Carbon black composite intercalated styrene-butadiene rubber and method for preparing the same

Abstract

This invention belongs to the field of rubber materials, specifically relating to a carbon black composite intercalated styrene-butadiene rubber and its preparation method. The method includes: 1) mixing raw materials according to the following mass percentages: modified carbon black 12-30 wt%, layered silicate 3-9 wt%, additives 1.5-4.2 wt%, with the balance being styrene-butadiene rubber; 2) pre-mixing the styrene-butadiene rubber to obtain a rubber matrix; 3) mixing the rubber matrix, during which modified carbon black, layered silicate, and additives are sequentially added to the rubber matrix to obtain a rubber precursor; 4) subjecting the rubber precursor to gradient temperature treatment, followed by compression molding to obtain a carbon black composite intercalated styrene-butadiene rubber. This invention constructs a "carbon black-silicate" two-phase filler system, utilizing the synergistic effect of the two materials to improve the material's modulus and enhance its barrier properties, achieving dual optimization of the material's mechanical properties and oil / solvent resistance.

Description

Technical Field

[0001] This invention belongs to the field of rubber materials, specifically relating to a carbon black composite intercalated styrene-butadiene rubber and its preparation method. Background Technology

[0002] In the field of rubber materials, traditional styrene-butadiene rubber (SBR) has poor compatibility with commonly used fillers such as carbon black due to its low molecular chain polarity. This incompatibility easily causes the filler to agglomerate in the rubber matrix, which has a significant negative impact on the mechanical and electrical properties of the material.

[0003] To improve the dispersibility of fillers in styrene-butadiene rubber (SBR), existing technologies typically employ methods such as increasing the amount of carbon black or surface modification of the fillers. However, these methods lead to significantly increased energy consumption, production costs, and material brittleness, severely limiting the performance of SBR in practical applications. Furthermore, single-filler systems have limitations in meeting material performance requirements, making it difficult to simultaneously achieve the dual goals of high strength and good electrical conductivity.

[0004] It is worth noting that layered silicate (such as montmorillonite) intercalation technology has shown some effectiveness in improving the modulus of materials. However, the synergistic effect between this technology and carbon black has not yet been fully explored and applied.

[0005] Therefore, it is particularly important to develop a styrene-butadiene rubber (SBR) modified by composite intercalation of carbon black and layered silicates. This novel SBR is expected to achieve efficient dispersion of fillers in the rubber matrix, exert multifunctional synergistic effects, and possess cost advantages, thus showing broad application prospects in multiple fields.

[0006] Further analysis reveals several inherent defects in styrene-butadiene rubber (SBR). Pure SBR has relatively low strength, necessitating the addition of highly reactive reinforcing agents for practical application. However, the poor dispersion of compounding agents within the rubber has consistently hampered the optimization of SBR's performance. From a microstructural perspective, SBR exhibits a high proportion of trans-structure, lacking molecular regularity, and containing benzene rings on its side groups. This directly leads to problems such as significant hysteresis loss, high heat generation, low elasticity, and poor cold resistance. Before vulcanization, the rubber material exhibits high shrinkage, low strength, and poor adhesion; during vulcanization, its vulcanization rate is relatively slow. Even after vulcanization, while the rubber shows good resistance to flexural cracking, the crack propagation rate is rapid, and its hot tear resistance is unsatisfactory. These defects, to some extent, limit the widespread application of SBR under various environments and working conditions. Summary of the Invention

[0007] The present invention addresses the technical challenges of poor dispersibility and insufficient mechanical properties of traditional styrene-butadiene rubber fillers by providing a carbon black composite intercalated styrene-butadiene rubber and its preparation method.

[0008] The main objective of this invention is to: 1. improve the mechanical strength of rubber.

[0009] II. Improve the compatibility of the components in the rubber.

[0010] Third, further optimize the oil resistance and solvent resistance of rubber.

[0011] To achieve the above objectives, the present invention adopts the following technical solution.

[0012] A method for preparing carbon black composite intercalated styrene-butadiene rubber, the method comprising: 1) mixing raw materials according to the following mass percentages: 12-30 wt% modified carbon black, 3-9 wt% layered silicate, 1.5-4.2 wt% additives, and the balance being styrene-butadiene rubber.

[0013] 2) Premix the styrene-butadiene rubber to obtain a rubber base material.

[0014] 3) The rubber matrix is ​​mixed, and during the process, modified carbon black, layered silicate and additives are added to the rubber matrix in sequence to obtain the rubber precursor.

[0015] 4) The rubber precursor is subjected to gradient temperature treatment and then pressed to obtain carbon black composite intercalated styrene-butadiene rubber.

