A toughening asphalt modifier, a toughening composite modified asphalt and its preparation method

Abstract

This application relates to a toughening asphalt modifier, a toughening composite modified asphalt, and a method for preparing the same, falling under the field of asphalt technology. This invention utilizes the hydrogen bonding and chemical bonding between polar functional groups and asphalt components to improve interfacial compatibility. An organic-inorganic interpenetrating crosslinking network is constructed through ring-opening esterification of carboxyl and epoxy groups, tetrasulfide bond sulfidation crosslinking, and isothiocyanate addition reaction. This enhances the interfacial bonding strength between the modifier and the asphalt matrix, improving the storage stability and high-temperature rutting resistance of the modified asphalt.

Description

Technical Field

[0001] This application relates to the field of asphalt technology, and in particular to a toughening asphalt modifier, a toughening composite modified asphalt, and a method for preparing the same. Background Technology

[0002] In road construction and related engineering fields, asphalt, as an important building material, directly affects the quality and service life of roads due to its performance. With the continuous increase in traffic volume and the gradual improvement of road performance requirements, the improvement and optimization of asphalt performance has become an important research direction in this field. High-quality asphalt materials can improve road smoothness, skid resistance, and durability, reduce the occurrence of road defects, thereby reducing maintenance costs, improving traffic safety, and promoting the development of the road construction industry.

[0003] Currently, the main technical approaches to improving the toughness of asphalt materials fall into two categories: polymer toughening and fiber-reinforced toughening. Common modifiers include SBS, rubber powder, and polyacrylonitrile fibers, whose toughening mechanisms primarily rely on the interpenetrating network structure or localized fiber network reinforcement formed by polymer swelling. However, these modifiers generally suffer from problems such as large differences in interfacial polarity and insufficient compatibility with asphalt, resulting in a bond between the two solely through physical adhesion, lacking a strong chemical interfacial link. Under conditions of large temperature difference cycling, high temperature stress can easily lead to relative sliding and debonding between the modifier and the asphalt matrix, thereby causing stress damage accumulation and macroscopic crack propagation. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a toughening asphalt modifier, a toughening composite modified asphalt, and a method for preparing the same.

[0005] The technical solution provided in this application for a toughening asphalt modifier, a toughening composite modified asphalt, and a method for preparing the same is as follows: In a first aspect, this application provides a toughening asphalt modifier, which adopts the following technical solution: A toughening asphalt modifier, the raw materials for which are prepared include the following components in parts by weight: Linear SBS 80-100 copies Bifunctional monomer grafted modified SBS 20-30 parts 10-20 parts glycidyl methacrylate grafted polyethylene 6-8 parts of KH560 modified nano silica 6-8 parts of dioctyl phthalate 2-3 parts sulfur Antioxidant 0.5-1 part; The bifunctional monomer-grafted modified SBS was prepared using the following steps: Linear SBS, N-(2-mercaptopropionyl)glycine and itaconic acid were added to 1,4-dioxane to prepare a polymer solution. An initiator was added, and the reaction was heated and stirred under a protective atmosphere. After the reaction was completed, the reaction solution was cooled, precipitated, washed, filtered, and dried to obtain bifunctional monomer-grafted modified SBS.

[0006] By compounding linear SBS with bifunctional monomer-grafted modified SBS, the latter introduces polar functional groups such as carboxyl and amide groups onto the SBS molecular chain through N-(2-mercaptopropionyl)glycine and itaconic acid. These functional groups form hydrogen bonds and chemical bonds with the polar components of asphalt, improving interfacial compatibility and SBS dispersion uniformity, and enhancing the storage stability of the modified asphalt. Simultaneously, the carboxyl groups can undergo ring-opening esterification with the epoxy groups of glycidyl methacrylate-grafted polyethylene and form active groups with the KH560 modified nano-silica surface-active groups. By constructing an organic-inorganic interpenetrating crosslinked network between the polymer and inorganic phases, the interfacial bonding strength and network integrity are enhanced, inhibiting interfacial sliding and debonding between the modifier and the asphalt matrix at high temperatures, thereby improving the high-temperature rutting resistance. The ester group of dioctyl phthalate forms hydrogen bonds with the aforementioned carboxyl and amide groups, promoting its stable distribution and reducing melt viscosity, which is beneficial for the uniform dispersion of each component and the uniform progress of the subsequent sulfur crosslinking reaction. The complementary functions of each component further enhance the anti-interfacial sliding and debonding ability of the modified asphalt under high-temperature service conditions.

[0007] Preferably, the mass ratio of the linear SBS, N-(2-mercaptopropionyl)glycine and itaconic acid is 1:(0.03-0.06):0.06.

