Environment-friendly high-dispersible combined active agent for rubber and preparation method thereof

Abstract

The application discloses an environment-friendly high-dispersion combined active agent for rubber and a preparation method thereof, relates to the technical field of rubber active agents, and comprises the following steps: taking amino-modified biochar and adding the same into a zinc oxide precursor, and uniformly stirring to obtain a modified biochar-zinc oxide precursor; taking the modified biochar-zinc oxide precursor, and performing temperature rising and microwave constant temperature; cooling, water washing, centrifugation, and drying to obtain modified biochar-zinc oxide; taking ubiquinone and adding the same into ethanol, and uniformly mixing to obtain a ubiquinone mixed solution; taking the modified biochar-zinc oxide and adding the same into the ubiquinone mixed solution, and performing reaction to obtain a modified biochar-zinc oxide compound; taking stearic acid, adding the same into n-butanol, and ultrasonic dissolving; then, the modified biochar-zinc oxide compound is added, and stirring is performed; centrifugation, alcohol washing, and drying are performed to obtain the environment-friendly high-dispersion combined active agent for rubber.

Description

Technical Field

[0001] This invention relates to the field of rubber activator technology, specifically to an environmentally friendly, highly dispersible combined activator for rubber and its preparation method. Background Technology

[0002] In rubber vulcanization systems, zinc oxide is the most commonly used rubber activator, playing a crucial activating role.

[0003] On the one hand, zinc oxide reacts with stearic acid to form zinc stearate, and zinc stearate forms complexes with accelerators such as thiazoles and sulfenamides, which increases the solubility of the accelerators in the vulcanization system and increases the vulcanization rate and crosslinking density.

[0004] On the other hand, the polysulfide bonds of polysulfides are easily broken to generate hydrogen sulfide. Hydrogen sulfide catalyzes the decomposition of rubber molecular chains. Zinc oxide reacts with hydrogen sulfide and polysulfides, consuming hydrogen sulfide and catalyzing the formation of shorter cross-linked bonds with higher stability of polysulfide bonds, thereby improving the tensile strength and tensile stress of rubber.

[0005] However, zinc oxide has poor dispersibility, is prone to agglomeration, and has low activity; the heavy metal zinc in it cannot be recycled in the natural environment and pollutes the environment, which is detrimental to human health; the rubber industry urgently needs a zinc reduction solution to replace the traditional vulcanizing activator zinc oxide.

[0006] To address the above problems, this invention provides an environmentally friendly, highly dispersible activator for rubber and its preparation method. Summary of the Invention

[0007] The purpose of this invention is to provide an environmentally friendly, highly dispersible activator for rubber and its preparation method, so as to solve the problems raised in the prior art.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] Step 1: Add lipoic acid to ethanol and mix well to obtain a lipoic acid mixed solution; add modified biochar-zinc oxide to the lipoic acid mixed solution and react to obtain a modified biochar-zinc oxide complex.

[0010] Step 2: Stearic acid is added to n-butanol and dissolved by ultrasonication. Then, modified biochar-zinc oxide complex is added and stirred. After centrifugation, the mixture is washed with alcohol and dried to obtain an environmentally friendly, highly dispersible activator for rubber.

[0011] A more optimized method for preparing modified biochar-zinc oxide is as follows: amino-modified biochar is added to the zinc oxide precursor and stirred evenly to obtain the modified biochar-zinc oxide precursor; the modified biochar-zinc oxide precursor is heated to 115-125℃ at a heating rate of 0.9-1.1℃ / min and microwaved for 25-35min; then cooled, washed with water, centrifuged, and dried to obtain the modified biochar-zinc oxide.

[0012] A more optimized method for preparing the zinc oxide precursor is as follows: zinc sulfate heptahydrate and sodium hydroxide are added to deionized water and mixed evenly to obtain a mixed solvent; then dodecyltrimethylammonium bromide is added and mixed evenly to obtain a mixed solution; silicon carbide is taken, washed with water, and dried at a temperature of 105-115℃ for 1.5-2.5h; it is added to the mixed solution and stirred evenly to obtain the zinc oxide precursor.

[0013] A more optimized method for preparing amino-modified biochar is as follows: Take biochar, pulverize, sieve, remove impurities, wash with water, and dry to obtain pretreated biochar; add diethylenetriamine to methanol and mix evenly to obtain a solvent; add glutaraldehyde to deionized water and mix evenly to obtain a glutaraldehyde solution; add the pretreated biochar to the solvent and stir for 23-25 ​​hours at a temperature of 25-35℃ and a rotation speed of 155-165 rpm; filter; add the glutaraldehyde solution and stir for 25-35 minutes at a temperature of 25-35℃ and a rotation speed of 155-165 rpm; filter, wash with water, and dry to obtain amino-modified biochar.

