Antistatic plastic doped with ultra-infiltrated carbon nanotubes and preparation method of antistatic plastic

Abstract

The invention discloses an anti-static plastic doped with ultra-infiltrated carbon nanotubes and a preparation method of the anti-static plastic, and belongs to the technical field of nano composite materials. The preparation method of the antistatic plastic doped with the ultra-infiltrated carbon nanotubes comprises the following steps: mixing the multi-walled carbon nanotubes with an ionic liquid, and carrying out high-temperature pyrolysis in an inert gas atmosphere to obtain the ultra-infiltrated carbon nanotubes; ball-milling the ultra-infiltrated carbon nanotubes, mixing the ultra-infiltrated carbon nanotubes with plastic, and performing extrusion granulation and film blowing to obtain the anti-static plastic doped with the ultra-infiltrated carbon nanotubes. The prepared super-infiltrated carbon nanotube has good interface wettability with a plastic base material, the dispersity of the carbon nanotube can be improved, the agglomeration tendency can be reduced, and an excellent antistatic effect can be obtained while the doping amount of a carbon material is reduced.

Description

Technical Field

[0001] This invention relates to the field of nanocomposite materials technology, and in particular to an antistatic plastic doped with superwetting carbon nanotubes and its preparation method. Background Technology

[0002] Static electricity is a common hazard in production and daily life, which can lead to short circuits, fires, and even explosions. Especially in the electronics and chip industries, static electricity not only troubles the production and processing process, but also causes electromagnetic interference, accelerates the aging of components, and leads to damage such as breakdown and short circuits.

[0003] When the volume resistivity of polymer materials is 10 4 -10 8 Within the Ωm range, good antistatic effects can be achieved. However, most polymer materials are insulators, so conductive fillers are usually added to improve their conductivity, including low-cost and highly conductive carbon materials such as conductive carbon black, carbon nanotubes, and graphene. However, the dispersion of carbon materials remains a major challenge. Due to the strong interactions between carbon nanoparticles (π-π interactions, etc.), the interfacial wettability between carbon materials and plastic substrates is insufficient, and carbon materials are prone to aggregation, reducing conductivity (uneven dispersion is not conducive to the formation of a continuous conductive network and increases the percolation threshold). To improve conductivity, the amount of carbon material is usually increased, but this leads to material waste, increased costs, and decreased mechanical properties (stress defects).

[0004] Currently, strategies such as carbon material oxidation and modification of carbon material surfaces with silane coupling agents are often used to address the issues of carbon material aggregation and poor compatibility with plastic substrates in antistatic plastics. However, the oxidation process disrupts the continuous conjugated network within the carbon material, leading to decreased conductivity. Furthermore, the use of silane coupling agents relies on hydroxyl groups generated during carbon material surface oxidation as bonding groups, increasing costs and, due to their non-conductive nature, increasing contact resistance between carbon materials. The amount of carbon material used in existing antistatic plastics is generally around 5%; excessive addition not only increases costs but also adversely affects the material's mechanical properties.

[0005] How to effectively solve the problem of carbon material agglomeration in antistatic plastic substrates, so that antistatic plastics have excellent antistatic properties, has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide an antistatic plastic doped with superwetting carbon nanotubes and its preparation method, thereby solving the problems existing in the prior art. The superwetting carbon nanotubes prepared by this invention have good interfacial wettability with the plastic substrate, which can improve the dispersibility of carbon nanotubes and reduce the tendency to agglomerate.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] One of the technical solutions of the present invention: a method for preparing an antistatic plastic doped with superwetting carbon nanotubes, comprising the following steps:

[0009] (1) Multi-walled carbon nanotubes were mixed with ionic liquid and pyrolyzed at high temperature in an inert gas atmosphere to obtain superwetted carbon nanotubes.

[0010] (2) The superwetting carbon nanotubes are ball-milled and then mixed with plastic, extruded and granulated, and blown into a film to obtain the antistatic plastic doped with superwetting carbon nanotubes.

[0011] Furthermore, in step (1), the ions in the ionic liquid include organic cations and anions; the anions are inorganic or organic anions;

[0012] The organic cation includes at least one of imidazole, piperidine, pyridine, pyrrole, quaternary ammonium, and quaternary phosphorus cations;

[0013] The anion includes at least one of halide ions, tetrafluoroborate, hexafluorophosphate, and bis(trifluoromethanesulfonyl)imide anions.

[0014] Furthermore, the imidazole cation is a 1,3-disubstituted imidazole cation, wherein the substituent at the 1-position is one of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl, and the substituent at the 3-position is methyl.

