Nano-grafted composite modifier and preparation method thereof, and high-performance modified asphalt and preparation method thereof

Abstract

The invention relates to the technical field of road engineering, and discloses a nano-grafted composite modifier and a preparation method thereof, and high-performance modified asphalt and a preparation method thereof, the nano-material is dispersed in a cosolvent by using ultrasonic equipment, the temperature is kept at 70-90 DEG C, the ultrasonic power is greater than or equal to 1000W, and the ultrasonic time is 30-40 minutes to form a uniformly distributed emulsion; modifying the emulsion by using a surface treating agent, and carrying out ultrasonic treatment for 60-90 minutes to form uniform and stable nano material dispersed slurry; uniformly mixing, melting and extruding the grafted monomer and the polymer at a high speed, and reacting at the temperature of 160-200 DEG C and the rotating speed of a screw rod of 150-300 rpm to obtain polymer grafted particles; and uniformly mixing the nano material dispersion slurry and the polymer grafted particles at a high speed, and carrying out melt extrusion to obtain the nano grafted composite modifier. Through an ultrasonic dispersion-melt grafting synergistic process, the problems of dispersion, compatibility and stability of the nano material in asphalt are solved.

Description

Technical Field

[0001] The present invention relates to the field of road engineering technology, and in particular to a nano-grafted composite modifier and a preparation method thereof. In addition, the present invention also relates to a high-performance modified asphalt comprising the nano-grafted composite modifier and a preparation method thereof. Background Art

[0002] Currently, high-molecular-weight polymers (such as styrene-butadiene-styrene block copolymer (SBS)) are commonly used in engineering to modify asphalt to improve its elasticity and crack resistance. However, due to the lack of sufficiently stable chemical interfacial interactions between elastic polymers like SBS and the asphalt matrix, phase separation and migration of the modifier and the asphalt matrix are very likely to occur during long-term storage or high-temperature environments. This leads to a continuous degradation of the modified asphalt's performance and an inability to maintain stable road performance over the long term.

[0003] On the other hand, with the development of nanotechnology, nanoparticles (such as nano-silica, nano-titanium dioxide, and organic montmorillonite) are considered ideal modification materials for enhancing the durability of asphalt materials due to their extremely large specific surface area, excellent UV reflection and shielding properties, and efficient oxygen barrier and isolation properties. They have gradually attracted attention and recognition from the industry. However, practical applications have shown that due to the high surface energy and extremely small particle size of nanomaterials, they are prone to agglomeration in high-viscosity asphalt systems. Traditional simple physical blending methods have difficulty achieving uniform dispersion and stable incorporation of nanomaterials in asphalt systems. This agglomeration phenomenon significantly limits the effectiveness of nanomaterial modification, resulting in minimal performance improvements, poor stability, and prone to sedimentation, stratification, and even failure during long-term storage.

[0004] To address these issues, existing technologies have attempted to improve the dispersion of nanomaterials in asphalt through nanomaterial surface modification techniques (such as surface treatment with silane coupling agents), intercalation techniques, and mechanical stirring enhancement techniques. However, these methods typically only achieve initial dispersion and are unable to achieve a long-term, stable, and uniform dispersion state. Furthermore, while some studies have employed ultrasonic technology to disperse nanomaterials, relying solely on physical ultrasonic action results in a dispersion effect that decays over time and fails to effectively address the long-term stability of nanoparticles in asphalt. Simultaneously, there have been studies applying polymer grafting technology to asphalt modification, but due to a lack of systematic research on the interfacial synergy between nanoparticles and polymers, the long-term dispersion and stability of nanomaterials in high-temperature, high-viscosity asphalt systems remains unresolved. Summary of the Invention

[0005] The present invention provides a nano-grafted composite modifier and a preparation method thereof, a high-performance modified asphalt and a preparation method thereof. By combining physical ultrasonic dispersion with chemical grafting reaction, the deep dispersion and long-term stability of nanomaterials in the asphalt system are achieved, and the high and low temperature performance, anti-ultraviolet aging performance and storage stability of the modified asphalt are significantly improved. It is suitable for road engineering applications under extreme environmental conditions such as severe cold and high ultraviolet light, so as to solve the technical problems of dispersion uniformity, interfacial compatibility and long-term stability of nanomaterials in high-temperature and high-viscosity asphalt systems.

