A graphene antistatic PC composite material and preparation method thereof

Abstract

The invention discloses a graphene antistatic PC composite material and a preparation method thereof, and belongs to the technical field of composite materials. 150-160 parts of polycarbonate resin, 10-20 parts of modified graphene, 2-5 parts of light stabilizer, 2-5 parts of ultraviolet absorber, and 2-5 parts of lubricant are weighed by weight and added to a high-speed mixer, and sent into a twin-screw extruder after mixing evenly, and after melt extrusion, cooled and pelletized to obtain a graphene antistatic PC composite material. The modified graphene contains graphene, quaternary ammonium salt structure and hindered phenol structure, and the modified graphene contains lipophilic benzene ring and long carbon chain, so the modified graphene has good compatibility with the polycarbonate resin containing benzene ring and other raw materials, and the modified graphene can be evenly dispersed in the composite material, and is not easy to agglomerate, so that the modified graphene can give full play to the effect, giving the composite material excellent antistatic, antibacterial and anti-aging properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and in particular, relates to a graphene antistatic PC composite material and a preparation method thereof. Background Art

[0002] Polycarbonate (PC) is a general term for a class of polymers containing carbonate groups in the molecular chain. Since the synthetic bisphenol A type PC has the largest output and the widest application, the polycarbonate generally referred to is bisphenol A type polycarbonate. Due to the particularity of the structure of polycarbonate, it has become the fastest growing general engineering plastic among the five major engineering plastics. Polycarbonate is a thermoplastic engineering plastic with excellent comprehensive performance. It has outstanding impact toughness, transparency and dimensional stability, excellent mechanical strength, electrical insulation, wide operating temperature range, good creep resistance, weather resistance and self-extinguishing properties. At present, polycarbonate has been widely used in electronics, electrical appliances, automobiles, optical materials and other fields due to its excellent performance.

[0003] However, the presence of carbonate bonds in the polycarbonate molecular chain is sensitive to water and heat, making it easy to degrade in high-temperature, aerobic and humid environments, seriously affecting the performance of polycarbonate materials, especially its antistatic properties. When the ambient humidity is high, the antistatic properties of polycarbonate will be significantly reduced, which greatly limits the application and development of polycarbonate.

[0004] In the prior art, the antistatic properties of polycarbonate can be significantly improved by adding antistatic agents or performing surface modification. Common antistatic agents include ionic and non-ionic antistatic agents, which reduce the generation and accumulation of static electricity by changing the surface properties of the material. The high specific surface area and excellent electron transport properties of graphene make it perform well in the antistatic field. When a small amount of graphene is added to the polycarbonate material, the antistatic properties of the material can be significantly improved. However, the surface energy of graphene is high, the interaction force between nanosheets is large, and the agglomeration is more serious, making it difficult to obtain effective peeling and uniform dispersion in the polycarbonate matrix. Therefore, it is urgent to design and prepare a graphene PC composite material with uniform graphene dispersion and excellent antistatic properties to expand the application and development of polycarbonate composite materials and meet market demand. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a graphene antistatic PC composite material and a preparation method thereof.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A graphene antistatic PC composite material comprises the following raw materials in parts by weight: 150-160 parts of polycarbonate resin, 10-20 parts of modified graphene, 2-5 parts of light stabilizer, 2-5 parts of ultraviolet absorber and 2-5 parts of lubricant.

