A styrene-maleic anhydride copolymer modified carbon nanotube-containing permanent antistatic ABS composite material and application
By grafting styrene-maleic anhydride copolymer onto carbon nanotubes, the problem of static electricity accumulation in ABS resin was solved, achieving efficient and long-lasting antistatic properties and improved mechanical properties, making it suitable for electronics, automotive industry, and medical devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGDONG UNIV OF TECH
- Filing Date
- 2026-02-13
- Publication Date
- 2026-06-02
AI Technical Summary
The high insulation properties of existing ABS resins make it easy for static electricity to accumulate, which may lead to safety accidents. Traditional antistatic agents become less effective at low humidity or the high filling amount leads to the deterioration of material toughness. Carbon nanotubes tend to agglomerate and entangle in non-polar ABS matrix, affecting the conductive network and mechanical properties.
Styrene-maleic anhydride copolymer was used to modify carbon nanotubes. SMA was grafted onto the carbon nanotubes through a covalent bridging mechanism to form SMA-g-CNT, which improved its dispersibility and interfacial compatibility in the ABS matrix, formed an efficient stress transfer network, and enhanced electrical conductivity and mechanical properties.
It achieves long-lasting antistatic properties and improved conductivity, reduces surface resistivity by 5 orders of magnitude, improves mechanical properties by 23.8% and 15.2%, and maintains good antistatic properties after multiple washes.
Smart Images
Figure CN122127729A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polymer materials technology, specifically to a permanent antistatic ABS composite material containing styrene-maleic anhydride copolymer-modified carbon nanotubes and its applications. Background Technology
[0002] Acrylonitrile-butadiene-styrene copolymer (ABS) is a thermoplastic engineering plastic with excellent overall performance. Due to its superior dimensional stability, low-temperature resistance, and processing fluidity, it is widely used in electronics, automotive, and medical devices. However, ABS resin inherently possesses high insulation properties (volume resistivity typically 10¹³–10¹⁰). 6 The high electrostatic discharge (ESD) concentration (Ω·cm) makes it prone to accumulating static charge during use. When the charge reaches a critical value, it can lead to electrical breakdown, dust accumulation, or even safety accidents such as fire or explosion. In the field of precision electronic packaging, ESD-induced component damage causes economic losses exceeding $5 billion annually. Therefore, developing high-performance antistatic ABS materials has become an important research direction in polymer functionalization modification.
[0003] Traditional antistatic technologies mainly include three categories: surfactants, conductive fillers, and polymeric permanent antistatic agents. Surfactants (such as ethoxylated alkylamines) rely on ambient moisture to form ionic conductive pathways, but their effectiveness decreases significantly when humidity is below 40%, and they also suffer from migration and precipitation problems, resulting in insufficient antistatic durability. Conductive fillers such as carbon black require 10–20 wt% to form conductive pathways; high filler content leads to deterioration of material toughness (impact strength decreases by 30–50%) and processing performance. Carbon nanotubes (CNTs), with their unique one-dimensional tubular structure, high aspect ratio (>1000), and intrinsic conductivity (conductivity 10³–10⁻⁶), offer superior performance. 5 CNTs (with a surface area of 1 / m) are ideal antistatic fillers. However, due to their large surface area and strong van der Waals forces, CNTs tend to agglomerate and entangle in non-polar ABS matrices, which not only hinders the formation of conductive networks but also causes stress concentration, leading to a decline in mechanical properties. Summary of the Invention
[0004] To address the aforementioned technical problems, this invention provides a permanent antistatic ABS composite material containing styrene-maleic anhydride copolymer-modified carbon nanotubes and its application. This antistatic ABS composite material uses SMA-grafted carbon nanotubes as an antistatic agent, which significantly improves the dispersion and interfacial compatibility of carbon nanotubes in the ABS matrix, effectively and permanently reducing the resistivity of the ABS composite material.
[0005] To solve the above-mentioned technical problems, the following technical solutions are provided: A permanent antistatic ABS composite material containing styrene-maleic anhydride copolymer-modified carbon nanotubes is provided, which is prepared by the following steps: Add the prescribed amount of multi-walled carbon nanotubes to concentrated sulfuric acid and disperse them by ultrasonication to ensure that the carbon nanotubes are fully dispersed to obtain a mixture. Add the prescribed amount of concentrated nitric acid to the mixture and reflux at 50℃~70℃ for 4h~7h. After the reaction is completed, dilute the first product with deionized water, separate it by centrifugation, and wash the first product repeatedly with deionized water until neutral. Place the first product in an oven at 50℃~65℃ and dry it for 10h~13h to obtain carboxylated carbon nanotubes. The carboxylated carbon nanotubes, DCC and DMAP were mixed in the prescribed amounts, DMF solvent was added to make the mixture uniform, and then the prescribed amount of ethylenediamine was added. The mixture was refluxed at 90℃~100℃ for 24 h. After the reaction was completed, the product was repeatedly washed with anhydrous ethanol to remove unreacted raw materials and by-products. The product was dried in an oven at 50℃~70℃ for 10 h~15 h to obtain aminated carbon nanotubes. The styrene-maleic anhydride copolymer and aminated carbon nanotubes were added to DMF in the prescribed amount and allowed to disperse and dissolve fully. Triethylamine was added, and the mixture was refluxed at 95℃~110℃ for 10 h~13 h. After the reaction was completed, the second product was repeatedly washed with tetrahydrofuran to remove unreacted raw materials and by-products. The product was then dried in a vacuum drying oven at 50℃~65℃ for 10 h~11 h to obtain styrene-maleic anhydride copolymer grafted with multi-walled carbon nanotubes. The styrene-maleic anhydride copolymer grafted with multi-walled carbon nanotubes and ABS resin were mixed in a torque rheometer at 180℃~240℃ and 40rpm~60rpm for 5min~10min to obtain a mixture. The mixture was placed in a flat vulcanizing apparatus and hot-pressed at 180℃~220℃ and 30MPa~60MPa for 10min~20min, followed by cold pressing at 10MPa~20MPa for 8min~15min to form the final product.
