] The present invention provides a method for preparing small-diameter graphene, comprising the following steps:

[0031] Mix graphite, water, glass beads, 1-pyrenemethanol and methanol and perform sand milling to obtain a graphene / glass bead mixed suspension; the glass beads include a first glass bead, a second glass bead, a third glass bead and a fourth glass bead, and the particle sizes of the first glass bead, the second glass bead, the third glass bead and the fourth glass bead are 400-600 μm, 150-300 μm, 50-100 μm and 1-40 μm respectively, and the mass ratio of the first glass bead, the second glass bead, the third glass bead and the fourth glass bead is (1-2):(2-3):(4-16):(8-20);

[0032] Let the graphene / glass bead mixed suspension stand for sedimentation to obtain an upper-layer graphene suspension;

[0033] Perform spray drying on the graphene suspension to obtain small-diameter graphene powder.

[0034] In the present invention, unless otherwise specified, the raw materials involved are commercially available products well-known to those skilled in the art.

[0035] The present invention mixes graphite, water, glass beads, 1-pyrenemethanol, and methanol and performs sand grinding to obtain a graphene / glass bead hybrid suspension. In the present invention, the graphite preferably includes flake graphite and / or expanded graphite. The flake graphite or expanded graphite has a relatively complete graphite structure, which is conducive to improving the structural integrity of graphene. The particle size of the graphite is preferably 5000 mesh to 20000 mesh, more preferably 8000 mesh to 20000 mesh, and specifically can be 8000 mesh, 10000 mesh, 15000 mesh, or 20000 mesh. The graphite with such a particle size is conducive to the efficient exfoliation of graphite sheets. In the present invention, the glass beads preferably include first glass beads, second glass beads, third glass beads, and fourth glass beads. The particle sizes of the first glass beads, second glass beads, third glass beads, and fourth glass beads are respectively preferably 400 - 600 μm, 150 - 300 μm, 50 - 100 μm, and 1 - 40 μm, and more respectively preferably 450 - 500 μm, 150 - 200 μm, 50 - 100 μm, 1 - 30 μm. The mass ratio of the first glass beads, second glass beads, third glass beads, and fourth glass beads is preferably (1 - 2):(2 - 3):(4 - 16):(8 - 20), and specifically can be 1:2:15:20, 1:2:6:11, 1:3:5:10, 2:3:4:8, or 1.6:3:4:8 (i.e., 8:15:20:40). During the sand grinding process, zirconium beads are used as the grinding medium. Compared with glass beads of a single particle size, the specific ratio of glass beads with different particle sizes used in the present invention can be stacked more densely, effectively filling the gaps between zirconium beads and graphite and between glass beads and graphite, enhancing the interaction force between graphite, zirconium beads, and glass beads, so that the exfoliation of graphite sheets is more efficient and significantly reduces the preparation time of graphene. Generally, the minimum particle size of zirconium beads used in sand grinding is much larger than the particle size of raw graphite, so the grinding effect on graphene during sand grinding is poor, resulting in an unsatisfactory exfoliation effect of graphite. The present invention selects a compound of glass beads with different particle sizes to effectively fill the difference in size between zirconium beads and graphite and increase the grinding efficiency of sand grinding. In the present invention, by mass, the graphite, water, glass beads, and 1-pyrenemethanol are respectively preferably 5 - 30 parts, 60 - 100 parts, 10 - 30 parts, and 1 - 10 parts, and more respectively preferably 5 - 10 parts, 80 - 100 parts, 10 - 30 parts, and 1 - 2 parts. The mass ratio of 1-pyrenemethanol to methanol is preferably (5 - 15):(60 - 95), and more preferably 5:(70 - 95). Methanol is used as the solvent for 1-pyrenemethanol to dissolve 1-pyrenemethanol better.In the present invention, the 1-pyrenemethanol is used as a small molecule dispersant. Adding 1-pyrenemethanol to disperse graphene in the present invention can prevent small-sized graphene sheets from re-stacking after exfoliation. Moreover, the small molecule dispersant has the characteristics of high dispersion efficiency and low addition amount. In addition, the pyrene structure contained in 1-pyrenemethanol itself can bind to graphene through π-π interaction, which can repair the defects of small-sized graphene sheets, thereby improving the structural integrity of small-sized graphene sheets.

[0036] In the present invention, the rate of sand milling is preferably 300 - 1500 rpm, more preferably 1000 - 1500 rpm. The time of sand milling is preferably 2 - 6 h, more preferably 4 - 6 h. The sand milling is specifically carried out in a sand mill. The present invention has no special requirements for the sand mill, and a sand mill well-known to those skilled in the art can be used. In the present invention, the specific operation of sand milling is preferably as follows: Graphite is slowly added to water and stirred to obtain a graphite / water suspension; glass beads are mixed to obtain a uniformly mixed glass bead mixture; 1-pyrenemethanol and methanol are mixed to obtain a 1-pyrenemethanol solution; after the graphite / water suspension is added to the sand mill and sand milled for 10 - 15 min (to completely immerse the graphite in water), the uniformly mixed glass bead mixture and the 1-pyrenemethanol solution are successively added thereto for sand milling. In the present invention, the 1-pyrenemethanol solution is preferably added dropwise slowly, and the dropping rate is preferably 10 - 30 mL / min; the sand milling time is calculated starting from the completion of the dropwise addition of the 1-pyrenemethanol solution. During the sand milling process, through the relative movement of glass beads with different particle sizes, frictional force is generated between them and the graphite sheet layer to exfoliate the graphite sheet, generating small-sized graphene sheets. At the same time, 1-pyrenemethanol is adsorbed on the graphene structure to disperse the graphene and prevent it from re-stacking after exfoliation. After the sand milling is completed, a graphene / glass bead mixed suspension is obtained, and the graphene / glass bead mixed suspension is poured out of the sand mill.

