Preparation method of high-performance regenerated rubber based on modified calcium sulfate whisker and rice husk charcoal

Abstract

The invention relates to the technical field of regenerated rubber preparation, in particular to a preparation method of high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal, which comprises the following steps: S1, mixing anhydrous calcium sulfate and absolute ethyl alcohol, pouring into a four-mouth bottle, carrying out ultrasonic treatment for 0.5 hour, heating to 80 DEG C while stirring in a water bath kettle, adding a surface modifier, and stirring for 0.5 hour; heating for 5 hours, centrifugally washing, and drying the final product in a vacuum drying oven for 2 hours to obtain the modified calcium sulfate whisker. S2, preparing modified rice husk charcoal; and S3, mixing the modified calcium sulfate whiskers, the modified rice husk charcoal and regenerated rubber by using an open mill, uniformly mixing, putting into a mold, and tabletting by using a press vulcanizer to obtain the high-performance regenerated rubber based on the modified calcium sulfate whiskers and the rice husk charcoal. The industrial by-product calcium sulfate and the agricultural waste rice husk are used as raw materials and have the characteristics of no pollution and regeneration cycle, the high-performance filler is prepared through a green process, and the production cost is reduced while the rubber performance is improved.

Description

Technical Field

[0001] The invention relates to the technical field of regenerated rubber preparation, in particular to a method for preparing high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal. Background Art

[0002] With the surge in global consumption of rubber products, the annual generation of waste rubber has exceeded 30 million tons (according to data from the International Rubber Research Organization). Its non-degradable nature has led to serious "black pollution." Recycled rubber, as a core resource for resource recycling, continues to see growing demand in tires, conveyor belts, and shock-absorbing materials. However, traditional recycled rubber faces three major technical bottlenecks: insufficient mechanical properties: During the recycling process, rubber molecular chains break, resulting in significantly lower tensile strength (generally less than 10 MPa), tear strength, and abrasion resistance than virgin rubber, making it difficult to meet the demands of high-end engineering applications; low filler reinforcement efficiency: Existing technologies often rely on carbon black or silica as reinforcing agents. While carbon black can improve strength, its production is energy-intensive (over 1,500 kWh per ton) and is derived from non-renewable petroleum resources; while silica improves processability, it is prone to agglomeration and poor dispersion, requiring the use of a silane coupling agent; and a conflict between environmental performance and cost: Although biomass fillers are inexpensive, unmodified natural biochar has poor interfacial compatibility with the rubber matrix, easily causing stress concentration points and reducing the material's durability. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the object of the present invention is to provide a method for preparing high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A method for preparing high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal comprises the following preparation steps:

[0006] S1. According to parts by mass, 2-5 parts of anhydrous calcium sulfate and 50-60 parts of anhydrous ethanol were mixed and poured into a four-necked flask. After being placed in an ultrasonic cleaner for 0.5h, the mixture was heated to 80 ° C while stirring in a water bath, and then 5.8-7 parts of a surface modifier were added. After heating for 5h, the mixture was centrifuged three times with anhydrous ethanol and washed. The final product was placed in a vacuum drying oven and dried for 2h to obtain modified calcium sulfate whiskers.

[0007] S2. Preparation of modified rice husk charcoal:

[0008] S21. The rice husk powder was separated from the fine material using a 60-mesh sieve, and then calcined in a tube furnace at 650° C. under a nitrogen atmosphere for 2 h to obtain rice husk charcoal;

[0009] S22. Place 3-5 parts of trimethyl borate upstream of a tube furnace, place 90-100 parts of the rice husk charcoal obtained in step S21 in the constant temperature zone of the tube furnace, pass nitrogen, and heat at 5 ° C / min to 300 ° C and hold for 1 hour to obtain a preliminary modified rice husk charcoal;

[0010] S23. The preliminarily modified rice husk char was added to 50-60 parts of the modification solution, 1.5-3 parts of dopamine hydrochloride was added, and the mixture was stirred at room temperature at a speed of 400-450 r / min for 10-12 h. The solid was collected by centrifugation, washed 3-4 times with deionized water, and dried in vacuo at 60 ° C for 10-12 h to obtain modified rice husk char;

[0011] S3. Modified calcium sulfate whiskers, modified rice husk charcoal, and regenerated rubber are mixed using an open mill. After the mixture is evenly mixed, it is placed in a mold and pressed into a sheet using a flat vulcanizer to obtain high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal.