[0006] According to one aspect of the present invention, a method for preparing a nano-grafted composite modifier is provided, comprising the following steps: S100, dispersing a nanomaterial in a cosolvent using an ultrasonic device, maintaining the temperature at 70°C to 90°C, performing ultrasonic dispersion treatment in an oil fraction using an ultrasonic device, with an ultrasonic power of ≥1000W and an ultrasonic time of 30 minutes to 40 minutes, to form a uniformly distributed emulsion; S200, modifying the emulsion using a surface treatment agent, maintaining the temperature at 70°C to 90°C, with an ultrasonic power of ≥1000W and an ultrasonic time of 60 minutes to 90 minutes, to form a uniform and stable nanomaterial dispersion slurry; S300, uniformly mixing a grafted monomer and a polymer at high speed, and then feeding them into a twin-screw extruder for melt extrusion, with a reaction temperature of 160°C to 200°C and a screw speed of 150 rpm to 300 rpm, to obtain polymer grafted particles; S400, uniformly mixing the nanomaterial dispersion slurry and the polymer grafted particles at high speed, and again feeding them into a twin-screw extruder for melt extrusion, to obtain a nano-grafted composite modifier.

[0007] Furthermore, the nanomaterial is selected from one or more of organic montmorillonite, nano silicon dioxide, and nano titanium dioxide.

[0008] Furthermore, the grafting monomer is selected from one or both of glycidyl methacrylate and maleic anhydride.

[0009] Furthermore, the polymer is a styrene-butadiene-styrene block copolymer.

[0010] Furthermore, the surface treatment agent is a silane coupling agent, selected from KH-550 and KH-570; and / or the cosolvent is cyclohexane oil.

[0011] Furthermore, glycidyl methacrylate (GMA) is selected as the grafting monomer; both KH-570 and GMA contain methacryloyl groups and can be grafted with SBS under the action of an initiator.

[0012] Furthermore, the initiator is one of dicumyl peroxide (DCP) or benzoyl peroxide (BPO).

[0013] According to another aspect of the present invention, a nano-grafted composite modifier is provided, which is prepared by the above-mentioned preparation method of the nano-grafted composite modifier.

[0014] According to another aspect of the present invention, a method for preparing high-performance modified asphalt is provided, which uses the above-mentioned nano-grafted composite modifier and includes the following steps: S500, high-speed shear blending the nano-grafted composite modifier with an ultraviolet absorber, a stabilizer, a rubber oil with aromatic hydrocarbons as the main component, and a molten matrix asphalt, with a shear speed of 4000 rpm to 6000 rpm and a mixing time of 30 minutes to 60 minutes; S600, performing a performance development treatment on the blended mixture prepared in S500 to obtain a high-performance modified asphalt material.

[0015] Furthermore, the performance development treatment in step S600 specifically includes: continuing to maintain the blended mixture prepared in S500 at 170°C to 180°C for performance development treatment, and continuously stirring for 20 minutes to 30 minutes, so that the nano-grafted composite modifier can further diffuse in the asphalt matrix and fully fuse with the matrix, ensuring that the composite structure of the nanomaterial and the polymer reaches the optimal distribution state in the asphalt system, so that the various properties of the prepared modified asphalt material can be fully improved and stabilized, and finally a high-performance modified asphalt material with excellent performance is obtained.

[0016] Furthermore, the ultraviolet absorber is selected from at least one of nano titanium dioxide and nano zinc oxide; and / or the stabilizer is sulfur.

[0017] According to another aspect of the present invention, there is also provided a high-performance modified asphalt, which is prepared using the above-mentioned method for preparing high-performance modified asphalt.