[0014] A more optimized zinc oxide precursor comprises the following components, in parts by weight: 7.85-7.87 parts by weight of zinc sulfate heptahydrate, 23-25 ​​parts by weight of sodium hydroxide, 200 parts by weight of deionized water, 11.87-11.89 parts by weight of dodecyltrimethylammonium bromide, and 4.37-4.39 parts by weight of silicon carbide.

[0015] A more optimized method for preparing biochar is as follows: take chestnut shells, wash, dry, crush, sieve, and dry to obtain chestnut shell powder; add chestnut shell powder to phosphoric acid and soak for 3-5 hours; wash with water, dry, and calcine for 1.5-2.5 hours; wash with water and dry to obtain biochar.

[0016] The optimal calcination temperature is 695-705℃.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. Preparation of amino-modified biochar: Biochar was prepared from chestnut shells via pyrolysis. Diethylenetriamine was selected as the amination reagent, and glutaraldehyde was selected as the crosslinking agent to obtain amino-modified biochar. In this process, the aldehyde group at one end of glutaraldehyde formed a covalent bond with the hydroxyl group on the surface of the biochar through a condensation reaction, forming a crosslinking network on the surface of the biochar. The aldehyde group at the other end formed an imine bond with the primary amino group of diethylenetriamine through a nucleophilic addition reaction, forming a "biochar-glutaraldehyde-diethylenetriamine" structure, thus obtaining amino-modified biochar.

[0019] On the one hand, the amino group in amino-modified biochar acts as a coordinating group, and the nitrogen atom on it contains lone pairs of electrons, which form coordinate bonds with the empty orbitals of zinc ions in nano-zinc oxide, thereby increasing the bonding strength between biochar and nano-zinc oxide and improving the loading efficiency of biochar loaded with nano-zinc oxide. On the other hand, the increased polarity of amino-modified biochar improves its compatibility in rubber matrices and enhances the stability and dispersibility of the system.

[0020] 2. Using zinc sulfate heptahydrate as the zinc source, sodium hydroxide as the alkali source, and dodecyltrimethylammonium bromide as the surfactant, nano-zinc oxide was prepared; using silicon carbide as the core and nano-zinc oxide as the shell, core-shell structured nano-zinc oxide was prepared; using amino-modified biochar as the carrier, modified biochar-zinc oxide was prepared.

[0021] Among them, dodecyltrimethylammonium bromide is used as a surfactant to prepare highly dispersible nano-zinc oxide; the core-shell structure of the nano-zinc oxide has the advantages of silicon carbide as the core and zinc oxide as the shell, resulting in a high specific surface area, which improves the reactivity and activation efficiency of the nano-zinc oxide; on the other hand, the nano-zinc oxide is dispersed on the surface of silicon carbide, making it less prone to agglomeration and improving its dispersibility; furthermore, amino-modified biochar is used as a carrier to further disperse the nano-zinc oxide through the porous structure of biochar.

[0022] 3. Prepare modified biochar-zinc oxide composite, using lipoic acid as a monomer, and induce the ring-opening polymerization of the five-membered ring in lipoic acid through thermal initiation to prepare polylipoic acid; wherein, the disulfide bond of lipoic acid has redox activity, and can achieve self-repair through molecular recombination and dynamic exchange, thereby improving the service life of rubber.

[0023] 4. Preparation of environmentally friendly, highly dispersible combined activator for rubber: The carboxyl group in stearic acid undergoes an esterification reaction with the hydroxyl group on the surface of biochar, and the ester group is grafted onto the surface of biochar. On the one hand, the alkyl chain of stearic acid grafted onto the surface of biochar increases the hydrophobicity of biochar, thereby improving the dispersibility of biochar in the rubber system through hydrophobic interactions. On the other hand, the ester group breaks during the subsequent vulcanization process, and the free stearic acid reacts with zinc oxide to form zinc stearate. Zinc stearate forms a complex with the rubber accelerator, thereby improving the activity of the accelerator. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] The sources and types of substances involved in this invention are not particularly limited, and exemplary examples include:

[0026] Diethylenetriamine, catalog number 00005, was supplied by Shanghai Fangye Chemical Co., Ltd.

[0027] The product code for zinc sulfate heptahydrate is S24313-500g, and it is provided by Shanghai Yuanye Biotechnology Co., Ltd.

[0028] The dodecyltrimethylammonium bromide, with product number 1119-94-4, was supplied by Hubei Chengfeng Chemical Co., Ltd.

[0029] The silicon carbide, with the part number XH-SiC-100, is supplied by Shanghai Xiaohuang Nanotechnology Co., Ltd.