[0006] In some embodiments, 100 mL to 150 mL of concentrated sulfuric acid and 40 to 50 mL of concentrated nitric acid are added to each gram of multi-walled carbon nanotubes.
[0007] In some embodiments, 2 g to 3 g of DCC, 0.3 g to 0.5 g of DMAP, and 40 mL to 60 mL of ethylenediamine are added per gram of carboxylated carbon nanotubes.
[0008] In some embodiments, the styrene-maleic anhydride copolymer is an SMA1000 type styrene-maleic anhydride copolymer.
[0009] In some embodiments, 5 g to 7 g of styrene-maleic anhydride copolymer is added to each gram of aminated carbon nanotubes, and 8 mL to 12 mL of triethylamine is added to each gram of aminated carbon nanotubes.
[0010] In some embodiments, the amount of the styrene-maleic anhydride copolymer added is 1% to 5%.
[0011] In some implementations, ultrasonic-assisted dispersion or mixing is used.
[0012] The invention also provides the application of the above-mentioned permanent antistatic ABS composite material containing styrene-maleic anhydride copolymer modified carbon nanotubes in the preparation of electronic appliances, automotive industry and medical devices.
[0013] Compared with the prior art, the present invention has the following beneficial effects: (1) In this invention, the styrene-maleic anhydride copolymer (SMA) molecular chain has hydrophobic styrene segments and hydrophilic maleic anhydride (MAH) groups. The hydrophilic and hydrophobic properties of SMA make it an excellent interface compatibilizer. Specifically, the MAH group has an active anhydride group. The anhydride can form a stable covalent bond with the amino group in the aminated carbon nanotube (CNT-NH2). By grafting SMA onto the carbon nanotube through the covalent bond bridging mechanism, SMA-g-CNT is obtained. The strong steric hindrance effect generated by the extended SMA-g-CNT is used to fundamentally prevent the nanotubes from approaching each other and agglomerating, thereby achieving long-term and stable dispersion of CNTs. Compared with the use of unmodified carbon nanotubes, this invention can achieve the percolation threshold and achieve antistatic effect by using a smaller amount of SMA-g-CNT. One end of SMA is covalently grafted onto the surface of carbon nanotubes, while the other end (styrene segment) is similar to the SAN component in ABS, exhibiting good compatibility. Through molecular chain entanglement and interpenetration, it tightly bonds with the ABS matrix, forming an efficient stress transfer network. This allows the high strength and high elastic modulus of CNTs to be fully utilized, improving the mechanical properties of the ABS composite. Furthermore, SMA-g-ABS has good compatibility and interfacial bonding with ABS, resulting in better wettability of the ABS matrix to SMA-g-ABS during blending. This reduces the possibility of cavities forming inside the material due to poor wettability and the inability of gas to escape from the SMA-g-ABS surface. This improves the continuity and uniformity of the internal conductive pathways, enhancing conductivity and acting as an electrostatic leakage agent. Additionally, it reduces stress concentration caused by cavities within the ABS, further improving mechanical properties.
[0014] (2) Further, in this invention, when the amount of carbon nanotubes modified with styrene-maleic anhydride copolymer added is 3wt%, the surface resistivity of the composite material decreases to 5.6×10⁻⁶.8 The Ω value is 5 orders of magnitude lower than that of pure ABS, meeting the requirements for antistatic materials.
[0015] (3) Furthermore, in this invention, the improved interfacial compatibility effectively enhances the stress transfer efficiency, enabling the permanent antistatic ABS composite material containing styrene-maleic anhydride copolymer modified carbon nanotubes to exhibit the best tensile and bending properties at an addition of 3~4 wt%, which are up to 23.8% and 15.2% higher than pure ABS, respectively. Attached Figure Description
[0016] Figure 1 The images are FT-IR spectra of SMA-g-CNT, CNT-NH2, CNT-COOH (carboxylated carbon nanotubes), and P-CNT (pure carbon nanotubes) from Experimental Example 1.
[0017] Figure 2 This is the TGA graph of P-CNT, CNT-COOH, CNT-NH2, SMA-g-CNT, and SMA from Experimental Example 1.
[0018] Figure 3 This is a diagram of the reaction process for preparing SMA-g-CNT / ABS.