[0015] Further, in step (1), the amount of the ionic liquid used is 2-20% of the total mass of the multi-walled carbon nanotubes and the ionic liquid;

[0016] The inert gas atmosphere includes an argon and / or nitrogen atmosphere;

[0017] The high-temperature pyrolysis is performed at a temperature of 200-800℃ for 1-5 hours.

[0018] Further, step (2) includes: ball milling the superwetting carbon nanotubes and adding them to plastic powder, and dispersing them in a solvent to obtain a dispersion;

[0019] After removing the solvent from the dispersion, antistatic masterbatch is obtained.

[0020] The antistatic masterbatch and plastic particles are mixed, extruded, granulated, and blown into a film to obtain the antistatic plastic doped with superwetting carbon nanotubes.

[0021] Furthermore, the solvent includes at least one selected from chloroform, ethyl acetate, tetrahydrofuran, acetonitrile, N-methylpyrrolidone, methanol, ethanol, and N,N-dimethylformamide.

[0022] Furthermore, the mass of the superwetted carbon nanotubes is 0.1-10% of the total mass of the superwetted carbon nanotubes and the plastic powder.

[0023] Furthermore, the mass ratio of the antistatic masterbatch to the plastic particles is 1:5 to 1:10.

[0024] The superwetting carbon nanotubes prepared by this invention achieve better antistatic effects at lower doping levels compared with existing similar systems.

[0025] The second technical solution of the present invention: an antistatic plastic doped with superwetting carbon nanotubes prepared by the above preparation method.

[0026] The third technical solution of the present invention: the application of the above-mentioned antistatic plastic doped with superwetting carbon nanotubes in the fields of electronic semiconductors, petrochemical energy, packaging or machining.

[0027] The present invention discloses the following technical effects:

[0028] (1) The superwetting carbon nanotubes prepared by the present invention have good interfacial wettability with plastic substrates, which can improve the dispersibility of carbon nanotubes and reduce the tendency to agglomerate.

[0029] (2) This invention modifies the surface of carbon nanotubes with elements such as N and F by mixing and pyrolyzing multi-walled carbon nanotubes with ionic liquids. This results in superwetting of both hydrophilic and hydrophobic surfaces, enhancing interfacial forces. Simultaneously, it weakens the π-π stacking effect between carbon nanotubes, reducing their agglomeration tendency and improving their dispersibility in plastic substrates. The excellent wettability and dispersibility allow antistatic plastics doped with superwetting carbon nanotubes to achieve good electrical conductivity with lower filler content. Furthermore, the reduced amount of carbon material improves the material's color to some extent.

[0030] (3) Compared with existing carbon-based antistatic plastics, the method of this invention has a lower doping amount and better conductivity. It exhibits significant performance advantages at a lower cost, demonstrating obvious innovation and market value. This method is also applicable to carbon materials other than carbon nanotubes, including carbon dots, graphene, etc. Furthermore, due to the superwetting properties of the carbon nanotubes, it exhibits superaffinity to both hexane and water, two solvents with significantly different surface tensions. Therefore, it has the potential to be applied to different polymer substrates and possesses good interfacial wettability.

[0031] (4) Compared with existing antistatic plastic composite materials doped with carbon materials such as carbon nanotubes, carbon black and graphene, the method of the present invention achieves better antistatic effect at a lower doping amount, and the resulting antistatic plastic has higher economic value and industrial added value. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 The contact angles of different solvents on the surface of the membrane material prepared by superwetting carbon nanotubes prepared in step (1) of Example 1, wherein (A) is water and (B) is n-hexane;

[0034] Figure 2 Scanning electron microscope images of commercially available multi-walled carbon nanotubes (CNTs, before pyrolysis) and superwetted carbon nanotubes prepared in step (1) of Example 1 (after pyrolysis), wherein (A) is commercially available multi-walled carbon nanotubes (CNTs) and (B) is superwetted carbon nanotubes prepared in step (1) of Example 1.

[0035] Figure 3 Raman comparison images of commercially available multi-walled carbon nanotubes (CNTs) and the superwetted carbon nanotubes (superwetted CNTs) prepared in step (1) of Example 1;

[0036] Figure 4 The images show the dispersions of commercially available multi-walled carbon nanotubes in Example 3 and the superwetted carbon nanotubes prepared in step (1) of Example 1 after sonication in N-methylpyrrolidone for 0.5 h. From left to right, the images show the dispersions of commercially available multi-walled carbon nanotubes (2 mg / mL), superwetted carbon nanotubes (2 mg / mL), and superwetted carbon nanotubes (5 mg / mL).