[0012] Preferably, the preparation of the modified solution comprises the following steps:

[0013] S231. According to parts by mass, 0.8-1.5 parts of γ-aminopropyltriethoxysilane and 50-60 parts of anhydrous ethanol were added to 1.5-3 parts of 1-butyl-3-methylimidazolium tetrafluoroborate and stirred at 300-350r / min speed for 10-15min to obtain a preliminary modified solution;

[0014] S232. Add 5-10 parts of deionized water to the preliminary modified solution, stir at 40°C for 25-30 minutes, then add 0.3-1 parts of trisodium citrate, and stir magnetically until completely dissolved to obtain a modified solution.

[0015] Preferably, the preparation of the surface modifier comprises the following steps:

[0016] S11. According to parts by mass, 3.5-5 parts KH560 and 0.5-1 parts were added to a three-necked flask and stirred at 300-350r / min at a speed of 8-10min in a 60 ° C water bath under nitrogen protection;

[0017] S12. Slowly add 1-3 parts of epoxidized soybean oil dropwise, raise the temperature to 80°C and react for 25-30 minutes to form an epoxy-siloxane prepolymer;

[0018] S13. Lower the temperature to 50°C, slowly add 0.8-1.5 parts of hexamethylene diisocyanate dropwise, and control the temperature to maintain at 63-67°C for 1 hour to finally obtain a surface modifier.

[0019] Preferably, the ultrasonic frequency in step S1 is 40 kHz.

[0020] Preferably, the flow rate of nitrogen in step S22 is 50 mL / min.

[0021] Preferably, the regenerated rubber in step S3 is selected from epoxidized natural rubber ENR-50.

[0022] Preferably, in step S3, the mass ratio of modified calcium sulfate whiskers, modified rice husk charcoal, and regenerated rubber is 8-12:15-20:100.

[0023] Preferably, the stirring speed in step S232 is 400-450 r / min.

[0024] Preferably, in step S11, the titanate coupling agent is selected from LICA12.

[0025] Preferably, the dripping rate of hexamethylene diisocyanate in step S13 is 0.5 ml / min.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The mechanical properties of the high-performance recycled rubber based on modified calcium sulfate whiskers and rice husk charcoal in the present invention are significantly improved compared with pure waste rubber. The interfacial compatibility is significantly improved after the addition of modified calcium sulfate whiskers. At the same time, according to previous studies, the addition of modified calcium sulfate whiskers and rice husk charcoal can play a role in increasing Mooney viscosity, which can meet the application needs of specific engineering fields and high-performance recycled rubber.

[0028] 2. The present invention utilizes the synergistic effect of modified calcium sulfate whiskers and modified rice husk charcoal to inhibit crack propagation through interfacial energy dissipation, significantly improving the tensile strength, tear strength, and elongation at break of the regenerated rubber compared to pure waste rubber. Simultaneously, the rubber is regenerated using mechanical processing at room temperature. These chemical compounds sever the chemical crosslinks in the vulcanized rubber through chemical substitution reactions, while also limiting oxidation damage to the rubber's main molecular chain, thereby restoring the rubber's plasticity and ensuring the regenerated vulcanized rubber possesses excellent physical properties.

[0029] 3. The present invention utilizes industrial by-product calcium sulfate and agricultural waste rice husks as raw materials, which are pollution-free and regenerative. High-performance fillers are prepared through green processes, which improves rubber performance while reducing production costs. The regeneration process is to regenerate the vulcanized rubber powder mixed with plant regeneration agents using an open mill or internal mixer at normal temperature and pressure. The regeneration process is very convenient, pollution-free, and odorless, achieving the goal of environmentally friendly and green regeneration of rubber powder, and meeting the requirements of sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a process flow chart for preparing high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal of the present invention;

[0031] Figure 2This is a Fourier transform infrared spectrum of the high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal obtained in Example 1 of the present invention, where a, b, and c are Fourier transform infrared spectra of the surface modifier, anhydrous calcium sulfate, and modified calcium sulfate whiskers, respectively;

[0032] Figure 3 The present invention is the XRD spectrum of the anhydrous calcium sulfate and modified calcium sulfate whiskers of the present invention;

[0033] Figure 4 Schematic diagram of the tensile strength of pure waste rubber, comparative example 1 of the present invention, and recycled rubber obtained in example 1;