[0037] After obtaining the graphene / glass bead mixed suspension, the present invention allows the graphene / glass bead mixed suspension to stand for sedimentation to obtain an upper-layer graphene suspension. In the present invention, the time of standing for sedimentation is preferably 1 - 2 h; the standing for sedimentation can be carried out at room temperature; after the standing for sedimentation, an upper-layer black suspension and a lower-layer glass bead are formed; the upper-layer black suspension is poured out, which is the upper-layer graphene suspension. After the sand milling is completed, the glass beads and graphene can be easily separated by a simple physical sedimentation method.

[0038] After obtaining the upper-layer graphene suspension, the present invention spray-dries the graphene suspension to obtain small-diameter graphene powder. The present invention has no special requirements for the specific operation method of the spray drying, and the well-known spray drying method in the art can be adopted; in the present invention, the temperature of the spray drying is preferably 200-250°C. During the spray drying process, water and methanol in the graphene suspension volatilize, and small-diameter graphene powder combined with 1-pyrenemethanol is obtained, that is, small-diameter graphene powder modified with 1-pyrenemethanol.

[0039] The preparation method provided by the present invention can simply and efficiently prepare graphene with a complete structure and a small diameter.

[0040] The present invention provides small-diameter graphene prepared by the preparation method described in the above technical solution; the small-diameter graphene includes graphene sheets and 1-pyrenemethanol compounded on the surface of the graphene sheets; the diameter of the graphene sheets is 0.1-5 μm, and the thickness of the graphene sheets is 0.34-3.4 nm.

[0041] The present invention provides the application of the small-diameter graphene described in the above technical solution in PET composites. The small-diameter graphene provided by the present invention has a smaller diameter and thinner sheets, so it can be more evenly dispersed in the PET material matrix; and the molecular dispersant 1-pyrenemethanol is compounded on the graphene structure, making the surface of the graphene have alcohol hydroxyl groups. When compounding with the polymer matrix material polyester, the hydroxyl groups on its surface can react with the terminal carboxyl groups of the polyester, thereby enhancing the interfacial bonding between the graphene and the polyester, which is beneficial to the dispersion of the graphene in the polymer matrix and the enhancement of the interfacial bonding force.

[0042] The present invention provides a PET composite material, which includes the following parts by mass of preparation raw materials:

[0043]

[0044] The graphene is the small-diameter graphene described in the above technical solution.

[0045] In the present invention, the PET (polyethylene terephthalate) can be virgin PET or recycled PET. The form of the PET can be particles or other fragmented forms, and the present invention does not make special requirements in this regard. In the present invention, by mass fraction, the graphene is preferably 30 to 40 parts, the PET is preferably 60 to 70 parts, the chain extender is preferably 0.003 to 0.01 part, and the antioxidant is preferably 0.003 to 0.01 part. In the present invention, the chain extender preferably includes one or more of 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, N,N-dihydroxy(diisopropyl)aniline, and hydroquinone-bis(β-hydroxyethyl) ether, and more preferably one or two of N,N-dihydroxy(diisopropyl)aniline and trimethylolpropane; the chain extender is used for molecular repair of PET to inhibit the reduction of PET viscosity. In the present invention, the antioxidant preferably includes one or more of antioxidant 1010, antioxidant 168, antioxidant 1076, antioxidant 1098, and antioxidant 225, and more preferably one or two of antioxidant 1010 and antioxidant 168; the antioxidant can preferentially react with external oxygen to reduce the oxidative degradation of PET during high-temperature processing.

[0046] The PET composite material provided by the present invention has excellent mechanical properties and electrical conductivity, and can be widely applied in fields such as engineering plastics (such as conductive plastics, antistatic plastics) or chemical fibers (such as antistatic or conductive polyester fibers).

[0047] The present invention provides a method for preparing the PET composite material described in the above technical solution, including the following steps:

[0048] Mix the graphene, PET, chain extender, and antioxidant and perform twin-screw extrusion to obtain the PET composite material.

[0049] In the present invention, the mixing of the graphene, PET, chain extender and antioxidant is preferably carried out in a mixer, and the mixing time is preferably 10 min. In the present invention, the twin-screw extrusion preferably includes a first extrusion temperature zone, a second extrusion temperature zone, a third extrusion temperature zone, a fourth extrusion temperature zone, a fifth extrusion temperature zone, a sixth extrusion temperature zone, a seventh extrusion temperature zone, an eighth extrusion temperature zone and a ninth extrusion temperature zone arranged in sequence; the temperatures of the first extrusion temperature zone, the second extrusion temperature zone, the third extrusion temperature zone, the fourth extrusion temperature zone, the fifth extrusion temperature zone, the sixth extrusion temperature zone, the seventh extrusion temperature zone, the eighth extrusion temperature zone and the ninth extrusion temperature zone are respectively preferably 215-225 °C, 225-235 °C, 240-250 °C, 255-265 °C, 255-265 °C, 255-265 °C, 255-265 °C, 255-265 °C and 250-260 °C, and more preferably 220 °C, 230 °C, 245 °C, 260 °C, 260 °C, 260 °C, 260 °C, 260 °C and 255 °C respectively; the screw speed of the twin-screw extrusion is preferably 220-320 rpm, and more preferably 250 rpm.

