MIL-68 (Al)-OH / SBR (styrene butadiene rubber) composite modifier as well as preparation method and application thereof

Abstract

The invention discloses an MIL-68 (Al)-OH / SBR (styrene butadiene rubber) composite modifier as well as a preparation method and application thereof, and belongs to the technical field of asphalt processing. The composite modifier is prepared from the following raw materials in percentage by mass: 31 to 38 percent of MIL-68 (Al)-OH, 51 to 56 percent of SBR (Styrene Butadiene Rubber), 0.3 to 0.5 percent of accelerant and 10.7 to 12.5 percent of compatilizer; the preparation method of the MIL-68 (Al)-OH comprises the following steps: S1, adding soluble aluminum salt and 2-hydroxyterephthalic acid into a solvent, carrying out ultrasonic treatment, reacting at 120-150 DEG C for 12-24 hours, and filtering and washing to obtain a solid product; and S2, heating the solid product obtained in the step S1 at the temperature of 100-150 DEG C for 10-20 hours to obtain the MIL-68 (Al)-OH crystal. The composite modifier disclosed by the invention can be used for efficiently storing aromatics, so that the effect of inhibiting gelatinization of an asphalt structure is achieved, and the anti-aging performance of asphalt is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of asphalt processing, and particularly relates to a MIL-68(Al)-OH / SBR composite modifier, a preparation method thereof, and an application thereof. Background Art

[0002] SBR modified asphalt pavement has been widely used in highway construction due to its excellent road performance, good anti-skid performance, comfortable driving, low cost, high safety, etc. However, when SBR modified asphalt undergoes long-term service and is affected by external environments such as heat, oxygen, and ultraviolet light, it will cause changes in its chemical composition and molecular structure (i.e., aging), making the pavement prone to pavement diseases such as rutting, spalling, cracks, and potholes, thus greatly reducing the service life of SBR modified asphalt. To obtain SBR modified asphalt with excellent comprehensive performance, it is necessary to enhance the anti-aging ability of SBR modified asphalt; whether it is thermal-oxidative aging or ultraviolet aging, it will cause the following changes in the components and structure of asphalt: aromatic fraction → resin → asphaltene. Specifically, the aromatic fraction and resin will react, resulting in a continuous decrease in their content, making the original colloidal structure of asphalt gradually gelify, thereby reducing the use performance of asphalt (such as an increase in viscosity, a decrease in ductility and adhesion, etc.), and ultimately severely shortening the service life of the asphalt pavement. It can be seen that retaining the aromatic components in asphalt and inhibiting the gelification of the asphalt structure are the keys to improving the anti-aging performance of asphalt.

[0003] MOF (Metal-Organic Framework) is formed by connecting metal ions or metal clusters with organic ligands through coordination bonds, and has a highly ordered pore structure and a large specific surface area. This structure enables MOF materials to exhibit excellent performance in gas adsorption, separation, and catalysis. In addition, the pore size and shape of MOF can be controlled by adjusting the structure and length of the ligand, so as to achieve selective adsorption of different molecules.

[0004] At present, some studies have proposed to use metal-organic framework materials to delay the aging of matrix asphalt. For example, Chinese Patent CN116444815A discloses an anti-aging agent, modified asphalt, and a preparation method based on a hybrid coordination polymerization type metal-organic framework. This patent mixes three metal-organic framework materials with different porosities, specific surface areas, and metal sites, and uses the synergistic effect of multiple MOFs materials to adsorb various aging components in asphalt, preventing asphalt from undergoing oxidative aging and achieving an anti-aging effect. However, the anti-aging effect achieved by using metal-organic frameworks alone is limited, and this anti-aging agent does not contain polar groups, cannot form hydrogen bonds with the π electron cloud on the benzene ring to generate H-π interactions, has limited adsorption capacity for benzene, and has limited effect on improving the anti-aging performance of asphalt, which restricts its application in asphalt.

