Activators for rubber vulcanization reactions and methods of making and using

Abstract

The application provides an activator for a rubber vulcanization reaction and a preparation method and application thereof, and belongs to the technical field of catalysts. The activator for the rubber vulcanization reaction comprises a carrier and zinc oxide. The carrier is a nanomaterial doped with a nonmetallic element. The zinc oxide is anchored to the outer surface of the carrier. The zinc oxide is coordinated with the nonmetallic element doped on the outer surface of the carrier to form a monatomic layer in the form of fully exposed sub-nanoclusters. The zinc atoms are not overlapped and are anchored to the outer surface of the carrier in the form of dispersed fully exposed sub-nanoclusters by coordination of the zinc oxide and the nonmetallic element doped on the outer surface of the carrier, so that the zinc atoms can be fully exposed to serve as active centers and improve catalytic activity. The activator can be applied to the vulcanization reaction in the rubber field, improves the vulcanization reaction efficiency, and can reduce the zinc consumption by 70-80% due to the full exposure of the zinc atoms, thereby saving industrial energy consumption and metal resources.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, specifically to an activator for rubber vulcanization reaction and its preparation method and application, and more specifically to a fully exposed sub-nano cluster material that can replace the vulcanization reaction. Background Technology

[0002] Rubber consumption is high, with my country consuming approximately 10 million tons annually. For vulcanized rubber, a significant amount of zinc oxide is added as an activator during the production process. Zinc oxide activates the vulcanization system, increases crosslinking density, and enhances the anti-aging properties of vulcanized rubber. Currently, zinc oxide remains a relatively effective rubber activator and plays a crucial role. However, zinc oxide is expensive, and excessive use can cause serious water pollution. Furthermore, the zinc oxide activators used are mostly granular nano-zinc oxide, which suffers from low zinc utilization and insufficient activity, making it difficult to reduce the amount of zinc used. Summary of the Invention

[0003] In view of this, in order to at least partially solve at least one of the aforementioned technical problems, the present invention provides an activator for rubber vulcanization reaction, a preparation method thereof, and its application.

[0004] According to one aspect of the present invention, an activator for rubber vulcanization reaction is provided, comprising: a carrier, the carrier being a nanomaterial doped with non-metallic elements; and zinc oxide anchored on the outer surface of the carrier; wherein the zinc oxide is coordinated with the non-metallic elements doped on the outer surface of the carrier to form a monoatom layer in the form of fully exposed sub-nano clusters.

[0005] According to an embodiment of the present invention, the mass ratio of zinc oxide to the carrier is (0.5~10):100.

[0006] According to embodiments of the present invention, the nanomaterial includes at least one of carbon black, silica, or graphene oxide; the non-metallic element includes at least one of nitrogen, oxygen, phosphorus, and boron; the carbon black has a particle size of 10-100 nm and a specific surface area of ​​50-150 m². 2 / g; the particle size of silica is 20~100nm, and the specific surface area is 100~300m². 2 / g; Graphene oxide has a size of 1~10μm, a thickness of 3~10nm, and a specific surface area of ​​100~400m². 2 / g.

[0007] According to an embodiment of the present invention, the doping amount of non-metallic elements accounts for 0.5 to 5% of the mass percentage of the nanomaterial.

[0008] According to another aspect of the present invention, a method for preparing an activator as described above is provided, comprising: dispersing a support in a first solvent to obtain a dispersion solution; adding a zinc metal salt and an alkaline solution to the dispersion solution to carry out a hydrolysis reaction to obtain an activator; wherein the support is a nanomaterial doped with non-metallic elements.

[0009] According to embodiments of the present invention, the alkaline solution includes any one of sodium hydroxide aqueous solution, lithium hydroxide aqueous solution, and potassium hydroxide aqueous solution.

[0010] According to an embodiment of the present invention, the temperature of the hydrolysis reaction is 15~25°C.

[0011] According to an embodiment of the present invention, before dispersing the support in the first solvent, the method further includes: dispersing the nanomaterial in a second solvent, adding a non-metallic compound, mixing and stirring to react, and obtaining the support; the non-metallic compound includes any one of nitrogen-containing compounds, sulfur-containing compounds, boron-containing compounds, and phosphorus-containing compounds.