[0030] The product number of lipoic acid is 251202, and it is provided by Hebei Hongtao Bioengineering Co., Ltd.

[0031] The stearic acid, catalog number S30473-500g, is supplied by Shanghai Yuanye Biotechnology Co., Ltd.

[0032] The natural rubber, with product code WD1620, was supplied by Hubei Wande Chemical Co., Ltd.

[0033] The carbon black, with product number YM210802, was supplied by Shijiazhuang Yingmei Chemical Products Co., Ltd.

[0034] N-tert-butyl-2-benzothiazole sulfenamide, catalog number TB2664, is supplied by Hubei Tuobang Chemical Co., Ltd.

[0035] Example 1: A method for preparing an environmentally friendly, highly dispersible activator for rubber;

[0036] Step 1: Preparation of amino-modified biochar

[0037] S1: Take chestnut shells, wash, dry, crush, sieve, and dry to obtain chestnut shell powder; add 10g of chestnut shell powder to 100mL of phosphoric acid and soak for 3h; wash with water, dry, and calcine at 695℃ for 1.5h; wash with water and dry to obtain biochar.

[0038] S2: Take the biochar prepared above, crush it, sieve it, remove impurities, wash it with water, and dry it to obtain pretreated biochar; take 9 mL of diethylenetriamine and add it to 89 mL of methanol, mix it evenly to obtain a solvent; take 1 mL of glutaraldehyde and add it to 99 mL of deionized water, mix it evenly to obtain a glutaraldehyde solution; take 10 g of pretreated biochar and add it to 100 mL of solvent, stir it for 23 h at 25 °C and 155 rpm, filter it, add 200 mL of glutaraldehyde solution, stir it for 25 min at 25 °C and 155 rpm, filter it, wash it with water, and dry it to obtain amino-modified biochar;

[0039] Step 2: Preparation of zinc oxide precursor

[0040] S1: Add 7.85g of zinc sulfate heptahydrate and 23g of sodium hydroxide to 200mL of deionized water and mix well to obtain a mixed solvent; then add 11.87g of dodecyltrimethylammonium bromide and mix well to obtain a mixed solution;

[0041] S2: Take 4.37g of silicon carbide, wash it with water, and dry it at 105℃ for 1.5h; add it to the mixed solution prepared above, stir evenly, and obtain zinc oxide precursor;

[0042] Step 3: Preparation of modified biochar-zinc oxide

[0043] Add 0.25g of amino-modified biochar to the zinc oxide precursor prepared above, stir evenly to obtain modified biochar-zinc oxide precursor; take the modified biochar-zinc oxide precursor prepared above, heat it to 115℃ at a heating rate of 0.9℃ / min, microwave it at a constant temperature for 25min; cool, wash with water, centrifuge, and dry to obtain modified biochar-zinc oxide.

[0044] Step 4: Preparation of environmentally friendly, highly dispersible activator for rubber

[0045] S1: Add 5 mL of lipoic acid to 95 mL of ethanol and mix well to obtain a lipoic acid mixed solution; add the modified biochar-zinc oxide prepared above to the lipoic acid mixed solution and react at 80℃ for 1.5 h to obtain the modified biochar-zinc oxide composite.

[0046] S2: Take 2.89g of stearic acid and add it to 100mL of n-butanol. Dissolve it by sonication, then add the modified biochar-zinc oxide composite prepared above. Stir for 25min at 29℃. Centrifuge, wash with alcohol, and dry to obtain an environmentally friendly, highly dispersed activator for rubber.

[0047] Example 2: A method for preparing an environmentally friendly, highly dispersible activator for rubber;

[0048] Step 1: Preparation of amino-modified biochar

[0049] S1: Take chestnut shells, wash, dry, crush, sieve, and dry to obtain chestnut shell powder; add 10g of chestnut shell powder to 100mL of phosphoric acid and soak for 4h; wash with water, dry, and calcine at 700℃ for 2h; wash with water and dry to obtain biochar.

[0050] S2: Take the biochar prepared above, crush it, sieve it, remove impurities, wash it with water, and dry it to obtain pretreated biochar; take 10 mL of diethylenetriamine and add it to 90 mL of methanol, mix it evenly to obtain a solvent; take 1 mL of glutaraldehyde and add it to 99 mL of deionized water, mix it evenly to obtain a glutaraldehyde solution; take 10 g of pretreated biochar and add it to 100 mL of solvent, stir it for 24 h at 30℃ and 160 rpm, filter it, add 200 mL of glutaraldehyde solution, stir it for 30 min at 30℃ and 160 rpm, filter it, wash it with water, and dry it to obtain amino-modified biochar;