[0008] By limiting the mass ratio of linear SBS, N-(2-mercaptopropionyl)glycine, and itaconic acid to a suitable range, the grafting density of polar functional groups such as carboxyl and amide groups on the SBS molecular chain is ensured. This not only fully improves the interfacial compatibility between the modifier and the asphalt matrix, allowing SBS to be uniformly dispersed in the asphalt and improving storage stability, but also enables it to form a moderate chemical bridging reaction with the epoxy groups of glycidyl methacrylate-grafted polyethylene and the surface-active groups of KH560 modified nano-silica during subsequent mixing. This constructs a structurally complete organic-inorganic interpenetrating cross-linked network between the polymer phase and the inorganic phase, enhancing the network's interfacial anti-slip ability under high-temperature conditions, thereby improving the high-temperature rutting resistance of the modified asphalt.

[0009] Preferably, the KH560 modified nano-silica is prepared by further modification treatment using the following steps: KH560 modified nano-silica was added to water and sonicated to obtain a suspension. A solution of bis-[3-(triethoxysilane)propyl]-tetrasulfide, adjusted to acidic pH, was added to the suspension. The mixture was heated and stirred. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain modified nano-silica.

[0010] KH560 modified nano-silica already possesses epoxy groups on its surface. These groups can undergo ring-opening esterification reactions with the carboxyl groups introduced by the bifunctional monomer grafted and modified SBS, constructing a chemical bridge between the nanoparticles and the polymer phase, thus initially improving the dispersion stability and interfacial bonding effect of the inorganic filler. Based on this, a secondary modification treatment with bis-[3-(triethoxysilyl)propyl]-tetrasulfide further introduces tetrasulfide active groups onto the nanoparticle surface. These groups can participate in the vulcanization crosslinking reaction during the high-temperature mixing stage of asphalt, enabling the nano-silica to further enhance the original epoxy- In addition to carboxyl esterification bridging, the modified silica is further integrated into the polymer network via a sulfur crosslinking pathway. The epoxy groups that did not participate in the silane condensation reaction continue to play a role in ring-opening esterification bridging with the carboxyl groups, while the tetrasulfide bonds participate in sulfur crosslinking during the high-temperature development stage of asphalt. This allows the nano-silica to be anchored in the polymer network in the form of multiple chemical bonds, further enhancing the bonding strength of the organic-inorganic interface and the overall stability of the crosslinking network. This inhibits the tendency of interfacial sliding and debonding between the modifier and the asphalt matrix at high temperatures, reduces the accumulation of permanent deformation, and improves the storage stability and high-temperature rutting resistance of the modified asphalt.

[0011] Preferably, the mass ratio of the KH560 modified nano silica to bis-[3-(triethoxysilane)propyl]-tetrasulfide is 1:(0.14-0.16).

[0012] By limiting the mass ratio of KH560-modified nano-silica to bis-[3-(triethoxysilyl)propyl]-tetrasulfide to a suitable range, the secondary modification process can introduce an appropriate density of tetrasulfide bond active groups on the nanoparticle surface without excessively consuming the original epoxy groups of KH560, thus preserving the esterification bridging ability of epoxy groups and carboxyl groups on the bifunctional monomer-grafted modified SBS. The tetrasulfide bonds participate in the vulcanization crosslinking reaction during the high-temperature development stage of asphalt, chemically bonding nano-silica into the polymer crosslinking network, enhancing the interfacial bonding strength between the inorganic and organic phases, suppressing the tendency of nanoparticle segregation and sedimentation during high-temperature storage, and improving the storage stability of the modified asphalt. Simultaneously, the combined effect of epoxy group esterification bridging and tetrasulfide bond vulcanization anchoring strengthens the structural integrity of the organic-inorganic interpenetrating network, slowing down interfacial slippage and debonding between the modifier and the asphalt matrix under high-temperature loads, reducing the accumulation of permanent deformation, and thus improving high-temperature rutting resistance.

[0013] Preferably, the raw materials used in the preparation also include terephthalic diisothiocyanate.

[0014] Adding terephthalic diisothiocyanate to the raw materials allows the isothiocyanate groups at both ends of the molecule to undergo an addition reaction with the amide groups on the side chains of the bifunctional monomer-grafted modified SBS, forming acylthiourea bonds and introducing additional chemical crosslinking nodes into the polymer network. These crosslinking points enhance the interfacial bonding strength between the SBS phase and the polar components, making the modifier less prone to segregation and floating during high-temperature asphalt storage, thus improving the storage stability of the modified asphalt. Simultaneously, the moderate increase in crosslinking density improves the deformation resistance of the network skeleton under high-temperature loads, suppresses the relative slippage tendency between the modifier and the asphalt matrix, reduces the accumulation of permanent strain, and thereby enhances the high-temperature rutting resistance of the modified asphalt.

[0015] Preferably, the amount of terephthalic diisothiocyanate added is 0.2-0.4 parts.

[0016] By limiting the amount of terephthalic diisothiocyanate added to the above range, the density of acylthiourea crosslinking points formed by the isothiocyanate groups and the amide groups of the SBS side chain grafted with bifunctional monomers is moderate. This not only enhances the chemical bonding strength within the polymer network to suppress the tendency of the modifier to segregate and float during high-temperature storage, but also avoids network embrittlement caused by excessive crosslinking, thus improving the storage stability of the modified asphalt. The moderate crosslinking structure improves the network skeleton's resistance to deformation under high-temperature loads, slows down the interfacial sliding and debonding between the modifier and the asphalt matrix, reduces the accumulation of permanent strain, and thus improves the high-temperature rutting resistance of the modified asphalt.