[0018] The present invention has the following beneficial effects: The preparation method of the nano-grafted composite modifier described in the present invention is to first subject the nanomaterial to ultrasonic dispersion treatment, and then add a surface treatment agent for further treatment to prevent the surface treatment agent from causing the nanomaterial to agglomerate; the cavitation effect of microjets, shock waves, etc. generated by high-power ultrasound (≥1000W) and a high temperature (70°C-90°C) environment are used to destroy the agglomerates of the nanomaterial and achieve uniform dispersion in the oil; the surface treatment agent modifies the surface of the nanomaterial by physical adsorption or chemical bonding, reduces the surface energy of the nanomaterial, thereby enhancing the compatibility of the nanomaterial with the oil and inhibiting re-agglomeration; the grafting monomer undergoes a free radical grafting reaction with the polymer during the melt extrusion process to form a grafted chain segment, the active groups of the grafted chain segment are further cross-linked with the surface-treated nanomaterial, the non-polar chain segment is compatible with the asphalt, and an "anchor-compatibility" dual-functional interface is constructed; the high shear force of the screw (150rpm-300rpm) promotes melt mixing and reaction mass transfer, thereby improving the grafting rate.

[0019] The preparation method of the nano-grafted composite modifier of the present invention comprises the following steps: preheating at 70°C-90°C in the ultrasonic stage to reduce the viscosity of the oil and improve the dispersion efficiency; the nanomaterials after ultrasonic dispersion form a stable slurry in the oil, providing a highly active surface for the subsequent grafting reaction; high temperature of 160°C-200°C in the extrusion stage activates the grafting reaction, while the shear force of the screw promotes the uniform distribution of the nanomaterials in the polymer matrix; during melt extrusion, the grafted monomers can be directly anchored to the surface of the pre-dispersed nanomaterials through chemical bonds, avoiding secondary agglomeration.

[0020] In the preparation method of the nano-grafted composite modifier of the present invention, the temperature of the ultrasonic stage in steps S100 and S200 is 70°C-90°C, the oil viscosity is reduced, the cavitation threshold is reduced, and the ultrasonic energy transfer efficiency is maximized; if the ultrasonic stage temperature is less than 70°C, the oil viscosity increases, resulting in severe ultrasonic energy dissipation and reduced dispersion efficiency; if the ultrasonic stage temperature is greater than 90°C, the volatilization of the co-solvent is intensified, and the slurry stability is reduced.

[0021] The preparation method of the nano-grafted composite modifier of the present invention has the following characteristics: the ultrasonic power is ≥1000W, the power density is >50 W / L, and the cavitation intensity is sufficient to peel off the nano-aggregates; when the ultrasonic power is <1000W, the dispersion time is prolonged, and D50 is >1μm.

[0022] In the preparation method of the nano-grafted composite modifier of the present invention, the temperature of the melt extrusion stage in step S300 and step S400 is 160°C-200°C, the activation energy of the grafting reaction is matched, and the grafting rate is improved; if the temperature of the melt extrusion stage is less than 160°C, the reaction rate is too low and the grafting rate is low; if the temperature of the melt extrusion stage is greater than 200°C, there is a risk of polymer degradation and a sudden change in the melt flow index.

[0023] In the preparation method of the nano-grafted composite modifier of the present invention, the screw speed in the melt extrusion stage in step S300 and step S400 is 150 rpm-300 rpm, and the shear rate is high, thereby achieving sufficient mixing and interface reaction of the nano material / polymer melt.

[0024] The preparation method of the nano-grafted composite modifier of the present invention solves the dispersion, compatibility and stability problems of nanomaterials in asphalt through the ultrasonic dispersion-melt grafting collaborative process, avoids the secondary agglomeration problem of the traditional step-by-step process, and improves the interfacial binding energy; high-temperature rutting resistance and low-temperature crack resistance are simultaneously improved, and the needle penetration ratio is increased after UV aging; thus, efficient and stable industrial production is achieved.

