Spray drying preparation process of graphene oxide / core-shell carbon black hybrid filler and its application in high-performance rubber composites
By using a spray drying process to prepare graphene oxide/core-shell carbon black hybrid filler, the dispersibility and interfacial interaction of carbon black in the rubber matrix are improved, the problem of poor dispersibility caused by carbon black agglomeration is solved, and the mechanical properties and wear resistance of rubber composites are enhanced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHONGBEI UNIV
- Filing Date
- 2026-05-09
- Publication Date
- 2026-07-31
AI Technical Summary
Carbon black tends to agglomerate in rubber matrices, resulting in poor dispersibility and affecting the mechanical properties and wear resistance of rubber composites.
A spray drying process for preparing graphene oxide/core-shell carbon black hybrid fillers was adopted. By combining polymer encapsulation and aqueous phase blending dispersion with spray drying, graphene oxide/core-shell carbon black hybrid fillers were prepared, which improved the dispersibility and interfacial interaction of the fillers in rubber.
It significantly improves the mechanical properties and wear resistance of rubber composite materials, and extends tire service life.
Smart Images
Figure CN122483609A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of graphene and functional rubber composite materials, specifically relating to a spray drying preparation process of graphene oxide / core-shell carbon black hybrid filler and its application in high-performance rubber composite materials. Background Technology
[0002] With the rapid development of modern industry and transportation, rubber composite materials, as an important engineering material, have played a key role in many industries.
[0003] Carbon black is a commonly used reinforcing filler in rubber, improving its strength, rigidity, abrasion resistance, and tear resistance. However, carbon black particles are prone to agglomeration, and these agglomerates are difficult to disperse sufficiently in the rubber matrix, limiting the reinforcing effect and potentially causing adverse changes in dynamic heat generation and abrasion properties. Therefore, improving the dispersibility of carbon black in the rubber matrix and its interfacial interaction with the matrix is one of the important ways to improve the performance of rubber composites.
[0004] However, while single carbon black fillers can improve the mechanical properties of rubber, they also have certain limitations, especially in improving mechanical properties and reducing wear. Rubber tires experience significant wear during high-speed operation, which is related to friction between fillers and between the filler and the matrix. Carbon black fillers tend to form agglomerates, resulting in poor dispersion within the rubber matrix and thus increasing friction. Therefore, optimizing their dispersion method is crucial for solving these problems.
[0005] In recent years, graphene oxide, as a novel nanomaterial, has been widely used in the reinforcement and modification of rubber due to its excellent mechanical strength, thermal conductivity, and surface functionalization properties. Graphene oxide, through its abundant surface functional groups, forms a strong interfacial bond with the rubber matrix, improving the compatibility between fillers and the matrix, enhancing the mechanical properties of composite materials, and helping to reduce friction between fillers. Against this backdrop, developing graphene oxide-carbon black hybrid fillers as synergistic reinforcing fillers can better improve the mechanical properties of rubber and enhance the overall performance of rubber products.
[0006] Spray drying is a highly efficient drying technology that directly converts liquid materials into powdered or granular products. It features: ① Extremely fast drying speed: The material is dispersed into micron-sized droplets through an atomizer, dramatically increasing its surface area. Upon contact with hot air, the moisture evaporates rapidly within seconds, completing the drying process. ② Directly obtainable powder products: No subsequent evaporation or pulverization processes are required. Liquid raw materials (such as solutions, emulsions, and suspensions) can be dried in a single step to obtain powders of 30-500 μm, simplifying the process. ③ Excellent product quality: The resulting particles are mostly near-spherical, porous, uniformly sized, and have good flowability, exhibiting excellent solubility, dispersibility, and rapid solubility. ④ Easy to automate and continuously operate: The entire process is a closed-loop pipeline operation, allowing for continuous feeding and discharging. This facilitates precise control of parameters such as temperature, airflow, and pressure, complying with GMP and other industrial standards. Spray drying technology plays a crucial role in the rubber industry, primarily for producing powdered rubber. It directly replaces traditional block raw rubber, simplifying formulation and processing. Specifically, its core applications and advantages are as follows: ① Main Applications: A) Powdered Rubber Production: Directly atomizes and dries latex or rubber solution into free-flowing powder, facilitating precise metering and automated production. B) Simplified Formulation and Processing: Powdered rubber can be directly used in dry mixing processes, eliminating multiple steps such as plasticizing and mixing in traditional rubber compounding. C) Improved Working Environment: Closed production significantly reduces dust emissions, improving workplace safety. ② Process Advantages: A) High-Efficiency Drying: Spray drying is fast and suitable for large-scale continuous production. B) Controllable Performance: By adjusting process parameters (such as inlet air temperature and atomization method), the particle size, surface structure (such as micropores), and molecular weight of the powdered rubber can be controlled, thereby optimizing the physical properties of the final product (such as vulcanization rate and mechanical strength). In summary, spray drying technology provides the rubber industry with a modern solution that is efficient, environmentally friendly, and offers controllable performance through the production of powdered rubber. Summary of the Invention
[0007] The purpose of this invention is to provide a spray drying preparation process for graphene oxide / core-shell carbon black hybrid filler and its application in high-performance rubber composites, so as to improve the dispersion and interfacial interaction of reinforcing fillers in the rubber matrix, thereby improving the mechanical properties and wear resistance of the composite material and extending the service life of tires.