[0017] Preferably, the antioxidant comprises pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0018] Secondly, this application provides a toughened composite modified asphalt, which adopts the following technical solution: A toughened composite modified asphalt using a toughening asphalt modifier is prepared from raw materials comprising the following components in parts by weight: 85-95 parts of base asphalt 5-10 parts toughening asphalt modifier Stabilizer 0.1-0.5 parts.

[0019] The toughening asphalt modifier, base asphalt, and stabilizer are compounded in the specified proportions. The polar functional groups in the toughening asphalt modifier form hydrogen bonds and chemical bonds with the asphalt components, improving the dispersion uniformity and interfacial bonding strength of the modifier in the asphalt. The addition of the stabilizer further inhibits the tendency of SBS phase segregation and floating under high-temperature storage conditions, thus improving the storage stability of the toughened composite modified asphalt. At the same time, the organic-inorganic interpenetrating cross-linked network inside the modifier forms a stable skeleton structure in the asphalt. The stabilizer helps to enhance the deformation resistance of this network under high-temperature loads, slows down the interfacial sliding and debonding between the modifier and the asphalt matrix, reduces the accumulation of permanent deformation, and thus improves the high-temperature rutting resistance of the toughened composite modified asphalt.

[0020] Thirdly, this application provides a method for preparing toughened composite modified asphalt, employing the following technical solution: A method for preparing toughened composite modified asphalt includes the following steps: After heating the base asphalt, a toughening asphalt modifier is added, and the mixture is stirred and swollen before shearing. A stabilizer is then added, and the mixture is heated and stirred to develop, resulting in toughened composite modified asphalt.

[0021] After heating the base asphalt, a toughening asphalt modifier is added and stirred to swell, allowing the SBS component to fully absorb the lightweight asphalt components and undergo volume expansion. Subsequently, high-speed shearing refines and disperses the swollen modifier into the continuous asphalt phase, promoting full contact and bonding between the bifunctional monomer-grafted SBS side chain polar functional groups and the polar asphalt components. The addition of a stabilizer helps to suppress the segregation and aggregation tendency of the SBS phase during the subsequent heating and stirring development stage, improving the storage stability of the toughened composite modified asphalt. During the development process, ring-opening esterification, sulfur crosslinking, and hydrogen and covalent bond interactions occur among the components in the system, gradually forming an organic-inorganic interpenetrating crosslinked network structure. This enhances the network skeleton's resistance to deformation and interfacial anti-slip performance under high-temperature loads, reduces the accumulation of permanent strain, and thus improves the high-temperature rutting resistance of the toughened composite modified asphalt.

[0022] In summary, this application includes at least one of the following beneficial technical effects: 1. By compounding linear SBS with bifunctional monomer-grafted modified SBS, the latter introduces polar functional groups such as carboxyl and amide groups onto the SBS molecular chain through N-(2-mercaptopropionyl)glycine and itaconic acid. These functional groups form hydrogen bonds and chemical bonds with the polar components of asphalt, improving interfacial compatibility and SBS dispersion uniformity, and enhancing the storage stability of the modified asphalt. Simultaneously, the carboxyl groups can undergo ring-opening esterification with the epoxy groups of glycidyl methacrylate-grafted polyethylene and form active groups with the KH560 modified nano-silica surface-active groups. Chemical bridging constructs an organic-inorganic interpenetrating crosslinked network between the polymer and inorganic phases, enhancing interfacial bonding strength and network integrity. This inhibits interfacial sliding and debonding between the modifier and the asphalt matrix at high temperatures, thereby improving high-temperature rutting resistance. The ester groups of dioctyl phthalate form hydrogen bonds with the aforementioned carboxyl and amide groups, promoting stable distribution and reducing melt viscosity. This facilitates uniform dispersion of the components and the uniformity of subsequent sulfur crosslinking reactions. The complementary functions of the components further enhance the modified asphalt's resistance to interfacial sliding and debonding under high-temperature service conditions.

[0023] 2. KH560 modified nano-silica already possesses epoxy groups on its surface. These groups can undergo ring-opening esterification reactions with the carboxyl groups introduced by the bifunctional monomer grafted and modified SBS, constructing a chemical bridge between the nanoparticles and the polymer phase, thus initially improving the dispersion stability and interfacial bonding effect of the inorganic filler. Based on this, a secondary modification treatment with bis-[3-(triethoxysilyl)propyl]-tetrasulfide further introduces tetrasulfide active groups onto the nanoparticle surface. These groups can participate in the vulcanization crosslinking reaction during the high-temperature mixing stage of asphalt, enabling the nano-silica to achieve a crosslinking effect within the original epoxy... In addition to carboxyl esterification bridging, it is further integrated into the polymer network through sulfur crosslinking pathway; epoxy groups that did not participate in the silane condensation reaction continue to undertake the ring-opening esterification bridging with carboxyl groups, while tetrasulfide bonds participate in sulfur crosslinking during the high-temperature development stage of asphalt, so that nano-silica is anchored in the polymer network in the form of multiple chemical bonds, which further enhances the bonding strength of the organic-inorganic interface and the overall stability of the crosslinking network, inhibits the tendency of interfacial sliding and debonding between the modifier and the asphalt matrix at high temperature, reduces the accumulation of permanent deformation, and improves the storage stability and high-temperature rutting resistance of modified asphalt.