[0034] Figure 5 This is a dumbbell-shaped mechanical pattern diagram of the present invention;

[0035] Figure 6 This is a line graph showing Mooney viscosity results of a Mooney test of the high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] See also Figure 1-6 , the present invention provides a technical solution:

[0038] Example 1

[0039] A method for preparing high-performance recycled rubber based on modified calcium sulfate whiskers and rice husk charcoal:

[0040] Before preparing high-performance recycled rubber based on modified calcium sulfate whiskers and rice husk charcoal, the surface modifier and modification liquid are prepared:

[0041] The preparation of the modified solution comprises the following steps:

[0042] S231. To 15g1-butyl-3-methylimidazolium tetrafluoroborate was added 8g of γ-aminopropyltriethoxysilane and 500ml of anhydrous ethanol and stirred at 300r / min for 10min to obtain a preliminary modified solution;

[0043] S232. Add 50 ml of deionized water to the preliminary modified solution, stir at 40 ° C for 25 min, then add 3 g of trisodium citrate and stir magnetically until completely dissolved to obtain a modified solution;

[0044] The preparation of the surface modifier comprises the following steps:

[0045] S11. Add 35g KH560 and 5g into a three-necked flask and stir at 300r / min for 8min in a 60°C water bath under nitrogen protection;

[0046] S12. Slowly add 10 g of epoxy soybean oil dropwise, raise the temperature to 80°C and react for 25 min to form an epoxy-siloxane prepolymer;

[0047] S13. The temperature was lowered to 50°C, and 8 g of hexamethylene diisocyanate was slowly added dropwise. The temperature was maintained at 63°C and the reaction was continued for 1 h to obtain a surface modifier.

[0048] S1. 20g of anhydrous calcium sulfate was mixed with 500ml of anhydrous ethanol and poured into a four-necked flask. After being placed in an ultrasonic cleaner for 0.5h, the mixture was heated to 80°C in a water bath while stirring. 58g of a surface modifier was then added. After heating for 5h, the mixture was centrifuged three times with anhydrous ethanol and washed. The final product was dried in a vacuum drying oven for 2h to obtain modified calcium sulfate whiskers.

[0049] S2. Preparation of modified rice husk charcoal:

[0050] S21. The rice husk powder was separated from the fine material using a 60-mesh sieve, and then calcined in a tube furnace at 650° C. under a nitrogen atmosphere for 2 h to obtain rice husk charcoal;

[0051] S22. 30 g of trimethyl borate was placed upstream of a tube furnace, and 900 g of the rice husk char obtained in step S21 was placed in the constant temperature zone of the tube furnace. Nitrogen was passed through the tube furnace at a flow rate of 50 mL / min, and the temperature was increased to 300 ° C at a rate of 5 ° C / min and then kept at this temperature for 1 h to obtain a preliminary modified rice husk char;

[0052] S23. The preliminarily modified rice husk char was added to 500 g of the modification solution, the pH was controlled at 8, 15 g of dopamine hydrochloride was added, and the mixture was stirred at 400 rpm for 10 h at room temperature. The solid was collected by centrifugation, washed three times with deionized water, and dried under vacuum at 60°C for 10 h to obtain modified rice husk char.

[0053] S3. 80 g of modified calcium sulfate whiskers, 150 g of modified rice husk charcoal, and 1000 g of epoxidized natural rubber ENR-50 were mixed on an open mill. After the mixture was evenly mixed, it was placed in a mold and pressed into a sheet using a flat vulcanizer to obtain a high-performance recycled rubber based on modified calcium sulfate whiskers and rice husk charcoal.

[0054] Example 2

[0055] A method for preparing high-performance recycled rubber based on modified calcium sulfate whiskers and rice husk charcoal:

[0056] Before preparing high-performance recycled rubber based on modified calcium sulfate whiskers and rice husk charcoal, the surface modifier and modification liquid are prepared:

[0057] The preparation of the modified solution comprises the following steps:

[0058] S231. To 30g1-butyl-3-methylimidazolium tetrafluoroborate was added 15g of γ-aminopropyltriethoxysilane and 600ml of anhydrous ethanol and stirred at 350r / min for 15min to obtain a preliminary modified solution;

[0059] S232. 100 ml of deionized water was added to the preliminary modified solution, stirred at 40 ° C for 30 min, and then 10 g of trisodium citrate was added and magnetically stirred until completely dissolved to obtain a modified modified solution;