[0008] This invention is achieved through the following technical solution: In a first aspect, a spray drying preparation process for a graphene oxide / core-shell carbon black hybrid filler includes the following steps: (1) Add carbon black to deionized water and stir at speed R1 for time t1 to obtain carbon black aqueous dispersion; then add polymer aqueous emulsion and react at temperature T1 and stirring speed R2 for time t2 to obtain modified carbon black aqueous dispersion; then add graphene oxide aqueous dispersion and sonicate at temperature T2 and ultrasonic power W1 for time t3 to obtain blended dispersion; The mass ratio of graphene oxide to polymer solids in the aqueous emulsion to carbon black is 0.05:0.5-1:10; the solid content of the polymer aqueous emulsion is 20-40 wt.%; the graphene oxide sheet diameter is 0.5-5 μm and the number of layers is 1-5; the concentration of the carbon black aqueous dispersion is 50-80 mg / mL, the concentration of the polymer aqueous emulsion is 200-400 mg / mL, the concentration of the modified carbon black aqueous dispersion is 60-80 mg / mL, the concentration of the graphene oxide aqueous dispersion is 4-6 mg / mL, and the concentration of the blended dispersion is 50-70 mg / mL. (2) The blended dispersion obtained in step (1) is pumped into a spray drying equipment by a peristaltic pump for rapid drying to obtain graphene oxide / core-shell carbon black hybrid filler; wherein, the rotation speed of the peristaltic pump is 9-20 rpm, the air inlet temperature of the spray drying equipment is 160-200 °C; the average particle size of the core of the obtained graphene oxide / core-shell carbon black hybrid filler is 0.5-5 μm.
[0009] As a further improvement to the technical solution of the present invention, in step (1), R1 is 4000-6000 rpm, time t1 is 30min-1 h, temperature T1 is 40-60 °C, time t2 is 20-30 min, rotation speed R2 is 300-500 rpm; the addition temperature T2 of the graphene oxide dispersion is room temperature, ultrasonic power W1 is 300-500 W, and time t3 is 10-20 min.
[0010] Secondly, the application of a graphene oxide / core-shell carbon black hybrid filler prepared by a spray drying process in high-performance rubber composites.
[0011] As a further improvement to the application technology solution of the present invention, the high-performance rubber composite material includes the following raw materials in parts by weight: 100 parts of rubber, 10-15 parts of rubber additives, and 35-95 parts of graphene oxide / core-shell carbon black hybrid filler; the content of the hybrid filler is to ensure that the content of graphene oxide in 100 parts of rubber is 0.3-0.8 parts.
[0012] As a further improvement to the application technology of the present invention, the rubber additives include antioxidants, activators, vulcanization accelerators, softeners and vulcanizing agents.
[0013] As a further improvement to the application technology of this invention, the vulcanization accelerator is at least one selected from N-tert-butyl-2-benzothiazole sulfenamide, N-cyclohexyl-2-benzothiazole sulfenamide, and N-(diethylidene oxide)-2-benzothiazole sulfenamide; the antioxidant is at least one selected from 2,6-di-tert-butyl-4-methylphenol, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and 2-thiol-benzimidazole; the antioxidant is N-(1,3-dimethylbutyl)-N The active ingredient is at least one of '-phenyl-p-phenylenediamine (4020), N-(1-methylisopentyl)-N'-phenyl-p-phenylenediamine, p-phenylaniline, and dilauryl thiodipropionate; the activator is at least one of zinc gluconate, zinc oxide, and magnesium oxide; the softener is at least one of stearic acid, dibutyl titanate, and dioctyl adipate; the mass ratio of antioxidant: antioxidant: activator: vulcanization accelerator: softener: vulcanizing agent is 2-3:1-2:4-6:1-2:1-3:1-2.
[0014] As a further improvement to the application technology solution of the present invention, the preparation process of the high-performance rubber composite material includes the following steps: S1. Rubber is mixed in an internal mixer at a temperature of T4 for a time of t4. During this time, rubber additives and graphene oxide / core-shell carbon black hybrid filler are added sequentially. After being dispersed evenly, the rubber compound is discharged and cooled to room temperature to obtain a premixed rubber. S2. Place the premixed rubber obtained in step S1 on a rolling mill at a temperature T5 for a time t5. During this time, add vulcanizing agent and mix evenly. After passing through a thin stream until the rubber compound is uniform and free of bubbles, the mixed rubber is obtained. S3. The compound obtained in step S2 is placed at temperature T6 for time t6, and then placed in a mold and vulcanized at temperature T7 and pressure P1 for time t7 to obtain a high-performance rubber composite material with graphene oxide / core-shell carbon black hybrid filler.
[0015] As a further improvement to the application technology solution of the present invention, T4 is 100-120 °C, t4 is 10-16 min, T5 is 50-70 °C, t5 is 10-15 min, T6 is room temperature, t6 is 20-30 h, T7 is 140-160 °C, P1 is 10-20 MPa, and t7 is 5-15 min.
[0016] The spray drying preparation process of graphene oxide / core-shell carbon black hybrid filler provided by this invention and its application in high-performance rubber composites have the following advantages compared with the prior art: ① By using a polymer encapsulation and aqueous phase blending dispersion process combined with spray drying, a graphene oxide / core-shell carbon black hybrid filler can be obtained, which is beneficial to improving the uniformity of filler dispersion and processing stability in rubber.