[0024] 3. Adding terephthalic diisothiocyanate to the raw materials allows the isothiocyanate groups at both ends of the molecule to undergo an addition reaction with the amide groups on the side chains of the bifunctional monomer-grafted modified SBS, forming acylthiourea bonds and introducing additional chemical crosslinking nodes into the polymer network. These crosslinking points enhance the interfacial bonding strength between the SBS phase and the polar components, making the modifier less prone to segregation and floating during high-temperature asphalt storage, thus improving the storage stability of the modified asphalt. Simultaneously, the moderate increase in crosslinking density improves the deformation resistance of the network skeleton under high-temperature loads, suppresses the relative slippage tendency between the modifier and the asphalt matrix, reduces the accumulation of permanent strain, and thereby enhances the high-temperature rutting resistance of the modified asphalt. Detailed Implementation

[0025] This application discloses a toughening asphalt modifier, a toughening composite modified asphalt, and a method for preparing the same. Unless otherwise specified, all raw materials used in this application are commercially available. The following examples further illustrate this application in detail: Raw material specifications: Linear SBS YH-791H was purchased from Dongguan Suwei New Materials Co., Ltd.; Glycidyl methacrylate-grafted polyethylene SH030 was purchased from Dongguan Shenghao Plastic Raw Materials Co., Ltd.; KH560 modified nano-silica was purchased from Hangzhou Hengge Nanotechnology Co., Ltd.; Dioctyl phthalate (CAS No.: 117-84-0); Sulfur was purchased from Kunshan Shengan Biotechnology Co., Ltd.; Pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (CAS No.: 6683-19-8); β-(3,5-di-tert-butyl- Octadecyl 4-hydroxyphenyl)propionate (CAS No.: 2082-79-3), No. 90 asphalt was purchased from Xingtai Jitong Asphalt Sales Co., Ltd., zinc oxide was purchased from Taizhou Huaye Zinc Industry Co., Ltd., C9 petroleum resin was purchased from Puyang Ruicheng Chemical Co., Ltd., bis-[3-(triethoxysilyl)propyl]-tetrasulfide (CAS No.: 40372-72-3) was purchased from Hubei Dali Chemical Co., Ltd., terephthalic diisothiocyanate (CAS No.: 4044-65-9), and epoxidized soybean oil were purchased from Shandong Kexing Chemical Co., Ltd. Example 1

[0026] Preparation of bifunctional monomer grafted modified SBS The mass ratio of linear SBS, N-(2-mercaptopropionyl)glycine and itaconic acid is 1:0.03:0.06, the amount of initiator (azobisisobutyronitrile) accounts for 0.5% of the mass of linear SBS, and the linear SBS model is YH-791H.

[0027] Linear SBS, N-(2-mercaptopropionyl)glycine and itaconic acid were added to 1,4-dioxane to prepare a polymer solution with a mass fraction of 12%. An initiator was added, and the mixture was stirred at 200 rpm for 10 h at 70 °C under a nitrogen atmosphere. After the reaction was completed, the reaction solution was cooled to room temperature and slowly poured into excess methanol to precipitate the grafted product. The product was washed with anhydrous ethanol, filtered, and dried under vacuum at 50 °C to constant weight to obtain bifunctional monomer-grafted modified SBS.

[0028] Preparation of toughened asphalt modifier Weigh the following components in parts by mass: 80 parts linear SBS, 20 parts bifunctional monomer-grafted modified SBS, 10 parts glycidyl methacrylate-grafted polyethylene, 6 parts KH560 modified nano silica, 6 parts dioctyl phthalate, 2 parts sulfur, and 0.5 parts antioxidant; the linear SBS is model YH-791H, the glycidyl methacrylate-grafted polyethylene is model SH030, and the antioxidant is composed of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate in a mass ratio of 1:0.5.

[0029] Linear SBS, bifunctional monomer-grafted modified SBS, glycidyl methacrylate-grafted polyethylene, KH560 modified nano-silica, dioctyl phthalate, sulfur, and antioxidants were added to a high-speed mixer and premixed at 800 rpm for 10 minutes at room temperature to obtain a uniform premix. The premix was fed into a twin-screw extruder and melt-extruded under the following conditions: barrel temperature 160℃ (feeding section) → 175℃ (compression section) → 185℃ (metering section) → 180℃ (die head) and screw speed 250 rpm. The extruded molten strip was cooled in a water tank and then pelletized by an air-cooled pelletizer. The pellets were then vacuum-dried at 60℃ for 6 hours to obtain the toughened asphalt modifier.