[0012] According to an embodiment of the present invention, the temperature of the mixing and stirring reaction is 80~85°C.

[0013] According to another aspect of the present invention, the application of the activator as described above in the rubber vulcanization reaction is provided.

[0014] According to embodiments of the present invention, by using nanomaterials doped with non-metallic elements as a carrier, a higher specific surface area and more abundant active sites can be provided. The doped non-metallic elements can adjust the electronic structure and chemical properties of the carrier. Zinc oxide forms coordination interactions with the non-metallic elements doped on the outer surface of the carrier, for example, by forming chemical bonds. This coordination interaction can form coordination-unsaturated zinc-oxygen bonds with the doped non-metallic elements, which helps to improve the catalytic activity of zinc oxide. Fully exposed sub-nano clusters refer to zinc oxide that is completely exposed on the outer surface of the carrier and bonded to the doped non-metallic elements through coordination bonds. Unlike traditionally formed nano-zinc oxide particles, the zinc oxide of the present invention is not embedded inside the activator but is entirely anchored on the outer surface of the carrier, forming a monoatom layer. Therefore, the zinc oxide in the activator of the present invention has a zinc atom utilization rate of nearly 100%. When subsequently applied to rubber vulcanization reactions, it can effectively replace existing nano-zinc oxide particles. Furthermore, because the zinc oxide of the present invention is in a fully exposed state, the amount of metallic zinc can be reduced by 70-80% compared to the amount of traditional zinc oxide nanoparticles, helping to conserve metal resources. The activator of this invention exhibits high activity when subsequently applied to rubber vulcanization reactions, which can shorten the positive vulcanization time and improve reaction efficiency, thereby facilitating industrial application and contributing to green and sustainable development.

[0015] According to embodiments of the present invention, the preparation process of the activator of the present invention is not highly dependent on temperature and can be prepared at room temperature. Compared with the traditional indirect method for preparing zinc oxide, which requires a high temperature of 1000°C, the method of the present invention can save industrial energy consumption and is easy to prepare industrially. Attached Figure Description

[0016] The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0017] Figure 1 A flowchart illustrating the preparation process of an activator for rubber vulcanization reaction according to an embodiment of the present invention is shown;

[0018] Figure 2 A transmission electron microscope (TEM) image of activator 1, which is suitable for rubber vulcanization reaction in Example 1 of the present invention, is shown. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0020] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0021] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "comprising" as used herein indicates the presence of features, steps, or operations, but does not exclude the presence or addition of one or more other features.

[0022] When using expressions such as "at least one of A, B, and C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.). When using expressions such as "at least one of A, B, or C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0023] In this invention, the term "fully exposed sub-nano clusters" refers to an atomically dispersed, fully exposed zinc oxide cluster activator composed of zinc oxide. The clusters are smaller than 1 nanometer in size and are dispersed on the outer surface of the carrier in the form of a monoatomic layer, thereby ensuring that all zinc oxide can participate in the adsorption and activation of the reactants.

[0024] Rubber vulcanization is an important industrial reaction that increases the crosslinking density of vulcanized rubber and improves its anti-aging properties. Currently, zinc oxide nanoparticles are a relatively effective rubber activator, but they suffer from problems such as low zinc utilization, insufficient activity, and high dosage.

[0025] In realizing the concept of this invention, it was discovered that by using nanomaterials doped with non-metallic elements as a carrier, zinc oxide can be anchored on the outer surface of the carrier, which can improve the dispersibility of zinc oxide and enable zinc oxide to coordinate with the non-metallic elements doped on the outer surface of the carrier to form coordination-unsaturated zinc-oxide chemical bonds. This results in the formation of a single atomic layer in the form of fully exposed sub-nano clusters, which helps to improve the catalytic activity of zinc oxide in the sulfidation reaction and the utilization rate of zinc atoms, and can effectively reduce the amount of zinc oxide used.