[0016] Preferably, the modified carbon black in step 1) is prepared by the following method: carbon black, azobisisobutyramidine hydrochloride, polyvinylpyrrolidone, styrene, ammonia, and deionized water are mixed evenly in a mass ratio of 3:(0.8-1.2):1:0.5:1:(4-6), ultrasonically dispersed for 20 min, and reacted for 8-12 h under a nitrogen atmosphere, at a temperature of 70-80 ℃ and a rotation speed of 200-300 rpm. Then, it is centrifuged and dried to prepare modified carbon black; the layered silicate in step 1) is montmorillonite.

[0017] Preferably, the additives in step 1) include a vulcanizing agent, an antioxidant, and an accelerator; the mass percentage of the additives in the raw materials is: vulcanizing agent 0.6-1.8 wt%, antioxidant 0.6-1.2 wt%, and accelerator 0.3-1.2 wt%; when the additives are added in step 3), the vulcanizing agent is added first and mixed for 3-5 minutes, followed by the antioxidant and accelerator.

[0018] Preferably, the premixing in step 2) is carried out by stirring at a temperature of 80-100°C for 20-30 minutes.

[0019] Preferably, the mixing in step 3) is carried out at a temperature of 75-80 ℃ for 15-30 min; during the mixing process in step 3), modified carbon black is first added and mixed for at least 5 min, then layered silicate is added and mixed for at least 3 min, and finally the additives are added and the mixing continues.

[0020] Preferably, the gradient temperature treatment in step 4) includes a first-stage mixing, a second-stage mixing, and a third-stage aging treatment; the first-stage mixing temperature is 80–100 °C, and the mixing time is 20–30 min; the second-stage mixing temperature is 120–140 °C, and the mixing time is 20–30 min; the third-stage aging treatment temperature is 65–70 °C, and the holding time is 10–20 min.

[0021] The core of this invention lies in combining modified carbon black with montmorillonite to construct a "carbon black-silicate" two-phase filler system. Compared to traditional single-filler applications, this invention utilizes the synergistic effect of the two materials to effectively overcome the functional limitations of single fillers. Carbon black acts as a reinforcing agent, enhancing the tensile strength of the material; montmorillonite, through its unique intercalation structure, increases the modulus and enhances barrier properties, thereby improving wear resistance and oil / solvent resistance. This combination achieves dual optimization of the material's mechanical properties and oil / solvent resistance.

[0022] In the technical solution of this invention, modified carbon black plays a crucial role. Specifically, by surface-modifying carbon black, its surface energy can be significantly reduced. This change greatly enhances the compatibility between modified carbon black and styrene-butadiene rubber (SBR), thereby effectively improving the dispersibility of carbon black in SBR. More importantly, the active sites generated on the surface of modified carbon black can form hydrogen bonds or van der Waals forces with the hydroxyl groups at the edges of silicate sheets, thus constructing a unique "carbon black-silicate" network structure. Simultaneously, under the action of shear force, rubber molecular chains gradually insert into the interlayer of silicate, ultimately forming an "intercalation-exfoliation" structure. This structure enables the silicate sheets to build a physical barrier in the matrix material, which not only effectively hinders crack propagation but also significantly improves the rigidity and barrier properties of the material. The coupling of dynamic vulcanization and intercalation composite is a major innovation of this invention. During the dynamic vulcanization process, the intercalation and dispersion of montmorillonite are simultaneously achieved, successfully avoiding the problems of high energy consumption and low production efficiency existing in traditional stepwise processes. During dynamic vulcanization, rubber molecular chains undergo cross-linking and orientation, forming a more regular and ordered network structure. Notably, the montmorillonite intercalation process can be completed simultaneously during this stage, effectively ensuring a tight bond between the filler and the rubber matrix. Through carbon black surface modification and silicate intercalation technology, the uniformity of filler dispersion in the rubber matrix is ​​significantly improved, and agglomeration is markedly reduced. Therefore, special attention must be paid to the order of material addition during the mixing process. Modified carbon black should be added first to create a suitable environment for montmorillonite addition, and other additives should be added only after the initial montmorillonite compounding is completed to minimize their impact on the process.

[0023] Another key element of this invention is the use of gradient temperature to optimize the rubber molecular chain.

[0024] In the first stage, setting a higher temperature has multiple positive effects. Higher temperatures significantly improve the fluidity of rubber molecular chains, creating favorable conditions for the further uniform dispersion of fillers (such as modified carbon black and montmorillonite) in the rubber matrix. This process not only helps the fillers integrate more fully into the rubber system but also effectively reduces the system's viscosity. Reduced viscosity directly leads to reduced mixing energy consumption, improving production efficiency while lowering production costs.

[0025] In the second stage, adjusting the temperature to a suitable range and applying specific shear force are crucial for the exfoliation and intercalation process of montmorillonite. Under these conditions, montmorillonite can be successfully exfoliated and intercalated between rubber molecular chains, thus forming a nanoscale dispersion structure. This nanoscale dispersion structure plays an indispensable role in improving the overall properties of the material, such as mechanical properties and barrier properties. Therefore, it is important to note that a relatively high mixing speed is required during the second stage of mixing, typically maintaining a speed of 90–150 rpm.