[0017] ② The use of the hybrid filler to fill rubber significantly improves the filler-matrix interface interaction, thereby improving the mechanical properties and wear resistance of the composite material.
[0018] ③ The preparation method of this invention mainly uses aqueous phase dispersion and spray drying as the main processes. The process route is simple and efficient, and has the potential for large-scale industrial preparation. Attached Figure Description
[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.
[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 SEM images of polyurethane-encapsulated core-shell carbon black prepared in this embodiment of the invention and unencapsulated carbon black prepared in Comparative Example 1.
[0022] Figure 2 These are SEM images of the brittle fracture surfaces of the natural rubber composite materials prepared in Example 1 and Comparative Example 1 of this invention.
[0023] Figure 3 The Raman spectral curves and peak fitting results of the hybrid fillers prepared in Examples 1-2 and Comparative Example 1 of this invention are shown.
[0024] Figure 4 The images show the FT-IR spectra of the hybrid packings prepared in Examples 1-2 and Comparative Example 1 of this invention.
[0025] Figure 5 The images show the TG spectra of the hybrid fillers prepared in Examples 1-2 and Comparative Example 1 of this invention.
[0026] Figure 6 Payne curves (i.e., curves showing the change of storage modulus G′ with strain) of the natural rubber compounds prepared in Examples 1-2 and Comparative Example 1 of this invention. Detailed Implementation
[0027] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.
[0028] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.
[0029] This invention provides a specific embodiment of a spray drying preparation process for graphene oxide / core-shell carbon black hybrid filler, comprising the following steps: (1) Add carbon black to deionized water and stir at speed R1 for time t1 to obtain carbon black aqueous dispersion; then add polymer aqueous emulsion and react at temperature T1 and stirring speed R2 for time t2 to obtain modified carbon black aqueous dispersion; then add graphene oxide aqueous dispersion and sonicate at temperature T2 and ultrasonic power W1 for time t3 to obtain blended dispersion; The mass ratio of graphene oxide to polymer solids in the aqueous emulsion to carbon black is 0.05:0.5-1:10; the solid content of the polymer aqueous emulsion is 20-40 wt.%; the graphene oxide sheet diameter is 0.5-5 μm and the number of layers is 1-5; the concentration of the carbon black aqueous dispersion is 50-80 mg / mL, the concentration of the polymer aqueous emulsion is 200-400 mg / mL, the concentration of the modified carbon black aqueous dispersion is 60-80 mg / mL, the concentration of the graphene oxide aqueous dispersion is 4-6 mg / mL, and the concentration of the blended dispersion is 50-70 mg / mL. (2) The blended dispersion obtained in step (1) is pumped into a spray drying equipment by a peristaltic pump for rapid drying to obtain graphene oxide / core-shell carbon black hybrid filler; wherein, the rotation speed of the peristaltic pump is 9-20 rpm, the air inlet temperature of the spray drying equipment is 160-200 °C; the average particle size of the core of the obtained graphene oxide / core-shell carbon black hybrid filler is 0.5-5 μm.
[0030] The graphene oxide / core-shell carbon black hybrid filler in this invention is composed of graphene oxide and polymer-encapsulated core-shell carbon black, wherein the polymer aqueous emulsion can be selected from polyurethane aqueous emulsion, styrene-acrylate copolymer emulsion, polyacrylate emulsion, silicone-acrylate copolymer emulsion, or polyacrylic acid emulsion.
[0031] Preferably, in step (1), R1 is 4000-6000 rpm, time t1 is 30 min-1 h, temperature T1 is 40-60 °C, time t2 is 20-30 min, rotation speed R2 is 300-500 rpm; the addition temperature T2 of the graphene oxide dispersion is room temperature, ultrasonic power W1 is 300-500 W, and time t3 is 10-20 min.
[0032] The present invention also provides an application of graphene oxide / core-shell carbon black hybrid filler prepared by spray drying process in high-performance rubber composite materials.
[0033] In one example provided by the present invention, the high-performance rubber composite material comprises the following raw materials in parts by weight: 100 parts rubber, 10-15 parts rubber additives, and 35-95 parts graphene oxide / core-shell carbon black hybrid filler; the content of the hybrid filler is such that the content of graphene oxide in 100 parts rubber is 0.3-0.8 parts.
[0034] In another example provided by the present invention, the rubber additives include antioxidants, activators, vulcanization accelerators, softeners, and vulcanizing agents.
[0035] In one example provided by the present invention, the vulcanization accelerator is at least one selected from N-tert-butyl-2-benzothiazole sulfenamide, N-cyclohexyl-2-benzothiazole sulfenamide, and N-(diethylidene oxide)-2-benzothiazole sulfenamide; the antioxidant is at least one selected from 2,6-di-tert-butyl-4-methylphenol, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and 2-thiol-benzimidazole; and the antioxidant is N-(1,3-dimethylbutyl)-N'- The active ingredient is at least one of phenyl-p-phenylenediamine (4020), N-(1-methylisopentyl)-N'-phenyl-p-phenylenediamine, p-phenylaniline, and dilauryl thiodipropionate; the activator is at least one of zinc gluconate, zinc oxide, and magnesium oxide; the softener is at least one of stearic acid, dibutyl titanate, and dioctyl adipate; the mass ratio of antioxidant to activator to accelerator to softener to accelerator is 2-3:1-2:4-6:1-2:1-3:1-2.