[0030] Preparation of toughened composite modified asphalt Weigh the following components in parts by mass: 85 parts base asphalt, 5 parts toughening asphalt modifier, and 0.1 parts stabilizer. The base asphalt is No. 90 asphalt, and the stabilizer is composed of zinc oxide and C9 petroleum resin in a mass ratio of 3:1.

[0031] After heating the base asphalt to 170℃, add the toughening asphalt modifier and swell for 20 minutes under low-speed stirring at 400 rpm. Then, raise the temperature to 175℃ and shear at high speed at 4500 rpm for 40 minutes. Add the stabilizer and develop at 170℃ and 200 rpm for 2.5 hours to obtain the toughened composite modified asphalt. Example 2

[0032] Preparation of bifunctional monomer grafted modified SBS The mass ratio of linear SBS, N-(2-mercaptopropionyl)glycine and itaconic acid is 1:0.06:0.06, the amount of initiator (azobisisobutyronitrile) accounts for 0.5% of the mass of linear SBS, and the linear SBS model is YH-791H.

[0033] Linear SBS, N-(2-mercaptopropionyl)glycine and itaconic acid were added to 1,4-dioxane to prepare a polymer solution with a mass fraction of 12%. An initiator was added, and the mixture was stirred at 200 rpm for 10 h at 70 °C under a nitrogen atmosphere. After the reaction was completed, the reaction solution was cooled to room temperature and slowly poured into excess methanol to precipitate the grafted product. The product was washed with anhydrous ethanol, filtered, and dried under vacuum at 50 °C to constant weight to obtain bifunctional monomer-grafted modified SBS.

[0034] Preparation of toughened asphalt modifier Weigh the following components in parts by mass: 100 parts linear SBS, 30 parts bifunctional monomer-grafted modified SBS, 20 parts glycidyl methacrylate-grafted polyethylene, 8 parts KH560 modified nano silica, 8 parts dioctyl phthalate, 3 parts sulfur, and 1 part antioxidant; the linear SBS is model YH-791H, the glycidyl methacrylate-grafted polyethylene is model SH030, and the antioxidant is composed of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate in a mass ratio of 1:0.5.

[0035] Linear SBS, bifunctional monomer-grafted modified SBS, glycidyl methacrylate-grafted polyethylene, KH560 modified nano-silica, dioctyl phthalate, sulfur, and antioxidants were added to a high-speed mixer and premixed at 800 rpm for 10 minutes at room temperature to obtain a uniform premix. The premix was fed into a twin-screw extruder and melt-extruded under the following conditions: barrel temperature 160℃ (feeding section) → 175℃ (compression section) → 185℃ (metering section) → 180℃ (die head) and screw speed 250 rpm. The extruded molten strip was cooled in a water tank and then pelletized by an air-cooled pelletizer. The pellets were then vacuum-dried at 60℃ for 6 hours to obtain the toughened asphalt modifier.

[0036] Preparation of toughened composite modified asphalt Weigh the following components in parts by mass: 95 parts base asphalt, 10 parts toughening asphalt modifier, and 0.5 parts stabilizer. The base asphalt is No. 90 asphalt, and the stabilizer is composed of zinc oxide and C9 petroleum resin in a mass ratio of 3:1.

[0037] After heating the base asphalt to 170℃, add the toughening asphalt modifier and swell for 20 minutes under low-speed stirring at 400 rpm. Then, raise the temperature to 175℃ and shear at high speed at 4500 rpm for 40 minutes. Add the stabilizer and develop at 170℃ and 200 rpm for 2.5 hours to obtain the toughened composite modified asphalt. Example 3

[0038] Preparation of bifunctional monomer grafted modified SBS The mass ratio of linear SBS, N-(2-mercaptopropionyl)glycine and itaconic acid is 1:0.045:0.06, the amount of initiator (azobisisobutyronitrile) accounts for 0.5% of the mass of linear SBS, and the linear SBS model is YH-791H.

[0039] Linear SBS, N-(2-mercaptopropionyl)glycine and itaconic acid were added to 1,4-dioxane to prepare a polymer solution with a mass fraction of 12%. An initiator was added, and the mixture was stirred at 200 rpm for 10 h at 70 °C under a nitrogen atmosphere. After the reaction was completed, the reaction solution was cooled to room temperature and slowly poured into excess methanol to precipitate the grafted product. The product was washed with anhydrous ethanol, filtered, and dried under vacuum at 50 °C to constant weight to obtain bifunctional monomer-grafted modified SBS.

[0040] Preparation of toughened asphalt modifier Weigh the following components in parts by mass: 90 parts linear SBS, 25 parts bifunctional monomer-grafted modified SBS, 15 parts glycidyl methacrylate-grafted polyethylene, 7 parts KH560 modified nano silica, 7 parts dioctyl phthalate, 2.5 parts sulfur, and 0.75 parts antioxidant; the linear SBS is model YH-791H, the glycidyl methacrylate-grafted polyethylene is model SH030, and the antioxidant is composed of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate in a mass ratio of 1:0.5.