[0051] Step 2: Preparation of zinc oxide precursor

[0052] S1: Add 7.86g of zinc sulfate heptahydrate and 24g of sodium hydroxide to 200mL of deionized water, mix well to obtain a mixed solvent; then add 11.88g of dodecyltrimethylammonium bromide, mix well to obtain a mixed solution;

[0053] S2: Take 4.38g of silicon carbide, wash it with water, and dry it at 110℃ for 2h; add it to the mixed solution prepared above, stir evenly, and obtain zinc oxide precursor;

[0054] Step 3: Preparation of modified biochar-zinc oxide

[0055] Add 0.3g of amino-modified biochar to the zinc oxide precursor prepared above, stir evenly to obtain modified biochar-zinc oxide precursor; take the modified biochar-zinc oxide precursor prepared above, heat it to 120℃ at a heating rate of 1℃ / min, microwave it at a constant temperature for 30min; cool, wash with water, centrifuge, and dry to obtain modified biochar-zinc oxide.

[0056] Step 4: Preparation of environmentally friendly, highly dispersible activator for rubber

[0057] S1: Add 5 mL of lipoic acid to 95 mL of ethanol and mix well to obtain a lipoic acid mixed solution; add the modified biochar-zinc oxide prepared above to the lipoic acid mixed solution and react at 85℃ for 2 h to obtain the modified biochar-zinc oxide composite.

[0058] S2: Take 2.91g of stearic acid and add it to 100mL of n-butanol. Dissolve it by sonication, then add the modified biochar-zinc oxide composite prepared above. Stir for 30min at 30℃. Centrifuge, wash with alcohol, and dry to obtain an environmentally friendly, highly dispersed activator for rubber.

[0059] Example 3: A method for preparing an environmentally friendly, highly dispersible activator for rubber;

[0060] Step 1: Preparation of amino-modified biochar

[0061] S1: Take chestnut shells, wash, dry, crush, sieve, and dry to obtain chestnut shell powder; add 10g of chestnut shell powder to 100mL of phosphoric acid and soak for 5h; wash with water, dry, and calcine at 705℃ for 2.5h; wash with water and dry to obtain biochar.

[0062] S2: Take the biochar prepared above, crush it, sieve it, remove impurities, wash it with water, and dry it to obtain pretreated biochar; take 11 mL of diethylenetriamine and add it to 91 mL of methanol, mix it evenly to obtain a solvent; take 1 mL of glutaraldehyde and add it to 99 mL of deionized water, mix it evenly to obtain a glutaraldehyde solution; take 10 g of pretreated biochar and add it to 100 mL of solvent, stir it for 25 h at 35℃ and 165 rpm, filter it, add 200 mL of glutaraldehyde solution, stir it for 35 min at 35℃ and 165 rpm, filter it, wash it with water, and dry it to obtain amino-modified biochar;

[0063] Step 2: Preparation of zinc oxide precursor

[0064] S1: Add 7.87g of zinc sulfate heptahydrate and 25g of sodium hydroxide to 200mL of deionized water, mix well to obtain a mixed solvent; then add 11.89g of dodecyltrimethylammonium bromide, mix well to obtain a mixed solution;

[0065] S2: Take 4.39g of silicon carbide, wash it with water, and dry it at 115℃ for 2.5h; add it to the mixed solution prepared above, stir evenly, and obtain zinc oxide precursor;

[0066] Step 3: Preparation of modified biochar-zinc oxide

[0067] Add 0.35g of amino-modified biochar to the zinc oxide precursor prepared above, stir evenly to obtain modified biochar-zinc oxide precursor; take the modified biochar-zinc oxide precursor prepared above, heat it to 125℃ at a heating rate of 1.1℃ / min, microwave it at a constant temperature for 35min; cool, wash with water, centrifuge, and dry to obtain modified biochar-zinc oxide.

[0068] Step 4: Preparation of environmentally friendly, highly dispersible activator for rubber

[0069] S1: Add 5 mL of lipoic acid to 95 mL of ethanol and mix well to obtain a lipoic acid mixed solution; add the modified biochar-zinc oxide prepared above to the lipoic acid mixed solution and react at 90℃ for 2.5 h to obtain the modified biochar-zinc oxide composite.

[0070] S2: Take 2.93g of stearic acid and add it to 100mL of n-butanol. Dissolve it by sonication, then add the modified biochar-zinc oxide composite prepared above. Stir for 35min at 31℃. Centrifuge, wash with alcohol, and dry to obtain an environmentally friendly, highly dispersed activator for rubber.