[0026] In the third stage, gradually reducing the temperature becomes a crucial operation. Gradual cooling promotes the orderly arrangement of rubber molecular chains, enabling the formation of a stable cross-linked network during the cross-linking reaction. This stable cross-linked network structure helps reduce stress concentration within the material, improving its stability and reliability.

[0027] From the perspective of phased dispersion, the entire process exhibits a synergistic mechanism among the components. At high temperatures, the modified carbon black, with its excellent dispersibility, preferentially achieves uniform dispersion. As the temperature decreases to the intermediate temperature range, silicates are successfully intercalated. At low temperatures, the rubber molecular chains are fixed, ultimately forming a gradient distribution structure of "carbon black-silicate-rubber." This unique gradient distribution structure fully leverages the advantages of each component, achieving an optimized combination of material properties.

[0028] In terms of interface strengthening, changes in temperature gradients may activate various functional groups on the filler surface, such as hydroxyl and carboxyl groups. These activated functional groups can significantly enhance the interaction between the filler and the rubber matrix, effectively improving interfacial bonding strength, whether through chemical bonding or physical adsorption. Improved interfacial bonding strength further enhances the overall performance of the material, enabling it to better transfer stress under external forces, thus exhibiting superior mechanical and performance characteristics. Simultaneously, the composite intercalation provides styrene-butadiene rubber with an internal rigid barrier interface, which significantly controls the swelling rate and oil seepage rate of styrene-butadiene rubber in terms of solvent resistance.

[0029] The beneficial effects of this invention are: by constructing a "carbon black-silicate" dual-phase filler system, this invention utilizes the synergistic effect of the two materials to improve the modulus of the material and enhance its barrier properties, thereby achieving dual optimization of the material's mechanical properties and oil / solvent resistance. Detailed Implementation

[0030] The present invention will be further described clearly and in detail below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0031] Unless otherwise specified, all raw materials used in the embodiments of this invention are commercially available or obtainable by those skilled in the art; unless otherwise specified, all methods used in the embodiments of this invention are methods mastered by those skilled in the art. Unless otherwise specified, the stirring and mixing speeds in the embodiments of this invention are all conventional speeds of 30 rpm.

[0032] Example 1: A method for preparing carbon black composite intercalated styrene-butadiene rubber, with the following ingredients: 12 wt% modified carbon black, 3 wt% layered silicate, 0.6 wt% vulcanizing agent, 0.6 wt% antioxidant, 0.3 wt% accelerator, and the balance being styrene-butadiene rubber.

[0033] The preparation process is as follows: 1) Styrene-butadiene rubber is kept at 80 ℃ and stirred for 30 min to obtain rubber substrate.

[0034] 2) Carbon black, azobisisobutyramidine hydrochloride, polyvinylpyrrolidone, styrene, ammonia and deionized water were mixed evenly in a mass ratio of 3:0.8:1:0.5:1:4, ultrasonically dispersed for 20 min, and reacted for 12 h under a nitrogen atmosphere, at a temperature of 70 ℃ and a rotation speed of 200 rpm. Then, the mixture was centrifuged, dried and ground into a fine powder to prepare modified carbon black.

[0035] 3) The rubber substrate was mixed at 75 ℃. Modified carbon black was added at the beginning of the mixing process and mixed for 5 min. Then montmorillonite was added and mixed for 5 min. Sulfur was added and mixed for 5 min. Finally, N-cyclohexyl-2-benzothiazole sulfenamide and antioxidant 4010NA were added to complete the mixing process. The total mixing time was 35 min, and the rubber precursor was obtained.

[0036] 4) The rubber precursor was mixed and stirred at 80 ℃ for 30 min in the first stage; stirred at 120 ℃ and 100 rpm for 30 min in the second stage; and kept at 65 ℃ for 20 min in the third stage. Then it was pressed and cooled to produce carbon black composite intercalated styrene-butadiene rubber.

[0037] The performance of the styrene-butadiene rubber prepared in the examples was tested. The specific testing steps and characterization results are as follows.

[0038] Mechanical property testing: The rubber material prepared in the example was prepared into a dumbbell-shaped test sample with a thickness of 2 mm and a gauge length of 25 mm according to GB / T 528-2009 "Vulcanized rubber or thermoplastic rubber. Determination of tensile stress-strain properties". The maximum tensile strength and elongation at break of the rubber material were recorded at a tensile rate of 500 mm / min.

[0039] Hardness testing: The rubber material prepared in the example was tested using a Shore A hardness tester according to GB / T 531.1-2008 "Indentation Hardness Test Method for Vulcanized Rubber or Thermoplastic Rubber". The tester was pressed vertically into the surface of the sample and the reading was taken after stabilizing for 5 seconds.