[0026] Specifically, according to one embodiment of the present invention, an activator for rubber vulcanization reaction is provided, comprising: a carrier and zinc oxide. The carrier is a nanomaterial doped with non-metallic elements. Zinc oxide is anchored to the outer surface of the carrier. The zinc oxide is coordinated with the non-metallic elements doped on the outer surface of the carrier, forming a monoatomic layer in the form of fully exposed sub-nano clusters.

[0027] According to embodiments of the present invention, by using nanomaterials doped with non-metallic elements as a support, a higher specific surface area and more abundant active sites can be provided. The doped non-metallic elements can adjust the electronic structure and chemical properties of the support. Zinc oxide forms coordination interactions with the non-metallic elements doped on the outer surface of the support, for example, by forming chemical bonds. This coordination interaction can form coordination-unsaturated zinc-oxygen bonds with the doped non-metallic elements, creating an anchoring interaction between zinc oxide and the support, which helps to improve the catalytic activity of zinc oxide. Fully exposed sub-nano clusters refer to zinc oxide that is entirely exposed on the outer surface of the support and bonded to the doped non-metallic elements through coordination bonds. Unlike traditionally formed nano-zinc oxide particles, the zinc oxide of the present invention is not embedded inside the activator but is entirely anchored on the outer surface of the support, forming a monoatom layer. Therefore, the zinc oxide in the activator of the present invention has a zinc atom utilization rate of nearly 100%, and can effectively replace existing nano-zinc oxide particles when subsequently applied to rubber vulcanization reactions. Furthermore, because the zinc oxide of the present invention is in a fully exposed state, the amount of metallic zinc can be reduced by 70-80% compared to the amount of traditional zinc oxide nanoparticles, helping to conserve metal resources. The activator of this invention exhibits high activity when subsequently applied to rubber vulcanization reactions, which can shorten the positive vulcanization time and improve reaction efficiency, thereby facilitating industrial application and contributing to green and sustainable development.

[0028] According to an embodiment of the present invention, zinc oxide is anchored in the form of sub-nano clusters at the active sites of non-metallic elements on the surface of a support, forming a single-atom layer. The formed fully exposed sub-nano clusters have a size of less than 1 nm, and are therefore in the form of sub-nano clusters. These clusters have a large specific surface area and high surface energy, which enables zinc oxide to be fully exposed and has coordination-unsaturated zinc-oxygen bonds, thereby increasing the atomic utilization rate of zinc atoms and catalytic activity.

[0029] According to embodiments of the present invention, the mass ratio of zinc oxide to the support is (0.5~10):100, for example, it can be 0.5:100, 1:100, 1.6:100, 2:100, 2.4:100, 3:100, 3.7:100, 4:100, 4.6:100, 5:100, 6:100, 7:100, 8:100, 9:100, or 10:100, but is not limited thereto. An appropriate mass ratio range ensures that there are sufficient transition metal oxides in the catalyst to provide high catalytic activity and prevents the aggregation or migration of fully exposed sub-nano clusters of zinc oxide, while avoiding the high cost caused by using excessive zinc oxide.

[0030] According to embodiments of the present invention, the nanomaterial includes at least one of carbon black, silica, or graphene oxide. The non-metallic element includes at least one of nitrogen, oxygen, phosphorus, and boron. For example, taking sulfur-doped graphene oxide, zinc atoms are linked to the support through zinc-oxygen-sulfur chemical bonds, which can effectively improve the surface activity and dispersibility of the zinc oxide activator, thereby enhancing its catalytic performance. Doping graphene oxide with sulfur introduces new active sites and improves the electronic properties of graphene oxide, enabling zinc oxide to connect to graphene oxide through sulfur atoms. Based on this, zinc oxide subnanoclusters can stably arrange themselves on the surface of the doped support, ensuring sufficient exposure of zinc atoms on the catalyst surface and improving the utilization rate of zinc atoms. Furthermore, the zinc oxide subnanoclusters possess coordinate-unsaturated zinc-oxygen bonds, which further enhances the activity of the activator.