[0071] Comparative Example 1: Diethylenetriamine was not added; all other procedures were the same as in Example 2. The specific operations are as follows:

[0072] Step 1: Preparation of amino-modified biochar

[0073] S1: Take chestnut shells, wash, dry, crush, sieve, and dry to obtain chestnut shell powder; add 10g of chestnut shell powder to 100mL of phosphoric acid and soak for 4h; wash with water, dry, and calcine at 700℃ for 2h; wash with water and dry to obtain biochar.

[0074] S2: Take the biochar prepared above, crush it, sieve it, remove impurities, wash it with water, and dry it to obtain pretreated biochar; take 90 mL of methanol, mix it evenly to obtain solvent; take 1 mL of glutaraldehyde and add it to 99 mL of deionized water, mix it evenly to obtain glutaraldehyde solution; take 10 g of pretreated biochar and add it to 100 mL of solvent, stir it for 24 h at 30℃ and 160 rpm, filter it, add 200 mL of glutaraldehyde solution, stir it for 30 min at 30℃ and 160 rpm, filter it, wash it with water, and dry it to obtain amino-modified biochar;

[0075] Step 2: Preparation of zinc oxide precursor

[0076] S1: Add 7.86g of zinc sulfate heptahydrate and 24g of sodium hydroxide to 200mL of deionized water, mix well to obtain a mixed solvent; then add 11.88g of dodecyltrimethylammonium bromide, mix well to obtain a mixed solution;

[0077] S2: Take 4.38g of silicon carbide, wash it with water, and dry it at 110℃ for 2h; add it to the mixed solution prepared above, stir evenly, and obtain zinc oxide precursor;

[0078] Step 3: Preparation of modified biochar-zinc oxide

[0079] Add 0.3g of amino-modified biochar to the zinc oxide precursor prepared above, stir evenly to obtain modified biochar-zinc oxide precursor; take the modified biochar-zinc oxide precursor prepared above, heat it to 120℃ at a heating rate of 1℃ / min, microwave it at a constant temperature for 30min; cool, wash with water, centrifuge, and dry to obtain modified biochar-zinc oxide.

[0080] Step 4: Preparation of environmentally friendly, highly dispersible activator for rubber

[0081] S1: Add 5 mL of lipoic acid to 95 mL of ethanol and mix well to obtain a lipoic acid mixed solution; add the modified biochar-zinc oxide prepared above to the lipoic acid mixed solution and react at 85℃ for 2 h to obtain the modified biochar-zinc oxide composite.

[0082] S2: Take 2.91g of stearic acid and add it to 100mL of n-butanol. Dissolve it by sonication, then add the modified biochar-zinc oxide composite prepared above. Stir for 30min at 30℃. Centrifuge, wash with alcohol, and dry to obtain an environmentally friendly, highly dispersed activator for rubber.

[0083] Comparative Example 2: Dodecyltrimethylammonium bromide was not added; all other procedures were the same as in Example 2, and the specific operations were as follows:

[0084] Step 1: Preparation of amino-modified biochar

[0085] S1: Take chestnut shells, wash, dry, crush, sieve, and dry to obtain chestnut shell powder; add 10g of chestnut shell powder to 100mL of phosphoric acid and soak for 4h; wash with water, dry, and calcine at 700℃ for 2h; wash with water and dry to obtain biochar.

[0086] S2: Take the biochar prepared above, crush it, sieve it, remove impurities, wash it with water, and dry it to obtain pretreated biochar; take 10 mL of diethylenetriamine and add it to 90 mL of methanol, mix it evenly to obtain a solvent; take 1 mL of glutaraldehyde and add it to 99 mL of deionized water, mix it evenly to obtain a glutaraldehyde solution; take 10 g of pretreated biochar and add it to 100 mL of solvent, stir it for 24 h at 30℃ and 160 rpm, filter it, add 200 mL of glutaraldehyde solution, stir it for 30 min at 30℃ and 160 rpm, filter it, wash it with water, and dry it to obtain amino-modified biochar;

[0087] Step 2: Preparation of zinc oxide precursor

[0088] S1: Add 7.86g of zinc sulfate heptahydrate and 24g of sodium hydroxide to 200mL of deionized water and mix well to obtain a mixed solvent;

[0089] S2: Take 4.38g of silicon carbide, wash it with water, and dry it at 110℃ for 2h; add it to the mixed solvent prepared above, stir evenly, and obtain zinc oxide precursor;

[0090] Step 3: Preparation of modified biochar-zinc oxide

[0091] Add 0.3g of amino-modified biochar to the zinc oxide precursor prepared above, stir evenly to obtain modified biochar-zinc oxide precursor; take the modified biochar-zinc oxide precursor prepared above, heat it to 120℃ at a heating rate of 1℃ / min, microwave it at a constant temperature for 30min; cool, wash with water, centrifuge, and dry to obtain modified biochar-zinc oxide.