[0040] Abrasion resistance test: The rubber material prepared in this example was made into a test sample with a diameter of 16 mm and a length of 6 mm, and its mass was recorded. Then, it was tested on the Akron abrasion tester with a stroke of 1.61 km. The mass after abrasion was weighed and the mass difference was calculated. The volumetric abrasion amount was calculated.

[0041] Spacing expansion detection: The rubber material prepared in this example was ground to 200 mesh, and the spacing expansion of the carbon black composite intercalation was recorded by XRD scanning.

[0042] Oil / solvent resistance test: The rubber material prepared in this example was made into a square thin sheet standard sample with a size of 50mm×50mm×2mm. The sample was immersed in methane at 23 ℃ for 24 h, and the swelling rate of the standard sample was calculated.

[0043] Table 1: Characterization results of the sample from Example 1:

[0044] Analysis of the characterization results in Table 1 shows that the carbon black composite intercalated styrene-butadiene rubber prepared in Example 1 exhibits excellent mechanical properties. Its maximum tensile strength reaches 30.2 MPa, and its elongation at break is 451.6%, indicating that the material possesses high strength and good toughness under external forces, effectively resisting deformation and fracture. The Shore A hardness value is 75.3, and this moderate hardness gives the material better adaptability and wear resistance in practical applications. Abrasion resistance testing results show that the volumetric wear is 0.04 cm. 3 The relatively low abrasion resistance of 1.6 km further confirms the material's excellent wear resistance. The spacing extended to 3.5 nm reflects the successful construction of the carbon black composite intercalation structure and the effective dispersion of the silicate sheets within the rubber matrix.

[0045] Compared to traditional styrene-butadiene rubber (SBR), the carbon black composite intercalated SBR prepared in Example 1 exhibits significant improvements in mechanical properties and abrasion resistance. Furthermore, compared to the high swelling rate of 150-200% in traditional SBR, the swelling rate of the rubber in this invention is only significantly reduced, indicating a significant optimization and improvement in its oil / solvent resistance. This is mainly attributed to the synergistic effect of modified carbon black and montmorillonite, as well as the optimization of the gradient temperature treatment process. The modified carbon black, through surface modification treatment, significantly improves its dispersibility and compatibility in SBR, thereby enhancing the tensile strength and abrasion resistance of the material. Simultaneously, the intercalation structure of montmorillonite effectively improves the modulus and barrier properties of the material, further enhancing abrasion resistance. The gradient temperature treatment process improves the stability and reliability of the material by optimizing the arrangement of rubber molecular chains and the cross-linking network structure.

[0046] Example 2: A method for preparing carbon black composite intercalated styrene-butadiene rubber, with the following ingredients: 21 wt% modified carbon black, 6 wt% layered silicate, 1.2 wt% vulcanizing agent, 0.9 wt% antioxidant, 0.9 wt% accelerator, and the balance being styrene-butadiene rubber.

[0047] The preparation process is as follows: 1) Styrene-butadiene rubber is kept at 90 ℃ and stirred for 25 min to obtain rubber substrate.

[0048] 2) Carbon black, azobisisobutyramidine hydrochloride, polyvinylpyrrolidone, styrene, ammonia and deionized water were mixed evenly in a mass ratio of 3:1:1:0.5:1:5, ultrasonically dispersed for 20 min, and reacted for 10 h under a nitrogen atmosphere, at a temperature of 75 ℃ and a rotation speed of 250 rpm. Then, the mixture was centrifuged, dried and ground into a fine powder to prepare modified carbon black.

[0049] 3) The rubber substrate was mixed at 78 ℃. Modified carbon black was added at the beginning of the mixing process and mixed for 5 min. Then montmorillonite was added and mixed for 5 min. Sulfur was added and mixed for 3 min. Finally, N-cyclohexyl-2-benzothiazole sulfenamide and antioxidant 4010NA were added to complete the mixing process. The total mixing time was 30 min to obtain the rubber precursor.

[0050] 4) The rubber precursor was first mixed and stirred at 90 ℃ for 25 min; the second stage was stirred at 130 ℃ and 125 rpm for 25 min; the third stage was kept at 68 ℃ for 15 min. Then it was pressed and cooled to produce carbon black composite intercalated styrene-butadiene rubber.

[0051] The performance of the styrene-butadiene rubber prepared in the examples was tested. The specific testing steps and characterization results are as follows.

[0052] Mechanical property testing: The rubber material prepared in the example was prepared into a dumbbell-shaped test sample with a thickness of 2 mm and a gauge length of 25 mm according to GB / T 528-2009 "Vulcanized rubber or thermoplastic rubber. Determination of tensile stress-strain properties". The maximum tensile strength and elongation at break of the rubber material were recorded at a tensile rate of 500 mm / min.