[0005] Therefore, it is of great significance to propose a new idea for exploring the anti-aging property of asphalt, design and prepare a new metal-organic framework compound material for storing aromatic components, and use it to improve the anti-aging property of SBR modified asphalt. Summary of the Invention

[0006] Aiming at the deficiencies of the above prior art, one of the purposes of the present invention is to provide a MIL-68(Al)-OH / SBR composite modifier. The composite modifier of the present invention can efficiently store aromatic components, thereby achieving the effect of inhibiting the gelation of the asphalt structure and significantly improving the anti-aging property of asphalt.

[0007] The above object of the present invention is achieved by the following technical solutions:

[0008] A MIL-68(Al)-OH / SBR composite modifier, comprising the following raw materials in mass fractions: MIL-68(Al)-OH 31% - 38%, SBR 51% - 56%, accelerator 0.3% - 0.5%, compatibilizer 10.7% - 12.5%;

[0009] The preparation method of the MIL-68(Al)-OH includes the following steps:

[0010] S1. Add soluble aluminum salt and 2-hydroxyterephthalic acid into a solvent, perform ultrasonic treatment, and then react at 120 - 150 °C for 12 - 24 h. After filtration and washing, a solid product is obtained;

[0011] S2. Heat the solid product obtained in step S1 at 100 - 150 °C for 10 - 20 h to obtain MIL-68(Al)-OH crystals.

[0012] The present invention first prepares MIL-68(Al)-OH, and then composites MIL-68(Al)-OH with SBR to prepare a composite modifier. On the one hand, due to the presence of organic ligands in the structure of MIL-68(Al)-OH, the affinity between the MIL-68(Al)-OH material and SBR particles can be enhanced, so that the two have good compatibility and stability. On the other hand, the MIL-68(Al)-OH material can design and regulate the pore characteristics and surface chemical characteristics by adjusting metal ions and organic ligands. When benzene series substances volatilize during the aging process of asphalt, MIL-68(Al)-OH can efficiently store them, and ultimately achieve the purpose of storing aromatic components and then improving the anti-aging performance of asphalt. Further, by hydroxyl functionalizing MIL-68(Al), on the one hand, the hydrogen atoms of the hydroxyl groups in MIL-68(Al)-OH can act as hydrogen bond donors to form hydrogen bonds with the π electron clouds on the benzene ring, enhancing the H-π interaction and improving the adsorption capacity of the composite modifier for benzene series substances; on the other hand, the hydroxyl group is a polar group, which can enhance the polarity of the composite modifier and improve its adsorption capacity for benzene series substances; thus efficiently storing aromatic components and effectively improving the anti-aging performance of asphalt.

[0013] Preferably, the composite modifier comprises the following raw materials in mass fractions: 35% of MIL-68(Al)-OH, 52% of SBR, 0.5% of accelerator, and 12.5% of compatibilizer.

[0014] Preferably, the mass ratio of the soluble aluminum salt to 2-hydroxyterephthalic acid is 1:(0.9 - 1.1).

[0015] Preferably, in step S1, the concentration of the soluble aluminum salt in the solvent is 1.5%wt - 2.5%wt.

[0016] Preferably, in step S1, the solvent is at least one of N,N-dimethylformamide, γ-valerolactone (GVL), N,N-diethylformamide (DEF), and ethanol.

[0017] Preferably, in step S1, the soluble aluminum salt is aluminum chloride and / or aluminum nitrate.

[0018] Preferably, the accelerator is at least one of tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, and bis(1,5-pentamethylene)tetramthiuram tetrasulfide; the compatibilizer is cut 3 vacuum gas oil.

[0019] Another object of the present invention is to provide a preparation method of the MIL-68(Al)-OH / SBR composite modifier, comprising the following steps:

[0020] P1. Prepare the MIL-68(Al)-OH, SBR, accelerator, and compatibilizer according to their respective mass fractions, and then place them in a mixer for blending. The blending temperature is 80 - 90 °C, and the speed is 1300 - 1500 r / min;

[0021] P2. Add the blend obtained in step P1 into a granulator to granulate and obtain the MIL-68(Al)-OH / SBR composite modifier.

[0022] Another object of the present invention is to provide an anti-aging MIL-68(Al)-OH / SBR modified asphalt containing the composite modifier, which includes the following raw materials with their respective mass fractions: asphalt 87.5% - 94.5%, MIL-68(Al)-OH / SBR composite modifier 5% - 12%, and stabilizer 0.1% - 0.5%.