[0025] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention is further described in detail below. DETAILED DESCRIPTION

[0026] The following examples of the present invention are described in detail, but the present invention can be implemented in a variety of different ways as defined and covered below. Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0027] The preparation method of the nano-grafted composite modifier of this embodiment includes the following steps: S100, adding the nano material to the cosolvent, and performing ultrasonic dispersion treatment in the oil using an ultrasonic device at a temperature of 70°C to 90°C, with an ultrasonic power of ≥1000W and a treatment time of 30 minutes to 40 minutes to form a uniformly distributed nano material emulsion; S200, modifying the emulsion using a surface treatment agent, with an ultrasonic power of ≥1000W, a treatment time of 60 minutes to 90 minutes, and a temperature of 70°C to 90°C to obtain a nano material dispersion slurry; S300, high-speed homogenizing the grafted monomer and the polymer, and then feeding them into a twin-screw extruder for melt extrusion, with a reaction temperature of 160°C to 200°C and a screw speed of 150 rpm to 300 rpm to obtain polymer grafted particles; S400, high-speed homogenizing the nano material dispersion slurry and the polymer grafted particles, and again feeding them into a twin-screw extruder for melt extrusion to obtain the nano-grafted composite modifier. The preparation method of the nano-grafted composite modifier described in the present invention is to first subject the nanomaterial to ultrasonic dispersion treatment, and then add a surface treatment agent for further treatment to prevent the surface treatment agent from causing the nanomaterial to agglomerate; the cavitation effect of microjets, shock waves, etc. generated by high-power ultrasound (≥1000W) and a high temperature (70°C-90°C) environment are used to destroy the agglomerates of the nanomaterial and achieve uniform dispersion in the oil; the surface treatment agent modifies the surface of the nanomaterial by physical adsorption or chemical bonding, reduces the surface energy of the nanomaterial, thereby enhancing the compatibility of the nanomaterial with the oil and inhibiting re-agglomeration; the grafting monomer undergoes a free radical grafting reaction with the polymer during the melt extrusion process to form a grafted chain segment, the active groups of the grafted chain segment are further cross-linked with the surface-treated nanomaterial, the non-polar chain segment is compatible with the asphalt, and an "anchor-compatibility" dual-functional interface is constructed; the high shear force of the screw (150rpm-300rpm) promotes melt mixing and reaction mass transfer, thereby improving the grafting rate. The preparation method of the nano-grafted composite modifier of the present invention comprises the following steps: preheating at 70°C-90°C in the ultrasonic stage to reduce the viscosity of the oil and improve the dispersion efficiency; the nanomaterials after ultrasonic dispersion form a stable slurry in the oil, providing a highly active surface for the subsequent grafting reaction; the high temperature of 160°C-200°C in the extrusion stage activates the grafting reaction, while the shear force of the screw promotes the uniform distribution of the nanomaterials in the polymer matrix; during melt extrusion, the grafted monomers are directly anchored to the surface of the pre-dispersed nanomaterials through chemical bonds to avoid secondary agglomeration. The preparation method of the nano-grafted composite modifier of the present invention comprises the following steps: the ultrasonic stage temperature in steps S100 and S200 is 70°C-90°C, the oil viscosity is reduced, the cavitation threshold is reduced, and the ultrasonic energy transfer efficiency is maximized; if the ultrasonic stage temperature is <70°C, the oil viscosity increases, resulting in severe ultrasonic energy dissipation and a decrease in dispersion efficiency; if the ultrasonic stage temperature is >90°C, the volatilization of the co-solvent is aggravated and the slurry stability is reduced.In the preparation method of the nano-grafted composite modifier of the present invention, the ultrasonic power is ≥1000W, the power density is >50W / L, and the cavitation intensity is sufficient to exfoliate the nanoaggregates. When the ultrasonic power is <1000W, the dispersion time is prolonged, and the D50 value is >1μm. In the preparation method of the nano-grafted composite modifier of the present invention, the temperature during the melt extrusion stage in steps S300 and S400 is 160°C-200°C, matching the activation energy of the grafting reaction and improving the grafting rate. If the melt extrusion stage temperature is <160°C, the reaction rate is too low, resulting in a low grafting rate. If the melt extrusion stage temperature is >200°C, there is a risk of polymer degradation and a sudden change in the melt flow index. In the preparation method of the nano-grafted composite modifier of the present invention, the screw speed during the melt extrusion stage in steps S300 and S400 is 150rpm-300rpm, achieving a high shear rate to achieve sufficient mixing of the nanomaterial / polymer melt and interfacial reaction. The preparation method of the nano-grafted composite modifier described in the present invention solves the dispersion, compatibility and stability problems of nanomaterials in asphalt through the ultrasonic dispersion-melt grafting collaborative process, avoids the secondary agglomeration problem of the traditional step-by-step process, and improves the interfacial binding energy; high-temperature rutting resistance and low-temperature crack resistance are simultaneously improved, and the needle penetration ratio is increased after UV aging; thus, efficient and stable industrial production is achieved.