[0060] The preparation of the surface modifier comprises the following steps:

[0061] S11. Add 50g KH560 and 10g to a three-necked flask and stir at 350r / min for 10min in a 60°C water bath under nitrogen protection;

[0062] S12. 30 g of epoxy soybean oil was slowly added dropwise and the temperature was raised to 80 ° C for 30 min to form an epoxy-siloxane prepolymer;

[0063] S13. The temperature was lowered to 50°C, and 15 g of hexamethylene diisocyanate was slowly added dropwise. The temperature was maintained at 67°C and the reaction was continued for 1 h to obtain a surface modifier.

[0064] S1. 50g of anhydrous calcium sulfate was mixed with 600ml of anhydrous ethanol and poured into a four-necked flask. After being placed in an ultrasonic cleaner for 0.5h, the mixture was heated to 80°C in a water bath while stirring. 70g of a surface modifier was added. After heating for 5h, the mixture was centrifuged three times with anhydrous ethanol and washed. The final product was dried in a vacuum drying oven for 2h to obtain modified calcium sulfate whiskers.

[0065] S2. Preparation of modified rice husk charcoal:

[0066] S21. The rice husk powder was separated from the fine material using a 60-mesh sieve, and then calcined in a tube furnace at 650° C. under a nitrogen atmosphere for 2 h to obtain rice husk charcoal;

[0067] S22. 50 g of trimethyl borate was placed upstream of a tube furnace, and 1000 g of the rice husk char obtained in step S21 was placed in the constant temperature zone of the tube furnace. Nitrogen was passed through the tube furnace at a flow rate of 50 mL / min, and the temperature was increased to 300 ° C at a rate of 5 ° C / min and then kept at this temperature for 1 h to obtain a preliminarily modified rice husk char;

[0068] S23. The preliminarily modified rice husk char was added to 600 g of the modification solution, the pH was controlled at 8.5, 30 g of dopamine hydrochloride was added, and the mixture was stirred at 450 rpm for 12 h at room temperature. The solid was collected by centrifugation, washed four times with deionized water, and dried under vacuum at 60°C for 12 h to obtain modified rice husk char.

[0069] S3. 120 g of modified calcium sulfate whiskers, 200 g of modified rice husk charcoal, and 1000 g of epoxidized natural rubber ENR-50 were mixed on an open mill. After the mixture was evenly mixed, it was placed in a mold and pressed into a sheet using a flat vulcanizer to obtain a high-performance recycled rubber based on modified calcium sulfate whiskers and rice husk charcoal.

[0070] Example 3

[0071] A method for preparing high-performance recycled rubber based on modified calcium sulfate whiskers and rice husk charcoal:

[0072] Before preparing high-performance recycled rubber based on modified calcium sulfate whiskers and rice husk charcoal, the surface modifier and modification liquid are prepared:

[0073] The preparation of the modified solution comprises the following steps:

[0074] S231. To 20g of 1-butyl-3-methylimidazolium tetrafluoroborate was added 10g of γ-aminopropyltriethoxysilane and 550ml of anhydrous ethanol and stirred at 320r / min for 11min to obtain a preliminary modified solution;

[0075] S232. Add 60 ml of deionized water to the preliminary modified solution, stir at 40 ° C for 27 min, then add 5 g of trisodium citrate, and stir magnetically until completely dissolved to obtain a modified solution;

[0076] The preparation of the surface modifier comprises the following steps:

[0077] S11. Add 40g KH560 and 6g to a three-necked flask and stir at 320r / min for 8-10min in a 60°C water bath under nitrogen protection;

[0078] S12. 20 g of epoxy soybean oil was slowly added dropwise, and the temperature was raised to 80°C and the reaction was carried out for 27 minutes to form an epoxy-siloxane prepolymer;

[0079] S13. The temperature was lowered to 50°C, and 10 g of hexamethylene diisocyanate was slowly added dropwise. The temperature was maintained at 64°C and the reaction was continued for 1 h to obtain a surface modifier.

[0080] S1. 30g of anhydrous calcium sulfate was mixed with 550ml of anhydrous ethanol and poured into a four-necked flask. After being placed in an ultrasonic cleaner for 0.5h, it was heated to 80°C in a water bath while stirring. 60g of the surface modifier was added. After heating for 5h, the centrifuge was repeated three times with anhydrous ethanol for centrifugation and washing. The final product was placed in a vacuum drying oven and dried for 2h to obtain modified calcium sulfate whiskers.