[0050] The following examples are used to describe in detail the small-diameter graphene provided by the present invention, its preparation method and application, and the PET composite material and its preparation method, but they should not be construed as limiting the protection scope of the present invention.

[0051] Example 1

[0052] 5 parts by mass of 8000-mesh flake graphite was slowly added to 100 parts by mass of water. After sufficient stirring, this suspension was added to a sand mill for grinding so that the graphite was completely immersed in water; 30 parts by mass of glass beads were weighed. The glass beads had different particle sizes, and their particle sizes were 450-500 μm, 150-200 μm, 50-100 μm, 1-30 μm respectively, and the mass ratio was 1:2:15:20. After the glass beads with different particle sizes were mixed evenly, they were added to the sand mill; 5 parts by mass of 1-pyrenemethanol and 95 parts by mass of methanol were mixed and dissolved to prepare a 1-pyrenemethanol / methanol solution. 30 parts by mass of the 1-pyrenemethanol / methanol solution was slowly added dropwise to the sand mill. After grinding and dispersing for 6 h (the sand grinding rate was 1500 rpm, and zirconium beads were used as the grinding medium), it was poured out of the sand mill to obtain a graphene / glass bead mixed suspension. After the above graphene / glass bead mixed suspension was allowed to stand for 1 h, the upper black graphene suspension was poured out to obtain a graphene suspension; through spray drying, the graphene suspension was dried to obtain 1-pyrenemethanol-modified small-diameter graphene powder.

[0053] 30 parts by mass of the above-mentioned small-size graphene powder, 70 parts by mass of PET particles, 0.01 parts by mass of antioxidant (antioxidant 1010) and 0.01 parts by mass of chain extender (trimethylolpropane) were added to a mixer and mixed for 10 minutes. The mixture was then added to a twin-screw extruder for extrusion and granulation to obtain a graphene / PET composite material, wherein the temperatures in each temperature zone of the twin-screw extruder were 220°C / 230°C / 245°C / 260°C / 260°C / 260°C / 260°C / 260°C / 255°C, and the screw speed was 250 rpm.

[0054] Example 2

[0055] 5 parts by mass of 8000 mesh flake graphite are slowly added to 100 parts by mass of water. After sufficient stirring, the suspension is added to a sand mill for grinding; 30 parts by mass of glass beads are weighed, wherein the glass beads have different particle sizes, and the particle sizes are 450-500 μm: 150-200 μm: 50-100 μm: 1-30 μm, respectively, with a mass ratio of 1:2:6:11. The glass beads of different particle sizes are mixed evenly and added to the sand mill; 5 parts by mass of 1-pyrene methanol and 95 parts by mass of methanol are weighed and mixed and dissolved to form a 1-pyrene methanol / methanol solution, 30 parts by mass of 1-pyrene methanol / methanol solution are slowly added dropwise to the sand mill, ground and dispersed for 6 hours (the sand milling rate is 1500 rpm, and zirconium beads are used as the grinding medium), and then poured out from the sand mill to obtain a graphene / glass bead mixed suspension. After the graphene / glass microbead mixed suspension was allowed to stand for 1 hour, the upper black graphene suspension was poured out to obtain a graphene suspension; the graphene suspension was dried by spray drying to obtain 1-pyrene methanol modified small-diameter graphene powder.

[0056] 30 parts by mass of the above-mentioned small-size graphene powder, 70 parts by mass of PET particles, 0.01 parts by mass of antioxidant (antioxidant 1010) and 0.01 parts by mass of chain extender (trimethylolpropane) were added to a mixer and mixed for 10 minutes. The mixture was then added to a twin-screw extruder for extrusion and granulation to obtain a graphene / PET composite material, wherein the temperatures in each temperature zone of the twin-screw extruder were 220°C / 230°C / 245°C / 260°C / 260°C / 260°C / 260°C / 260°C / 255°C, and the screw speed was 250 rpm.

[0057] Example 3

[0058] 5 parts by mass of 8000-mesh flake graphite was slowly added to 100 parts by mass of water. After sufficient stirring, this suspension was added to a sand mill for grinding; 30 parts by mass of glass microspheres were weighed. The glass microspheres had different particle sizes, and their particle sizes were 450 - 500 μm: 150 - 200 μm: 50 - 100 μm: 1 - 30 μm, with a mass ratio of 1:3:5:10. After the glass microspheres with different particle sizes were mixed evenly, they were added to the sand mill; 5 parts by mass of 1-pyrenemethanol and 70 parts by mass of methanol were mixed and dissolved to prepare a 1-pyrenemethanol / methanol solution. 30 parts by mass of the 1-pyrenemethanol / methanol solution was slowly added dropwise to the sand mill. After grinding and dispersing for 6 h (the grinding rate was 1500 rpm, and zirconium beads were used as the grinding medium), it was poured out from the sand mill to obtain a graphene / glass microsphere mixed suspension. After the above graphene / glass microsphere mixed suspension was allowed to stand for 1 h, the upper black graphene suspension was poured out to obtain a graphene suspension; through spray drying, the graphene suspension was dried to obtain 1-pyrenemethanol-modified small-diameter graphene powder.

