Modified thermal cracking carbon black / carbon nanotube composite filler and application thereof

Abstract

The invention provides a modified thermal cracking carbon black / carbon nanotube composite filler and application thereof, and belongs to the technical field of rubber composite materials. The method comprises the following steps: firstly, uniformly mixing thermal cracking carbon black and carbon nanotubes according to a specific proportion, and then carrying out plasma modification on the obtained compound. The dispersity of the prepared modified composite filler in a rubber matrix is obviously improved, and the interface interaction between the modified composite filler and the rubber matrix is obviously enhanced, so that the vulcanization efficiency, the crosslinking density, the 300% stress at definite elongation and the wear resistance of a filled rubber system are improved, and the modified composite filler is particularly suitable for preparing tire tread rubber with high wear resistance.

Description

Technical Field

[0001] This invention relates to the field of rubber composite materials technology, specifically a modified pyrolytic carbon black / carbon nanotube composite filler and its application. Background Technology

[0002] In the field of rubber materials, various fillers are often added to improve the performance of rubber products. CBp and CNT, due to their unique structure and properties, are commonly used rubber fillers. Currently, research on the modification of CBp and CNT mainly focuses on the treatment of single fillers, lacking in-depth exploration of the synergistic mechanism between the two. This isolated modification method makes it difficult to optimize the interface structure between filler aggregates and between the filler and the rubber matrix, resulting in poor filler dispersion, low vulcanization efficiency, and limited improvement in the overall performance of the composite material. Traditional methods of adding CBp and CNT to rubber mainly have the following problems. For example, unmodified CBp / CNT has poor dispersion in rubber, making it difficult to fully realize the performance of the composite material. Plasma treatment of CBp alone without treating CNT (MCBp / CNT), or treatment of CBp and CNT separately and then mixing them (MCBp / MCNT), although improving some properties to a certain extent, still does not reach the ideal state. Currently, there is an urgent need for a new method that can significantly improve the dispersion of CBp and CNT in rubber, thereby comprehensively improving the performance of rubber composite materials. Summary of the Invention

[0003] The purpose of this invention is to propose a modified pyrolytic carbon black / carbon nanotube composite filler prepared by first mixing and then plasma modification through optimizing the modification process of CBp and CNT. This improves the dispersibility of the composite filler, enhances the interfacial interaction between the composite filler and the rubber matrix, increases the crosslinking density, 300% tensile stress, and wear resistance of the composite material, and reduces hysteresis loss.

[0004] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for preparing plasma-modified pyrolytic carbon black / carbon nanotube composite filler to improve the vulcanization efficiency, crosslinking density, and abrasion resistance of rubber. The preparation method comprises the following steps: (1) Pyrolytic carbon black and carbon nanotubes are mixed uniformly at a certain mass ratio and stirred evenly to obtain pyrolytic carbon black / carbon nanotube composite. (2) Plasma modification of the thermally decomposed carbon black / carbon nanotube composite was carried out to prepare plasma-modified thermally decomposed carbon black / carbon nanotube composite filler.

[0005] Preferably, the specific mass ratio is 58:2; Secondly, the present invention provides a plasma-modified pyrolytic carbon black / carbon nanotube composite filler for improving the vulcanization efficiency, crosslinking density and wear resistance of rubber. The plasma-modified pyrolytic carbon black / carbon nanotube composite filler is prepared by the above-described preparation method.

[0006] Thirdly, the present invention provides a rubber composite material, which is composed of a rubber matrix, a plasma-modified pyrolytic carbon black / carbon nanotube composite filler, and additives. The plasma-modified pyrolysis carbon black / carbon nanotube composite filler is prepared by the preparation method described in claim 1.

[0007] Preferably, the rubber composite material comprises, by weight, 100 phr rubber matrix, 60 phr plasma-modified pyrolytic carbon black / carbon nanotube composite filler, and 11.5 phr additives.