[0041] Linear SBS, bifunctional monomer-grafted modified SBS, glycidyl methacrylate-grafted polyethylene, KH560 modified nano-silica, dioctyl phthalate, sulfur, and antioxidants were added to a high-speed mixer and premixed at 800 rpm for 10 minutes at room temperature to obtain a uniform premix. The premix was fed into a twin-screw extruder and melt-extruded under the following conditions: barrel temperature 160℃ (feeding section) → 175℃ (compression section) → 185℃ (metering section) → 180℃ (die head) and screw speed 250 rpm. The extruded molten strip was cooled in a water tank and then pelletized by an air-cooled pelletizer. The pellets were then vacuum-dried at 60℃ for 6 hours to obtain the toughened asphalt modifier.

[0042] Preparation of toughened composite modified asphalt Weigh the following components in parts by mass: 90 parts base asphalt, 7.5 parts toughening asphalt modifier, and 0.3 parts stabilizer. The base asphalt is No. 90 asphalt, and the stabilizer is composed of zinc oxide and C9 petroleum resin in a mass ratio of 3:1.

[0043] After heating the base asphalt to 170℃, add the toughening asphalt modifier and swell for 20 minutes under low-speed stirring at 400 rpm. Then, raise the temperature to 175℃ and shear at high speed at 4500 rpm for 40 minutes. Add the stabilizer and develop at 170℃ and 200 rpm for 2.5 hours to obtain the toughened composite modified asphalt. Example 4

[0044] Example 4 is based on Example 3. The only difference between Example 4 and Example 3 is that in Example 4, the mass ratio of linear SBS, N-(2-mercaptopropionyl)glycine and itaconic acid is 1:0.01:0.06 when preparing the bifunctional monomer grafted modified SBS. Example 5

[0045] Example 5 is based on Example 3. The only difference between Example 5 and Example 3 is that in Example 5, the mass ratio of linear SBS, N-(2-mercaptopropionyl)glycine and itaconic acid is 1:0.08:0.06 when preparing the bifunctional monomer grafted modified SBS. Example 6

[0046] Example 6 is based on Example 3. The only difference between Example 6 and Example 3 is that the KH560 modified nano-silica in Example 6 undergoes further modification treatment and is prepared using the following steps: The mass ratio of KH560 modified nano silica to bis-[3-(triethoxysilane)propyl]-tetrasulfide is 1:0.14.

[0047] KH560 modified nano-silica was added to deionized water and sonicated for 30 min to obtain a suspension (solid-liquid ratio 1 g / 100 mL). A 5% (w / w) aqueous solution of bis-[3-(triethoxysilane)propyl]-tetrasulfide was added dropwise to the suspension, with the pH adjusted to 4 using 0.1 mol / L acetic acid aqueous solution. The addition was completed within 30 min. The mixture was stirred at 400 rpm at 80 °C for 2 h. After the reaction was completed, the solid product was separated by centrifugation, washed three times with anhydrous ethanol, and dried under vacuum at 60 °C to obtain modified nano-silica. Example 7

[0048] Example 7 is based on Example 6. The only difference between Example 7 and Example 6 is that in Example 7, the mass ratio of KH560 modified nano-silica to bis-[3-(triethoxysilane)propyl]-tetrasulfide is 1:0.16 when preparing modified nano-silica. Example 8

[0049] Example 8 is based on Example 6. The only difference between Example 8 and Example 6 is that in Example 8, the mass ratio of KH560 modified nano-silica to bis-[3-(triethoxysilane)propyl]-tetrasulfide is 1:0.15 when preparing modified nano-silica. Example 9

[0050] Example 9 is based on Example 6. The only difference between Example 9 and Example 6 is that in Example 9, the mass ratio of KH560 modified nano-silica to bis-[3-(triethoxysilane)propyl]-tetrasulfide is 1:0.12 when preparing modified nano-silica. Example 10

[0051] Example 10 is based on Example 6. The only difference between Example 10 and Example 6 is that in Example 10, the mass ratio of KH560 modified nano-silica to bis-[3-(triethoxysilane)propyl]-tetrasulfide is 1:0.18 when preparing modified nano-silica. Example 11

[0052] Example 11 is based on Example 3. The only difference between Example 11 and Example 3 is that the raw materials for preparing the toughening asphalt modifier in Example 11 also include 0.2 parts of terephthalic diisothiocyanate.

[0053] Preparation of toughened asphalt modifier Weigh the following components in parts by mass: 90 parts linear SBS, 25 parts bifunctional monomer-grafted modified SBS, 15 parts glycidyl methacrylate-grafted polyethylene, 7 parts KH560 modified nano silica, 7 parts dioctyl phthalate, 2.5 parts sulfur, 0.75 parts antioxidant, and 0.2 parts terephthalic diisothiocyanate; the linear SBS is model YH-791H, the glycidyl methacrylate-grafted polyethylene is model SH030, and the antioxidant is composed of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate in a mass ratio of 1:0.5.