[0019] Figure 4 This is a comparison chart of tensile strength data for P-CNT / ABS (permanent antistatic ABS composite material containing carbon nanotubes), CNT-NH / ABS (permanent antistatic ABS composite material containing aminated carbon nanotubes), and SMA-g-CNT / ABS (permanent antistatic ABS composite material containing styrene-maleic anhydride copolymer modified carbon nanotubes).
[0020] Figure 5 This is a comparison chart of the flexural strength of P-CNT / ABS, CNT-NH / ABS, and SMA-g-CNT / ABS.
[0021] Figure 6 This is a comparison chart of impact strength data for P-CNT / ABS, CNT-NH / ABS, and SMA-g-CNT / ABS.
[0022] Figure 7 This is a graph showing the glass transition temperatures of ABS, P-CNT / ABS, CNT-NH / ABS, and SMA-g-CNT / ABS.
[0023] Figure 8 This is a chart showing the water washability data for ABS, P-CNT / ABS, CNT-NH / ABS, and SMA-g-CNT / ABS.
[0024] Figure 9These are surface resistivity diagrams for ABS, P-CNT / ABS, CNT-NH / ABS, and SMA-g-CNT / ABS. Detailed Implementation
[0025] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0026] Example 1
[0027] This embodiment discloses a permanently antistatic ABS composite material containing styrene-maleic anhydride copolymer-modified carbon nanotubes. Please refer to [link to relevant documentation]. Figure 3 It is prepared through the following steps: The prescribed amount of multi-walled carbon nanotubes were added to concentrated sulfuric acid and ultrasonically dispersed to ensure full dispersion of the carbon nanotubes, resulting in a mixed solution. The prescribed amount of concentrated nitric acid was added to the mixed solution, and the mixture was refluxed at 50°C for 4 hours. After the reaction was completed, the first product was diluted with deionized water and centrifuged. The first product was then repeatedly washed with deionized water until neutral. The first product was then dried in a 50°C oven for 10 hours to obtain carboxylated carbon nanotubes. In the above steps, the multi-walled carbon nanotubes are first ultrasonically reacted in sulfuric acid and then reacted in nitric acid. This avoids the problem that the mixture of the two acids will release heat and cause the concentrated sulfuric acid to easily volatilize, thus enabling the efficient preparation of carboxylated carbon nanotubes.
[0028] The carboxylated carbon nanotubes, DCC (N,N'-dicyclohexylcarbodiimide), and DMAP (4-dimethylaminopyridine) were mixed in the prescribed amounts, and DMF (N,N-dimethylformamide) solvent was added to make the mixture uniform. Then, the prescribed amount of ethylenediamine was added, and the mixture was refluxed at 90°C for 24 h. After the reaction was completed, the product was repeatedly washed with anhydrous ethanol to remove unreacted raw materials and by-products. The product was then dried in an oven at 50°C for 10 h to obtain aminated carbon nanotubes. The styrene-maleic anhydride copolymer and aminated carbon nanotubes were added to DMF in the prescribed amount and allowed to disperse and dissolve fully. Triethylamine was added and the mixture was refluxed at 95°C for 10 h. After the reaction was completed, the second product was repeatedly washed with tetrahydrofuran to remove unreacted raw materials and by-products. The product was then dried in a vacuum drying oven at 50°C for 10 h to obtain styrene-maleic anhydride copolymer grafted with multi-walled carbon nanotubes. The styrene-maleic anhydride copolymer grafted with multi-walled carbon nanotubes and ABS resin were mixed in a torque rheometer at 180°C and 40 rpm for 5 min to obtain a mixture. The mixture was placed in a flat vulcanizing apparatus and hot-pressed at 180°C and 30 MPa for 10 min, followed by cold-pressing at 10 MPa for 8 min to form the final product.
[0029] In this embodiment, 100 mL of concentrated sulfuric acid and 40 mL of concentrated nitric acid are added to each gram of multi-walled carbon nanotubes. The specific dosage can be adjusted according to the actual situation.
[0030] In this embodiment, 2g DCC, 0.3g DMAP, and 40mL ethylenediamine are added per gram of carboxylated carbon nanotubes. The specific dosage can be adjusted according to the actual situation.
[0031] In this embodiment, the styrene-maleic anhydride copolymer is SMA1000 type styrene-maleic anhydride copolymer. SMA1000 type styrene-maleic anhydride copolymer is a classic low molecular weight styrene-maleic anhydride copolymer produced by Cray Valley (now TotalEnergies), and is one of the models in the SMA resin series. The type of styrene-maleic anhydride copolymer can be selected according to the actual situation.
[0032] In this embodiment, 5g of styrene-maleic anhydride copolymer is added to each gram of aminated carbon nanotubes, and 8mL of triethylamine is added to each gram of aminated carbon nanotubes. The specific dosage can be adjusted according to the actual situation.
[0033] In this embodiment, the amount of styrene-maleic anhydride copolymer added is 1%, and the specific amount can be adjusted according to the actual situation.
[0034] In this embodiment, ultrasonic-assisted dispersion or mixing is used.