[0008] Further, the modified graphene is prepared by the following steps:

[0009] (1) Under nitrogen protection, 4-bromo-2,6-di-tert-butylphenol, pyridine and methanol were added to a dry three-necked flask, stirred and dissolved, and then the temperature was raised to 60°C. Then, a mixed solution of 3-butene-1-amine and methanol was slowly added. After the addition was completed, the mixture was kept at 60°C for 3 hours. After the reaction was completed, the mixture was cooled to room temperature and distilled under reduced pressure to obtain intermediate 1; the amount ratio of 4-bromo-2,6-di-tert-butylphenol, 3-butene-1-amine, pyridine and methanol was 28.5 g:7.7 g:9.7 mL:200 mL;

[0010] Pyridine is used as an acid-binding agent to control the molar ratio of 4-bromo-2,6-di-tert-butylphenol to 3-butene-1-amine to be 1:1.05-1.1, then the -Br of 4-bromo-2,6-di-tert-butylphenol and the -NH of 3-butene-1-amine 2 A substitution reaction occurs under heating, and the reaction process is as follows:

[0011]

[0012] (2) Under nitrogen protection, add intermediate 1, triethylamine and chloroform to a dry three-necked flask, stir and dissolve, then heat to 70°C, slowly add tetradecane bromide, and continue to react at 70°C for 4 hours. After the reaction is completed, cool to room temperature and distill under reduced pressure to obtain intermediate 2; the dosage ratio of intermediate 1, tetradecane bromide, triethylamine and chloroform is 24.8 g:58 mL:27.5 mL:240 mL;

[0013] Triethylamine is used as an acid binding agent to control the molar ratio of intermediate 1 to tetradecane bromide to be 1:2.1-2.2. 2 The -Br of tetradecane bromide undergoes a di-substitution reaction under heating, and the reaction process is as follows:

[0014]

[0015] (3) Add hydrobromic acid to the aqueous suspension of graphene oxide, stir at room temperature for 2 hours, then add thiourea, heat to 80°C and keep warm for 20 hours, add sodium hydroxide, cool the product to room temperature, filter and wash on a nylon membrane, disperse the filtered solid in deionized water and ultrasonically treat for 10 minutes, repeat three times, then disperse in anhydrous ethanol and ultrasonically treat for 10 minutes, repeat three times, and vacuum dry at 80°C for 12 hours to obtain pretreated graphene; at room temperature, stir the intermediate 2, pretreated graphene, benzoin dimethyl ether and dimethyl sulfoxide until they are well mixed, then place them under 365nm ultraviolet light for 15 minutes, and distill them under reduced pressure after the reaction to obtain modified graphene; the ratio of graphene oxide to thiourea is 0.3g:0.25mol; the ratio of intermediate 2, pretreated graphene, benzoin dimethyl ether and dimethyl sulfoxide is 45g:0.3g:0.77g:240mL.

[0016] By reducing graphene oxide with thiourea, thiolated graphene, i.e. pretreated graphene, can be obtained, whose surface contains abundant thiol groups; benzoin dimethyl ether is used as a photoinitiator, and the carbon-carbon double bond on the intermediate 2 undergoes a thiol-ene click reaction with the -SH of the pretreated graphene. The reaction process is as follows:

[0017]

[0018] The graphene in the modified graphene has a high specific surface area and excellent electron transport performance, so when the modified graphene is added to the composite material, the antistatic performance of the composite material can be significantly improved. The quaternary ammonium salt in the modified graphene, as a kind of cationic surfactant, has a special chemical structure and property, can effectively absorb moisture in the air, thereby showing an excellent antistatic effect. Therefore, the quaternary ammonium salt in the modified graphene synergizes with the graphene, giving the modified graphene an excellent antistatic effect, thereby making the composite material excellent in antistatic effect and expanding the scope of application.

[0019] In addition, quaternary ammonium salts also have antibacterial effects. The antibacterial mechanism of quaternary ammonium salts is mainly attributed to their positive charges. These positive charges combine with negatively charged genes on the cell wall of microorganisms to destroy the cell wall, leading to bacteriolysis and cell death; in addition, quaternary ammonium salts can also denature proteins and cause cell death, destroy the semipermeability of cell membranes, and reduce the nutrient intake to maintain life; the mechanism of action of quaternary ammonium salts also includes adsorption and penetration of cell membranes, causing disorder in the cell membrane structure, leading to leakage of small molecules in cells, and then protein and nucleic acid degradation, and finally self-lytic enzymes cause cell disintegration until death. At the same time, the quaternary ammonium salt of the present invention contains a long carbon chain (14 carbons), which further enhances the antibacterial effect of quaternary ammonium salts. Therefore, adding modified graphene containing quaternary ammonium salts into composite materials can give composite materials excellent antibacterial effects.