[0031] According to embodiments of the present invention, the particle size of the carbon black is 10~100 nm, for example, it can be 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm or 100 nm, but is not limited thereto. The specific surface area is 50~150 m². 2 / g, for example, could be 50m 2 / g、60m 2 / g、70m 2 / g、80m 2 / g、90m 2 / g, 100m 2 / g、110m 2 / g、120m 2 / g、130m 2 / g, 140m 2 / g or 150m 2 / g. The particle size of silica is 20~100nm, for example, it can be 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm or 100nm, but is not limited to this. Specific surface area is 100~300m². 2 / g, for example, could be 100m 2 / g, 150m 2 / g、200m 2 / g、250m 2 / g or 300m 2 / g. The size of graphene oxide is 1~10μm, for example, it can be 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm or 10μm, but is not limited thereto. The thickness is 3~10nm, for example, it can be 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm or 10nm, but is not limited thereto. The specific surface area is 100~400m². 2 / g, for example, could be 100m 2 / g, 150m 2 / g、200m 2 / g、250m 2 / g、300m 2 / g, 350m 2 / g or 400m 2 / g, but not limited to this. The size range of the above nanomaterials can provide a large specific surface area, which helps the dispersion and anchoring of zinc oxide, thereby improving the catalytic activity and selectivity of the activator, increasing the utilization rate of zinc atoms, thus improving catalytic efficiency, and saving costs.

[0032] According to embodiments of the present invention, the doping amount of non-metallic elements accounts for 0.5% to 5% of the mass of the nanomaterial, for example, 0.6%, 1.5%, 2.5%, 3.4%, 4.1%, etc., but is not limited to the listed values; other unlisted values ​​within this range are also applicable. This range of doping amounts can effectively improve the surface properties of magnesium oxide and introduce new active sites into the nanomaterial to enhance the performance of the support, while avoiding the degradation of support performance caused by excessive doping.

[0033] Figure 1 A flowchart illustrating the preparation process of an activator for rubber vulcanization reaction according to an embodiment of the present invention is shown.

[0034] According to another aspect of the present invention, a method for preparing an activator as described above is provided; please refer to... Figure 1 As shown, it includes steps S101 to S102.

[0035] In step S101, the carrier is dispersed in the first solvent to obtain a dispersion solution.

[0036] In step S102, zinc metal salt and alkaline solution are added to the dispersion solution to carry out a hydrolysis reaction and obtain an activator.

[0037] According to an embodiment of the present invention, the support is a nanomaterial doped with non-metallic elements. The first solvent includes any one of water and ethanol. Dispersing the support in the first solvent promotes uniform dispersion of the support, forming a stable dispersion solution, providing abundant contact area and reactive sites for subsequent reactions. The zinc metal salt, which is the precursor solution for zinc oxide, and the alkali react with the support through hydrolysis to convert the zinc metal salt into zinc oxide, forming coordination bonds with the non-metallic elements on the support. This anchors the zinc oxide to the outer surface of the support, facilitating the formation of fully exposed sub-nano clusters, thus serving as an activator in the rubber vulcanization process. This activator promotes cross-linking reactions between rubber molecular chains, thereby improving the physical properties of the rubber.

[0038] According to embodiments of the present invention, the carrier includes carbon black doped with non-metallic elements, silica doped with non-metallic elements, and graphene oxide doped with non-metallic elements, wherein the doped non-metallic elements are selected from any one of nitrogen, sulfur, phosphorus, and boron. The zinc metal salt includes at least one of zinc nitrate, zinc chloride, zinc sulfate, and zinc acetate.

[0039] According to embodiments of the present invention, the hydrolysis reaction temperature is 15~25℃, for example, 15℃, 20℃ or 25℃, but not limited thereto. The preparation process of the activator of the present invention is not highly dependent on temperature and can be prepared at room temperature. Compared with the traditional indirect method for preparing zinc oxide, which requires a high temperature of 1000℃, the method of the present invention can save industrial energy consumption and is easy to prepare industrially.

[0040] According to embodiments of the present invention, the alkaline solution includes any one of an aqueous solution of sodium hydroxide, an aqueous solution of lithium hydroxide, or an aqueous solution of potassium hydroxide. For example, it can be selected based on the actual reaction conditions and the required pH range to promote the anchoring of zinc oxide on the carrier surface in the form of fully exposed sub-nano clusters.