[0035] Example 2
[0036] This embodiment discloses a permanently antistatic ABS composite material containing styrene-maleic anhydride copolymer-modified carbon nanotubes. Please refer to [link to relevant documentation]. Figure 3 It is prepared through the following steps: The prescribed amount of multi-walled carbon nanotubes were added to concentrated sulfuric acid and ultrasonically dispersed to ensure full dispersion of the carbon nanotubes, resulting in a mixed solution. The prescribed amount of concentrated nitric acid was added to the mixed solution, and the mixture was refluxed at 70°C for 7 hours. After the reaction was completed, the first product was diluted with deionized water and centrifuged. The first product was then repeatedly washed with deionized water until neutral. The first product was then dried in an oven at 65°C for 13 hours to obtain carboxylated carbon nanotubes. In the above steps, the multi-walled carbon nanotubes are first ultrasonically reacted in sulfuric acid and then reacted in nitric acid. This avoids the problem that the mixture of the two acids will release heat and cause the concentrated sulfuric acid to easily volatilize, thus enabling the efficient preparation of carboxylated carbon nanotubes.
[0037] The carboxylated carbon nanotubes, DCC (N,N'-dicyclohexylcarbodiimide), and DMAP (4-dimethylaminopyridine) were mixed in the prescribed amounts, and DMF (N,N-dimethylformamide) solvent was added to make the mixture uniform. Then, the prescribed amount of ethylenediamine was added, and the mixture was refluxed at 100°C for 24 h. After the reaction was completed, the product was repeatedly washed with anhydrous ethanol to remove unreacted raw materials and by-products. The product was then dried in an oven at 70°C for 15 h to obtain aminated carbon nanotubes. The styrene-maleic anhydride copolymer and aminated carbon nanotubes were added to DMF in the prescribed amount and allowed to disperse and dissolve fully. Triethylamine was added and the mixture was refluxed at 110°C for 13 h. After the reaction was completed, the second product was repeatedly washed with tetrahydrofuran to remove unreacted raw materials and by-products. The product was then dried in a vacuum drying oven at 65°C for 11 h to obtain styrene-maleic anhydride copolymer grafted with multi-walled carbon nanotubes. The styrene-maleic anhydride copolymer grafted with multi-walled carbon nanotubes and ABS resin were mixed in a torque rheometer at 240°C and 60 rpm for 10 min to obtain a mixture. The mixture was placed in a flat vulcanizing apparatus and hot-pressed at 190°C and 60 MPa for 20 min, followed by cold-pressing at 20 MPa for 15 min to form the final product.
[0038] In this embodiment, 120 mL of concentrated sulfuric acid and 45 mL of concentrated nitric acid are added to each gram of multi-walled carbon nanotubes. The specific dosage can be adjusted according to the actual situation.
[0039] In this embodiment, 3g DCC, 0.5g DMAP, and 60mL ethylenediamine are added per gram of carboxylated carbon nanotubes. The specific dosage can be adjusted according to the actual situation.
[0040] In this embodiment, the styrene-maleic anhydride copolymer is SMA1000 type styrene-maleic anhydride copolymer. SMA1000 type styrene-maleic anhydride copolymer is a classic low molecular weight styrene-maleic anhydride copolymer produced by Cray Valley (now TotalEnergies), and is one of the models in the SMA resin series. The type of styrene-maleic anhydride copolymer can be selected according to the actual situation.
[0041] In this embodiment, 7g of styrene-maleic anhydride copolymer is added to each gram of aminated carbon nanotubes, and 12mL of triethylamine is added to each gram of aminated carbon nanotubes. The specific dosage can be adjusted according to the actual situation.
[0042] In this embodiment, the amount of styrene-maleic anhydride copolymer added is 5%, and the specific amount can be adjusted according to the actual situation.
[0043] In this embodiment, ultrasonic-assisted dispersion or mixing is used.
[0044] Example 3
[0045] This embodiment discloses a permanently antistatic ABS composite material containing styrene-maleic anhydride copolymer-modified carbon nanotubes. Please refer to [link to relevant documentation]. Figure 3 It is prepared through the following steps: Add the prescribed amount of multi-walled carbon nanotubes to concentrated sulfuric acid and disperse them by ultrasonication to ensure that the carbon nanotubes are fully dispersed to obtain a mixture. Add the prescribed amount of concentrated nitric acid to the mixture and reflux at 60°C for 4-7 hours. After the reaction is completed, dilute the first product with deionized water, separate it by centrifugation, and wash the first product repeatedly with deionized water until it is neutral. Place the first product in a 55°C oven and dry it for 12 hours to obtain carboxylated carbon nanotubes. In the above steps, the multi-walled carbon nanotubes are first ultrasonically reacted in sulfuric acid and then reacted in nitric acid. This avoids the problem that the mixture of the two acids will release heat and cause the concentrated sulfuric acid to easily volatilize, thus enabling the efficient preparation of carboxylated carbon nanotubes.