[0036] In another example provided by the present invention, the preparation process of the high-performance rubber composite material includes the following steps: S1. Rubber is mixed in an internal mixer at a temperature of T4 for a time of t4. During this time, rubber additives and graphene oxide / core-shell carbon black hybrid filler are added sequentially. After being dispersed evenly, the rubber compound is discharged and cooled to room temperature to obtain a premixed rubber. S2. Place the premixed rubber obtained in step S1 on a rolling mill at a temperature T5 for a time t5. During this time, add vulcanizing agent and mix evenly. After passing through a thin stream until the rubber compound is uniform and free of bubbles, the mixed rubber is obtained. S3. The compound obtained in step S2 is placed at temperature T6 for time t6, and then placed in a mold and vulcanized at temperature T7 and pressure P1 for time t7 to obtain a high-performance rubber composite material with graphene oxide / core-shell carbon black hybrid filler.
[0037] In one example provided by the present invention, T4 is 100-120 °C, t4 is 10-16 min, T5 is 50-70 °C, t5 is 10-15 min, T6 is room temperature, t6 is 20-30 h, T7 is 140-160 °C, P1 is 10-20 MPa, and t7 is 5-15 min.
[0038] The specific embodiments of the present invention will be described in detail below.
[0039] Example 1: A spray drying preparation process for a graphene oxide / core-shell carbon black hybrid filler and its high-performance natural rubber composite material, specifically including the following steps: 1. 35 phr of N330 carbon black was added to deionized water and stirred at 5000 rpm for 40 min to obtain a carbon black aqueous dispersion with a concentration of 66 mg / mL. Then, a polyurethane aqueous emulsion with a concentration of 300 mg / mL and a solid content of 30% wt. was added, and the mixture was treated at 50 °C and 400 rpm for 25 min to obtain a modified carbon black aqueous dispersion with a concentration of 68.5 mg / mL. Next, a graphene oxide aqueous dispersion with a concentration of 5 mg / mL was added, and the mixture was sonicated at room temperature and 400 W for 15 min to obtain a blended dispersion with a concentration of 59 mg / mL. The mass ratio of graphene oxide:polyurethane:carbon black was 0.05:0.6:10; the graphene oxide sheet diameter was 2 μm, and the number of layers was 2-3. II. The blended dispersion obtained in step I is pumped into a spray drying device using a peristaltic pump for rapid drying to obtain the graphene oxide / core-shell carbon black hybrid filler; wherein, the rotation speed of the peristaltic pump is 12 rpm, the inlet air temperature of the spray drying device is 180 °C; the average particle size of the core of the obtained graphene oxide / core-shell carbon black hybrid filler is 2.5 μm; III. Natural rubber is mixed in a mixer at 110 °C for 4 min. Then, 2 phr of antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (4020), 2 phr of antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD), and 2 phr of vulcanization accelerator CZ are added. After mixing for 4 min, 5 phr of activator zinc oxide and 2 phr of softener stearic acid are added. The mixture is then mixed for 4 min. Finally, the graphene oxide / core-shell carbon black hybrid filler prepared in step II is added. After mixing for 4 min, the rubber compound is discharged and cooled to room temperature to obtain the premixed rubber. IV. The premixed rubber obtained in step III is milled at 60 °C on a two-roll mill for 10 min. During this time, 2 phr of sulfur is added and mixed evenly. After passing through a thin stream until the rubber compound is uniform and free of bubbles, the mixed rubber is obtained. V. The compound obtained in step IV is left at room temperature for 24 hours, then placed in a mold and vulcanized for 6 minutes at 150 °C and 15 MPa according to the TC90 obtained by the rubber processing analyzer to obtain a high-performance rubber composite material with graphene oxide / core-shell carbon black hybrid filler.
[0040] Example 2: A spray-drying preparation process for a graphene oxide / core-shell carbon black hybrid filler and its high-performance natural rubber composite material, comprising the following steps: I. 35 phr of N330 carbon black was added to deionized water and stirred at 4000 rpm for 30 min to obtain a carbon black aqueous dispersion with a concentration of 77 mg / mL. Then, a polyurethane aqueous emulsion with a concentration of 250 mg / mL and a solid content of 35% wt. was added, and the mixture was treated at 55 °C and a stirring speed of 450 rpm for 25 min to obtain a modified carbon black aqueous dispersion with a concentration of 80 mg / mL. Next, a graphene oxide aqueous dispersion with a concentration of 5 mg / mL was added, and the mixture was sonicated at room temperature and an ultrasonic power of 400 W for 15 min to obtain a blended dispersion with a concentration of 70 mg / mL. The mass ratio of graphene oxide:polyurethane:carbon black was 0.05:0.7:10; the graphene oxide sheet diameter was 1.5 μm, and the number of layers was 2-4. II. The blended dispersion obtained in step I is rapidly dried in a spray drying device using a peristaltic pump to obtain the graphene oxide / core-shell carbon black hybrid filler. The peristaltic pump speed is 16 rpm, and the inlet air temperature of the spray drying device is 170 °C. The average particle size of the core of the obtained graphene oxide / core-shell carbon black hybrid filler is approximately 3 μm. III. Natural rubber is internally mixed in a mixer at 110 °C for 4 min. Then, 2 phr of antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (4020), 2 phr of antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD), and 2 phr of vulcanization accelerator CZ are added. After mixing for 4 min, 5 phr of activator zinc oxide and 2 phr of softener stearic acid are added, and the mixture is mixed for 4 min. Finally, the graphene oxide / core-shell carbon black hybrid filler prepared in step II is added, and the mixture is mixed for 4 min. After min, the adhesive is discharged and cooled to room temperature to obtain the premixed adhesive; IV. The premixed rubber obtained in step III is milled at 60 °C on a two-roll mill for 10 min. During this time, 2 phr of sulfur is added and mixed evenly. After passing through a thin stream until the rubber compound is uniform and free of bubbles, the mixed rubber is obtained. V. The compound obtained in step IV is left at room temperature for 24 hours, then placed in a mold and vulcanized for 6 minutes at 150 °C and 15 MPa according to the tc90 obtained by the rubber processing analyzer to obtain a high-performance rubber composite material of graphene oxide / core-shell carbon black hybrid filler.