[0020] The hindered phenol structure in the modified graphene can provide hydrogen atoms to the free radicals to terminate the chain reaction, or directly combine with the active free radicals to form new relatively stable free radicals, thereby destroying any step in the free radical reaction process, playing a protective role and maintaining the stability of the appearance and mechanical properties of the composite material. Therefore, the addition of modified graphene can effectively prevent the fading, yellowing, hardening and cracking of the composite material and extend its service life.

[0021] The surface of the modified graphene contains benzene rings and long lipophilic carbon chains. Therefore, the modified graphene has good compatibility with polycarbonate resins containing benzene rings and other raw materials. The modified graphene can be evenly dispersed in the composite material and is not easy to agglomerate. Therefore, the modified graphene can fully play its role and give the composite material excellent antistatic, antibacterial and anti-aging properties.

[0022] Furthermore, the light stabilizer is one or more of the light stabilizer GW-540, the light stabilizer 744, and the light stabilizer HPT.

[0023] Furthermore, the ultraviolet absorber is one or more of ultraviolet absorber RMB, ultraviolet absorber UVP-327, and ultraviolet absorber UV-531.

[0024] Furthermore, the lubricant is one or more of stearic acid, calcium stearate, zinc stearate, magnesium stearate, and ethylene bisstearamide.

[0025] A method for preparing a graphene antistatic PC composite material comprises the following steps:

[0026] The raw materials are weighed by weight and added into a high-speed mixer. After being mixed evenly, they are sent into a twin-screw extruder. After melt extrusion, the extruders are cooled and pelletized to obtain a graphene antistatic PC composite material.

[0027] The invention has the beneficial effects that the modified graphene contains graphene, a quaternary ammonium salt structure and a hindered phenol structure, and the modified graphene contains a lipophilic benzene ring and a long carbon chain, so the modified graphene has good compatibility with a polycarbonate resin containing a benzene ring and other raw materials, the modified graphene can be uniformly dispersed in the composite material and is not easy to agglomerate, so that the modified graphene can fully play its role and endow the composite material with excellent antistatic, antibacterial and anti-aging properties. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Example 1, preparing modified graphene, the specific steps are as follows:

[0030] (1) Under nitrogen protection, 28.5 g of 4-bromo-2,6-di-tert-butylphenol, 9.7 mL of pyridine and 180 mL of methanol were added to a 500 mL dry three-necked flask. After stirring and dissolving, the temperature was raised to 60°C. Then, a mixed solution of 7.7 g of 3-butene-1-amine and 20 mL of methanol was slowly added. After the addition was completed, the mixture was kept warm at 60°C for 3 h. After the reaction was completed, the mixture was cooled to room temperature and distilled under reduced pressure to obtain intermediate 1.

[0031] (2) Under nitrogen protection, add 24.8 g of intermediate 1, 27.5 mL of triethylamine and 240 mL of chloroform to a 500 mL dry three-necked flask, stir to dissolve, then heat to 70°C, slowly add 58 mL of tetradecane bromide, and continue to react at 70°C for 4 h. After the reaction is completed, cool to room temperature and distill under reduced pressure to obtain intermediate 2;

[0032] (3) Add 24 mL of hydrobromic acid to 300 mL of an aqueous suspension containing 0.3 g of graphene oxide, stir at room temperature for 2 h, then add 19 g of thiourea, heat to 80 °C and keep warm for 20 h, add 24 g of sodium hydroxide, cool the product to room temperature, filter and wash on a 0.45 µm nylon membrane, disperse the filtered solid in deionized water and ultrasonically treat for 10 min, repeat three times, then disperse in anhydrous ethanol and ultrasonically treat for 10 min, repeat three times, and vacuum dry at 80 °C for 12 h to obtain pretreated graphene; at room temperature, fully stir 45 g of intermediate 2, 0.3 g of pretreated graphene, 0.77 g of benzoin dimethyl ether and 240 mL of dimethyl sulfoxide until mixed evenly, then irradiate under a 365 nm ultraviolet lamp for 15 min, and distill under reduced pressure after the reaction to obtain modified graphene.