[0046] The carboxylated carbon nanotubes, DCC (N,N'-dicyclohexylcarbodiimide), and DMAP (4-dimethylaminopyridine) were mixed in the prescribed amounts, and DMF (N,N-dimethylformamide) solvent was added to make the mixture uniform. Then, the prescribed amount of ethylenediamine was added, and the mixture was refluxed at 95°C for 24 h. After the reaction was completed, the product was repeatedly washed with anhydrous ethanol to remove unreacted raw materials and by-products. The product was then dried in an oven at 65°C for 11 h to obtain aminated carbon nanotubes. The styrene-maleic anhydride copolymer and aminated carbon nanotubes were added to DMF in the prescribed amount and allowed to disperse and dissolve fully. Triethylamine was added and the mixture was refluxed at 100°C for 12 h. After the reaction was completed, the second product was repeatedly washed with tetrahydrofuran to remove unreacted raw materials and by-products. The product was then dried in a vacuum drying oven at 55°C for 10.5 h to obtain styrene-maleic anhydride copolymer grafted with multi-walled carbon nanotubes. The styrene-maleic anhydride copolymer grafted with multi-walled carbon nanotubes and ABS resin were mixed in a torque rheometer at 190°C and 50 rpm for 8 min to obtain a mixture. The mixture was placed in a flat vulcanizing apparatus and hot-pressed at 220°C and 50 MPa for 15 min, followed by cold-pressing at 15 MPa for 10 min to form the final product.
[0047] In this embodiment, 150 mL of concentrated sulfuric acid and 50 mL of concentrated nitric acid are added to each gram of multi-walled carbon nanotubes. The specific dosage can be adjusted according to the actual situation.
[0048] In this embodiment, 2.5g DCC, 0.4g DMAP, and 50mL ethylenediamine are added per gram of carboxylated carbon nanotubes. The specific dosage can be adjusted according to the actual situation.
[0049] In this embodiment, the styrene-maleic anhydride copolymer is SMA1000 type styrene-maleic anhydride copolymer. SMA1000 type styrene-maleic anhydride copolymer is a classic low molecular weight styrene-maleic anhydride copolymer produced by Cray Valley (now TotalEnergies), and is one of the models in the SMA resin series. The type of styrene-maleic anhydride copolymer can be selected according to the actual situation.
[0050] In this embodiment, 6g of styrene-maleic anhydride copolymer is added to each gram of aminated carbon nanotubes, and 10mL of triethylamine is added to each gram of aminated carbon nanotubes. The specific dosage can be adjusted according to the actual situation.
[0051] In this embodiment, the amount of styrene-maleic anhydride copolymer added is 3%, and the specific amount can be adjusted according to the actual situation.
[0052] In this embodiment, ultrasonic-assisted dispersion or mixing is used.
[0053] To further illustrate the properties of the permanent antistatic ABS composite material containing styrene-maleic anhydride copolymer-modified carbon nanotubes of the present invention, the following experiments were conducted: Experimental Example 1: Preparation of SMA-g-CNT / ABS (a permanent antistatic ABS composite material containing carbon nanotubes modified with styrene-maleic anhydride copolymer).
[0054] 1. Preparation of carboxylated carbon nanotubes (CNT-COOH): 0.5 g of multi-walled carbon nanotubes were added to 75 mL of concentrated sulfuric acid and ultrasonically dispersed for 30 min to ensure complete dispersion. Then, 25 mL of concentrated nitric acid was added to the mixture, and the mixture was refluxed at 60 °C for 6 h. After the reaction, the product was diluted with a large amount of deionized water, centrifuged, and repeatedly washed with deionized water until neutral. The product was then dried in a 60 °C oven for 12 h to obtain carboxylated carbon nanotubes (CNT-COOH).
[0055] 2. Preparation of aminated carbon nanotubes (CNT-NH2): 0.5 g CNT-COOH, 1 g DCC, and 0.2 g DMAP were placed in a two-necked flask, DMF solvent was added, and the mixture was sonicated for 30 min to ensure homogeneity. Then, 25 mL of ethylenediamine was added, and the mixture was refluxed at 100 °C for 24 h. After the reaction was complete, the product was repeatedly washed with anhydrous ethanol to remove unreacted raw materials and byproducts. Finally, the product was dried in an oven at 60 °C for 12 h to obtain aminated carbon nanotubes (CNT-NH2).
[0056] 3. Preparation of SMA-grafted multi-walled carbon nanotubes (SMA-g-CNT): SMA and CNT-NH2 were added to DMF at a mass ratio of 1:5 and sonicated for 30 min to ensure complete dispersion and dissolution. 10 mL of triethylamine was added, and the mixture was refluxed at 100 °C for 12 h. After the reaction, the product was repeatedly washed with tetrahydrofuran (THF) to remove unreacted raw materials and byproducts. Finally, the product was dried in a vacuum drying oven at 60 °C for 12 h to obtain SMA-grafted multi-walled carbon nanotubes (SMA-g-CNT).
[0057] 4. Preparation of SMA-g-CNT / ABS composite material: SMA-g-CNT was mixed with ABS resin at proportions of 1%, 2%, 3%, 4%, and 5% respectively in a torque rheometer at 185℃ and 50 rpm for 10 min. The mixed material was placed in a flat vulcanizing apparatus and hot-pressed at 185℃ and 20 MPa for 15 min, followed by cold pressing at 20 MPa for 10 min to form the final product.