[0081] S2. Preparation of modified rice husk charcoal:

[0082] S21. The rice husk powder was separated from the fine material using a 60-mesh sieve, and then calcined in a tube furnace at 650° C. under a nitrogen atmosphere for 2 h to obtain rice husk charcoal;

[0083] S22. 40 g of trimethyl borate was placed upstream of a tube furnace, and 950 g of the rice husk char obtained in step S21 was placed in the constant temperature zone of the tube furnace. Nitrogen was passed through the tube furnace at a flow rate of 50 mL / min, and the temperature was increased to 300 ° C at a rate of 5 ° C / min and then kept at this temperature for 1 h to obtain a preliminary modified rice husk char;

[0084] S23. The preliminarily modified rice husk char was added to 550 g of the modification solution, the pH was controlled at 8.2, 20 g of dopamine hydrochloride was added, and the mixture was stirred at 420 rpm for 11 h at room temperature. The solid was collected by centrifugation, washed three times with deionized water, and dried under vacuum at 60°C for 11 h to obtain modified rice husk char.

[0085] S3. 100 g of modified calcium sulfate whiskers, 170 g of modified rice husk charcoal, and 1000 g of epoxidized natural rubber ENR-50 were mixed on an open mill. After the mixture was evenly mixed, it was placed in a mold and pressed into a sheet using a flat vulcanizer to obtain a high-performance recycled rubber based on modified calcium sulfate whiskers and rice husk charcoal.

[0086] Example 4

[0087] A method for preparing high-performance recycled rubber based on modified calcium sulfate whiskers and rice husk charcoal:

[0088] Before preparing high-performance recycled rubber based on modified calcium sulfate whiskers and rice husk charcoal, the surface modifier and modification liquid are prepared:

[0089] The preparation of the modified solution comprises the following steps:

[0090] S231. To 25g1-butyl-3-methylimidazolium tetrafluoroborate was added 12g of γ-aminopropyltriethoxysilane and 580ml of anhydrous ethanol, and stirred at 340r / min for 14min to obtain a preliminary modified solution;

[0091] S232. 80 ml of deionized water was added to the preliminary modified solution, stirred at 40 ° C for 28 min, and then 8 g of trisodium citrate was added and magnetically stirred until completely dissolved to obtain a modified modified solution;

[0092] The preparation of the surface modifier comprises the following steps:

[0093] S11. Add 45g KH560 and 8g to a three-necked flask and stir at 340r / min for 9min in a 60°C water bath under nitrogen protection;

[0094] S12. 25 g of epoxidized soybean oil was slowly added dropwise, and the temperature was raised to 80°C and the reaction was carried out for 28 minutes to form an epoxy-siloxane prepolymer;

[0095] S13. The temperature was lowered to 50°C, and 14 g of hexamethylene diisocyanate was slowly added dropwise. The temperature was maintained at 65°C for 1 h to obtain a surface modifier.

[0096] S1. 40g of anhydrous calcium sulfate was mixed with 580ml of anhydrous ethanol and poured into a four-necked flask. After being placed in an ultrasonic cleaner for 0.5h, it was heated to 80°C in a water bath while stirring. 65g of the surface modifier was added. After heating for 5h, the centrifuge was repeated three times with anhydrous ethanol for centrifugation and washing. The final product was placed in a vacuum drying oven and dried for 2h to obtain modified calcium sulfate whiskers.

[0097] S2. Preparation of modified rice husk charcoal:

[0098] S21. The rice husk powder was separated from the fine material using a 60-mesh sieve, and then calcined in a tube furnace at 650° C. under a nitrogen atmosphere for 2 h to obtain rice husk charcoal;

[0099] S22. 45 g of trimethyl borate was placed upstream of a tube furnace, and 980 g of the rice husk char obtained in step S21 was placed in the constant temperature zone of the tube furnace. Nitrogen was passed through the tube furnace at a flow rate of 50 mL / min, and the temperature was increased to 300 ° C at a rate of 5 ° C / min and then kept at this temperature for 1 h to obtain a preliminary modified rice husk char;

[0100] S23. The preliminarily modified rice husk char was added to 580 g of the modification solution, the pH was controlled at 8.4, 25 g of dopamine hydrochloride was added, and the mixture was stirred at 440 rpm for 11.5 h at room temperature. The solid was collected by centrifugation, washed four times with deionized water, and dried under vacuum at 60°C for 11.5 h to obtain modified rice husk char.