[0041] Example 3: The process was exactly the same as in Example 1, except that the mass ratio of graphene oxide:polymer solids in the aqueous emulsion:carbon black was 0.05:0.5:10, resulting in a blended dispersion with a concentration of 66 mg / mL.
[0042] Example 4: The process was exactly the same as in Example 1, except that the mass ratio of graphene oxide:polymer solids in the aqueous emulsion:carbon black was 0.05:1:10, resulting in a blended dispersion with a concentration of 71 mg / mL.
[0043] Example 5:
[0044] The process was exactly the same as in Example 1, except that the concentration of the polyurethane aqueous emulsion was 200 mg / mL, resulting in a blended dispersion with a concentration of 56 mg / mL.
[0045] Example 6: The process was exactly the same as in Example 1, except that the concentration of the polyurethane aqueous emulsion was 400 mg / mL, resulting in a blended dispersion with a concentration of 72 mg / mL.
[0046] Example 7: The process is exactly the same as in Example 1, except that the amount of deionized water added in step I is increased so that the concentration of the blended dispersion obtained in step I is 50 mg / mL.
[0047] Example 8: The process is exactly the same as in Example 1, except that the amount of deionized water added in step I is reduced so that the concentration of the blended dispersion obtained in step I is 70 mg / mL.
[0048] Example 9: It is exactly the same as Example 1, except that the peristaltic pump rotates at 9 rpm.
[0049] Example 10: It is exactly the same as Example 1, except that the peristaltic pump rotates at 20 rpm.
[0050] Example 11: It is exactly the same as Example 1, except that the inlet air temperature of the spray drying equipment is 160 °C.
[0051] Example 12: It is exactly the same as Example 1, except that the inlet air temperature of the spray drying equipment is 200 °C.
[0052] Comparative Example 1: A spray drying preparation process for a graphene oxide / carbon black blend filler and its natural rubber composite material is exactly the same as that in Example 1, except that polyurethane aqueous emulsion is not added in step (I).
[0053] Comparative Example 2: The process was exactly the same as in Example 1, except that the mass ratio of graphene oxide:polymer solids in the aqueous emulsion:carbon black was 0.05:0.3:10, resulting in a blended dispersion with a concentration of 57 mg / mL.
[0054] Comparative Example 3: The process was exactly the same as in Example 1, except that the mass ratio of graphene oxide:polymer solids in the aqueous emulsion:carbon black was 0.05:1.2:10, resulting in a blended dispersion with a concentration of 61 mg / mL.
[0055] Comparative Example 4: The process was exactly the same as in Example 1, except that the concentration of the polyurethane aqueous emulsion was 180 mg / mL, resulting in a blended dispersion with a concentration of 55 mg / mL.
[0056] Comparative Example 5: The process was exactly the same as in Example 1, except that the concentration of the polyurethane aqueous emulsion was 420 mg / mL, resulting in a blended dispersion with a concentration of 74 mg / mL.
[0057] Comparative Example 6: It is exactly the same as Example 1, except that the amount of deionized water added in step (I) is increased so that the concentration of the blended dispersion obtained in step (I) is 45 mg / mL.
[0058] Comparative Example 7: It is exactly the same as Example 1, except that the amount of deionized water added in step (I) is reduced so that the concentration of the blended dispersion obtained in step (I) is 75 mg / mL.
[0059] Comparative Example 8: It is exactly the same as Example 1, except that the peristaltic pump rotates at 8 rpm.
[0060] Comparative Example 9: It is exactly the same as Example 1, except that the peristaltic pump rotates at 22 rpm.
[0061] Comparative Example 10: It is exactly the same as Example 1, except that the inlet air temperature of the spray drying equipment is 150 °C.
[0062] Comparative Example 11: It is exactly the same as Example 1, except that the inlet air temperature of the spray drying equipment is 210 °C.
[0063] The natural rubber composites obtained in Examples 1-12 and Comparative Examples 1-11 were subjected to performance tests. The tensile properties were tested according to GB / T 528-2009, with a tensile rate of 500 mm / min. The tear properties were tested according to GB / T 529-2008. The hardness was tested according to GB / T 531.1-2008. The abrasion properties were tested according to GB / T 9867-2008. The heat generation properties were tested according to GB / T 1687.1-2016.