[0054] Linear SBS, bifunctional monomer-grafted modified SBS, glycidyl methacrylate-grafted polyethylene, KH560 modified nano-silica, dioctyl phthalate, sulfur, antioxidant, and terephthalic acid diisothiocyanate were added to a high-speed mixer and premixed at 800 rpm for 10 min at room temperature to obtain a uniform premix. The premix was fed into a twin-screw extruder and melt-extruded under the following conditions: barrel temperature 160℃ (feeding section) → 175℃ (compression section) → 185℃ (metering section) → 180℃ (die head) and screw speed 250 rpm. The extruded molten strip was cooled in a water tank and then pelletized by an air-cooled pelletizer. The pellets were then vacuum-dried at 60℃ for 6 h to obtain the toughened asphalt modifier. Example 12

[0055] Example 12 is based on Example 11. The only difference between Example 12 and Example 11 is that the amount of p-phenylenediisothiocyanate added in Example 12 is 0.4 parts. Example 13

[0056] Example 13 is based on Example 11. The only difference between Example 13 and Example 11 is that the amount of p-phenylenediisothiocyanate added in Example 13 is 0.3 parts. Example 14

[0057] Example 14 is based on Example 11. The only difference between Example 14 and Example 11 is that the amount of p-phenylenediisothiocyanate added in Example 14 is 0.1 parts. Example 15

[0058] Example 15 is based on Example 11. The only difference between Example 15 and Example 11 is that the amount of p-phenylenediisothiocyanate added in Example 15 is 0.6 parts.

[0059] Comparative Example 1 Comparative Example 1 is based on Example 3. The only difference between Comparative Example 1 and Example 3 is that the bifunctional monomer grafted modified SBS in Comparative Example 1 is replaced with modified SBS prepared in the following steps.

[0060] Preparation of modified SBS The mass ratio of linear SBS to N-(2-mercaptopropionyl)glycine is 1:0.045, the amount of initiator (azobisisobutyronitrile) is 0.5% of the mass of linear SBS, and the linear SBS model is YH-791H.

[0061] Linear SBS and N-(2-mercaptopropionyl)glycine were added to 1,4-dioxane to prepare a polymer solution with a mass fraction of 12%. An initiator was added, and the mixture was stirred at 200 rpm for 10 h at 70 °C under a nitrogen atmosphere. After the reaction was completed, the reaction solution was cooled to room temperature and slowly poured into excess methanol to precipitate the grafted product. The product was washed with anhydrous ethanol, filtered, and dried under vacuum at 50 °C to constant weight to obtain bifunctional monomer-grafted modified SBS.

[0062] Comparative Example 2 Comparative Example 2 is based on Example 3. The only difference between Comparative Example 2 and Example 3 is that KH560 modified nano-silica is not added in Comparative Example 2.

[0063] Comparative Example 3 Comparative Example 3 is based on Example 3, except that in Comparative Example 3, dioctyl phthalate is replaced with epoxidized soybean oil. Performance testing experiment

[0064] (1) Select "JTG E20-2011 T 0661-2011 Polymer Modified Asphalt Segregation Test" as the standard. Pour about 50g of toughened composite modified asphalt heated to a fluid state into an aluminum sample tube and place it vertically in an oven at 163℃ for 48h. After taking it out, immediately place it in a freezer at -20℃ for 4h. After the sample is completely solidified, cut the aluminum tube into three equal parts. Take the top and bottom 1 / 3 of the sample and determine the softening point according to "T 0606-2011 Asphalt Softening Point Test". Calculate the difference between the softening points of the upper and lower sections, which is the segregation softening point difference. The smaller the difference, the better the compatibility of the modifier with the asphalt and the better the chemical anchoring effect. Prepare three samples for each sample, and take the average value after measurement. Record the results in Table 1.

[0065] (2) The standard “JTG E20-2011 T 0628-2011 Asphalt Rheological Properties Test (Dynamic Shear Rheometer Method)” was selected. A 1g toughened composite modified asphalt sample was clamped between 25mm parallel plates (1mm spacing) of the dynamic shear rheometer (DSR). The oscillation test was carried out at 70℃ and angular frequency of 10rad / s. The instrument automatically measured and output the complex shear modulus G and phase angle δ. The rutting factor G / sinδ was calculated. The larger the value, the stronger the asphalt’s resistance to permanent deformation at high temperature. Three samples were prepared for each sample. The average value was taken after measurement and the results were recorded in Table 1.

[0066] Table 1. Test results of storage stability and high-temperature rutting resistance. Example 1 1.0 5.8 Example 2 0.7 6.6 Example 3 0.6 7.2 Example 4 1.7 5.3 Example 5 1.5 5.6 Example 6 0.3 8.1 Example 7 0.4 7.9 Example 8 0.3 8.2 Example 9 0.5 7.7 Example 10 0.6 7.5 Example 11 0.2 8.5 Example 12 0.3 8.3 Example 13 0.2 8.6 Example 14 0.4 7.8 Example 15 0.5 7.4 Comparative Example 1 2.3 4.9 Comparative Example 2 1.2 4.5 Comparative Example 3 1.8 5.1 As shown in Table 1, the segregation softening point difference of Examples 1-3 is below 1.0℃ and the rutting factor is above 5.8kPa. This indicates that the toughening asphalt modifier prepared in this application has good performance, and the toughened composite modified asphalt prepared has good storage stability and high-temperature rutting resistance.