[0033] Example 2, preparing graphene antistatic PC composite material, the specific steps are as follows:

[0034] 150 parts of polycarbonate resin, 10 parts of modified graphene prepared in Example 1, 2 parts of light stabilizer GW-540, 2 parts of ultraviolet absorber RMB, and 2 parts of stearic acid were weighed by weight and added to a high-speed mixer. After mixing evenly, they were sent to a twin-screw extruder. After melt extrusion, they were cooled and pelletized to obtain a graphene antistatic PC composite material.

[0035] Example 3, preparing graphene antistatic PC composite material, the specific steps are as follows:

[0036] 155 parts of polycarbonate resin, 15 parts of modified graphene prepared in Example 1, 4 parts of light stabilizer 744, 4 parts of ultraviolet absorber UVP-327, 2 parts of calcium stearate, and 2 parts of ethylene bisstearamide were weighed by weight and added to a high-speed mixer. After mixing evenly, they were sent to a twin-screw extruder. After melt extrusion, they were cooled and pelletized to obtain a graphene antistatic PC composite material.

[0037] Example 4, preparing graphene antistatic PC composite material, the specific steps are as follows:

[0038] 160 parts of polycarbonate resin, 20 parts of modified graphene prepared in Example 1, 2 parts of light stabilizer 744, 3 parts of light stabilizer HPT, 3 parts of ultraviolet absorber UVP-327, 2 parts of ultraviolet absorber UV-531, 1 part of zinc stearate, 1 part of magnesium stearate, and 3 parts of ethylene bisstearamide were weighed by weight and added to a high-speed mixer. After mixing evenly, the mixture was sent to a twin-screw extruder. After melt extrusion, the mixture was cooled and pelletized to obtain a graphene antistatic PC composite material.

[0039] Comparative Example 1: preparing a composite material, the specific steps are as follows:

[0040] The remaining steps remain unchanged, except that the modified graphene in Example 2 is replaced by graphene without any treatment to prepare a composite material.

[0041] Comparative Example 2: preparing a composite material, the specific steps are as follows:

[0042] The remaining steps remain unchanged, only the modified graphene in Example 2 is removed to prepare a composite material.

[0043] Performance Testing

[0044] The composite materials prepared in Examples 2-4 and Comparative Examples 1-2 were prepared into corresponding specimens with reference to ASTM D638 "Standard Test Method for Tensile Properties of Plastics", and the tensile strength was tested. Then, the composite materials were dry-heat aged for 120 hours at 110°C, and the tensile strength was tested again to evaluate the anti-aging performance of the composite materials. The surface resistivity of the composite materials prepared in Examples 2-4 and Comparative Examples 1-2 was tested with reference to GB / T 1410-2006 "Test Method for Volume Resistivity and Surface Resistivity of Solid Insulating Materials". The test results of all items are shown in Table 1 below:

[0045] Table 1

[0046]

[0047] It can be seen from the test results in Table 1 above that the addition of modified graphene greatly improves the antistatic and anti-aging properties of the graphene PC composite materials in Examples 2-4 of the present invention, thereby greatly expanding the application range of the graphene PC composite materials prepared in Examples 2-4 of the present invention.

[0048] The antibacterial properties of the composite materials prepared in Examples 2-4 and Comparative Examples 1-2 were tested with reference to QB / T2591-2003 "Antibacterial Plastics - Antibacterial Performance Test Method and Antibacterial Effect". The test results are shown in Table 2 below:

[0049] Table 2

[0050]

[0051] “ / ” indicates no antibacterial activity.