[0092] Step 4: Preparation of environmentally friendly, highly dispersible activator for rubber

[0093] S1: Add 5 mL of lipoic acid to 95 mL of ethanol and mix well to obtain a lipoic acid mixed solution; add the modified biochar-zinc oxide prepared above to the lipoic acid mixed solution and react at 85℃ for 2 h to obtain the modified biochar-zinc oxide composite.

[0094] S2: Take 2.91g of stearic acid and add it to 100mL of n-butanol. Dissolve it by sonication, then add the modified biochar-zinc oxide composite prepared above. Stir for 30min at 30℃. Centrifuge, wash with alcohol, and dry to obtain an environmentally friendly, highly dispersed activator for rubber.

[0095] Comparative Example 3: No silicon carbide was added; all other procedures were the same as in Example 2. The specific operations are as follows:

[0096] Step 1: Preparation of amino-modified biochar

[0097] S1: Take chestnut shells, wash, dry, crush, sieve, and dry to obtain chestnut shell powder; add 10g of chestnut shell powder to 100mL of phosphoric acid and soak for 4h; wash with water, dry, and calcine at 700℃ for 2h; wash with water and dry to obtain biochar.

[0098] S2: Take the biochar prepared above, crush it, sieve it, remove impurities, wash it with water, and dry it to obtain pretreated biochar; take 10 mL of diethylenetriamine and add it to 90 mL of methanol, mix it evenly to obtain a solvent; take 1 mL of glutaraldehyde and add it to 99 mL of deionized water, mix it evenly to obtain a glutaraldehyde solution; take 10 g of pretreated biochar and add it to 100 mL of solvent, stir it for 24 h at 30℃ and 160 rpm, filter it, add 200 mL of glutaraldehyde solution, stir it for 30 min at 30℃ and 160 rpm, filter it, wash it with water, and dry it to obtain amino-modified biochar;

[0099] Step 2: Preparation of zinc oxide precursor

[0100] S1: Add 7.86g of zinc sulfate heptahydrate and 24g of sodium hydroxide to 200mL of deionized water, mix well to obtain a mixed solvent; then add 11.88g of dodecyltrimethylammonium bromide, mix well to obtain a mixed solution;

[0101] S2: Add the mixed solution prepared above, stir evenly, and obtain the zinc oxide precursor;

[0102] Step 3: Preparation of modified biochar-zinc oxide

[0103] Add 0.3g of amino-modified biochar to the zinc oxide precursor prepared above, stir evenly to obtain modified biochar-zinc oxide precursor; take the modified biochar-zinc oxide precursor prepared above, heat it to 120℃ at a heating rate of 1℃ / min, microwave it at a constant temperature for 30min; cool, wash with water, centrifuge, and dry to obtain modified biochar-zinc oxide.

[0104] Step 4: Preparation of environmentally friendly, highly dispersible activator for rubber

[0105] S1: Add 5 mL of lipoic acid to 95 mL of ethanol and mix well to obtain a lipoic acid mixed solution; add the modified biochar-zinc oxide prepared above to the lipoic acid mixed solution and react at 85℃ for 2 h to obtain the modified biochar-zinc oxide composite.

[0106] S2: Take 2.91g of stearic acid and add it to 100mL of n-butanol. Dissolve it by sonication, then add the modified biochar-zinc oxide composite prepared above. Stir for 30min at 30℃. Centrifuge, wash with alcohol, and dry to obtain an environmentally friendly, highly dispersed activator for rubber.

[0107] Comparative Example 4: Stearic acid was not added; all other procedures were the same as in Example 2. The specific operations are as follows:

[0108] Step 1: Preparation of amino-modified biochar

[0109] S1: Take chestnut shells, wash, dry, crush, sieve, and dry to obtain chestnut shell powder; add 10g of chestnut shell powder to 100mL of phosphoric acid and soak for 4h; wash with water, dry, and calcine at 700℃ for 2h; wash with water and dry to obtain biochar.

[0110] S2: Take the biochar prepared above, crush it, sieve it, remove impurities, wash it with water, and dry it to obtain pretreated biochar; take 10 mL of diethylenetriamine and add it to 90 mL of methanol, mix it evenly to obtain a solvent; take 1 mL of glutaraldehyde and add it to 99 mL of deionized water, mix it evenly to obtain a glutaraldehyde solution; take 10 g of pretreated biochar and add it to 100 mL of solvent, stir it for 24 h at 30℃ and 160 rpm, filter it, add 200 mL of glutaraldehyde solution, stir it for 30 min at 30℃ and 160 rpm, filter it, wash it with water, and dry it to obtain amino-modified biochar;