[0041] According to embodiments of the present invention, the concentration of the carrier is 5-10 g / L, for example, 5.5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, or 9.5 g / L, but is not limited thereto. The amount of zinc metal salt added is 2.5-40% of the carrier mass fraction, for example, 3%, 5%, 10%, 15%, 20%, 25%, 30%, or 35%, but is not limited thereto. The pH range of the hydrolysis reaction is 9-11, for example, 9, 10, or 11, but is not limited thereto.

[0042] According to an embodiment of the present invention, before dispersing the support in the first solvent, the method further includes: dispersing the nanomaterial in a second solvent, adding a non-metallic compound, mixing and stirring to react, thereby obtaining the support. The non-metallic compound includes any one of nitrogen-containing compounds, sulfur-containing compounds, boron-containing compounds, and phosphorus-containing compounds. Nitrogen-containing compounds may, for example, be selected from any one of ammonia, formamide, and 2-methylimidazole. Sulfur-containing compounds may, for example, be selected from any one of thiourea, potassium persulfate, sodium thiosulfate, and n-dodecyl mercaptan. Phosphorus-containing compounds may, for example, be selected from any one of triphenylphosphine, potassium dihydrogen phosphate, and phosphonic acid. Boron-containing compounds may, for example, be selected from any one of boric acid, boric anhydride, and boronamide.

[0043] According to embodiments of the present invention, the second solvent may be, for example, water, ethanol, or N,N-dimethylformamide.

[0044] According to embodiments of the present invention, the mixing and stirring reaction temperature is 80-85°C, for example, 81°C, 82°C, 83°C, or 84°C, but is not limited to the listed values; other unlisted values ​​within this range are also applicable. This temperature range is beneficial for promoting the reaction of nitrogen-containing compounds, sulfur-containing compounds, phosphorus-containing compounds, or boron-containing compounds with nanomaterials, thereby achieving effective doping. By precisely controlling these parameters, the preparation process of the support can be optimized, thereby improving the performance and efficiency of the support.

[0045] According to an embodiment of the present invention, when the support is sulfur-doped graphene oxide, the process for preparing the support is as follows:

[0046] Graphene oxide powder and thiourea were added to water and mixed evenly. After stirring, the mixture was filtered and dried to obtain sulfur-doped graphene oxide. The hydrogen sulfide (H2S) gas produced by the decomposition of thiourea reacts with oxygen-containing groups (such as carboxyl and hydroxyl groups) on the surface of graphene oxide (GO). Sulfur atoms replace oxygen atoms on the surface of graphene oxide or react with oxygen-containing groups to form functional groups such as thioethers (-S-) or thiophenols (-SH). Volatile components and chemically bound water are removed through thermal decomposition, forming a sulfur-doped graphene oxide carrier (S-GO).

[0047] More specifically, the process for preparing sulfur-doped graphene oxide is as follows: At room temperature, 2g of graphene oxide powder is added to 500mL of water and stirred until homogeneous. Then, 0.25g of thiourea is added and stirring continues. The mixture is heated to 80-85℃ and stirred for 12 hours at a speed of 800-1000rpm. The mixture is filtered to obtain a solid, which is then dried and ground to obtain the sulfur-doped graphene oxide support (S-GO).

[0048] According to an embodiment of the present invention, when the zinc metal salt is zinc chloride (ZnCl2), the reaction formula for the preparation process of the activator suitable for the rubber vulcanization reaction is as follows:

[0049] ZnCl2+S-GO+2NaOH→ZnO-S-GO+2NaCl+H2O.

[0050] According to another aspect of the present invention, the application of the activator as described above in the rubber vulcanization reaction is provided.