[0053] Hardness testing: The rubber material prepared in the example was tested using a Shore A hardness tester according to GB / T 531.1-2008 "Indentation Hardness Test Method for Vulcanized Rubber or Thermoplastic Rubber". The tester was pressed vertically into the surface of the sample and the reading was taken after stabilizing for 5 seconds.

[0054] Abrasion resistance test: The rubber material prepared in this example was made into a test sample with a diameter of 16 mm and a length of 6 mm, and its mass was recorded. Then, it was tested on the Akron abrasion tester with a stroke of 1.61 km. The mass after abrasion was weighed and the mass difference was calculated. The volumetric abrasion amount was calculated.

[0055] Spacing expansion detection: The rubber material prepared in this example was ground to 200 mesh, and the spacing expansion of the carbon black composite intercalation was recorded by XRD scanning.

[0056] Oil / solvent resistance test: The rubber material prepared in this example was made into a square thin sheet standard sample with a size of 50mm×50mm×2mm. The sample was immersed in methane at 23 ℃ for 24 h, and the swelling rate of the standard sample was calculated.

[0057] Table 2: Characterization results of samples from Example 2:

[0058] Analyzing the characterization results in Table 2, in Example 2, by adjusting the content of carbon black and silicate, as well as parameters such as temperature and rotation speed during the preparation process, the prepared carbon black composite intercalated styrene-butadiene rubber exhibited excellent mechanical properties. Its maximum tensile strength reached 30.3 MPa, elongation at break was 451.8%, Shore hardness was 75.4, abrasion resistance volumetric wear was 0.03 cm³ / 1.6 km, spacing expansion was 3.7 nm, and swelling rate was 46.2%. These data indicate that the material in Example 2 achieved high levels of mechanical properties, hardness, abrasion resistance, and oil / solvent resistance, and the carbon black composite intercalation structure was effectively constructed.

[0059] Compared to Example 1, Example 2 made minor adjustments to the formulation and process, but the prepared carbon black composite intercalated styrene-butadiene rubber did not show a significant decrease in performance; on the contrary, some indicators were improved. This further confirms the stability and reliability of the method provided by this invention, as well as the superiority of the synergistic effect of modified carbon black and montmorillonite. In Example 2, by increasing the content of modified carbon black and silicate, and appropriately adjusting conditions such as temperature and rotation speed during the preparation process, the performance of the material can be further optimized. Increasing the content of modified carbon black can enhance the tensile strength and abrasion resistance of the material, while increasing the content of silicate helps to improve the modulus and barrier properties of the material. At the same time, the optimization of the gradient temperature treatment process can also promote the arrangement of rubber molecular chains and the formation of cross-linked network structures, thereby improving the stability and reliability of the material.

[0060] Example 3: A method for preparing carbon black composite intercalated styrene-butadiene rubber, with the following ingredients: 30 wt% modified carbon black, 9 wt% layered silicate, 1.8 wt% vulcanizing agent, 1.2 wt% antioxidant, 1.2 wt% accelerator, and the balance being styrene-butadiene rubber.

[0061] The preparation process is as follows: 1) Styrene-butadiene rubber is kept at 100 ℃ and stirred for 20 min to obtain rubber substrate.

[0062] 2) Carbon black, azobisisobutyramidine hydrochloride, polyvinylpyrrolidone, styrene, ammonia and deionized water were mixed evenly in a mass ratio of 3:1.2:1:0.5:1:6, ultrasonically dispersed for 20 min, and reacted for 8 h under a nitrogen atmosphere, at a temperature of 80 ℃ and a rotation speed of 300 rpm. Then, the mixture was centrifuged, dried and ground into a fine powder to prepare modified carbon black.

[0063] 3) The rubber substrate was mixed at 80 ℃. Modified carbon black was added at the beginning of the mixing process and mixed for 5 min. Then montmorillonite was added and mixed for 3 min. Sulfur was added and mixed for 3 min. Finally, N-cyclohexyl-2-benzothiazole sulfenamide and antioxidant 4010NA were added to complete the mixing process. The total mixing time was 20 min to obtain the rubber precursor.

[0064] 4) The rubber precursor was first mixed and stirred at 100 ℃ for 20 min; the second stage was stirred at 140 ℃ and 150 rpm for 20 min; and the third stage was kept at 70 ℃ for 10 min. Then it was pressed and cooled to produce carbon black composite intercalated styrene-butadiene rubber.

[0065] The performance of the styrene-butadiene rubber prepared in the examples was tested. The specific testing steps and characterization results are as follows.

[0066] Mechanical property testing: The rubber material prepared in the example was prepared into a dumbbell-shaped test sample with a thickness of 2 mm and a gauge length of 25 mm according to GB / T 528-2009 "Vulcanized rubber or thermoplastic rubber. Determination of tensile stress-strain properties". The maximum tensile strength and elongation at break of the rubber material were recorded at a tensile rate of 500 mm / min.