[0111] Step 2: Preparation of zinc oxide precursor

[0112] S1: Add 7.86g of zinc sulfate heptahydrate and 24g of sodium hydroxide to 200mL of deionized water, mix well to obtain a mixed solvent; then add 11.88g of dodecyltrimethylammonium bromide, mix well to obtain a mixed solution;

[0113] S2: Take 4.38g of silicon carbide, wash it with water, and dry it at 110℃ for 2h; add it to the mixed solution prepared above, stir evenly, and obtain zinc oxide precursor;

[0114] Step 3: Preparation of modified biochar-zinc oxide

[0115] Add 0.3g of amino-modified biochar to the zinc oxide precursor prepared above, stir evenly to obtain modified biochar-zinc oxide precursor; take the modified biochar-zinc oxide precursor prepared above, heat it to 120℃ at a heating rate of 1℃ / min, microwave it at a constant temperature for 30min; cool, wash with water, centrifuge, and dry to obtain modified biochar-zinc oxide.

[0116] Step 4: Preparation of environmentally friendly, highly dispersible activator for rubber

[0117] S1: Add 5 mL of lipoic acid to 95 mL of ethanol and mix well to obtain a lipoic acid mixed solution; add the modified biochar-zinc oxide prepared above to the lipoic acid mixed solution and react at 85℃ for 2 h to obtain the modified biochar-zinc oxide composite.

[0118] S2: Add 100 mL of n-butanol, then add the modified biochar-zinc oxide composite prepared above, stir for 30 min at 30 °C; centrifuge, wash with alcohol, and dry to obtain an environmentally friendly, highly dispersed activator for rubber.

[0119] experiment:

[0120] The mechanical properties of the environmentally friendly, highly dispersed activator for rubber prepared in Examples 1-3 and Comparative Examples 1-4 were determined.

[0121] Take 100 parts by weight of natural rubber, 8 parts by weight of environmentally friendly high-dispersibility activator for rubber, and 35 parts by weight of carbon black, and mix them at 60℃ and 60 rpm. Add 2.25 parts by weight of sulfur and 0.7 parts by weight of accelerator N-tert-butyl-2-benzothiazole sulfenamide, roll the mixture, feed it into powder, re-mix it, form a triangle, roll it thinly, and pass it through a thin tube 5 times to control the thickness of the rubber sheet to 1.5 mm. Let it stand for 24 hours. Then, vulcanize it on a flat plate at 143℃ and 10 MPa to obtain the compound rubber.

[0122] (1) Tensile property testing

[0123] Referring to GB / T528-2009 "Vulcanized rubber or thermoplastic rubber - Determination of tensile stress-strain properties", the total length of the compound sample is 75 mm, the width is 2 mm, and the moving speed of the testing machine is 500 mm / min;

[0124] (2) Tear performance test

[0125] Refer to GB / T529-2008 "Determination of tear strength of vulcanized rubber or thermoplastic rubber (trouser-shaped, right-angled and crescent-shaped specimens)";

[0126] The data obtained from the above experiment are shown in Table 1 below:

[0127] Table 1

[0128] Tensile strength (MPa) Tear strength kN / m Example 1 35.8 93.8 Example 2 36.1 94.6 Example 3 35.7 93.4 Comparative Example 1 28.3 81.3 Comparative Example 2 27.9 78.6 Comparative Example 3 26.6 73.5 Comparative Example 4 27.5 76.1

[0129] Conclusion: Analysis of the above experimental data shows that the rubber compounds prepared by the environmentally friendly, highly dispersible activator combination in Examples 1-3 of this invention have significantly higher tensile and tear strengths than the comparative examples. This indicates that the environmentally friendly, highly dispersible activator combination in Examples 1-3 has higher reactivity, reacts more fully with the accelerator, and has better dispersibility. It can replace more zinc oxide in the vulcanization system, resulting in better zinc reduction. Although the environmentally friendly, highly dispersible activator combination in Comparative Examples 1-4 has certain tensile and tear strengths, the difference compared to the experimental data of Examples 1-3 is significant, indicating lower reactivity and poorer dispersibility.

[0130] Comparative analysis of Comparative Example 1 (without diethylenetriamine) and Example 2 shows that biochar prepared from chestnut shells via pyrolysis, further using diethylenetriamine as an amination reagent and glutaraldehyde as a crosslinking agent, yields amino-modified biochar. On one hand, the amino group in the amino-modified biochar acts as a coordinating group, and its nitrogen atom contains lone pairs of electrons, forming coordinate bonds with the empty orbitals of zinc ions in nano-zinc oxide, thus increasing the bonding strength between biochar and nano-zinc oxide and improving the loading efficiency of nano-zinc oxide on biochar. On the other hand, the amino-modified biochar has increased polarity, improving its compatibility in rubber matrices and enhancing the stability and dispersibility of the system.