[0051] According to embodiments of the present invention, since zinc oxide exists in the form of fully exposed sub-nano clusters, each zinc oxide atom can directly participate in the reaction, providing more active sites and thus improving the efficiency of the rubber vulcanization reaction. Because zinc oxide forms coordination bonds with non-metallic elements doped on the support surface, this interaction further enhances the catalytic performance of zinc oxide, making the vulcanization reaction more rapid and thorough. The uniform distribution of monolayer zinc oxide on the outer surface of the support helps achieve uniform cross-linking between rubber molecular chains, thereby improving the consistency and quality of the rubber material. Due to the high efficiency of the activator, the vulcanization process can be completed in a shorter time, helping to save energy and reduce production costs. Furthermore, since nanomaterials doped with non-metallic elements are used as the support, the amount of zinc oxide used can be reduced, making the entire activator preparation and application system more environmentally friendly and reducing potential environmental impact.

[0052] According to embodiments of the present invention, when the activator of the present invention is used for rubber vulcanization reaction, the vulcanized rubber can have superior mechanical properties.

[0053] According to embodiments of the present invention, additives may be added to carry out the vulcanization reaction, such as stearic acid, antioxidants, accelerators, sulfur, etc.

[0054] According to embodiments of the present invention, the rubber includes at least one of natural rubber, styrene-butadiene rubber, nitrile rubber, chloroprene rubber, ethylene propylene diene monomer (EPDM) rubber, and butadiene rubber.

[0055] The present invention will be further illustrated by the following embodiments. In the detailed description below, numerous specific details are set forth for ease of explanation to provide a comprehensive explanation of the embodiments of the present invention. However, it will be apparent that one or more embodiments may be practiced without these specific details. Moreover, the details in the following embodiments can be arbitrarily combined to form other feasible embodiments without conflict.

[0056] Unless otherwise specified, all experimental materials and reagents used in the following examples are commercially available. Specifically, zinc nitrate, zinc chloride, zinc sulfate, sodium hydroxide, and thiourea, used for catalyst preparation, are supplied in 500g units and manufactured by a certain group chemical reagent company (Shanghai). Graphene oxide is manufactured by a company in Suzhou. Carbon black N330, silica, commercial zinc oxide (99.7% purity), natural rubber, and rubber additives are manufactured by a rubber raw material company in Guangzhou. Unless otherwise specified, all methods described in the examples are conventional and can be performed according to the techniques or conditions described in the literature or the product instructions.

[0057] Example 1:

[0058] Preparation process of sulfur-doped graphene oxide support:

[0059] Add 2g of graphene oxide powder to 500mL of water at room temperature and stir until uniformly dispersed. Then add 0.25g of thiourea, raise the solution temperature to about 82℃, and continue stirring for 12 hours at a stirring speed of 850rpm. Filter and dry the solution, and then grind it to obtain sulfur-doped graphene oxide support.

[0060] Preparation process of activator 1:

[0061] 1 g of sulfur-doped graphene oxide support was weighed and added to 200 mL of water and stirred until homogeneous. Then, 0.2 g of zinc nitrate and 10 mL of 0.1 M sodium hydroxide solution were added, and the mixture was stirred continuously for 12 hours at a speed of 900 rpm. The resulting suspension was filtered and dried in an oven at 100 °C for 12 hours to obtain activator 1 suitable for rubber vulcanization. The sulfur-doped graphene oxide support had zinc oxide subnano clusters 1 (denoted as ZnO-S-GO) loaded on its surface.

[0062] Figure 2 A transmission electron microscope (TEM) image of activator 1, suitable for rubber vulcanization reaction, is shown in Example 1 of the present invention. Figure 2 As can be seen, the bright spot circled in dashed lines represents zinc oxide subnanometer cluster 1, surrounded by a sulfur-doped graphene oxide support. It is evident that zinc oxide subnanometer cluster 1 is effectively anchored to the outer surface of the sulfur-doped graphene oxide support, and the zinc atoms are completely dispersed, without overlapping. This verifies that the obtained zinc oxide is in a fully exposed state, effectively revealing the catalytic active sites. The cluster diameter, measured using electron microscopy at high magnification, is less than 1 nm, thus representing a subnanometer scale.

[0063] Example 2:

[0064] A catalyst suitable for rubber vulcanization was prepared using the same method as in Example 1, the only difference being that the 0.25 g thiourea added in Example 1 was replaced with 1 mL ammonia. The zinc oxide subnanoclusters 2 were supported on a nitrogen-doped graphene oxide support, and these zinc oxide subnanoclusters 2 were denoted as ZnO-N-GO.