[0064] Depend on Figure 1 It can be seen that, compared with the uncoated carbon black prepared in Comparative Example 1, the apparent particle size of the polyurethane-coated carbon black particles prepared in the embodiments of the present invention is about 30-50 nm, while the apparent particle size of the polyurethane-coated carbon black is about 20-30 nm.
[0065] Depend on Figure 2 It can be seen that, compared with Comparative Example 1, the filler in the rubber composite material prepared in Example 1 of the present invention is more uniformly dispersed.
[0066] Depend on Figure 3 It can be seen that the various hybrid filler samples are at approximately 1350 cm⁻¹ -1 and 1580 cm -1Characteristic peaks of the D and G bands appear at these locations, respectively. The D band corresponds to defect structures in carbon materials, and the G band corresponds to sp. 2 The ordered structure of carbon atoms. Compared with Comparative Example 1, the hybrid fillers prepared in Examples 1 and 2 have I D / I G The values decreased from 0.71 to 0.58 and 0.44, respectively, indicating that the structural order of the graphene oxide and core-shell carbon black prepared in the examples was significantly improved and the degree of defects was reduced. The results show that during the spray drying process, significant interfacial interactions occurred between the graphene oxide and the core-shell carbon black, making the microstructure of the hybrid filler more regular, rather than a simple physical mixture.
[0067] Depend on Figure 4 It can be seen that, for Comparative Example 1, at approximately 3400 cm -1 The presence of a distinct -OH stretching vibration absorption peak indicates that the surface of the hybrid filler contains abundant oxygen-containing functional groups. Compared to Comparative Example 1, the intensity of the -OH absorption peak is significantly weakened in the spectra of the hybrid fillers prepared in Examples 1 and 2, while the intensity is also significantly reduced at approximately 1000-1200 cm⁻¹. -1 The changes in the characteristic peaks of COC and CN in the region indicate that the oxygen-containing functional groups on the graphene oxide surface interact with the core-shell carbon black surface. Furthermore, the changes in the peak shapes of functional groups such as C=O further suggest the existence of interfacial bonding between the two, thus forming a stable hybrid structure.
[0068] Depend on Figure 5 As can be seen from the spectrum of Comparative Example 1, significant weight loss occurs in the 200-400℃ range, corresponding to the thermal decomposition process of the oxygen-containing functional groups of graphene oxide, with a low final residual mass. In contrast, the thermal weight loss process of the hybrid fillers prepared in Examples 1 and 2 is significantly milder, indicating that a stable hybrid structure is formed between graphene oxide and core-shell carbon black, which improves the thermal stability of graphene oxide and suppresses its thermal decomposition behavior. This improvement in thermal stability indicates a strong interfacial interaction between the two.
[0069] Raman, FT-IR, and TG spectra revealed that functional groups such as -OH on the surface of core-shell carbon black adsorb onto functional groups such as -OH and -COC- on the surface of graphene oxide through hydrogen bonding and dipole-dipole interactions, forming a stable interfacial bond. Furthermore, a synergistic enhancement effect was observed in thermal stability and structural order, indicating that a stable hybrid structure has been formed, thus confirming the successful preparation of a graphene oxide / core-shell carbon black hybrid filler.
[0070] Depend on Figure 6It can be seen that, compared with Comparative Example 1, the initial G′ values of the rubber composite materials prepared in Examples 1-2 of the present invention are all larger. The magnitude of the initial G′ value represents the strength of the filler network in the mixed rubber, indicating that the graphene oxide / core-shell carbon black hybrid filler of the present invention does have a more significant positive influence on the filler network in the natural rubber composite material and the interaction between the filler and the matrix.
[0071] Table 1. Overall performance of Examples 1-2 and Comparative Example 1
[0072] As shown in Table 1, compared with the natural rubber composite material prepared in Comparative Example 1 without polyurethane-modified carbon black (i.e., pure carbon black was introduced), the tensile strength, tear strength, hardness, dynamic compression heat generation performance, and abrasion resistance of the natural rubber composite material prepared in Examples 1-2 of this invention with graphene oxide / core-shell carbon black hybrid filler synergistic modification are all improved.
[0073] Table 2 Properties of the modified natural rubber composites obtained in Examples 3-12 and Comparative Examples 2-11
[0074] The process parameters of spray drying are like the "soul" of this technology, directly determining whether the final powder is high-quality or defective. Spray drying process parameters constitute a complex, interconnected system, and their importance lies in their role as the core control method for achieving high-quality, high-efficiency, and high-stability production. Mastering these parameters is crucial for the successful application of spray drying technology. Many factors influence the spray drying process; some of the main parameters and their roles in this invention are detailed below: ① Process parameters: A) Inlet Air Temperature: Inlet air temperature is crucial, directly affecting the drying rate and product moisture content. The difference between Examples 11-12 and Comparative Examples 10-11 lies in the inlet air temperature of the spray drying equipment. It can be seen that when the inlet air temperature is below 160°C, the moisture evaporation rate is insufficient, the particles are not fully dried, and collapse or adhesion to the walls is likely to occur, leading to uneven polyurethane coating on the carbon black surface and unstable structure of the obtained graphene oxide / core-shell carbon black hybrid filler. When the inlet air temperature is above 200°C, a dense layer quickly forms on the surface of the droplets, hindering internal moisture migration and easily causing structural defects. It may also weaken the interfacial bonding between graphene oxide and core-shell carbon black. Only when the inlet air temperature is between 160-200°C in this invention can a high-performance graphene oxide / core-shell carbon black hybrid filler be obtained, resulting in a graphene oxide / core-shell carbon black hybrid filler synergistically modified natural rubber composite material with significantly improved tensile strength, tear strength, hardness, dynamic compression heat generation performance, and abrasion resistance, as shown in Table 2.