[0023] Preferably, the stabilizer is sulfur.

[0024] The present invention also provides a preparation method of the anti-aging modified asphalt, which includes the following steps: Prepare the asphalt, MIL-68(Al)-OH / SBR composite modifier, and stabilizer according to their respective mass fractions; then heat the asphalt to a flowing state, and slowly add the MIL-68(Al)-OH / SBR composite modifier and stabilizer while stirring, keep the temperature at 170 - 180 °C, stir at a speed of 4000 - 6000 rpm for 1 - 3 h, and then continue to stir at a speed of 400 - 600 rpm for 1 - 3 h to obtain the anti-aging modified asphalt.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] (1) In the composite modifier of the present invention, MIL-68(Al)-OH adjusts metal ions and organic ligands, and then designs and controls pore characteristics and surface chemical characteristics. When benzene series substances volatilize during the aging process of asphalt, MIL-68(Al)-OH can efficiently store these aromatic components, thereby achieving the effect of inhibiting its gelation. That is, it can effectively improve the anti-aging performance of asphalt.

[0027] (2) By hydroxyl functionalizing MIL-68(Al) to obtain MIL-68(Al)-OH, the present invention can significantly improve the adsorption capacity of the composite modifier for benzene series substances, thereby efficiently storing aromatic components and effectively improving the anti-aging performance of asphalt.

[0028] (3) MIL-68(Al)-OH in the composite modifier of the present invention has a benzene ring and the ability to absorb ultraviolet light. In addition, the benzene ring structure introduced by MIL-68(Al)-OH can cooperate with the benzene ring in the stored aromatic fraction to jointly absorb ultraviolet light, effectively inhibiting the damage of ultraviolet light to asphalt, thereby enhancing the anti-ultraviolet aging performance of asphalt.

[0029] (4) The presence of organic ligands in the structure of MIL-68(Al)-OH in the composite modifier of the present invention can enhance the affinity between the MOF material and SBR particles, so that the two have good compatibility and stability. Specific Embodiments

[0030] The technical solutions of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0031] The embodiments of the present invention provide a MIL-68(Al)-OH / SBR composite modifier, which includes the following raw materials in mass fractions: MIL-68(Al)-OH 31% - 38%, SBR 51% - 56%, accelerator 0.3% - 0.5%, compatibilizer 10.7% - 12.5%;

[0032] The preparation method of the MIL-68(Al)-OH includes the following steps:

[0033] S1. Add soluble aluminum salt and 2-hydroxyterephthalic acid to a solvent, perform ultrasonic treatment, and then react at 120 - 150 °C for 12 - 24 h. After filtration and washing, a solid product is obtained;

[0034] S2. Heat the solid product obtained in step S1 at 100 - 150 °C for 10 - 20 h to obtain MIL-68(Al)-OH crystals.

[0035] In some embodiments, the mass ratio of the soluble aluminum salt to 2-hydroxyterephthalic acid is 1:(0.9 - 1.1); for example, the mass ratio of the soluble aluminum salt to 2-hydroxyterephthalic acid can be 1:1, 1:0.9, 1:1.1, etc.

[0036] In some embodiments, the concentration of the soluble aluminum salt in the solvent is 1.5%wt - 2.5%wt; for example, the concentration of the soluble aluminum salt in the solvent can be 1.5%wt, 1.6%wt, 1.7%wt, 1.9%wt, 2.0%wt, 2.1%wt, 2.2%wt, 2.3%wt, 2.5%wt, etc.

[0037] In some embodiments, the solvent may be at least one of N,N-dimethylformamide, γ-valerolactone (GVL), N,N-diethylformamide (DEF), and ethanol; and the soluble aluminum salt may be aluminum chloride and / or aluminum nitrate.

[0038] In some embodiments, the accelerator is at least one of tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, and bis(1,5-pentylene)thiuram tetrasulfide.