[0065] Example 3

[0066] Preparation process of sulfur-doped carbon black carrier:

[0067] Add 2g of carbon black powder to 500mL of water at room temperature and stir until evenly dispersed. Then add 0.25g of thiourea, raise the solution temperature to about 82℃, and continue stirring for 12 hours at a stirring speed of 850rpm. Filter and dry the solution, and then grind it to obtain the sulfur-doped carbon black carrier.

[0068] Weigh 1g of sulfur-doped carbon black support and add it to 200mL of water, stirring until homogeneous. Then add 0.2g of zinc nitrate and 10mL of 0.1M sodium hydroxide solution, and continue stirring for 12 hours at a speed of 900rpm. Filter the resulting suspension and dry it in an oven at 100℃ for 12 hours to obtain activator 3 suitable for rubber vulcanization. The sulfur-doped carbon black support has zinc oxide subnano clusters 3 (denoted as ZnO-S-CB) loaded on its surface.

[0069] Example 4

[0070] Preparation process of sulfur-doped silica support:

[0071] Add 2g of silica powder to 500mL of water at room temperature and stir until evenly dispersed. Then add 0.25g of thiourea, raise the solution temperature to about 82℃, and continue stirring for 12 hours at a stirring speed of 850rpm. Filter and dry the solution, and then grind it to obtain sulfur-doped silica support.

[0072] 1 g of sulfur-doped silica support was weighed and added to 200 mL of water and stirred until homogeneous. Then, 0.2 g of zinc nitrate and 10 mL of 0.1 M sodium hydroxide solution were added, and the mixture was stirred continuously for 12 hours at a speed of 900 rpm. The resulting suspension was filtered and dried in an oven at 100 °C for 12 hours to obtain activator 4 suitable for rubber vulcanization. The sulfur-doped silica support had zinc oxide subnano clusters 4 (denoted as ZnO-S-Silica) loaded on its surface.

[0073] Test example:

[0074] The activators suitable for rubber vulcanization reactions prepared in Examples 1-4 were used for performance testing experiments, with commercial ZnO nanoparticles (99.7%) as a control:

[0075] Chemical property analysis of zinc oxide sub-nano clusters 1 to 4 and commercial zinc oxide nanoparticles.

[0076] Table 1 shows the chemical property analysis parameters of Examples 1-4 and commercial ZnO (99.7%).

[0077]

[0078] As shown in Examples 1 to 4 in Table 1, the zinc content in these examples is lower than that in commercial zinc oxide, and the specific surface area is larger than that in commercial zinc oxide nanoparticles.

[0079] Vulcanized rubber was prepared using zinc oxide sub-nano clusters 1 to 4, and the formulation of the vulcanized rubber is shown in Table 2.

[0080] Table 2. Vulcanized rubber formulations of Examples 1–4 and commercial ZnO (99.7%) (unit: phr)

[0081]

[0082] Based on the zinc content in Table 1, the zinc dosages for Examples 1-4 and the commercial ZnO (99.7%) in Table 2 were calculated to be 0.784, 0.72, 0.96, 0.93, and 3.2 phr, respectively. phr represents the amount of zinc oxide required per 100 parts of natural rubber. Therefore, compared to the commercial ZnO (99.7%), the zinc dosage in Examples 1-4 was reduced by 75.5%, 77.5%, 70.0%, and 70.9%, respectively, thus verifying that the zinc dosage can be reduced by 70-80%.

[0083] According to the rubber formulation in Table 2 above, the rubber compound is first mixed on a two-roll mill, and then various additives (stearic acid, antioxidant 4010NA, accelerator NS, sulfur, etc.) are added to obtain a compound. Then, it is vulcanized at 150℃ for the specified vulcanization time to obtain vulcanized rubber. The tensile strength and elongation at break of the vulcanized rubber are tested according to the national standard GB / T528-2009. The vulcanization performance of activators 1 to activator 4 is tested using a vulcanizing apparatus at 150℃, and the performance comparison is shown in Table 3 below.