[0075] B) Feeding parameters: including feed rate and feed speed. Excessive feed rate may exceed drying capacity, leading to wall adhesion or excessively high product moisture content. Feed speed affects the contact time between droplets and hot air, thus affecting drying efficiency. The difference between Examples 9-10 and Comparative Examples 8-9 lies in the rotational speed of the peristaltic pump, i.e., the feed speed. It can be seen that when the peristaltic pump speed (feed speed) is below 9 rpm, the feed rate is insufficient, the hot air utilization rate decreases, and it may also cause the hybrid filler to remain in the drying chamber for too long, resulting in localized overheating, and even thermal decomposition or structural changes of the polyurethane, affecting the integrity of the polyurethane-encapsulated carbon black core-shell structure. Furthermore, it may prevent the atomizer from stably forming uniform droplets, leading to a wider droplet size distribution, which in turn affects the morphology and shell uniformity of the final obtained graphene oxide / core-shell carbon black hybrid filler. When the peristaltic pump speed (feed rate) exceeds 20 rpm, the drying capacity is insufficient to match the feed rate, resulting in excessively high particle moisture content and agglomeration or adhesion to the walls, leading to uneven structure. The atomizer may also fail to adequately break the material into fine droplets, causing some large droplets to drip directly, resulting in decreased yield and uneven particle size distribution. Furthermore, excessively fast feeding may interfere with the drying trajectory, preventing timely shell formation or densification, thus weakening the integrity and stability of the core-shell structure. Therefore, when preparing core-shell structured particles, it is necessary to optimize the feed rate to ensure it matches the atomization capacity, hot air parameters, and material characteristics to maintain structural integrity and product quality. Only when the peristaltic pump speed (feed rate) is within 9-20 rpm of this invention can a high-performance graphene oxide / core-shell carbon black hybrid filler be obtained, resulting in a graphene oxide / core-shell carbon black hybrid filler synergistic modification of natural rubber composite material with significantly improved tensile strength, tear strength, hardness, dynamic compression heat generation performance, and abrasion resistance, as shown in Table 2.
[0076] ② Material properties: The physical properties of the feed solution, including viscosity, surface tension, concentration, and solids content, all affect atomization effect, drying rate, and product morphology. While excessively low feed solution viscosity may prevent wall adhesion, it weakens the formation efficiency of the core-shell structure and reduces product yield. Conversely, excessively high viscosity significantly negatively impacts the atomization process, particle morphology, equipment operation, and final product quality. Therefore, comprehensive control based on solids content and atomization conditions is necessary. While excessively high feed solution concentration may improve energy efficiency and promote core-shell structure formation, exceeding the process tolerance limit will lead to atomization failure, structural damage, and reduced yield. Insufficiently low concentration is detrimental to the efficient and stable preparation of core-shell structures. Excessively high solids content in the feed solution can cause nozzle clogging, poor atomization, particle adhesion, and reduced yield during spray drying. Insufficient solids content significantly weakens the formation quality, structural integrity, and process economy of the core-shell structure. Claim 1 of this invention ensures the smooth implementation of the spray drying process and the quality of the obtained graphene oxide / core-shell carbon black hybrid filler by specifying the concentration and relevant ratio of various materials. Furthermore, a comparison between Examples 3-8 and Comparative Examples 2-7 further confirms the importance of the physical properties of the feed solution. As shown in Table 2, compared to Comparative Examples 2-7, the tensile strength, tear strength, hardness, dynamic compression heat generation performance, and abrasion resistance of the natural rubber composite materials synergistically modified with the graphene oxide / core-shell carbon black hybrid filler prepared in Examples 3-8 of this invention are all improved.
[0077] ③ Other factors: A) Balance between drying temperature and time: Excessively high temperatures or excessively fast drying speeds may cause surface hardening, preventing internal moisture from escaping (forming a "hard shell"), or deactivating heat-sensitive components. Insufficient temperatures result in incomplete drying. B) Matching of drying airflow and feed rate: An optimal match needs to be found. Excessive airflow may carry away fine particles, causing waste; insufficient airflow leads to incomplete drying. A feed rate that is too fast will result in incomplete drying, while a rate that is too slow will reduce efficiency.
[0078] This invention coordinates the concentrations and proportions of various materials, as well as the inlet air temperature and the peristaltic pump speed (feed rate), to ensure the smooth implementation of the spray drying process and the quality of the obtained graphene oxide / core-shell carbon black hybrid filler. Furthermore, a comparison between Examples 1-12 and Comparative Examples 2-11 demonstrates the importance of balancing drying temperature and time, and matching drying air volume and feed rate, for the smooth implementation of the spray drying process and ensuring the quality of the obtained graphene oxide / core-shell carbon black hybrid filler. Table 2 shows that, compared to Comparative Examples 2-11, the tensile strength, tear strength, hardness, dynamic compression heat generation performance, and abrasion resistance of the natural rubber composite material synergistically modified with graphene oxide / core-shell carbon black hybrid filler prepared in Examples 1-12 of this invention are significantly improved.