[0101] S3. 110 g of modified calcium sulfate whiskers, 180 g of modified rice husk charcoal, and 1000 g of epoxidized natural rubber ENR-50 were mixed on an open mill. After the mixture was evenly mixed, it was placed in a mold and pressed into a sheet using a flat vulcanizer to obtain a high-performance recycled rubber based on modified calcium sulfate whiskers and rice husk charcoal.

[0102] Comparative Example 1

[0103] Comparative Example 1 differs from Example 1 in the following manner: the addition of modified rice husk charcoal is omitted in Comparative Example 1, and the remaining steps are identical in Comparative Example 1 and Example 1.

[0104] Performance testing:

[0105] A certain amount of the high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal obtained in Example 1 was mixed with potassium bromide and ground into a powder. The powder was then pressed into thin slices using a tablet press and placed on a solid ATR tester for spectral analysis. Standard ATR calibration was used in OMNIC 9.2 software to eliminate bandwidth distortion caused by the nature of the ATR experiment. The resulting Fourier transform infrared spectrum is shown in the attached figure. Figure 2 As shown in the figure, a, b, and c are the Fourier transform infrared spectra of the surface modifier, anhydrous calcium sulfate, and modified calcium sulfate whiskers, respectively. As can be seen from the figure, in b, 3618cm -1 、3560cm -1 The OH stretching peaks of CSW are 2947 and 2843 cm -1 The peak between 852 cm and 853 cm is related to the CH stretching vibration of -CH3, -CH2 and -CH in the silane coupling agent. -1 The absorption peak near 910 cm is the Si-O asymmetric stretching vibration. -1 The peak is the stretching vibration peak of the epoxy group on the surface modifier. The sample was thoroughly washed to completely eliminate physical adsorption, proving the reaction between the surface modifier and the hydroxyl group on the surface of anhydrous calcium sulfate, indicating that the surface modifier and anhydrous calcium sulfate have successfully reacted. The above infrared analysis verified that high-performance recycled rubber based on modified calcium sulfate whiskers and rice husk charcoal has been successfully obtained.

[0106] Attachment Figure 3 The following are XRD spectra of the anhydrous calcium sulfate and modified calcium sulfate whiskers of the present invention. Because the coating and grafting occur only on the whisker surface and fail to alter the internal lattice structure and atomic arrangement, the characteristic peaks of the crystals do not change significantly after coating and grafting, demonstrating that the surface modifier has no effect on the crystal structure of anhydrous calcium sulfate.

[0107] Attachment Figure 4 This is a schematic diagram of the tensile strength of pure waste rubber, comparative example 1 of the present invention, and the regenerated rubber obtained in Example 1. The high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal obtained in Example 1 of the present invention is significantly better than the pure waste rubber and the regenerated rubber obtained in Comparative Example 1, demonstrating that the high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal obtained in the present invention has better mechanical properties.

[0108] The high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal obtained in Example 1 was placed in a flat vulcanizing machine for sheeting and then cut into the following pieces: Figure 5 The dumbbell-shaped mechanical style shown is used for mechanical testing, and the remaining part after cutting is used to measure Mooney viscosity. Cut two discs with a diameter of 45-50mm and a thickness of 3-6mm from the bubble-free rubber compound, and punch a hole with a diameter of 8mm in the center of one of the discs. Preheat the instrument to the set temperature (usually 100°C), place the sample in the mold cavity and isolate it with cellophane. The preheating time is usually 1 minute to ensure uniform temperature. Start the rotor rotation (standard speed 2rpm) and record the torque-time curve within 4 minutes. The results are expressed as ML 100 ℃ 1+4 Indicates (M is Mooney value, L is large rotor, 1+4 is preheating 1 minute + testing 4 minutes). Figure 6 This is a line graph showing the Mooney viscosity results of a Mooney test on the high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal obtained in Example 1 of the present invention. In the figure, A, B, C, D, and E are the Mooney viscosities at 10, 20, 30, 40, and 50 minutes, respectively. The graph shows a gradual increase in the Mooney viscosity of the high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal obtained in Example 1.