[0084] Table 3. Test parameters for the sulfidation performance of Examples 1-4 and commercial ZnO (99.7%).

[0085]

[0086] M H and M L Table 3 shows the maximum and minimum torque values, respectively; a larger difference indicates a better vulcanization effect. Ts2 represents the scorch time, and its impact on vulcanization performance can be evaluated in conjunction with T90. T90 is the positive vulcanization time; a shorter time indicates higher activator activity. Ts2 represents the scorch time, and its impact on vulcanization performance can be evaluated in conjunction with T90, with the vulcanization effect mainly affected by the value of T90. As shown in Table 3, the difference between the maximum and minimum torque values ​​in Examples 1-4 is greater than that of commercial zinc oxide particles, proving that the vulcanization effect of the activator prepared in these examples is higher than that of commercial zinc oxide particles. Based on the comparison of T90, the positive vulcanization time in Examples 1-4 is shorter than that of commercial zinc oxide particles, indicating that the activity of the activator prepared in Examples 1-4 is higher than that of the commercial product.

[0087] Mechanical and aging properties were tested on Examples 1 to 4 and commercial zinc oxide nanoparticles. The aging test conditions were 100℃ × 72h.

[0088] Table 4 shows the mechanical and aging performance parameters of Examples 1-4 and commercial ZnO (99.7%).

[0089]

[0090] As shown in Table 4, the activator 1 prepared in Example 1 exhibits the highest tensile strength and elongation after vulcanization and aging of the rubber product. Furthermore, the tensile strength and elongation in Examples 1-4 are all higher than those of commercial zinc oxide nanoparticles, indicating that the activators 1-4 provided by this invention for rubber vulcanization not only possess excellent activity (shorter positive vulcanization time) but also impart superior mechanical properties to vulcanized rubber while reducing zinc oxide consumption by 70%-80%, thus significantly conserving metal resources and promoting sustainable development. In addition, this material has broad prospects for industrial application and significant practical value.

[0091] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An activator for rubber vulcanization reaction, comprising: The carrier is a nanomaterial doped with non-metallic elements; Zinc oxide is anchored to the outer surface of the carrier; In this embodiment, zinc oxide is coordinated with non-metallic elements doped on the outer surface of the carrier to form a single-atom layer in the form of fully exposed sub-nano clusters; the mass ratio of zinc oxide to the carrier is (0.5~10):100; the nanomaterial includes at least one of carbon black, silica, or graphene oxide. The non-metallic element includes at least one of nitrogen, oxygen, phosphorus, and boron; The carbon black has a particle size of 10~100nm and a specific surface area of ​​50~150m². 2 / g; the particle size of the precipitated silica is 20~100nm, and the specific surface area is 100~300m². 2 / g; the graphene oxide has a size of 1~10μm, a thickness of 3~10nm, and a specific surface area of ​​100~400m². 2 / g; the doping amount of the non-metallic element accounts for 0.5~5% of the mass percentage of the nanomaterial.

2. A method for preparing the activator as described in claim 1, comprising: The carrier is dispersed in the first solvent to obtain a dispersion solution; A zinc metal salt and an alkaline solution are added to the dispersion solution to carry out a hydrolysis reaction, thereby obtaining the activator; The carrier is a nanomaterial doped with non-metallic elements.

3. The preparation method according to claim 2, wherein, The alkaline solution includes any one of sodium hydroxide aqueous solution, lithium hydroxide aqueous solution, and potassium hydroxide aqueous solution.

4. The preparation method according to claim 2, wherein, The hydrolysis reaction is carried out at a temperature of 15~25℃.

5. The preparation method according to claim 2, wherein, Before dispersing the support in the first solvent, the process also includes: The nanomaterials are dispersed in a second solvent, and a non-metallic compound is added and stirred to react, thus obtaining the carrier. The non-metallic compounds include any one of nitrogen-containing compounds, sulfur-containing compounds, boron-containing compounds, and phosphorus-containing compounds.

6. The preparation method according to claim 5, wherein, The mixing and stirring reaction is carried out at a temperature of 80~85℃.

7. The application of the activator as described in claim 1 in the rubber vulcanization reaction.

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