[0067] As shown in Table 1, the only difference between Examples 4 and 5 and Example 3 is that the synthesis ratio of the bifunctional monomer grafted modified SBS was disrupted in Examples 4 and 5. Too high or too low N-(2-mercaptopropionyl)glycine will affect the balance of performance and the performance will decrease.

[0068] As shown in Table 1, the only difference between Examples 6-10 and Example 3 is that in Examples 6-8, KH560 modified nano-silica was modified according to a defined ratio, which enabled the nanoparticles to be better anchored in the polymer network in the form of chemical bonds, forming an organic-inorganic interpenetrating network and improving the performance of asphalt; Examples 9 and 10 disrupted the optimal ratio, and the performance improvement effect was reduced.

[0069] As shown in Table 1, the only difference between Examples 11-15 and Example 3 is that in Examples 11-13, terephthalic diisothiocyanate was added according to the specified dosage, resulting in improved performance. However, Examples 14 and 15 disrupted the optimal dosage range, leading to a decrease in the performance improvement effect.

[0070] As shown in Table 1, the only difference between Comparative Example 1 and Example 3 is that the modified SBS in Comparative Example 1 is modified only with N-(2-mercaptopropionyl)glycine, resulting in a decrease in polar anchor density and a deterioration in performance.

[0071] As shown in Table 1, the only difference between Comparative Example 2 and Example 3 is that Comparative Example 2 does not contain KH560 modified nano-silica, lacks nano-reinforcement and organic-inorganic bridging effect, and its high-temperature rutting resistance is greatly reduced.

[0072] As shown in Table 1, the only difference between Comparative Example 3 and Example 3 is that in Comparative Example 3, dioctyl phthalate was replaced with epoxidized soybean oil, which significantly reduced the synergistic effect with other components in the system and degraded the performance.

[0073] This specific embodiment is merely an explanation of this application and is not intended to limit it. Based on the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of this application. The technical scope of this application is not limited to the contents of the specification but must be determined according to the scope of the claims.

Claims

1. A toughening asphalt modifier, characterized in that: The raw materials for preparation include the following components in parts by weight: Linear SBS 80-100 copies Bifunctional monomer grafted modified SBS 20-30 parts 10-20 parts glycidyl methacrylate grafted polyethylene 6-8 parts of KH560 modified nano silica 6-8 parts of dioctyl phthalate 2-3 parts sulfur Antioxidant 0.5-1 part; The bifunctional monomer-grafted modified SBS was prepared using the following steps: Linear SBS, N-(2-mercaptopropionyl)glycine and itaconic acid were added to 1,4-dioxane to prepare a polymer solution. An initiator was added, and the reaction was heated and stirred under a protective atmosphere. After the reaction was completed, the reaction solution was cooled, precipitated, washed, filtered, and dried to obtain bifunctional monomer-grafted modified SBS.

2. The toughening asphalt modifier according to claim 1, characterized in that: The mass ratio of the linear SBS, N-(2-mercaptopropionyl)glycine and itaconic acid is 1:(0.03-0.06):0.

06.

3. The toughening asphalt modifier according to claim 1, characterized in that: The KH560 modified nano-silica was further modified and prepared using the following steps: KH560 modified nano-silica was added to water and sonicated to obtain a suspension. A solution of bis-[3-(triethoxysilane)propyl]-tetrasulfide, adjusted to acidic pH, was added to the suspension. The mixture was heated and stirred. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain modified nano-silica.

4. The toughening asphalt modifier according to claim 3, characterized in that: The mass ratio of the KH560 modified nano silica to bis-[3-(triethoxysilane)propyl]-tetrasulfide is 1:(0.14-0.16).

5. The toughening asphalt modifier according to claim 1, characterized in that: The raw materials used in the preparation also include terephthalic diisothiocyanate.

6. The toughening asphalt modifier according to claim 5, characterized in that: The amount of terephthalic diisothiocyanate added is 0.2-0.4 parts.

7. The toughening asphalt modifier according to claim 1, characterized in that: The antioxidants include pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

8. A toughened composite modified asphalt using the toughening asphalt modifier as described in any one of claims 1-7, characterized in that: The raw materials for preparation include the following components in parts by weight: 85-95 parts of base asphalt 5-10 parts toughening asphalt modifier Stabilizer 0.1-0.5 parts.

9. A method for preparing toughened composite modified asphalt as described in claim 8, characterized in that: Includes the following steps: After heating the base asphalt, a toughening asphalt modifier is added, and the mixture is stirred and swollen before shearing. A stabilizer is then added, and the mixture is heated and stirred to develop, resulting in toughened composite modified asphalt.