[0059] 30 parts by mass of the above small-diameter graphene powder, 70 parts by mass of PET particles, 0.01 part by mass of an antioxidant (antioxidant 1010), and 0.01 part by mass of a chain extender (trimethylolpropane) were added to a mixer and mixed for 10 min. Subsequently, the mixed material was added to a twin-screw extruder for pelletizing to obtain a graphene / PET composite material. Among them, the temperatures of each temperature zone of the twin-screw were 220 °C / 230 °C / 245 °C / 260 °C / 260 °C / 260 °C / 260 °C / 260 °C / 255 °C, and the screw speed was 250 rpm.

[0060] Example 4

[0061] 5 parts by mass of 8000 mesh flake graphite are slowly added to 100 parts by mass of water. After sufficient stirring, the suspension is added to a sand mill for grinding; 30 parts by mass of glass beads are weighed, wherein the glass beads have different particle sizes, and the particle sizes are 450-500 μm: 150-200 μm: 50-100 μm: 1-30 μm, respectively, with a mass ratio of 2:3:4:8. The glass beads of different particle sizes are mixed evenly and added to the sand mill; 5 parts by mass of 1-pyrene methanol and 95 parts by mass of methanol are weighed and mixed and dissolved to form a 1-pyrene methanol / methanol solution, 30 parts by mass of 1-pyrene methanol / methanol solution are slowly added dropwise to the sand mill, ground and dispersed for 6 hours (the sand milling rate is 1500 rpm, and zirconium beads are used as the grinding medium), and then poured out from the sand mill to obtain a graphene / glass bead mixed suspension. After the graphene / glass microbead mixed suspension was allowed to stand for 1 hour, the upper black graphene suspension was poured out to obtain a graphene suspension; the graphene suspension was dried by spray drying to obtain 1-pyrene methanol modified small-diameter graphene powder.

[0062] 30 parts by mass of the above-mentioned small-size graphene powder, 70 parts by mass of PET particles, 0.01 parts by mass of antioxidant (antioxidant 1010) and 0.01 parts by mass of chain extender (trimethylolpropane) were added to a mixer and mixed for 10 minutes. The mixture was then added to a twin-screw extruder for extrusion and granulation to obtain a graphene / PET composite material, wherein the temperatures in each temperature zone of the twin-screw extruder were 220°C / 230°C / 245°C / 260°C / 260°C / 260°C / 260°C / 260°C / 255°C, and the screw speed was 250 rpm.

[0063] Example 5

[0064] 5 parts by mass of 10,000 mesh flake graphite are slowly added to 100 parts by mass of water. After sufficient stirring, the suspension is added to a sand mill for grinding; 30 parts by mass of glass beads are weighed, wherein the glass beads have different particle sizes, and the particle sizes are 450-500 μm: 150-200 μm: 50-100 μm: 1-30 μm, respectively, with a mass ratio of 8:15:20:40. The glass beads of different particle sizes are mixed evenly and added to the sand mill; 5 parts by mass of 1-pyrene methanol and 95 parts by mass of methanol are weighed and mixed and dissolved to form a 1-pyrene methanol / methanol solution, 20 parts by mass of 1-pyrene methanol / methanol solution are slowly added dropwise to the sand mill, ground and dispersed for 4 hours (the sand milling rate is 1500 rpm, with zirconium beads as the grinding medium), and then poured out from the sand mill to obtain a graphene / glass bead mixed suspension. After the graphene / glass microbead mixed suspension was allowed to stand for 1 hour, the upper black graphene suspension was poured out to obtain a graphene suspension; the graphene suspension was dried by spray drying to obtain 1-pyrene methanol modified small-diameter graphene powder.

[0065] 30 parts by mass of the above-mentioned small-size graphene powder, 70 parts by mass of PET particles, 0.01 parts by mass of antioxidant (antioxidant 1010) and 0.01 parts by mass of chain extender (trimethylolpropane) were added to a mixing tank and mixed for 10 minutes. The mixture was then added to a twin-screw extruder for extrusion and granulation to obtain a graphene / PET composite material, wherein the temperatures in each temperature zone of the twin-screw extruder were 220°C / 230°C / 245°C / 260°C / 260°C / 260°C / 260°C / 260°C / 255°C, and the screw speed was 250 rpm.

[0066] Example 6

[0067] 5 parts by mass of 15000 mesh flake graphite are slowly added to 100 parts by mass of water, and after sufficient stirring, the suspension is added to a sand mill for grinding; 30 parts by mass of glass beads are weighed, the glass beads have different particle sizes, and the particle sizes are 450-500 μm: 150-200 μm: 50-100 μm: 1-30 μm = 8:15:20:40, and the glass beads of different particle sizes are mixed evenly and added to the sand mill; 5 parts by mass of 1-pyrene methanol and 95 parts by mass of methanol are weighed and mixed and dissolved to form a 1-pyrene methanol / methanol solution, 20 parts by mass of 1-pyrene methanol / methanol solution are slowly added dropwise to the sand mill, ground and dispersed for 4 hours (the sand milling rate is 1500 rpm, and zirconium beads are used as the grinding medium), and then poured out from the sand mill to obtain a graphene / glass bead mixed suspension. After the graphene / glass microbead mixed suspension was allowed to stand for 1 hour, the upper black graphene suspension was poured out to obtain a graphene suspension; the graphene suspension was dried by spray drying to finally obtain 1-pyrene methanol modified small-diameter graphene powder.