[0058] Comparative Example 1: Preparation of P-CNT / ABS (permanent antistatic ABS composite material containing carbon nanotubes)
[0059] 1%, 2%, 3%, 4%, and 5% of the original MWCNT were mixed with ABS resin in a torque rheometer at 185°C and 50 rpm for 10 min. The mixed material was then placed in a flat vulcanizing apparatus and hot-pressed at 185°C and 20 MPa for 15 min, followed by cold-pressing at 20 MPa for 10 min to form the final product.
[0060] Comparative Example 2: Preparation of CNT-NH / ABS (a permanent antistatic ABS composite material containing aminated carbon nanotubes).
[0061] 1. Preparation of aminated carbon nanotubes (CNT-NH2): 0.5 g CNT-COOH, 1 g DCC, and 0.2 g DMAP were placed in a two-necked flask, DMF solvent was added, and the mixture was sonicated for 30 min to ensure homogeneity. Then, 25 mL of ethylenediamine was added, and the mixture was refluxed at 100 °C for 24 h. After the reaction was complete, the product was repeatedly washed with anhydrous ethanol to remove unreacted raw materials and byproducts. Finally, the product was dried in a 60 °C oven for 12 h to obtain aminated carbon nanotubes (CNT-NH2).
[0062] CNT-NH2 at proportions of 1%, 2%, 3%, 4%, and 5% was mixed with ABS resin in a torque rheometer at 185°C and 50 rpm for 10 min. The mixed material was then placed in a flat vulcanizing apparatus and hot-pressed at 185°C and 20 MPa for 15 min, followed by cold-pressing at 20 MPa for 10 min to form the final product.
[0063] The above-mentioned P-CNT / ABS, CNT-NH / ABS, and SMA-g-CNT / ABS were characterized and their performance was tested, and the following data were obtained: 1. FT-IR analysis from Figure 1 It can be seen that P-CNTs are located at 1635.3 cm. - ¹ and 1396.2 cm - Two weak absorption peaks appear at position ¹, which are attributed to the stretching vibration of the C=C double bond and the bending vibration of the C–H bond, respectively.
[0064] CNT-COOH is 1220.2 cm compared to P-CNT. - ¹ and 1720.3 cm - Two new absorption peaks appear at ¹, attributed to the stretching vibrations of the C–O and C=O bonds, respectively, while at 1396 cm⁻¹... - The absorption peak at ¹ is significantly enhanced, which is due to the in-plane bending vibration of O–H. The co-occurrence of these three peaks indicates that carboxyl groups were successfully introduced onto the surface of carbon nanotubes via mixed acid oxidation.
[0065] CNT-NH2 compared to CNT-COOH, 1720.3 cm - The absorption peak at ¹ disappears, while at 1635.3 cm⁻¹... - A new strong absorption peak appears at ¹, which is a result of the bending vibration of the N–H bond in the primary amine, indicating that the amino group reacts with the carboxyl group to form an amide bond. Furthermore, at 3448.1 cm⁻¹... - ¹、3150.8 cm - ¹ and 1403.9 cm -The absorption peaks at ¹ are attributed to N–H stretching vibration, N–H asymmetric stretching vibration, and C–N stretching vibration, respectively, indicating that amino groups were successfully introduced onto the surface of carbon nanotubes through amidation reaction.
[0066] Compared to CNT-NH2, SMA-g-CNT has a lower concentration at 1450.3 cm⁻¹. - ¹, 1488.5cm - ¹、1172.2cm - ¹ and 1720.5cm - Four new absorption peaks appear at position ¹, which are attributed to the C=C stretching vibration of the benzene ring, the C–O–C stretching vibration after the ring-opening of the acid anhydride, and the C=O stretching vibration of the carboxylic acid produced by the partial hydrolysis of SMA, respectively. (1630.1 cm⁻¹) - ¹and 1577.4 cm - The absorption peaks at ¹ correspond to the amide I band (C=O) and the amide II band (N–H bending vibration and C–N stretching vibration), respectively, indicating that the carboxyl groups of SMA reacted with the aminated carbon nanotubes. Therefore, it can be confirmed that SMA has been successfully grafted onto the surface of carbon nanotubes.
[0067] 2. TGA Analysis
[0068] P-CNTs only lose 4.34% of their mass at 600℃, which is due to other carbonaceous impurities adhering to the carbon nanotubes during the production process and the oxidation of amorphous carbon nanotubes below 500℃.
[0069] The CNT-COOH mass loss was 9.26% at 600℃. This was due to the destruction of part of the carbon nanotube surface structure by the carboxylation process, and the decomposition of the carboxylic acid groups on its surface at about 400℃.
[0070] The CNT-NH2 mass loss was 12.13% in the range of 190–300℃, which was caused by the decomposition of amino groups grafted onto the surface of carbon nanotubes.
[0071] The SMA-g-CNTs exhibited a 3.82% mass loss within the 190–250 °C range, attributed to the decomposition of residual amino groups that did not react with SMA. Combined with the thermogravimetric behavior of SMA, the mass loss within the 250–500 °C range indicates that the mass loss originates from the decomposition of SMA segments grafted onto the carbon nanotubes.