[0008] Preferably, the rubber matrix comprises: a natural rubber matrix and a styrene-butadiene rubber matrix; The additives consist of 5 phr zinc oxide, 2 phr stearic acid, 1 phr antioxidant RD, 2 phr accelerator NS, and 1.5 phr sulfur.

[0009] Preferably, the crosslinking density of the composite material is ≥8.13×10⁻⁶. -5 mol / m 3 DIN wear volume ≤ 0.143mm 3 .

[0010] Fourthly, the present invention provides the application of rubber composite materials in the preparation of tire tread compounds with high wear resistance.

[0011] Fifthly, the present invention provides a method for preparing a rubber composite material, the method comprising the following steps: (1) Add rubber matrix, zinc oxide, stearic acid, antioxidant RD, plasma modified pyrolysis carbon black / carbon nanotube composite filler, sulfur, and accelerator NS in sequence to the open mill; (2) After the thin sheet passes through the vent, the air is discharged and the sheet is lowered; (3) Curing at 150 °C.

[0012] Preferably, the rubber matrix comprises: a natural rubber matrix and a styrene-butadiene rubber matrix; By weight, the rubber matrix comprises 100 phr, the zinc oxide comprises 5 phr, the stearic acid comprises 2 phr, the plasma-modified pyrolytic carbon black / carbon nanotube composite filler comprises 60 phr, the antioxidant RD comprises 1 phr, the sulfur comprises 1.5 phr, and the accelerator NS comprises 2 phr.

[0013] The beneficial effects of this invention are as follows: The pre-mixing and post-modification process employed in this invention enables CBp and CNT to form a pre-crosslinked structure under plasma irradiation, reducing adsorption on the sulfur-promoting system and allowing more vulcanizing agent to participate in the reaction, thereby shortening the vulcanization time (the optimal vulcanization time is the shortest) and increasing the crosslinking density to 8.13 × 10⁻⁶. -5 mol / m 3 Meanwhile, the modified filler surface polar groups enhance the physical entanglement and chemical bonding with the rubber molecular chains, resulting in the maximum torque difference of the composite material, with a 300% constant elongation stress of 13.6 MPa and a reduced DIN wear volume compared to the unmodified system.

[0014] This invention achieves synergistic optimization of the interface between CBp and CNT through a process of mixing followed by plasma modification. The resulting M(CBp / CNT) composite filler exhibits the weakest Payne effect when filling vulcanized rubber, indicating good dispersibility of the composite filler in the rubber matrix. This significantly improves the vulcanization efficiency, crosslinking density, 300% tensile stress, and abrasion resistance of the rubber composite material, while reducing hysteresis loss. This method is simple to operate and has low energy consumption, providing an effective approach for the resource utilization of waste tires and the preparation of high-performance rubber materials, particularly suitable for tire tread rubber and industrial wear-resistant products. Attached Figure Description

[0015] Figure 1 shows the crosslinking density of CBp / CNT filled SBR vulcanizates with different modification methods; Figure 2 shows the DIN wear volume of CBp / CNT filled SBR vulcanizates with different modification methods; Figure 3 The values ​​represent the changes in E', E'', and tanδ with strain for CBp / CNT-filled SBR vulcanizates with different modification methods. Detailed Implementation

[0016] To better understand the present invention, the following embodiments are further illustrations of the present invention, but the content of the present invention is not limited to the following embodiments.

[0017] Example 1 Preparation of plasma-modified CBp / CNT composite filler (M(CBp / CNT)) (1) Weigh 58 phr of pyrolysis carbon black (CBp, purchased from Qingdao Yikesda Technology Co., Ltd., item number EN330) and 2 phr of carbon nanotubes (CNT, purchased from Shandong Dazhan Nanomaterials Co., Ltd., item number GT217) according to the mass ratio, and stir them in a high-speed mixer at 1000 rpm / min for 5 minutes to make the two evenly mixed; (2) Place the mixed CBp / CNT packing material into the sample chamber of the plasma processor and seal the chamber; (3) Under a high-purity argon atmosphere, the discharge power is 400 W and the treatment time is 3 minutes to obtain plasma-modified CBp / CNT composite filler (M(CBp / CNT)).