[0068] 30 parts by mass of the above-mentioned small-size graphene powder, 70 parts by mass of PET particles, 0.01 parts by mass of antioxidant (antioxidant 1010) and 0.01 parts by mass of chain extender (trimethylolpropane) were added to a mixer and mixed for 10 minutes. The mixture was then added to a twin-screw extruder for extrusion and granulation to obtain a graphene / PET composite material, wherein the temperatures in each temperature zone of the twin-screw extruder were 220°C / 230°C / 245°C / 260°C / 260°C / 260°C / 260°C / 260°C / 255°C, and the screw speed was 250 rpm.

[0069] Example 7

[0070] 5 parts by mass of 20,000 mesh flake graphite are slowly added to 100 parts by mass of water, and after sufficient stirring, the suspension is added to a sand mill for grinding; 30 parts by mass of glass beads are weighed, wherein the glass beads have different particle sizes, and the particle sizes are 450-500 μm: 150-200 μm: 50-100 μm: 1-30 μm, respectively, with a mass ratio of 8:15:20:40, and the glass beads of different particle sizes are mixed evenly and added to the sand mill; 5 parts by mass of 1-pyrene methanol and 95 parts by mass of methanol are weighed and mixed and dissolved to form a 1-pyrene methanol / methanol solution, 20 parts by mass of the 1-pyrene methanol / methanol solution are slowly added dropwise to the sand mill, ground and dispersed for 4 hours (the sand milling rate is 1500 rpm, and zirconium beads are used as the grinding medium), and then poured out from the sand mill to obtain a graphene / glass bead mixed suspension. After the graphene / glass microbead mixed suspension was allowed to stand for 1 hour, the upper black graphene suspension was poured out to obtain a graphene suspension; the graphene suspension was dried by spray drying to obtain 1-pyrene methanol modified small-diameter graphene powder.

[0071] 30 parts by mass of the above-mentioned graphene powder, 70 parts by mass of PET particles, 0.01 parts by mass of antioxidant (antioxidant 1010) and 0.01 parts by mass of chain extender (trimethylolpropane) were added to a mixer and mixed for 10 minutes. The mixture was then added to a twin-screw extruder for extrusion and granulation to obtain a graphene / PET composite material, wherein the temperatures in each temperature zone of the twin-screw extruder were 220°C / 230°C / 245°C / 260°C / 260°C / 260°C / 260°C / 260°C / 255°C, and the screw speed was 250 rpm.

[0072] Example 8

[0073] 5 parts by mass of 8000 mesh flake graphite are slowly added to 100 parts by mass of water. After sufficient stirring, the suspension is added to a sand mill for grinding; 20 parts by mass of glass beads are weighed, wherein the glass beads have different particle sizes, and the particle sizes are 450-600 μm: 150-200 μm: 50-100 μm: 1-30 μm, respectively, with a mass ratio of 8:15:20:40, and are added to a sand mill after mixing evenly; 5 parts by mass of 1-pyrene methanol and 95 parts by mass of methanol are weighed and mixed and dissolved to form a 1-pyrene methanol / methanol solution, 30 parts by mass of 1-pyrene methanol / methanol solution are slowly added dropwise to the sand mill, ground and dispersed for 6 hours (the sand milling rate is 1500 rpm, with zirconium beads as the grinding medium), and then poured out from the sand mill to obtain a graphene / glass bead mixed suspension. After the graphene / glass microbead mixed suspension was allowed to stand for 1 hour, the upper black graphene suspension was poured out to obtain a graphene suspension; the graphene suspension was dried by spray drying to obtain 1-pyrene methanol modified small-diameter graphene powder.

[0074] 30 parts by mass of the above-mentioned small-size graphene powder, 70 parts by mass of PET particles, 0.01 parts by mass of antioxidant (antioxidant 1010) and 0.01 parts by mass of chain extender (trimethylolpropane) were added to a mixer and mixed for 10 minutes. The mixture was then added to a twin-screw extruder for extrusion and granulation to obtain a graphene / PET composite material, wherein the temperatures in each temperature zone of the twin-screw extruder were 220°C / 230°C / 245°C / 260°C / 260°C / 260°C / 260°C / 260°C / 255°C, and the screw speed was 250 rpm.

[0075] Example 9

[0076] 5 parts by mass of 8000-mesh flake graphite was slowly added to 100 parts by mass of water. After thorough stirring, this suspension was added to a sand mill for grinding; 10 parts by mass of glass microspheres were weighed. The glass microspheres had different particle sizes, with particle sizes of 450 - 600 μm: 150 - 200 μm: 50 - 100 μm: 1 - 30 μm, and the mass ratio was 8:15:20:40. After the glass microspheres with different particle sizes were mixed evenly, they were added to the sand mill; 5 parts by mass of 1-pyrenemethanol and 95 parts by mass of methanol were mixed and dissolved to prepare a 1-pyrenemethanol / methanol solution. 30 parts by mass of the 1-pyrenemethanol / methanol solution was slowly added dropwise to the sand mill. After grinding and dispersing for 6 h (the sand grinding rate was 1500 rpm, and zirconium beads were used as the grinding medium), it was poured out from the sand mill to obtain a graphene / glass microsphere mixed suspension. After the above graphene / glass microsphere mixed suspension was allowed to stand for 1 h, the upper black graphene suspension was poured out to obtain a graphene suspension; through spray drying, the graphene suspension was dried to obtain 1-pyrenemethanol-modified small-diameter graphene powder.