[0037] Figure 5 The images show physical pictures of the antistatic plastics doped with superwetted carbon nanotubes prepared in Examples 1 and 6, where (A) is Example 1 and (B) is Example 6.

[0038] Figure 6 The volume resistivity of the antistatic plastics doped with superwetted carbon nanotubes prepared in Examples 1-7 and imported commercial films at a voltage of 10V. Detailed Implementation

[0039] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0040] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0041] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0042] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0043] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0044] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0045] Example 1

[0046] A method for preparing an antistatic plastic doped with superwetting carbon nanotubes:

[0047] (1) Commercially available multi-walled carbon nanotubes (CNTs) and commercially available ionic liquid (1-ethyl-3-methylimidazolium bis(trifluoromethyl)sulfonylimide) were mixed in a mass ratio of 6:1 and pyrolyzed at high temperature (300°C for 5 hours) under an argon atmosphere to obtain superwetted carbon nanotubes.

[0048] (2) After ball milling the superwetted carbon nanotubes at 300 rpm for 10 h, PP (the mass ratio of superwetted carbon nanotubes to PP is 1:19) was added. Then the powder was added to N-methylpyrrolidone and ultrasonically dispersed to obtain a dispersion with a PP concentration of 95 mg / mL and a superwetted carbon nanotube concentration of 5 mg / mL.

[0049] The solvent in the dispersion was recovered by vacuum distillation to obtain antistatic PP masterbatch, in which the mass fraction of superwetted carbon nanotubes was 5%.

[0050] Antistatic PP masterbatch was mixed with PP (the mass ratio of antistatic PP masterbatch to PP was 1:7.33), extruded, granulated and blown into film to obtain antistatic plastic (i.e. antistatic plastic film with a doping amount of superwetting carbon nanotubes of 0.6 wt%).

[0051] The PP used is Sabic PP 549RQ granules, which are crushed and then sieved through a 200-mesh screen.

[0052] The ultrasonic instrument used for ultrasonic dispersion was a cell disruptor with an ultrasonic power of 150W and an ultrasonic time of 30 minutes.

[0053] The extrusion granulation conditions are set as follows: Zone 1 180℃, Zone 2 200℃, Zone 3 210℃, Zone 4 220℃, Zone 5 210℃, and the cylindrical particles are 2mm (diameter) × 4mm (column length).

[0054] The blown film conditions were set as follows: Zone 1 180℃, Zone 2 205℃, Zone 3 220℃, Die head Zone 1 220℃, Die head Zone 2 215℃, and film thickness 20μm.

[0055] Example 2

[0056] Same as Example 1, except that the doping amount of superwetted carbon nanotubes in the antistatic plastic is 0.7 wt%.

[0057] Example 3

[0058] Same as Example 1, except that the doping amount of superwetted carbon nanotubes in the antistatic plastic is 0.725 wt%.

[0059] Example 4

[0060] Same as Example 1, except that the doping amount of superwetted carbon nanotubes in the antistatic plastic is 0.75 wt%.

[0061] Example 5

[0062] Same as Example 1, except that the doping amount of superwetted carbon nanotubes in the antistatic plastic is 0.775 wt%.

[0063] Example 6

[0064] Same as Example 1, except that the doping amount of superwetted carbon nanotubes in the antistatic plastic is 0.8 wt%.

[0065] Example 7

[0066] Same as Example 1, except that the doping amount of superwetted carbon nanotubes in the antistatic plastic is 0.85 wt%.

[0067] Example 8

[0068] Same as Example 1, except that PP is replaced with an equal amount of LDPE.

[0069] Example 9

[0070] Same as Example 1, except that PP is replaced with an equal amount of LLDPE.

[0071] Example 10

[0072] Same as Example 1, except that PP is replaced with an equal amount of MLLDPE.

[0073] The carbon nanotubes in the antistatic plastics doped with superwetted carbon nanotubes prepared in Examples 1-10 are well dispersed and have no obvious pitting. Furthermore, due to the low amount of carbon material added, the resulting antistatic plastics still have a certain degree of light transmittance.

[0074] Example 1

[0075] The superwetting carbon nanotubes prepared in step (1) of Example 1 were pressed into membrane materials using a flat vulcanizing machine (pressed at room temperature for 10 minutes at 10 MPa). The contact angles of water, n-hexane, methanol, ethanol, chloroform, and dodecane on the surface of the membrane materials were measured. It was found that the contact angles of the membrane materials prepared using superwetting carbon nanotubes with water, n-hexane, methanol, ethanol, chloroform, and dodecane were all 0°, exhibiting superwetting properties (the contact angles of different solvents on the surface of the membrane materials prepared using superwetting carbon nanotubes prepared in step (1) of Example 1 are shown in [reference]). Figure 1 , Figure 1 (Figure A) represents water, and (Figure B) represents n-hexane.