[0067] Hardness testing: The rubber material prepared in the example was tested using a Shore A hardness tester according to GB / T 531.1-2008 "Indentation Hardness Test Method for Vulcanized Rubber or Thermoplastic Rubber". The tester was pressed vertically into the surface of the sample and the reading was taken after stabilizing for 5 seconds.

[0068] Abrasion resistance test: The rubber material prepared in this example was made into a test sample with a diameter of 16 mm and a length of 6 mm, and its mass was recorded. Then, it was tested on the Akron abrasion tester with a stroke of 1.61 km. The mass after abrasion was weighed and the mass difference was calculated. The volumetric abrasion amount was calculated.

[0069] Spacing expansion detection: The rubber material prepared in this example was ground to 200 mesh, and the spacing expansion of the carbon black composite intercalation was recorded by XRD scanning.

[0070] Oil / solvent resistance test: The rubber material prepared in this example was made into a square thin sheet standard sample with a size of 50mm×50mm×2mm. The sample was immersed in methane at 23 ℃ for 24 h, and the swelling rate of the standard sample was calculated.

[0071] Table 3: Characterization results of samples from Example 3:

[0072] Analyzing the characterization results in Table 3 above, in Example 3, by further adjusting the content of carbon black and silicate, as well as parameters such as temperature, rotation speed, and time during the preparation process, the prepared carbon black composite intercalated styrene-butadiene rubber also exhibited excellent mechanical properties. Its maximum tensile strength was 30.2 MPa, elongation at break reached 451.7%, Shore hardness was 75.3, abrasion resistance volumetric wear was 0.05 cm³ / 1.6 km, spacing expansion was 3.2 nm, and swelling rate was 43.1%. These data indicate that the material in Example 3 maintained high levels of mechanical properties, hardness, abrasion resistance, and oil / solvent resistance, and the carbon black composite intercalation structure was effectively maintained.

[0073] Compared to Examples 1 and 2, Example 3 involves more significant adjustments to the formulation and process. However, the prepared carbon black composite intercalated styrene-butadiene rubber did not show a significant decrease in performance, further verifying the flexibility and stability of the method provided by this invention. In Example 3, by further increasing the content of modified carbon black and appropriately adjusting the silicate content, as well as optimizing the temperature and rotation speed during the preparation process, a high-performance carbon black composite intercalated styrene-butadiene rubber was successfully prepared. The characterization results of Example 3 also show that the material maintains high mechanical properties while exhibiting good wear resistance and stability of the carbon black composite intercalation structure. This is mainly due to the synergistic effect of modified carbon black and montmorillonite, as well as the optimization of the gradient temperature treatment process.

[0074] Comparative Example 1: Based on Example 2, this example only modifies the styrene-butadiene rubber component; the remaining steps are the same as in Example 2. The specific settings are as follows: Table 4: Comparison of styrene-butadiene rubber components between Comparative Example 1 and Example 2:

[0075] The performance testing method for the comparative product is completely consistent with that of Example 1, and the characterization results are shown in Table 5 below.

[0076] Table 5: Characterization results of Comparative Example 1:

[0077] Analyzing the characterization results in Table 5 above, in the comparative examples, different modifications were made to the styrene-butadiene rubber (SBR) components to explore the role of modified carbon black and montmorillonite in carbon black composite intercalation of SBR. Compared with Example 2, group D1-1, which used only modified carbon black as the rubber matrix modifier, showed a decrease in maximum tensile strength to 20.4 MPa, an elongation at break of 391.7%, a Shore hardness of 69.4, an increase in abrasion resistance volumetric wear to 0.16 cm³ / 1.6 km, and a swelling rate of 132.3%. These data indicate that while using only modified carbon black can improve some properties of the material, its overall performance is lower compared to the synergistic effect of modified carbon black and montmorillonite in Example 2. Furthermore, due to the inability to form a composite intercalation barrier, the rubber swelling rate increased dramatically, indicating that the carbon black-montmorillonite synergistic intercalation barrier significantly improves the oil / solvent resistance of the rubber.

[0078] Group D1-2 used only montmorillonite as the rubber-based modifier, achieving a maximum tensile strength of 23.7 MPa, an elongation at break of 426.1%, a Shore hardness of 62.4, and an increased volumetric abrasion resistance of 0.21 cm³ / 1.6 km. Its swelling rate reached a high of 162.8%, comparable to conventional styrene-butadiene rubber. Compared to group D1-1, most properties of group D1-2 were slightly improved, but still significantly lower than in Example 2. This further confirms the important role of modified carbon black in improving the tensile strength and abrasion resistance of materials. Regarding oil / solvent resistance, theoretically, the layered montmorillonite is the main intercalation barrier that acts as an oil / solvent barrier. However, the swelling rate of this sample is extremely high. Theoretically, layered montmorillonite has good barrier properties and rigidity that can effectively limit oil seepage and swelling of the material. However, in this sample, the montmorillonite was used directly and did not form a uniform dispersion and barrier intercalation structure within the rubber. Instead, it may lead to segregation, agglomeration, etc., resulting in a significant decrease in all its properties. It may even produce structural defects, resulting in a higher swelling rate than the D1-1 sample.