[0039] In the following examples and comparative examples, aluminum chloride hexahydrate and N,N-dimethylformamide were purchased from Shanghai McLean Biochemical Technology Co., Ltd., 2-hydroxyterephthalic acid was purchased from Shanghai Haohong Biomedical Technology Co., Ltd., methanol was purchased from Shanghai Titan Technology Co., Ltd., SBR was purchased from Hunan Yueyang Baling Petrochemical Co., Ltd., tetramethylthiuram disulfide was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., and three-line oil was purchased from Changqing Oilfield Branch of China National Petroleum Corporation; all raw materials are common raw materials on the market. In the following examples and comparative examples, unless otherwise specified, the 20°C density of the three-line oil is 800~1000kg / m 3 , 40°C kinematic viscosity is 15~30mm 2 / s; the asphalt is road petroleum asphalt, with a needle penetration of 60~120dm at 25°C, a softening point of 40~55°C, and an elongation of 15~25cm at 10°C.

[0040] Example 1

[0041] This embodiment provides a MIL-68(Al)-OH / SBR composite modifier, which is composed of the following raw materials by mass fraction: 35.00% MIL-68(Al)-OH, 52.00% SBR, 0.50% tetramethylthiuram disulfide, and 12.50% three-line oil;

[0042] The preparation method of MIL-68(Al)-OH comprises the following steps:

[0043] S1. Aluminum chloride hexahydrate, 2-hydroxyterephthalic acid and N,N-dimethylformamide are mixed in a mass ratio of 1:1:58, and after ultrasonic dissolution, the mixture is loaded into a polytetrafluoroethylene reactor;

[0044] S2, react in an oven at 130°C for 18 hours, and collect the precipitate by centrifugation;

[0045] S3, washing the product with N,N-dimethylformamide and methanol three times respectively and collecting by centrifugation;

[0046] S4. Place the product in an oven at 100 °C and dry it for 12 h to obtain metal-organic framework MIL-68(Al)-OH crystals. The preparation method of the MIL-68(Al)-OH / SBR composite modifier in this example includes the following steps:

[0047] P1. Prepare MIL-68(Al)-OH, SBR, tetramethylthiuram disulfide, and third-stage reduced crude oil according to their respective mass fractions, then place them in a mixer for blending. The blending temperature is 85 °C, the speed is 1400 r / min, and the time is 10 min.

[0048] P2. Add the blend obtained in step P1 to a granulator to granulate and obtain the MIL-68(Al)-OH / SBR composite modifier. The head temperature is 175 °C.

[0049] Example 2

[0050] The MIL-68(Al)-OH / SBR composite modifier in this example is basically the same as that in Example 1, except that, by mass fraction, it consists of the following raw materials: 38.00% MIL-68(Al)-OH, 51.00% SBR, 0.30% tetramethylthiuram disulfide, and 10.70% third-stage reduced crude oil.

[0051] Example 3

[0052] The MIL-68(Al)-OH / SBR composite modifier in this example is basically the same as that in Example 1, except that, by mass fraction, it consists of the following raw materials: 31.00% MIL-68(Al)-OH, 56.00% SBR, 0.50% tetramethylthiuram disulfide, and 12.50% third-stage reduced crude oil.

[0053] Example 4

[0054] The MIL-68(Al)-OH / SBR composite modifier in this example is basically the same as that in Example 1, except that in step S1, the mass ratio of aluminum chloride hexahydrate, 2-hydroxyterephthalic acid, and N,N-dimethylformamide is 1:0.9:58.

[0055] Example 5

[0056] The MIL-68(Al)-OH / SBR composite modifier in this example is basically the same as that in Example 1, except that in step S1, the mass ratio of aluminum chloride hexahydrate, 2-hydroxyterephthalic acid, and N,N-dimethylformamide is 1:1.1:58.

[0057] Comparative Example 1

[0058] The composite modifier of this comparative example consists of the following raw materials by mass fraction: 87.00% SBR, 0.50% tetramethylthiuram disulfide, and 12.50% third-line reducing oil.

[0059] That is, compared with Example 1, the composite modifier of this comparative example lacks MIL-68(Al)-OH.