[0077] 30 parts of the above-mentioned small-diameter graphene powder, 70 parts by mass of PET particles, 0.01 part by mass of antioxidant (antioxidant 1010), and 0.01 part by mass of chain extender (trimethylolpropane) were added to a mixing tank and mixed for 10 min. Subsequently, the mixed material was added to a twin-screw extruder for pelletizing to obtain a graphene / PET composite material. Among them, the temperatures of each temperature zone of the twin-screw were 220 °C / 230 °C / 245 °C / 260 °C / 260 °C / 260 °C / 260 °C / 260 °C / 255 °C, and the screw speed was 250 rpm.

[0078] Comparative Example 1

[0079] 5 parts by mass of 8000-mesh flake graphite was slowly added to 100 parts by mass of water. After thorough stirring, this suspension was added to a sand mill for grinding; 5 parts by mass of 1-pyrenemethanol and 95 parts by mass of methanol were mixed and dissolved to prepare a 1-pyrenemethanol / methanol solution. 30 parts by mass of the 1-pyrenemethanol / methanol solution was slowly added dropwise to the sand mill. After grinding and dispersing for 6 h (the sand grinding rate was 1500 rpm, and zirconium beads were used as the grinding medium), it was poured out from the sand mill. After the obtained suspension was allowed to stand for 1 h, the upper black graphene suspension was poured out to obtain a graphene suspension; through spray drying, the graphene suspension was dried to obtain 1-pyrenemethanol-modified graphene powder.

[0080] 30 parts by mass of the above-mentioned graphene powder, 70 parts by mass of PET particles, 0.01 parts by mass of antioxidant (antioxidant 1010) and 0.01 parts by mass of chain extender (trimethylolpropane) were added to a mixer and mixed for 10 minutes. The mixture was then added to a twin-screw extruder for extrusion and granulation to obtain a graphene / PET composite material, wherein the temperatures in each temperature zone of the twin-screw were 220°C / 230°C / 245°C / 260°C / 260°C / 260°C / 260°C / 260°C / 255°C, and the screw speed was 250 rpm.

[0081] Comparative Example 2

[0082] 5 parts by mass of 8000 mesh flake graphite are slowly added to 100 parts by mass of water. After sufficient stirring, the suspension is added to a sand mill for grinding; 2 parts by mass of glass beads are weighed, the glass beads having different particle sizes, and the particle sizes are 450-500 μm: 150-200 μm: 50-100 μm: 1-30 μm, respectively, with a mass ratio of 1:2:15:20. The glass beads of different particle sizes are mixed evenly and added to the sand mill; 5 parts by mass of 1-pyrene methanol and 95 parts by mass of methanol are weighed and mixed and dissolved to form a 1-pyrene methanol / methanol solution, 30 parts by mass of 1-pyrene methanol / methanol solution is slowly added dropwise to the sand mill, ground and dispersed for 6 hours (the sand milling rate is 1500 rpm, with zirconium beads as the grinding medium), and then poured out from the sand mill to obtain a graphene / glass bead mixed suspension. After the graphene / glass microbead mixed suspension was allowed to stand for 1 hour, the upper black graphene suspension was poured out to obtain a graphene suspension; the graphene suspension was dried by spray drying to obtain 1-pyrene methanol-modified graphene powder.

[0083] 30 parts by mass of the above-mentioned graphene powder, 70 parts by mass of PET particles, 0.01 parts by mass of antioxidant (antioxidant 1010) and 0.01 parts by mass of chain extender (trimethylolpropane) were added to a mixer and mixed for 10 minutes. The mixture was then added to a twin-screw extruder for extrusion and granulation to obtain a graphene / PET composite material, wherein the temperatures in each temperature zone of the twin-screw extruder were 220°C / 230°C / 245°C / 260°C / 260°C / 260°C / 260°C / 260°C / 255°C, and the screw speed was 250 rpm.

[0084] Comparative Example 3

[0085] 5 parts by mass of 8000-mesh flake graphite was slowly added to 100 parts by mass of water. After sufficient stirring, this suspension was added to a sand mill for grinding; 30 parts by mass of glass beads were weighed. The glass beads had different particle sizes, and their particle sizes were 450 - 500 μm: 150 - 200 μm: 50 - 100 μm: 1 - 30 μm, with a mass ratio of 40:20:10:0.5. After the glass beads with different particle sizes were mixed evenly, they were added to the sand mill; 5 parts by mass of 1-pyrenemethanol and 95 parts by mass of methanol were mixed and dissolved to prepare a 1-pyrenemethanol / methanol solution. 30 parts by mass of the 1-pyrenemethanol / methanol solution was slowly added dropwise to the sand mill. After grinding and dispersing for 6 h (the grinding rate was 1500 rpm, and zirconium beads were used as the grinding medium), it was poured out from the sand mill to obtain a graphene / glass bead mixed suspension. After the above graphene / glass bead mixed suspension was allowed to stand for 1 h, the upper black graphene suspension was poured out to obtain a graphene suspension; through spray drying, the graphene suspension was dried to obtain 1-pyrenemethanol-modified graphene powder.