[0131] Comparative analysis of Comparative Example 2 (without dodecyltrimethylammonium bromide) and Example 2 shows that highly dispersed nano-zinc oxide can be prepared by using zinc sulfate heptahydrate as the zinc source, sodium hydroxide as the alkali source, and dodecyltrimethylammonium bromide as the surfactant.

[0132] Comparative analysis of Comparative Example 3 (without silicon carbide) and Example 2 shows that silicon carbide is used as the core and zinc oxide nanoparticles are used as the shell to prepare core-shell structured zinc oxide nanoparticles. On the one hand, the silicon carbide core and zinc oxide nanoparticles as the shell have a high specific surface area, which improves the reactivity and activation efficiency of zinc oxide nanoparticles. On the other hand, the zinc oxide nanoparticles are dispersed on the silicon carbide surface and are not easy to agglomerate, which improves the dispersibility of zinc oxide nanoparticles.

[0133] Comparative analysis of Comparative Example 4 (without stearic acid) and Example 2 shows that the carboxyl groups in stearic acid undergo esterification with the hydroxyl groups on the surface of biochar, and the ester groups are grafted onto the surface of biochar. On the one hand, the alkyl chains of stearic acid grafted onto the surface of biochar improve the hydrophobicity of biochar, thereby improving the dispersibility of biochar in the rubber system through hydrophobic interactions. On the other hand, the ester groups break during subsequent vulcanization, and the free stearic acid reacts with zinc oxide to form zinc stearate. Zinc stearate forms a complex with the rubber accelerator, thereby improving the activity of the accelerator.

[0134] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing an environmentally friendly, highly dispersible activator for rubber, characterized in that: Includes the following steps: Step 1: Take biochar, crush, sieve, remove impurities, wash with water, and dry to obtain pretreated biochar; add diethylenetriamine to methanol and mix evenly to obtain solvent; add glutaraldehyde to deionized water and mix evenly to obtain glutaraldehyde solution; add pretreated biochar to the solvent and stir for 23-25 ​​hours at 25-35℃ and 155-165 rpm, filter, add glutaraldehyde solution, and stir for 25-35 minutes at 25-35℃ and 155-165 rpm, filter, wash with water, and dry to obtain amino-modified biochar; Step 2: Add zinc sulfate heptahydrate and sodium hydroxide to deionized water and mix well to obtain a mixed solvent; then add dodecyltrimethylammonium bromide and mix well to obtain a mixed solution; take silicon carbide, wash it with water, and dry it at 105-115℃ for 1.5-2.5h; add it to the mixed solution and stir well to obtain the zinc oxide precursor; Step 3: Add amino-modified biochar to the zinc oxide precursor and stir evenly to obtain modified biochar-zinc oxide precursor; take the modified biochar-zinc oxide precursor and heat it to 115-125℃ at a heating rate of 0.9-1.1℃ / min, microwave it for 25-35min; cool, wash with water, centrifuge, and dry to obtain modified biochar-zinc oxide. Step 4: Add lipoic acid to ethanol and mix well to obtain a lipoic acid mixed solution; add modified biochar-zinc oxide to the lipoic acid mixed solution and react to obtain a modified biochar-zinc oxide complex. Step 5: Add stearic acid to n-butanol, sonicate to dissolve, then add modified biochar-zinc oxide complex, stir; centrifuge, wash with alcohol, and dry to obtain environmentally friendly highly dispersible combined activator for rubber.

2. The method for preparing an environmentally friendly, highly dispersible activator for rubber according to claim 1, characterized in that: The zinc oxide precursor comprises the following components, in parts by weight: 7.85-7.87 parts by weight of zinc sulfate heptahydrate, 23-25 ​​parts by weight of sodium hydroxide, 200 parts by weight of deionized water, 11.87-11.89 parts by weight of dodecyltrimethylammonium bromide, and 4.37-4.39 parts by weight of silicon carbide.

3. The method for preparing an environmentally friendly, highly dispersible activator for rubber according to claim 1, characterized in that: The method for preparing the biochar is as follows: take chestnut shells, wash, dry, crush, sieve, and dry to obtain chestnut shell powder; add chestnut shell powder to phosphoric acid and soak for 3-5 hours; wash with water, dry, and calcine for 1.5-2.5 hours; wash with water and dry to obtain biochar.

4. The method for preparing an environmentally friendly, highly dispersible activator for rubber according to claim 3, characterized in that: The calcination temperature is 695-705℃.

5. An environmentally friendly, highly dispersible combined activator for rubber prepared by the method described in any one of claims 1-4.