[0060] Comparative Example 2

[0061] The composite modifier of this comparative example consists of the following raw materials by mass fraction: 87.00% MIL-68(Al), 0.50% tetramethylthiuram disulfide, and 12.50% third-line reducing oil;

[0062] The preparation method of MIL-68(Al) includes the following steps:

[0063] S1. Mix aluminum chloride hexahydrate, terephthalic acid, and N,N-dimethylformamide in a mass ratio of 1:1:58, ultrasonically dissolve them, and then load them into a polytetrafluoroethylene reaction kettle;

[0064] S2. React in an oven at 130 °C for 18 h, and centrifuge to collect the precipitate;

[0065] S3. Wash the product 3 times with N,N-dimethylformamide and methanol respectively and centrifuge to collect;

[0066] S4. Place the product in an oven at 100 °C and dry it for 12 h to obtain metal-organic framework MIL-68(Al) crystals.

[0067] That is, compared with Example 1, the composite modifier of this comparative example lacks SBS and does not perform hydroxyl functionalization on MIL-68(Al).

[0068] Comparative Example 3

[0069] The composite modifier of this comparative example consists of the following raw materials by mass fraction: 87.00% MIL-68(Al)-OH, 0.50% tetramethylthiuram disulfide, and 12.50% third-line reducing oil;

[0070] That is, compared with Example 1, the composite modifier of this comparative example lacks SBS.

[0071] Example 6

[0072] This example provides an aging-resistant modified asphalt modified by a MIL-68(Al)-OH / SBR composite modifier. By mass fraction, the modified asphalt consists of the following raw materials: 91.50% asphalt, 8.00% MIL-68(Al)-OH / SBR composite modifier prepared in Example 1, and 0.50% sulfur;

[0073] The preparation method of the anti-aging MIL-68(Al)-OH / SBR composite modifier modified asphalt is as follows:

[0074] Prepare materials according to the mass fractions of asphalt, MIL-68(Al)-OH / SBR composite modifier, and sulfur respectively; then heat the asphalt to a flowing state, stir at a speed of 500 rpm, and simultaneously slowly add the MIL-68(Al)-OH / SBR composite modifier and sulfur, keep the temperature at 175 °C, stir at a speed of 5300 rpm for 2 h, and then continue to stir at a speed of 500 rpm for 2 h to obtain the anti-aging MIL-68(Al)-OH / SBR composite modifier modified asphalt.

[0075] Example 7

[0076] This example provides an anti-aging modified asphalt modified by the MIL-68(Al)-OH / SBR composite modifier. By mass fraction, the modified asphalt is composed of the following raw materials: 94.50% asphalt, 5.00% MIL-68(Al)-OH / SBR composite modifier prepared in Example 2, and 0.50% sulfur; the preparation method of the anti-aging MIL-68(Al)-OH / SBR composite modifier modified asphalt is the same as that of Example 6.

[0077] Example 8

[0078] This example provides an anti-aging modified asphalt modified by the MIL-68(Al)-OH / SBR composite modifier. By mass fraction, the modified asphalt is composed of the following raw materials: 87.50% asphalt, 12.00% MIL-68(Al)-OH / SBR composite modifier prepared in Example 3, and 0.50% sulfur; the preparation method of the anti-aging MIL-68(Al)-OH / SBR composite modifier modified asphalt is the same as that of Example 6.

[0079] Example 9

[0080] The anti-aging modified asphalt in this example is basically the same as that in Example 6, except that the MIL-68(Al)-OH / SBR composite modifier prepared in Example 4 is used to replace the MIL-68(Al)-OH / SBR composite modifier prepared in Example 1.

[0081] Example 10

[0082] The anti-aging modified asphalt in this example is basically the same as that in Example 6, except that the MIL-68(Al)-OH / SBR composite modifier prepared in Example 5 is used to replace the MIL-68(Al)-OH / SBR composite modifier prepared in Example 1.

[0083] Comparative Example 4

[0084] The anti-aging modified asphalt of this comparative example is basically the same as that of Example 6, except that the composite modifier prepared in Comparative Example 1 is used to replace the MIL-68(Al)-OH / SBR composite modifier prepared in Example 1.

[0085] Comparative Example 5

[0086] The anti-aging modified asphalt of this comparative example is basically the same as that of Example 6, except that the composite modifier prepared in Comparative Example 2 is used to replace the MIL-68(Al)-OH / SBR composite modifier prepared in Example 1.