[0086] 30 parts by mass of the above graphene powder, 70 parts by mass of PET particles, 0.01 part by mass of an antioxidant (antioxidant 1010), and 0.01 part by mass of a chain extender (trimethylolpropane) were added to a mixer and mixed for 10 min. Subsequently, the mixed material was added to a twin-screw extruder for pelletizing to obtain a graphene / PET composite material. Among them, the temperatures of each temperature zone of the twin-screw were 220 °C / 230 °C / 245 °C / 260 °C / 260 °C / 260 °C / 260 °C / 260 °C / 255 °C, and the screw speed was 250 rpm.

[0087] Comparative Example 4

[0088] Under the condition that other conditions of Comparative Example 3 remained unchanged, the glass bead ratio was changed from 450 - 500 μm: 150 - 200 μm: 50 - 100 μm: 1 - 30 μm = 40:20:10:0.5 (mass ratio) to 450 - 500 μm: 150 - 200 μm: 50 - 100 μm: 1 - 30 μm = 1:2:50:60 (mass ratio).

[0089] Comparative Example 5

[0090] 5 parts by mass of 8000 mesh flake graphite are slowly added to 100 parts by mass of water, and after sufficient stirring, the suspension is added to a sand mill for grinding; 30 parts by mass of glass beads are weighed, the glass beads having different particle sizes, and the particle sizes are 450-500 μm: 150-200 μm: 50-100 μm: 1-30 μm, respectively, with a mass ratio of 8:15:20:40, and the glass beads of different particle sizes are mixed evenly and added to the sand mill; 5 parts by mass of 1-pyrene methanol and 95 parts by mass of methanol are weighed and mixed and dissolved to form a 1-pyrene methanol / methanol solution, 5 parts by mass of 1-pyrene methanol / methanol solution are taken and slowly added dropwise to the sand mill, ground and dispersed for 6 hours (the sand milling rate is 1500 rpm, with zirconium beads as the grinding medium), and then poured out from the sand mill to obtain a graphene / glass bead mixed suspension. After the graphene / glass microbead mixed suspension was allowed to stand for 1 hour, the upper black graphene suspension was poured out to obtain a graphene suspension; the graphene suspension was dried by spray drying to obtain 1-pyrene methanol-modified graphene powder.

[0091] 30 parts by mass of the above-mentioned graphene powder, 70 parts by mass of PET particles, 0.01 parts by mass of antioxidant (antioxidant 1010) and 0.01 parts by mass of chain extender (trimethylolpropane) were added to a mixing tank and mixed for 10 minutes. The mixture was then added to a twin-screw extruder for extrusion and granulation to obtain a graphene / PET composite material, wherein the temperatures in each temperature zone of the twin-screw extruder were 220°C / 230°C / 245°C / 260°C / 260°C / 260°C / 260°C / 260°C / 255°C, and the screw speed was 250 rpm.

[0092] Figure 1 This is the SEM image of the small-diameter graphene prepared in Example 1. Figure 1 It can be seen that the graphene prepared in Example 1 is small in size and thin in layer. The diameter of the graphene sheets prepared in Examples 1 to 9 is 0.1 to 4.6 μm, and the thickness of the graphene sheets is 0.34 to 3.1 nm.

[0093] Figure 2 The graphene Raman test spectrum prepared in Example 1 is Figure 2 It can be seen that the prepared graphene has a relatively complete graphene structure.

[0094] Figure 3 The cross-sectional SEM image of the graphene / PET composite material prepared in Example 1 is shown in FIG. Figure 2 It can be seen that the small-diameter graphene is evenly dispersed in the PET matrix, and there is a strong interfacial interaction between the two, and there is no interfacial detachment phenomenon.

[0095] The graphene / PET composites prepared in each example and comparative example were subjected to performance tests, including tensile strength, elongation at break, flexural strength, notched impact strength, and surface resistivity. Among them, the test standards for tensile strength and elongation at break were ASTM D638, the test standard for flexural strength was ASTM D790, the test standard for notched impact strength was ASTM D256, and the test standard for surface resistivity was GB / T 1410-1989. The test results are shown in Table 1:

[0096] Table 1 Performance test results of graphene / PET composites prepared in each example and comparative example

[0097]

[0098] In Examples 1 to 4, the ratio of glass microspheres of different sizes was changed. The change in the ratio of glass microspheres mainly affected the exfoliation effect of graphite, that is, the sheet thickness of graphene, which directly affected the surface resistivity and mechanical properties of the composite material. The better the exfoliation effect, the thinner the graphene sheets and the more the number of sheets generated, and the more obvious the influence on the mechanical and electrical conductivity of the PET composite material. The proportion of small-sized glass microspheres in Examples 1 to 4 gradually decreased, and the exfoliation effect on graphite flakes weakened, the generated graphene sheets thickened, and the number of sheets decreased. Therefore, the enhancement effect on the mechanical and electrical conductivity of the PET composite material weakened. In Examples 5 to 7, different sheet diameters of graphite were selected as raw materials. As the graphite sheet diameter decreased, the π-π interaction between graphite layers weakened, and it was more easily exfoliated into graphene under the action of sanding. Therefore, the decrease in the graphite sheet diameter was beneficial to the exfoliation of graphite flakes, the generated graphene sheets were thinner and more easily dispersed in the PET matrix, so its improvement of the mechanical properties of the composite material was more significant. For the electrical conductivity of the composite material, the smaller the graphite sheet diameter, the lower the structural integrity and the lower the electrical conductivity, so the overall electrical conductivity of the PET composite material decreased finally. In Examples 8 and 9, the addition amount of glass microspheres was reduced. As the addition amount of glass microspheres decreased, the exfoliation effect of graphite flakes became worse, and the number of generated graphene decreased. Therefore, the mechanical and electrical conductivity of the composite material decreased.