[0079] The D1-3 group samples used commercially available carbon black N330 instead of the modified carbon black of this invention. It can be seen that the mechanical properties are similar, with the most significant differences being the maximum tensile strength and elongation at break. This is mainly due to the distribution of carbon black. However, the swelling rate is worse than that of the sample in Example 2 of this invention. This is mainly because ordinary carbon black cannot generate active sites like the modified carbon black of this invention, and cannot form hydrogen bonds or van der Waals forces with the hydroxyl groups at the edge of the silicate layers to build a unique "carbon black-silicate" network structure. This leads to phenomena such as segregation, and montmorillonite cannot exert its ability to build barrier intercalation structures.

[0080] Groups D1-4 modified the filler system, achieving a maximum tensile strength of 29.3 MPa, an elongation at break of 396.4%, an increased Shore hardness of 76.6, a wear resistance volumetric wear loss of 0.25 cm³ / 1.6 km, and a swelling rate of 89.3%. These data indicate that adding other fillers to the filler system of this invention has a high probability of disrupting the original unique "carbon black-silicate" network structure, leading to a multifaceted decline in its performance.

[0081] In this invention, modified carbon black is uniformly dispersed in a rubber matrix in the form of nano-sized particles, while silicate sheets are constructed into a layered structure through an "intercalation-exfoliation" process. These two materials interact at the interface to form a three-dimensional reinforcing network. The interaction (e.g., hydrogen bonding) between the modified groups on the carbon black surface and the hydroxyl groups of the silicate enhances the interfacial adhesion between the filler and the matrix, thereby reducing stress concentration. Carbon black enhances the tensile strength of the rubber through physical adsorption and chemical crosslinking points; while silicate sheets inhibit molecular chain slippage through a "pinning effect," thus increasing the modulus. The layered structure of silicate forms a self-lubricating layer during friction, effectively reducing surface wear; simultaneously, its barrier effect helps reduce crack propagation paths. The construction of the vulcanization crosslinking network is carried out simultaneously with the silicate intercalation process, effectively avoiding the problem of reduced interfacial compatibility that may occur in step-by-step processes.

[0082] Comparative Example 2: Based on Example 2, this example only changes the processing environment for the gradient temperature treatment of the rubber precursor; the remaining steps are the same as in Example 2. The specific settings are as follows: Table 6: Comparison of processing environments between Comparative Example 2 and Example 2:

[0083] The performance testing method for the comparative product is completely consistent with that of Example 1, and the characterization results are shown in Table 7 below.

[0084] Table 7: Characterization results of Comparative Example 2:

[0085] Analyzing the characterization results in Table 7 above, in the D2-1 experimental group of Comparative Example 2, the effect of temperature on the properties of carbon black composite intercalated styrene-butadiene rubber was investigated by changing the processing environment temperature of the rubber precursor. Compared with Example 2, the D2-1 group was processed at a constant temperature of 150 ℃, resulting in a decrease in maximum tensile strength to 24.7 MPa, an elongation at break of 462.7%, an increase in Shore hardness to 78.2, an increase in abrasion volume loss to 0.08 cm³ / 1.6 km, and a spacing expansion to 2.9 nm. These data indicate that excessively high processing environment temperatures may adversely affect the mechanical properties of carbon black composite intercalated styrene-butadiene rubber, leading to a decrease in tensile strength, while hardness and abrasion resistance increase. The decrease in spacing expansion and the significant increase in swelling rate may mean that the intercalation effect of silicate layers is compromised to some extent at high temperatures, thus affecting the overall properties of the material.

[0086] The D2-2 experimental group showed that the high-speed shearing of the second-stage mixing also has an important impact on the construction and distribution of the intercalation structure. Compared with the D2-1 experimental group, the D2-2 experimental group showed both advantages and disadvantages in terms of mechanical properties, but the degree of deterioration of the swelling rate was greater than that of D2-1, which also shows the necessity of high-speed shearing.

[0087] Comparative Example 3: This example uses the traditional step vulcanization process, and the specific operation steps are as follows.

[0088] 1) Styrene-butadiene rubber was kept at 90 ℃ and stirred for 20 min to obtain a rubber substrate.

[0089] 2) Add 2 wt% sulfur and 1.2 wt% N-cyclohexyl-2-benzothiazole sulfenamide to the rubber substrate and vulcanize dynamically at 150 °C for 15 min.

[0090] 3) The vulcanized rubber was transferred to a twin-screw extruder, and 9 wt% montmorillonite and 30 wt% modified carbon black prepared by the same process as in Example 2 were added. Intercalation compounding was carried out under environmental conditions of 130 °C and 100 rpm.