[0087] Comparative Example 6

[0088] The anti-aging modified asphalt of this comparative example is basically the same as that of Example 6, except that the composite modifier prepared in Comparative Example 3 is used to replace the MIL-68(Al)-OH / SBR composite modifier prepared in Example 1.

[0089] Comparative Example 7

[0090] The anti-aging modified asphalt of this comparative example is basically the same as that of Example 6, except that by mass fraction, the modified asphalt is composed of the following raw materials: 97.50% asphalt, 2.00% MIL-68(Al)-OH / SBR composite modifier prepared in Example 1, and 0.50% sulfur;

[0091] That is, compared with Example 6, a small amount of MIL-68(Al)-OH / SBR composite modifier is used in this comparative example to modify the asphalt.

[0092] Comparative Example 8

[0093] The anti-aging modified asphalt of this comparative example is basically the same as that of Example 6, except that by mass fraction, the modified asphalt is composed of the following raw materials: 78.50% asphalt, 20.00% MIL-68(Al)-OH / SBR composite modifier prepared in Example 1, and 0.50% sulfur;

[0094] That is, compared with Example 6, a large amount of MIL-68(Al)-OH / SBR composite modifier is used in this comparative example to modify the asphalt.

[0095] Anti-aging performance test of modified asphalt

[0096] The modified asphalt prepared in the above examples and comparative examples was respectively subjected to short-term thermal-oxidative aging (RTFOT, temperature of 163 °C, aging time of 5 hours) and ultraviolet accelerated aging test (UV, ultraviolet light intensity of 1200 μW / cm 2, at a temperature of 60 °C and an aging time of 9 days); then, the properties of each specimen before and after aging were tested respectively, and the residual penetration (residual penetration = penetration after aging / penetration before aging × 100%), softening point increment (softening point increment = softening point after aging - softening point before aging), and ductility retention rate (ductility retention rate = ductility after aging / ductility before aging × 100%) were calculated. The test results are listed in Table 1.

[0097] Table 1 Test Results of Aging Resistance Performance of Modified Asphalt

[0098]

[0099] As can be seen from Table 1, the modified asphalt prepared with the composite modifier of the present invention has excellent anti-aging performance. Compared with Example 6, the composite modifier in Comparative Example 4 lacks MIL-68(Al)-OH, and the composite modifier in Comparative Example 6 lacks SBR. After the obtained modified asphalt undergoes thermal-oxidative aging and ultraviolet aging, its residual penetration and ductility retention rates are both less than those of the modified asphalt prepared with the MIL-68(Al)-OH / SBR composite modifier of the present invention, while the softening point increment is greater than that of the modified asphalt prepared in the present invention; this shows that MIL-68(Al)-OH can cooperate with SBR to improve the modification effect of the composite modifier. Under the combined action of MIL-68(Al)-OH and SBR, the composite modifier can significantly improve the anti-aging performance of asphalt, and the obtained modified asphalt has better thermal-oxidative aging and ultraviolet aging resistance. Compared with Example 6, the composite modifier in Comparative Example 5 does not contain SBR and does not perform hydroxyl functionalization on MIL-68(Al), and is directly composed of MIL-68(Al), accelerator and compatibilizer. After the obtained modified asphalt undergoes thermal-oxidative aging and ultraviolet aging, its residual penetration and ductility retention rates are also less than those of the modified asphalt prepared with the composite modifier of the present invention, while the softening point increment is greater than that of the modified asphalt prepared in the present invention. By comparing Comparative Example 5 and Comparative Example 6, it can be seen that hydroxyl functionalization of MIL-68(Al) can effectively improve the anti-aging performance of asphalt. Compared with Example 6, in Comparative Example 7, a small amount of MIL-68(Al)-OH / SBR composite modifier is used to modify asphalt. After the obtained modified asphalt undergoes thermal-oxidative aging and ultraviolet aging, its residual penetration and ductility retention rates are both less than those of the modified asphalt prepared in the present invention, while the softening point increment is greater than that of the modified asphalt prepared in the present invention; compared with Example 6, in Comparative Example 8, a large amount of MIL-68(Al)-OH / SBR composite modifier is used to modify asphalt. After the obtained modified asphalt undergoes thermal-oxidative aging and ultraviolet aging, its residual penetration and ductility retention rates are both less than those of the modified asphalt prepared in the present invention, while the softening point increment is greater than that of the modified asphalt prepared in the present invention; this shows that the effect of the modified asphalt prepared with too little or too much MIL-68(Al)-OH / SBR composite modifier is not good, and the MIL-68(Al)-OH / SBR composite modifier should be used appropriately.