[0018] Example 2 Preparation of styrene-butadiene rubber composites containing composite filler M (CBp / CNT) (1) Mix 100 phr of styrene-butadiene rubber, 5 phr of zinc oxide, 2 phr of stearic acid, 1 phr of antioxidant RD and 60 phr of composite filler M (CBp / CNT) evenly on a two-roll mill; (2) Add 1.5 phr of sulfur and 2 phr of accelerator NS, and after thinning, vulcanize and form at 150°C in a flat vulcanizing machine.

[0019] Example 3 Preparation of natural rubber composite materials containing composite filler M (CBp / CNT) (1) Mix 100 phr of natural rubber, 5 phr of zinc oxide, 2 phr of stearic acid, 1 phr of antioxidant RD and 60 phr of composite filler M (CBp / CNT) evenly on a two-roll mill; (2) Add 1.5 phr of sulfur and 2 phr of accelerator NS, and after thinning, vulcanize and form at 150°C in a flat vulcanizing machine.

[0020] Comparative Example 1 Preparation of styrene-butadiene rubber composites containing CBp / CNT (unmodified) (1) Mix 100 phr of styrene-butadiene rubber, 5 phr of zinc oxide, 2 phr of stearic acid, 1 phr of antioxidant RD, 58 phr of pyrolytic carbon black and 2 phr of carbon nanotubes on a two-roll mill; (2) Add 1.5 phr of sulfur and 2 phr of accelerator NS, and after thinning, vulcanize and form at 150°C in a flat vulcanizing machine.

[0021] Comparative Example 2 Preparation of styrene-butadiene rubber composites containing MCBp / CNT (first modifying CBp and then mixing it with unmodified CNTs). (1) Mix 100 phr of styrene-butadiene rubber, 5 phr of zinc oxide, 2 phr of stearic acid, 1 phr of antioxidant RD, 58 phr of MCBp (plasma-modified pyrolysis carbon black) and 2 phr of carbon nanotubes evenly on a two-roll mill. (2) Add 1.5 phr of sulfur and 2 phr of accelerator NS, and after thinning, vulcanize and form at 150°C in a flat vulcanizing machine.

[0022] The modification steps for MCBp are as follows: (1) Weigh an appropriate amount of CBp and place it in the sample chamber of the plasma processor, then seal the chamber; (2) Under a high-purity argon atmosphere, with a discharge power of 400 W, the plasma-modified CBp (MCBp) was obtained after 3 minutes of treatment.

[0023] Comparative Example 3 Preparation of styrene-butadiene rubber composites containing MCBp / MCNT (CBp and CNT are modified separately and then mixed). (1) Mix 100 phr of styrene-butadiene rubber, 5 phr of zinc oxide, 2 phr of stearic acid, 1 phr of antioxidant RD, 58 phr of MCBp (plasma-modified pyrolysis carbon black) and 2 phr of MCNT (plasma-modified carbon nanotubes) evenly on a two-roll mill. (2) Add 1.5 phr of sulfur and 2 phr of accelerator NS, and after thinning, vulcanize and form at 150°C in a flat vulcanizing machine.

[0024] The modification steps for MCBp are as follows: (1) Weigh an appropriate amount of CBp and place it in the sample chamber of the plasma processor, then seal the chamber; (2) Under a high-purity argon atmosphere, with a discharge power of 400 W, the plasma-modified CBp (MCBp) was obtained after 3 minutes of treatment.