[0109] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing high-performance recycled rubber based on modified calcium sulfate whiskers and rice husk charcoal, characterized in that: The method comprises the following preparation steps: S1. According to parts by mass, 2-5 parts of anhydrous calcium sulfate and 50-60 parts of anhydrous ethanol were mixed and poured into a four-necked flask. After being placed in an ultrasonic cleaner for 0.5h, the mixture was heated to 80 ° C while stirring in a water bath, and then 5.8-7 parts of a surface modifier were added. After heating for 5h, the mixture was centrifuged three times with anhydrous ethanol and washed. The final product was placed in a vacuum drying oven and dried for 2h to obtain modified calcium sulfate whiskers. S2. Preparation of modified rice husk charcoal: S21. The rice husk powder was separated from the fine material using a 60-mesh sieve, and then calcined in a tube furnace at 650° C. under a nitrogen atmosphere for 2 h to obtain rice husk charcoal; S22. Place 3-5 parts of trimethyl borate upstream of a tube furnace, place 90-100 parts of the rice husk charcoal obtained in step S21 in the constant temperature zone of the tube furnace, pass nitrogen, and heat at 5 ° C / min to 300 ° C and hold for 1 hour to obtain a preliminary modified rice husk charcoal; S23. The preliminarily modified rice husk char was added to 50-60 parts of the modification solution, 1.5-3 parts of dopamine hydrochloride was added, and the mixture was stirred at room temperature at a speed of 400-450 r / min for 10-12 h. The solid was collected by centrifugation, washed 3-4 times with deionized water, and dried in vacuo at 60 ° C for 10-12 h to obtain modified rice husk char; S3. Modified calcium sulfate whiskers, modified rice husk charcoal, and regenerated rubber are mixed using an open mill. After the mixture is evenly mixed, it is placed in a mold and pressed into a sheet using a flat vulcanizer to obtain high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal.

2. The method for preparing high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal according to claim 1, characterized in that: The preparation of the modified solution comprises the following steps: S231. According to parts by mass, 0.8-1.5 parts of γ-aminopropyltriethoxysilane and 50-60 parts of anhydrous ethanol were added to 1.5-3 parts of 1-butyl-3-methylimidazolium tetrafluoroborate and stirred at 300-350r / min speed for 10-15min to obtain a preliminary modified solution; S232. Add 5-10 parts of deionized water to the preliminary modified solution, stir at 40°C for 25-30 minutes, then add 0.3-1 parts of trisodium citrate, and stir magnetically until completely dissolved to obtain a modified solution.

3. The method for preparing high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal according to claim 1, characterized in that: The preparation of the surface modifier comprises the following steps: S11. According to parts by mass, 3.5-5 parts KH560 and 0.5-1 parts were added to a three-necked flask and stirred at 300-350r / min at a speed of 8-10min in a 60 ° C water bath under nitrogen protection; S12. Slowly add 1-3 parts of epoxidized soybean oil dropwise, raise the temperature to 80°C and react for 25-30 minutes to form an epoxy-siloxane prepolymer; S13. Lower the temperature to 50°C, slowly add 0.8-1.5 parts of hexamethylene diisocyanate dropwise, and control the temperature to maintain at 63-67°C for 1 hour to finally obtain a surface modifier.

4. The method for preparing high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal according to claim 1, characterized in that: The ultrasonic frequency in step S1 is 40 kHz.

5. The method for preparing high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal according to claim 1, characterized in that: The flow rate of nitrogen in step S22 is 50 mL / min.

6. The method for preparing high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal according to claim 1, characterized in that: In step S3, the regenerated rubber is selected from epoxidized natural rubber ENR-50.

7. The method for preparing high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal according to claim 1, characterized in that: In step S3, the mass ratio of modified calcium sulfate whiskers, modified rice husk charcoal, and regenerated rubber is 8-12:15-20:

100.

8. The method for preparing high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal according to claim 2, characterized in that: The stirring speed in step S232 is 400-450 r / min.

9. The method for preparing high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal according to claim 3, characterized in that: In step S11, the titanate coupling agent is selected from LICA12.

10. The method for preparing high-performance regenerated rubber based on modified calcium sulfate whiskers and rice husk charcoal according to claim 3, characterized in that: The dropping rate of hexamethylene diisocyanate in step S13 is 0.5 ml / min.

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