[0052] It can be seen from the test results in Table 2 above that the graphene PC composite materials prepared in Examples 2-4 of the present invention have excellent antibacterial activity, and because the modified graphene is evenly dispersed in the composite material, the antibacterial activity is more stable, so the antibacterial rate of the graphene PC composite materials prepared in Examples 2-4 is still as high as more than 99% after 60 days, which is much better than the composite material prepared in Comparative Example 1.

[0053] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0054] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A graphene antistatic PC composite material, characterized in that: The invention comprises the following raw materials in parts by weight: 150-160 parts of polycarbonate resin, 10-20 parts of modified graphene, 2-5 parts of light stabilizer, 2-5 parts of ultraviolet absorber and 2-5 parts of lubricant; Wherein, the modified graphene is prepared by the following steps: (1) Under nitrogen protection, 4-bromo-2,6-di-tert-butylphenol, pyridine and methanol were added to a dry three-necked flask, stirred and dissolved, and then the temperature was raised to 60°C. Then, a mixed solution of 3-butene-1-amine and methanol was slowly added. After the addition was completed, the mixture was kept at 60°C for 3 hours. After the reaction was completed, the mixture was cooled to room temperature and distilled under reduced pressure to obtain intermediate 1; the amount ratio of 4-bromo-2,6-di-tert-butylphenol, 3-butene-1-amine, pyridine and methanol was 28.5 g:7.7 g:9.7 mL:200 mL; (2) Under nitrogen protection, add intermediate 1, triethylamine and chloroform to a dry three-necked flask, stir and dissolve, then heat to 70°C, slowly add tetradecane bromide, and continue to react at 70°C for 4 hours. After the reaction is completed, cool to room temperature and distill under reduced pressure to obtain intermediate 2; the dosage ratio of intermediate 1, tetradecane bromide, triethylamine and chloroform is 24.8 g:58 mL:27.5 mL:240 mL; (3) Add hydrobromic acid to the aqueous suspension of graphene oxide, stir at room temperature for 2 hours, then add thiourea, heat to 80°C and keep warm for 20 hours, add sodium hydroxide, cool the product to room temperature, filter and wash on a nylon membrane, disperse the filtered solid in deionized water and ultrasonically treat for 10 minutes, repeat three times, then disperse in anhydrous ethanol and ultrasonically treat for 10 minutes, repeat three times, and vacuum dry at 80°C for 12 hours to obtain pretreated graphene; at room temperature, stir the intermediate 2, pretreated graphene, benzoin dimethyl ether and dimethyl sulfoxide until they are well mixed, then place them under 365nm ultraviolet light for 15 minutes, and distill them under reduced pressure after the reaction to obtain modified graphene; the ratio of graphene oxide to thiourea is 0.3g:0.25mol; the ratio of intermediate 2, pretreated graphene, benzoin dimethyl ether and dimethyl sulfoxide is 45g:0.3g:0.77g:240mL.

2. The graphene antistatic PC composite material according to claim 1, characterized in that: The light stabilizer is one or more of the light stabilizer GW-540, the light stabilizer 744, and the light stabilizer HPT.

3. The graphene antistatic PC composite material according to claim 1, characterized in that: The ultraviolet absorber is one or more of ultraviolet absorber RMB, ultraviolet absorber UVP-327, and ultraviolet absorber UV-531.

4. The graphene antistatic PC composite material according to claim 1, characterized in that: The lubricant is one or more of stearic acid, calcium stearate, zinc stearate, magnesium stearate, and ethylene bis stearamide.

5. The method for preparing a graphene antistatic PC composite material according to claim 1, characterized in that: The following steps are involved: The raw materials are weighed by weight and added into a high-speed mixer. After being mixed evenly, they are sent into a twin-screw extruder. After melt extrusion, the extruders are cooled and pelletized to obtain a graphene antistatic PC composite material.

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