[0025] The modification steps for MCNT are as follows: (1) Weigh 2 phr CNTs and place them in the sample chamber of the plasma processor, then seal the chamber; (2) Under a high-purity argon atmosphere, the discharge power is 400 W and the treatment time is 3 minutes to obtain plasma-modified CNTs (MCNTs).

[0026] Experimental Example 1 Differences in vulcanization characteristics of CBp / CNT-filled SBR vulcanizates with different modification methods were detected. The vulcanization characteristics of CBp / CNT filled SBR vulcanizates with different modification methods are shown in Table 1.

[0027] Table 1. Vulcanization characteristics of CBp / CNT filled SBR vulcanizates with different modification methods

[0028] As can be seen from the experimental results in Table 1, the vulcanization performance of CBp / CNT-filled SBR vulcanizates showed significant differences after different modification treatments. Among them, the M(CBp / CNT) system exhibited the best vulcanization characteristics, with a torque difference (ΔM = M) of optimal value. H - M L The viscosity reached 23.8 dN·m, which is 2.0 dN·m higher than that of the unmodified CBp / CNT system (21.8 dN·m), representing an increase of approximately 9.2%. This indicates that the modification method significantly enhances the vulcanization degree of the rubber system.

[0029] Meanwhile, the process positive vulcanization time (t) of M(CBp / CNT) c90 The vulcanization time was shortened to 8.84 min, compared to 9.81 min for the CBp / CNT system, indicating a significant improvement in vulcanization efficiency and superior processing performance. This demonstrates that this modification method not only helps improve the final physical properties of the vulcanizate but also accelerates the vulcanization reaction rate to a certain extent, thereby increasing production efficiency.

[0030] The crosslinking density of CBp / CNT filled SBR vulcanizates with different modification methods was detected as follows: Figure 1 As shown.

[0031] from Figure 1 The results show that the crosslinking density of M(CBp / CNT) is 8.13 × 10⁻⁶. -5 mol / m 3 It is significantly higher than other modification methods, 12.4% higher than MCBp / CNT and 22.4% higher than MCBp / MCNT (MCBp / CNT is 7.23×10⁻⁶). -5 mol / m 3 The MCBp / MCNT ratio is 6.64 × 10⁻⁶. -5 mol / m 3 This indicates that the M(CBp / CNT) modification method is more conducive to promoting effective cross-linking between rubber molecular chains, thereby forming a denser and more stable three-dimensional network structure.

[0032] Experimental Example 2 Mechanical and abrasion resistance properties of CBp / CNT filled SBR vulcanizates with different modification methods were tested. The mechanical properties of CBp / CNT-filled SBR vulcanizates with different modification methods are shown in Table 2: The DIN wear volume of CBp / CNT filled SBR vulcanizates with different modification methods was detected as follows: Figure 2 As shown; The changes in E', E'', and tanδ of CBp / CNT-filled SBR vulcanizates with different modification methods as a function of strain are shown in the figure below. Figure 3 As shown.

[0033] Table 2 Mechanical properties of CBp / CNT filled SBR vulcanizates with different modification methods

[0034] Combination Figures 2 to 3 As can be clearly seen from the experimental results shown in Table 2, the rubber composite material prepared by plasma-modified composite filler M (CBp / CNT) exhibits significant advantages in terms of mechanical properties, filler dispersibility, wear resistance, and hysteresis loss.

[0035] From a mechanical property perspective, the 300% tensile stress of the M(CBp / CNT) composite material is 13.6 MPa, which is 11.5% higher than that of CBp / CNT, 5.4% higher than that of MCBp / CNT, and 9.7% higher than that of MCBp / MCNT, indicating that the material still has high rigidity and load-bearing capacity under large deformation. Regarding dynamic mechanical properties, the loss modulus and loss factor values ​​of the M(CBp / CNT) composite material are significantly lower than those of the unmodified CBp / CNT composite system, and ΔE' is smaller. This indicates that the pre-mixing and subsequent modification method can improve filler dispersion, promote the formation of particle networks between fillers, and increase the cross-linking network between the composite filler and the rubber molecular chains. Under external force, this restricts molecular chain movement, reduces hysteresis loss, and correspondingly lowers the loss modulus.