[0091] 4) A method for preparing carbon black composite intercalated styrene-butadiene rubber by compression molding and cooling.

[0092] The process used in this example was recorded, and some performance tests were performed with reference to Example 1. The specific characterization results are as follows.

[0093] Energy consumption monitoring: The power consumption (kW) of the internal mixer and twin-screw extruder is recorded in real time using an electricity meter, and the unit energy consumption is recorded according to the following formula.

[0094] .

[0095] Table 8: Characterization results of Comparative Example 3:

[0096] Analyzing the characterization results in Table 8 above, in Comparative Example 3, carbon black composite intercalated styrene-butadiene rubber was prepared using a conventional stepwise vulcanization process, and its properties were compared with those of Example 2. The results show that the rubber material prepared by the conventional stepwise vulcanization process in group D3-1 is slightly lower than that in Example 2 in terms of maximum tensile strength, elongation at break, and Shore hardness. Specifically, the maximum tensile strength of group D3-1 is 27.7 MPa, the elongation at break is 425.6%, and the Shore hardness is 75.1, all of which are lower than the corresponding values ​​in Example 2. Furthermore, the abrasion resistance volumetric wear of group D3-1 is 0.09 cm³ / 1.6 km, which is similar to that of Example 2, but the unit energy consumption is as high as 2.5 kWh / kg, significantly higher than the 1.8 kWh / kg of Example 2. These data indicate that the conventional stepwise vulcanization process, in preparing carbon black composite intercalated styrene-butadiene rubber, is not only slightly inferior to the method provided by this invention in terms of mechanical properties, but also has a significant difference in energy consumption. This is mainly attributed to the separation of the vulcanization and intercalation steps in traditional processes, which may lead to reduced interfacial compatibility and thus affect the overall performance of the material. Simultaneously, the step-by-step process also increases energy consumption and cost during production. Therefore, the preparation method provided by this invention achieves effective energy reduction while maintaining high performance.

Claims

1. A method for preparing carbon black composite intercalated styrene-butadiene rubber, characterized in that, The method includes: 1) Prepare the raw materials according to the following mass percentages: Modified carbon black 12–30 wt%, layered silicate 3–9 wt%, additives 1.5–4.2 wt%, balance styrene-butadiene rubber; 2) The styrene-butadiene rubber is pre-mixed to obtain a rubber base material; 3) The rubber matrix is ​​mixed, and during the process, modified carbon black, layered silicate and additives are added to the rubber matrix in sequence to obtain the rubber precursor; 4) The rubber precursor is subjected to gradient temperature treatment and then pressed to obtain carbon black composite intercalated styrene-butadiene rubber. Step 1) The modified carbon black is prepared by the following method: carbon black, azobisisobutyramidine hydrochloride, polyvinylpyrrolidone, styrene, ammonia and deionized water are mixed evenly in a mass ratio of 3:(0.8-1.2):1:0.5:1:(4-6), ultrasonically dispersed for 20 min, and reacted for 8-12 h under nitrogen atmosphere, temperature of 70-80 ℃ and rotation speed of 200-300 rpm. Then, it is centrifuged and dried to prepare modified carbon black. In step 3), during the mixing process, first add modified carbon black and mix for at least 5 minutes, then add layered silicate and mix for at least 3 minutes, and finally add additives and continue mixing. Step 4) The gradient temperature treatment includes a first stage of mixing, a second stage of mixing, and a third stage of aging treatment; The mixing temperature in the first stage is 80–100 ℃, and the mixing time is 20–30 min; The second stage of mixing is carried out at a temperature of 120–140 °C, a speed of 90–150 rpm, and a duration of 20–30 min. The third stage of aging treatment is carried out at a temperature of 65–70 °C for 10–20 min.

2. The method for preparing carbon black composite intercalated styrene-butadiene rubber according to claim 1, characterized in that, Step 1) The layered silicate is montmorillonite.

3. The method for preparing carbon black composite intercalated styrene-butadiene rubber according to claim 2, characterized in that, Step 1) The additives include vulcanizing agents, antioxidants, and accelerators; The mass percentages of the additives in the raw materials are as follows: vulcanizing agent 0.6–1.8 wt%, antioxidant 0.6–1.2 wt%, and accelerator 0.3–1.2 wt%. When the additives are added in step 3), the vulcanizing agent is added first and mixed for 3-5 minutes, followed by the antioxidant and accelerator.

4. The method for preparing carbon black composite intercalated styrene-butadiene rubber according to claim 1, characterized in that, Step 2) The premixing is carried out by stirring at a temperature of 80-100 ℃ for 20-30 min.

5. The method for preparing carbon black composite intercalated styrene-butadiene rubber according to claim 1, characterized in that, Step 3) The mixing is carried out at a temperature of 75-80 ℃ for 20-35 min.

6. A carbon black composite intercalated styrene-butadiene rubber prepared by the method described in any one of claims 1 to 5.

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