[0072]
[0073] In formula (1), w is the grafting rate of SMA in SMA-g-CNT, and γ1, γ2, and γ3 are the coke yields of CNT-NH2, SMA-g-CNT, and SMA, respectively. According to formula 1, the grafting rate of SMA in SMA-g-CNT is approximately 10.8%.
[0074] Experimental data
[0075] Tensile strength data: Test conditions: According to national standard GB / T 1040.2-2022, the composite material specimens were compressed into dumbbell-shaped strips, and the dimensions of the strips met the requirements of the national standard. The test was conducted on a universal electronic testing machine (UTM 6103, 2000 N) at a test speed of 10 mm / min, and each sample was tested in parallel five times.
[0076] from Figure 4 It is evident that P-CNT / ABS and CNT-NH / ABS exhibit decreased tensile properties due to agglomeration at high addition levels (4wt%), while SMA-g-CNT / ABS shows continuously improved mechanical properties due to its better dispersibility and compatibility with ABS.
[0077] Bending strength data: Test conditions: The bending strength test was conducted according to the national standard GB / T 9341-2008. The sample was prepared into a thin sheet with dimensions of 80×10×4 mm³ using the pellet cutting method, and tested using a testing machine (UTM 6103, 2000 N). The test was conducted at a speed of 2 mm / min, with 5 parallel tests performed for each sample.
[0078] from Figure 5 It can be seen that P-CNT / ABS and CNT-NH / ABS show a decrease in flexural strength due to agglomeration at high addition levels (4wt%), while SMA-g-CNT / ABS shows a continuous increase in flexural strength due to its better dispersibility and compatibility with ABS.
[0079] It is evident that when the addition amount of SMA-g-CNT is 3–4 wt%, it exhibits the best tensile and flexural properties, with improvements of up to 23.8% and 15.2% respectively compared to pure ABS.
[0080] Impact strength data: Test conditions: According to the national standard GB / T 1043.1-2008, to test the notched impact strength of composite materials, samples were compressed into A-type notched strips with dimensions of 80×10×4 mm³, and tested using a digital display pendulum impact testing machine. Before testing, the samples were placed in an environment with a temperature of 23℃ and a relative humidity of 50% for 24 hours to reach a stable state. During the test, an impact head with a pendulum energy of 5.5 J was used. Each sample underwent 5 parallel tests.
[0081] from Figure 6It is evident that the addition of fillers makes ABS more rigid and harder, but also more brittle, and it cannot effectively absorb impact energy through plastic deformation, resulting in reduced impact performance. However, it is also evident that SMA-g-CNT / ABS can still maintain an impact strength almost identical to P-CNT / ABS and CNT-NH / ABS.
[0082] Experimental data on glass transition temperature: Test conditions: Weigh 10 mg of sample and place it in an aluminum pot. Under a nitrogen atmosphere of 50 ml / min, first heat the sample from 25 °C to 200 °C at a heating rate of 10 °C / min, and hold for 5 min to eliminate thermal history. A second heating under the same conditions is performed to determine the glass transition temperature of the material.
[0083] from Figure 7 It is evident that the addition of nanofillers can restrict the movement of polymer chain segments to some extent, thereby increasing the glass transition temperature of polymer materials. However, the interfacial interaction between P-CNT and ABS is relatively weak, limiting its effect on raising the glass transition temperature. Surface-grafted SMA-g-CNT significantly enhances the interaction between the filler and ABS, effectively restricting polymer chain segment movement and resulting in a significant increase in the glass transition temperature. This also overcomes the problem of low glass transition temperatures found in traditional P-CNT / ABS and CNT-NH / ABS materials.
[0084] Water wash resistance data: Test conditions: The sample was immersed in water with 1% detergent and wiped for 5 minutes to simulate the washing process. After washing, the sample was placed in a 60℃ oven to dry for 2 hours. The above process was repeated. After 10, 20, 30, 40 and 50 cycles, the surface resistance of the material was measured.
[0085] from Figure 8 It is evident that the CNT-g-SMA / ABS composite material exhibits good water wash resistance, and its antistatic properties are less affected by water washing. This is because SMA grafting improves the dispersion of the carbon nanotube antistatic material within the matrix, reducing agglomeration. Simultaneously, the presence of styrene chains in the SMA enhances its compatibility with the matrix and strengthens its bond with ABS, making it less prone to detachment after repeated washing compared to unmodified carbon nanotubes, thus better preserving its original antistatic properties.
[0086] Experimental resistivity data: The surface resistance of SMA-g-CNT / ABS from Experimental Example 1, P-CNT / ABS from Comparative Example 1, and CNT-NH / ABS from Comparative Example 2, as well as the surface resistance of ABS with 0% antistatic agent, were tested respectively. Figure 9It can be seen that when the SMA-g-CNT addition amount is 3 wt%, the surface resistivity of the ABS composite material is 5.6 × 10⁻⁶. 8 Ω±1×10 8 The surface resistivity (SMR) of SMA-g-CNT / ABS is reduced by five orders of magnitude compared to pure ABS. Simultaneously, with an antistatic agent content of 3 wt%, the SMR of SMA-g-CNT / ABS is lower than that of P-CNT / ABS and CNT-NH / ABS. Although the surface resistivity of P-CNT / ABS is lower than that of SMA-g-CNT / ABS with increasing antistatic agent content, the impact on the mechanical properties of the material also increases with the increase in the amount of antistatic agent added. Therefore, the SMA-g-CNT / ABS of this invention can balance the antistatic properties of ABS composites with the mechanical properties of ABS composites, making it suitable for large-scale production and application.