[0076] Example 2

[0077] (1) Scanning electron microscope images of commercially available multi-walled carbon nanotubes (CNTs, before pyrolysis) and the superwetted carbon nanotubes prepared in step (1) of Example 1 (after pyrolysis) are shown in the figure. Figure 2 , Figure 2 Figure (A) shows commercially available multi-walled carbon nanotubes (CNTs), and Figure (B) shows the superwetted carbon nanotubes prepared in step (1) of Example 1.

[0078] from Figure 2 As can be seen, no significant changes in the morphology of carbon nanotubes were observed before and after pyrolysis.

[0079] (2) Raman comparison images of commercially available multi-walled carbon nanotubes (CNTs) and the superwetted carbon nanotubes (superwetted CNTs) prepared in step (1) of Example 1 are shown below. Figure 3 .

[0080] from Figure 3 As can be seen, commercially available multi-walled carbon nanotubes (CNTs) and the superwetted carbon nanotubes (superwetted CNTs) prepared in step (1) of Example 1 exhibit almost the same D-band and G-band intensities. This indicates that the superwetted carbon nanotubes prepared by pyrolysis maintain the conjugated structure of the carbon nanotubes. In contrast, carbon nanotubes whose conjugated structure is destroyed after oxidation exhibit significant D-band enhancement, corresponding to SP... 2 Hybridized carbon atoms are converted to SP 3 Hybridization leads to a decrease in conductivity.

[0081] Example 3

[0082] Commercially available multi-walled carbon nanotubes (CNTs) were added to N-methylpyrrolidone and ultrasonically dispersed (ultrasonic power of 150W, ultrasonic time of 30min) to obtain a commercially available multi-walled carbon nanotube dispersion with a concentration of 2mg / mL.

[0083] The superwetted carbon nanotubes prepared in step (1) of Example 1 were added to N-methylpyrrolidone and ultrasonically dispersed (ultrasonic power of 150W, ultrasonic time of 30min) to obtain superwetted carbon nanotube dispersions with concentrations of 2mg / mL and 5mg / mL, respectively.

[0084] See the actual image of the dispersion. Figure 4 , Figure 4 From left to right, the images show a commercially available multi-walled carbon nanotube dispersion at 2 mg / mL, a super-wetted carbon nanotube dispersion at 2 mg / mL, and a super-wetted carbon nanotube dispersion at 5 mg / mL.

[0085] from Figure 4 As can be seen, the 2 mg / mL commercially available multi-walled carbon nanotube dispersion exhibits obvious aggregation, while the 2 mg / mL and 5 mg / mL superwetted carbon nanotube dispersions are uniformly dispersed without obvious aggregation.

[0086] Example of effect 4

[0087] Physical images of the antistatic plastics doped with superwetted carbon nanotubes prepared in Examples 1 and 6 are shown below. Figure 5 , Figure 5 Figure (A) in the figure is Example 1, and Figure (B) is Example 6.

[0088] from Figure 5 As can be seen, the carbon nanotubes are well dispersed without obvious pitting, and due to the low amount of carbon material added, the resulting antistatic plastic still has a certain degree of light transmittance.

[0089] Example 5

[0090] The antistatic plastics prepared using doped superwetting carbon nanotubes in Examples 1-7 were compared with imported commercial films (doped with TUBALL, manufactured by OCSiAl in Luxembourg) using an electrochemical workstation. TM The volume resistivity of polyethylene antistatic plastic (containing single-walled carbon nanotubes and ionic liquids) at a voltage of 10V is shown in the figure. Figure 6 .

[0091] from Figure 6 As can be seen, the conductivity of antistatic plastics with a doping content of ≥0.7wt% superwetting carbon nanotubes exceeds that of imported commercial films, the required conductive filler is far lower than the market standard of around 5wt%, and the volume resistivity is below 10. 4 -10 8 It has good antistatic effect within the range of Ωm.

[0092] Comparative Example 1

[0093] Same as Example 1, except that the ionic liquid used is 1-ethyl-3-methylimidazolium bromide.