[0099] In Comparative Example 1, glass microspheres were not added. Therefore, the exfoliation effect of the graphite sheets during the sanding process was poor, and the generated graphene sheet diameter was relatively thick or even the graphene structure could not be generated. Therefore, the mechanical and electrical conductivity of the composite material obtained by compounding it with PET were both poor. In Comparative Example 2, a small amount of glass microspheres was added, and the effect was improved compared to Comparative Example 1, but it was still lower than the performance of the composite material in Example 1. In Comparative Example 3, the ratio of glass microspheres with different particle sizes was changed, and the large-sized glass microspheres were much more than the small-sized glass microspheres. The effect of preparing graphene was also significantly deteriorated because a higher proportion of small-sized glass microspheres could increase the sanding area with the graphite sheets and thus improve the exfoliation efficiency. If the proportion of small-sized glass microspheres is too high, it will cause the relatively large graphite sheets or graphene to completely wrap the microspheres, thereby weakening the relative movement between the two and also affecting the exfoliation effect, as shown in Comparative Example 4. In Comparative Example 5, the addition amount of 1-pyrenemethanol was significantly reduced. The reduction of the 1-pyrenemethanol content would cause the already exfoliated graphene to re-stack under the π-π interaction and also reduce the interfacial interaction between the graphene and the PET matrix, thereby decreasing the mechanical and electrical conductivity of the composite material.

[0100] As can be seen from the above examples, the preparation method provided by the present invention can simply and efficiently prepare graphene with a complete structure and a relatively small sheet diameter. Applying the prepared small-diameter graphene to the PET composite material can significantly improve the mechanical and electrical conductivity of the PET material.

[0101] The above description is only a preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A PET composite material, characterized in that, The preparation raw materials include the following parts by mass: 5 - 45 parts of graphene, 50 - 90 parts of PET, 0.003 - 0.01 part of chain extender, 0.003 - 0.01 part of antioxidant; The graphene is small - diameter graphene, and the small - diameter graphene includes graphene sheets and 1 - pyrenemethanol compounded on the surface of the graphene sheets; the sheet diameter of the graphene sheets is 0.1 - 5 μm, and the thickness of the graphene sheets is 0.34 - 3.4 nm; The preparation method of the small - diameter graphene includes the following steps: Mix graphite, water, glass beads, 1 - pyrenemethanol and methanol and carry out sand milling to obtain a graphene / glass bead mixed suspension; the glass beads include the first glass beads, the second glass beads, the third glass beads and the fourth glass beads, and the particle diameters of the first glass beads, the second glass beads, the third glass beads and the fourth glass beads are 400 - 600 μm, 150 - 300 μm, 50 - 100 μm and 1 - 40 μm respectively, and the mass ratio of the first glass beads, the second glass beads, the third glass beads and the fourth glass beads is (1 - 2):(2 - 3):(4 - 16):(8 - 20); by mass, the graphite, water, glass beads and 1 - pyrenemethanol are 5 - 30 parts, 60 - 100 parts, 10 - 30 parts and 1 - 10 parts respectively; Let the graphene / glass bead mixed suspension stand for sedimentation to obtain an upper - layer graphene suspension; Carry out spray drying on the graphene suspension to obtain small - diameter graphene powder.

2. The PET composite material according to claim 1, wherein The graphite includes flake graphite and / or expanded graphite; the particle diameter of the graphite is 5000 mesh - 20000 mesh.

3. The PET composite material according to claim 1, characterized in that The rate of the sand milling is 300 - 1500 rpm, and the time is 2 - 6 h; the time of the static sedimentation is 1 - 2 h.

4. The PET composite material according to claim 1, characterized in that, The chain extender includes one or more of 1,4 - butanediol, 1,6 - hexanediol, trimethylolpropane, N,N - dihydroxy(diisopropyl)aniline and hydroquinone - bis(β - hydroxyethyl)ether; the antioxidant includes one or more of antioxidant 1010, antioxidant 168, antioxidant 1076, antioxidant 1098 and antioxidant 225.

5. The preparation method of the PET composite material according to any one of claims 1 to 4, characterized in that, It includes the following steps: Mix the graphene, PET, chain extender and antioxidant and carry out twin - screw extrusion to obtain a PET composite material.

6. The preparation method according to claim 5, characterized in that, The twin - screw extrusion includes successively arranged first extrusion temperature zone, second extrusion temperature zone, third extrusion temperature zone, fourth extrusion temperature zone, fifth extrusion temperature zone, sixth extrusion temperature zone, seventh extrusion temperature zone, eighth extrusion temperature zone and ninth extrusion temperature zone; the temperatures of the first extrusion temperature zone, second extrusion temperature zone, third extrusion temperature zone, fourth extrusion temperature zone, fifth extrusion temperature zone, sixth extrusion temperature zone, seventh extrusion temperature zone, eighth extrusion temperature zone and ninth extrusion temperature zone are 215 - 225 °C, 225 - 235 °C, 240 - 250 °C, 255 - 265 °C, 255 - 265 °C, 255 - 265 °C, 255 - 265 °C, 255 - 265 °C and 250 - 260 °C respectively; the screw rotation speed of the twin - screw extrusion is 220 - 320 rpm.

Images