[0036] In terms of wear resistance, the DIN wear volume of M(CBp / CNT) is 0.143 mm³, which is significantly lower than that of the unmodified CBp / CNT system (0.156 mm³), representing a reduction of 8.3%. This result indicates that plasma treatment effectively improves the dispersibility of the filler in the rubber matrix and its interfacial interaction with rubber molecules, thereby significantly enhancing the wear resistance of the material.

[0037] In summary, M(CBp / CNT) not only demonstrates outstanding mechanical properties but also exhibits superior wear resistance, fully validating the effectiveness of the strategy of mixing fillers before plasma modification in improving the overall performance of composite materials.

Claims

1. A method for preparing plasma-modified pyrolytic carbon black / carbon nanotube composite filler to improve rubber vulcanization efficiency, crosslinking density, and abrasion resistance, characterized in that, The preparation method steps are as follows: (1) Pyrolytic carbon black and carbon nanotubes are mixed in a certain mass ratio and stirred evenly to obtain a pyrolytic carbon black / carbon nanotube composite. (2) Plasma modification of the thermally decomposed carbon black / carbon nanotube composite was carried out to prepare plasma-modified thermally decomposed carbon black / carbon nanotube composite filler.

2. The preparation method according to claim 1, characterized in that, The specified mass ratio is 58:

2.

3. A plasma-modified pyrolytic carbon black / carbon nanotube composite filler for improving rubber vulcanization efficiency, crosslinking density, and abrasion resistance, characterized in that, The plasma-modified pyrolysis carbon black / carbon nanotube composite filler is prepared by the preparation method described in claim 1 or 2.

4. A rubber composite material, characterized in that, The rubber composite material is composed of a rubber matrix, plasma-modified pyrolytic carbon black / carbon nanotube composite filler, and additives. The plasma-modified pyrolysis carbon black / carbon nanotube composite filler is prepared by the preparation method described in claim 1.

5. The rubber composite material according to claim 4, characterized in that, The rubber composite material, by mass fraction, consists of a 100 phr rubber matrix, a 60 phr plasma-modified pyrolytic carbon black / carbon nanotube composite filler, and 11.5 phr additives.

6. The rubber composite material according to claim 5, characterized in that, The rubber matrix includes: a natural rubber matrix and a styrene-butadiene rubber matrix; The additives consist of 5 phr zinc oxide, 2 phr stearic acid, 1 phr antioxidant RD, 2 phr accelerator NS, and 1.5 phr sulfur.

7. The rubber composite material according to claim 4, characterized in that, The crosslinking density of the composite material is ≥8.13×10⁻⁶. -5 mol / m 3 DIN wear volume ≤ 0.143 mm 3 .

8. The use of the rubber composite material according to any one of claims 4-7 in the preparation of tire tread compound with high wear resistance.

9. The method for preparing the rubber composite material according to any one of claims 4-7, characterized in that, The preparation method includes the following steps: (1) Add rubber matrix, zinc oxide, stearic acid, antioxidant RD, plasma modified pyrolysis carbon black / carbon nanotube composite filler, sulfur, and accelerator NS in sequence to the open mill; (2) After thinning, the air is vented and the sheet is lowered; (3) Vulcanize at 150 °C.

10. The preparation method according to claim 9, wherein the rubber matrix comprises: Natural rubber matrix and styrene-butadiene rubber matrix; By weight, the rubber matrix comprises 100 phr, the zinc oxide comprises 5 phr, the stearic acid comprises 2 phr, the antioxidant RD comprises 1 phr, the plasma-modified pyrolytic carbon black / carbon nanotube composite filler comprises 60 phr, the sulfur comprises 1.5 phr, and the accelerator NS comprises 2 phr.

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