[0094] The carbon nanotubes prepared in this comparative example were pressed into membrane materials using a flat vulcanizing machine (pressed at room temperature for 10 minutes at 10 MPa), and the contact angles of water and n-hexane on the surface of the membrane material were measured. It was found that the contact angle between the obtained carbon nanotubes and n-hexane was 0°, and the contact angle with water was 132°.

[0095] Comparative Example 2

[0096] Same as Example 1, except that the ionic liquid used is 1-ethyl-3-methylimidazolium hexafluorophosphate.

[0097] The carbon nanotubes prepared in this comparative example were pressed into a membrane material using a flat vulcanizing machine (pressed at room temperature for 10 minutes at 10 MPa). The contact angles of water and n-hexane on the surface of the membrane material were measured. It was found that the contact angle between the obtained carbon nanotubes and n-hexane was 0°, and the contact angle with water was 137°.

[0098] Example 6

[0099] The effect is the same as in Example 5, except that the antistatic plastic doped with superwetted carbon nanotubes used is the same as that prepared in Example 8.

[0100] Testing revealed that the volume resistivity of the antistatic plastic doped with superwetted carbon nanotubes prepared in Example 8 was 1.2 × 10⁻⁶. 7 Ωm.

[0101] Example 7

[0102] The effect is the same as in Example 5, except that the antistatic plastic doped with superwetted carbon nanotubes used is the same as that prepared in Example 9.

[0103] Testing revealed that the volume resistivity of the antistatic plastic doped with superwetted carbon nanotubes prepared in Example 9 was 1.5 × 10⁻⁶. 7 Ωm.

[0104] Example 8

[0105] Similar to Example 5, except that the antistatic plastic doped with superwetting carbon nanotubes used was prepared in Example 10.

[0106] Testing revealed that the volume resistivity of the antistatic plastic doped with superwetted carbon nanotubes prepared in Example 10 was 1.4 × 10⁻⁶. 7 Ωm.

[0107] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing an antistatic plastic doped with superwetting carbon nanotubes, characterized in that, Includes the following steps: (1) Multi-walled carbon nanotubes were mixed with ionic liquid and pyrolyzed at high temperature in an inert gas atmosphere to obtain superwetted carbon nanotubes. (2) The superwetting carbon nanotubes are ball-milled and then mixed with plastic, extruded and granulated, and blown into a film to obtain the antistatic plastic doped with superwetting carbon nanotubes.

2. The preparation method according to claim 1, characterized in that, In step (1), the ions in the ionic liquid include organic cations and anions; the anions are inorganic or organic anions; And / or, the organic cation includes at least one of imidazole, piperidine, pyridine, pyrrole, quaternary ammonium, and quaternary phosphorus cations; And / or, the anion includes at least one of a halide ion, tetrafluoroborate, hexafluorophosphate, and bis(trifluoromethanesulfonyl)imide anion.

3. The preparation method according to claim 2, characterized in that, The imidazole cation is a 1,3-disubstituted imidazole cation, wherein the substituent at the 1-position is one of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl, and the substituent at the 3-position is methyl.

4. The preparation method according to claim 1, characterized in that, In step (1), the amount of ionic liquid used is 2-20% of the total mass of multi-walled carbon nanotubes and ionic liquid; And / or, the inert gas atmosphere includes an argon and / or nitrogen atmosphere; And / or, the high-temperature pyrolysis temperature is 200-800℃ and the time is 1-5h.

5. The preparation method according to claim 1, characterized in that, Step (2) includes: ball milling the superwetting carbon nanotubes and adding them to plastic powder, and dispersing them in a solvent to obtain a dispersion; After removing the solvent from the dispersion, antistatic masterbatch is obtained. The antistatic masterbatch and plastic particles are mixed, extruded, granulated, and blown into a film to obtain the antistatic plastic doped with superwetting carbon nanotubes.

6. The preparation method according to claim 5, characterized in that, The solvent includes at least one selected from chloroform, ethyl acetate, tetrahydrofuran, acetonitrile, N-methylpyrrolidone, methanol, ethanol, and N,N-dimethylformamide.

7. The preparation method according to claim 5, characterized in that, The mass of the superwetted carbon nanotubes is 0.1-10% of the total mass of the superwetted carbon nanotubes and plastic powder.

8. The preparation method according to claim 5, characterized in that, The mass ratio of the antistatic masterbatch to the plastic granules is 1:5 to 1:

10.

9. An antistatic plastic doped with superwetting carbon nanotubes prepared by the preparation method according to any one of claims 1-8.

10. The application of the antistatic plastic doped with superwetting carbon nanotubes as described in claim 9 in the fields of electronic semiconductors, petrochemical energy, packaging, or machining.

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