[0079] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Although detailed descriptions have been provided with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments, and they should all be covered within the protection scope of the claims.
Claims
1. A process for the spray-drying preparation of graphene oxide / core-shell carbon black hybrid fillers, characterized in that, Includes the following steps: (1) Add carbon black to deionized water and stir at speed R1 for time t1 to obtain carbon black aqueous dispersion; then add polymer aqueous emulsion and react at temperature T1 and stirring speed R2 for time t2 to obtain modified carbon black aqueous dispersion; then add graphene oxide aqueous dispersion and sonicate at temperature T2 and ultrasonic power W1 for time t3 to obtain blended dispersion; The mass ratio of graphene oxide to polymer solids in the aqueous emulsion to carbon black is 0.05:0.5-1:10; the solid content of the polymer aqueous emulsion is 20-40 wt.%; the graphene oxide sheet diameter is 0.5-5 μm and the number of layers is 1-5; the concentration of the carbon black aqueous dispersion is 50-80 mg / mL, the concentration of the polymer aqueous emulsion is 200-400 mg / mL, the concentration of the modified carbon black aqueous dispersion is 60-80 mg / mL, the concentration of the graphene oxide aqueous dispersion is 4-6 mg / mL, and the concentration of the blended dispersion is 50-70 mg / mL. (2) The blended dispersion obtained in step (1) is pumped into a spray drying equipment by a peristaltic pump for rapid drying to obtain graphene oxide / core-shell carbon black hybrid filler; wherein, the rotation speed of the peristaltic pump is 9-20 rpm, the air inlet temperature of the spray drying equipment is 160-200 °C; the average particle size of the core of the obtained graphene oxide / core-shell carbon black hybrid filler is 0.5-5 μm.
2. The process for the spray drying preparation of graphene oxide / core-shell carbon black hybrid fillers according to claim 1, characterized in that, In step (1), R1 is 4000-6000 rpm, time t1 is 30 min-1 h, temperature T1 is 40-60 °C, time t2 is 20-30 min, and rotation speed R2 is 300-500 rpm; the addition temperature T2 of the graphene oxide dispersion is room temperature, the ultrasonic power W1 is 300-500 W, and the time t3 is 10-20 min.
3. The application of the graphene oxide / core-shell carbon black hybrid filler prepared by the spray drying process of the graphene oxide / core-shell carbon black hybrid filler as described in claim 1 or 2 in high-performance rubber composite materials.
4. The application as described in claim 3, characterized in that, The high-performance rubber composite material comprises the following raw materials in parts by weight: 100 parts rubber, 10-15 parts rubber additives, and 35-95 parts graphene oxide / core-shell carbon black hybrid filler; the content of the hybrid filler is such that the content of graphene oxide in 100 parts rubber is 0.3-0.8 parts.
5. The application as described in claim 4, characterized in that, The rubber additives include antioxidants, activators, vulcanization accelerators, softeners, and vulcanizing agents.
6. The application as described in claim 5, characterized in that, The vulcanization accelerator is at least one selected from N-tert-butyl-2-benzothiazole sulfenamide, N-cyclohexyl-2-benzothiazole sulfenamide, and N-(diethylidene oxide)-2-benzothiazole sulfenamide; the antioxidant is at least one selected from 2,6-di-tert-butyl-4-methylphenol, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and 2-thiol-benzimidazole; the antioxidant is N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylene oxide. At least one of diamine, N-(1-methylisopentyl)-N'-phenyl-p-phenylenediamine, p-phenylaniline, and dilauryl thiodipropionate; the activator is at least one of zinc gluconate, zinc oxide, and magnesium oxide; the softener is at least one of stearic acid, dibutyl titanate, and dioctyl adipate; the mass ratio of antioxidant to activator to vulcanizing agent to softener to vulcanizing agent is 2-3:1-2:4-6:1-2:1-3:1-2.
7. The application as described in claim 3, characterized in that, The preparation process of the high-performance rubber composite material includes the following steps: S1. Rubber is mixed in an internal mixer at a temperature of T4 for a time of t4. During this time, rubber additives and graphene oxide / core-shell carbon black hybrid filler are added sequentially. After being dispersed evenly, the rubber compound is discharged and cooled to room temperature to obtain a premixed rubber. S2. Place the premixed rubber obtained in step S1 on a rolling mill at a temperature T5 for a time t5. During this time, add vulcanizing agent and mix evenly. After passing through a thin stream until the rubber compound is uniform and free of bubbles, the mixed rubber is obtained. S3. The compound obtained in step S2 is placed at temperature T6 for time t6, and then placed in a mold and vulcanized at temperature T7 and pressure P1 for time t7 to obtain a high-performance rubber composite material with graphene oxide / core-shell carbon black hybrid filler.
8. The application as described in claim 7, characterized in that, The values are as follows: T4 is 100-120 °C, t4 is 10-16 min, T5 is 50-70 °C, t5 is 10-15 min, T6 is room temperature, t6 is 20-30 h, T7 is 140-160 °C, P1 is 10-20 MPa, and t7 is 5-15 min.