[0087] Any modifications, equivalent substitutions, or improvements made within the scope of this invention should be included within the protection scope of this invention.
[0088] In this application, "multiple" refers to two or more.
[0089] In this application, unless otherwise expressly defined, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0090] The terms “first,” “second,” “third,” “fourth,” etc., in this application (if present) are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.
[0091] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.
[0092] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, if the method includes steps A and B, it means that the method may include steps A and B performed sequentially, or it may include steps B and A performed sequentially. For example, if the method may also include step C, it means that step C may be added to the method in any order. For example, the method may include steps A, B, and C, or it may include steps A, C, and B, or it may include steps C, A, and B, etc.
[0093] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A permanently antistatic ABS composite material containing styrene-maleic anhydride copolymer-modified carbon nanotubes, characterized in that, It is prepared through the following steps: Add the prescribed amount of multi-walled carbon nanotubes to concentrated sulfuric acid to fully disperse the carbon nanotubes and obtain a mixture. Add the prescribed amount of concentrated nitric acid to the mixture and reflux at 50℃~70℃ for 4h~7h. After the reaction is completed, the first product is obtained. Dilute the first product with deionized water, separate by centrifugation, and wash the first product repeatedly with deionized water until neutral. Place the first product in an oven at 50℃~65℃ and dry for 10h~13h to obtain carboxylated carbon nanotubes. The carboxylated carbon nanotubes, DCC and DMAP were mixed in the prescribed amounts, DMF solvent was added to make the mixture uniform, and then the prescribed amount of ethylenediamine was added. The mixture was refluxed at 90℃~100℃ for 24 h. After the reaction was completed, the product was repeatedly washed with anhydrous ethanol to remove unreacted raw materials and by-products. The product was dried in an oven at 50℃~70℃ for 10 h~15 h to obtain aminated carbon nanotubes. The styrene-maleic anhydride copolymer and aminated carbon nanotubes were added to DMF in the prescribed amount to ensure full dispersion and dissolution. Triethylamine was added, and the mixture was refluxed at 95℃~110℃ for 10 h~13 h. After the reaction was completed, a second product was obtained. The second product was repeatedly washed with tetrahydrofuran and dried in a vacuum drying oven at 50℃~65℃ for 10 h~11 h to obtain styrene-maleic anhydride copolymer grafted with multi-walled carbon nanotubes. The styrene-maleic anhydride copolymer grafted with multi-walled carbon nanotubes and ABS resin were mixed in a torque rheometer at 180℃~240℃ and 40rpm~60rpm for 5min~10min to obtain a mixture. The mixture was placed in a flat vulcanizing apparatus and hot-pressed at 180℃~220℃ and 30MPa~60MPa for 10min~20min, followed by cold pressing at 10MPa~20MPa for 8min~15min to form the final product.
2. The permanently antistatic ABS composite material containing styrene-maleic anhydride copolymer-modified carbon nanotubes according to claim 1, characterized in that, Add 100 mL to 150 mL of concentrated sulfuric acid and 40 mL to 50 mL of concentrated nitric acid to each gram of multi-walled carbon nanotubes.
3. The permanently antistatic ABS composite material containing styrene-maleic anhydride copolymer-modified carbon nanotubes according to claim 1, characterized in that, For every gram of carboxylated carbon nanotubes, add 2g~3g DCC, 0.3g~0.5g DMAP, and 40mL~60mL ethylenediamine.
4. The permanently antistatic ABS composite material containing styrene-maleic anhydride copolymer-modified carbon nanotubes according to claim 1, characterized in that, The styrene-maleic anhydride copolymer is an SMA1000 type styrene-maleic anhydride copolymer.
5. The permanently antistatic ABS composite material containing styrene-maleic anhydride copolymer-modified carbon nanotubes according to claim 1, characterized in that, Add 5g~7g of styrene-maleic anhydride copolymer to each gram of aminated carbon nanotubes, and add 8mL~12mL of triethylamine to each gram of aminated carbon nanotubes.
6. The permanently antistatic ABS composite material containing styrene-maleic anhydride copolymer-modified carbon nanotubes according to claim 1, characterized in that, The amount of the styrene-maleic anhydride copolymer added is 1% to 5%.
7. The permanently antistatic ABS composite material containing styrene-maleic anhydride copolymer-modified carbon nanotubes according to claim 1, characterized in that, Use ultrasound to help disperse or mix evenly.
8. The application of the styrene-maleic anhydride copolymer-modified carbon nanotube permanent antistatic ABS composite material according to any one of claims 1 to 7 in the preparation of electronic appliances, automotive industry and medical devices.