[0100] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A MIL-68(Al)-OH / SBR composite modifier, characterized in that: The raw materials include the following mass fractions: MIL-68(Al)-OH 31%~38%, SBR 51%~56%, accelerator 0.3%~0.5%, compatibilizer 10.7%~12.5%; The preparation method of the MIL-68(Al)-OH comprises the following steps: S1. Add soluble aluminum salt and 2-hydroxyterephthalic acid into a solvent, perform ultrasonic treatment, react at 120-150° C. for 12-24 hours, and obtain a solid product after filtering and washing; S2. The solid product obtained in step S1 is heated at 100-150° C. for 10-20 hours to obtain MIL-68(Al)-OH crystals.

2. A MIL-68(Al)-OH / SBR composite modifier according to claim 1, characterized in that: The composition comprises the following raw materials in the following mass fractions: MIL-68(Al)-OH 35%, SBR 52%, accelerator 0.5%, and compatibilizer 12.5%.

3. A MIL-68(Al)-OH / SBR composite modifier according to claim 1, characterized in that: The mass ratio of the soluble aluminum salt to 2-hydroxyterephthalic acid is 1:(0.9-1.1).

4. A MIL-68(Al)-OH / SBR composite modifier according to claim 1, characterized in that: In step S1, the concentration of the soluble aluminum salt in the solvent is 1.5%wt~2.5%wt.

5. A MIL-68(Al)-OH / SBR composite modifier according to claim 1, characterized in that: In step S1, the solvent is at least one of N,N-dimethylformamide, γ-valerolactone, N,N-diethylformamide, and ethanol.

6. A MIL-68(Al)-OH / SBR composite modifier according to claim 1, characterized in that: In step S1, the soluble aluminum salt is aluminum chloride and / or aluminum nitrate.

7. A MIL-68(Al)-OH / SBR composite modifier according to claim 1, characterized in that: The accelerator is at least one of tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, and bis(1,5-pentylene)thiuram tetrasulfide; and the compatibilizer is three-line oil.

8. The method for preparing the MIL-68(Al)-OH / SBR composite modifier according to any one of claims 1 to 7, characterized in that: The following steps are involved: P1. Prepare the MIL-68(Al)-OH, SBR, accelerator and compatibilizer according to their respective mass fractions, and then blend them in a mixer at a blending temperature of 80-90° C. and a blending speed of 1300-1500 r / min; P2. Add the blend obtained in step P1 into a granulator for granulation to obtain the MIL-68(Al)-OH / SBR composite modifier.

9. An aging-resistant MIL-68(Al)-OH / SBR modified asphalt comprising the composite modifier according to any one of claims 1 to 7, characterized in that: The method comprises the following raw materials in the following mass fractions: 87.5% to 94.5% of asphalt, 5% to 12% of MIL-68(Al)-OH / SBR composite modifier, and 0.1% to 0.5% of stabilizer.

10. The method for preparing the aging-resistant MIL-68(Al)-OH / SBR modified asphalt according to claim 9, characterized in that: The method comprises the following steps: preparing materials according to the mass fractions of the asphalt, the MIL-68(Al)-OH / SBR composite modifier and the stabilizer; then heating the asphalt to a fluid state, slowly adding the MIL-68(Al)-OH / SBR composite modifier and the stabilizer while stirring, maintaining the temperature at 170-180°C, stirring at a speed of 4000-6000 rpm for 1-3 hours, and then continuing to stir at a speed of 400-600 rpm for 1-3 hours, so as to obtain the aging-resistant MIL-68(Al)-OH / SBR modified asphalt.

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