[0028] In this embodiment, the nanomaterial is selected from one or more of organic montmorillonite, nano silicon dioxide, and nano titanium dioxide.

[0029] Organic montmorillonite (OMMT), the local high temperature and high pressure generated by ultrasonic power (≥1000W) act on the organic montmorillonite interlayer, overcoming the van der Waals force, expanding the interlayer spacing of the organic montmorillonite, and forming nano-scale exfoliation layers; the oil component acts as a dispersion medium, and its lower molecular weight is easily inserted into the organic montmorillonite interlayer under the action of ultrasonic impact, thereby improving the affinity with the oil component; the surface modifier can absorb the exposed hydroxyl groups on the surface and bond to the OMMT surface through Si-O-Si, giving it active functional groups and improving the dispersion; during the melt extrusion stage (160-200℃), the grafting monomer reacts with the amino group (-NH2) or carbon double bond (C=C) on the montmorillonite surface through imidization, epoxy ring opening or free radical grafting to form amide bonds (-NH-CO-) or copolymeric carbon chains; the high speed of the screw (150-300 The shear force of 100 rpm orients the montmorillonite flakes along the flow direction, allowing the grafted chains to penetrate the interlamellar gaps, forming an interpenetrating "polymer-montmorillonite" network. Ultrasonic cavitation simultaneously exfoliates the montmorillonite and activates its surface active sites (such as hydroxyl and organic ammonium groups), improving the efficiency of the grafting reaction. The modified montmorillonite flakes dispersed in the oil fraction directly participate in the melt grafting reaction, avoiding the weak interfacial bonding problem encountered in traditional dry-process modification. The organic montmorillonite, through a synergistic ultrasonic dispersion-melt grafting process, achieves efficient exfoliation of the nanosheets and interfacial chemical bonding. The flake network restricts asphalt flow, while the grafted chains provide toughness and crack resistance. UV shielding and free radical capture synergistically delay aging.

[0030] Nano-silica and nano-titanium dioxide, ultrasonic power (≥1000W) generates cavitation bubble collapse shock waves and microjets, destroying the hydrogen bond aggregates of nano-SiO2; ultrasonic treatment in oil fraction promotes the condensation reaction between the hydroxyl group (-OH) on the surface of nano-SiO2 and the silane coupling agent (KH550, KH570), forming a hydrophobic surface and improving its dispersion stability in asphalt; in the melt extrusion stage (160-200℃), the grafted monomer undergoes esterification, imidization, free radical copolymerization and other reactions with the hydroxyl group, amino group and carbon double bond on the surface of nano-SiO2 to form strong cross-linking bonds , and can also (using KH570, with the participation of an initiator) combine with polymer backbone free radicals to construct a "nanoparticle-grafted chain-polymer matrix" trinity interface; the shear force of the high screw speed (150-300rpm) further refines the nano-SiO2 agglomerates and promotes the uniform distribution of the grafted chains in the polymer melt; ultrasonic treatment simultaneously achieves nano-SiO2 dispersion and surface coupling agent modification, which increases the density of active sites in the grafting reaction and the grafting rate; nano-SiO2 pre-dispersed in the oil fraction directly participates in the melt grafting reaction, improving the interfacial binding energy. Nano-silica achieves uniform dispersion of high-specific surface area nanoparticles and interfacial chemical bonding through the ultrasonic dispersion-melt grafting synergistic process; rigid particles hinder the flow of asphalt, and the grafted chains are toughened and crack-resistant; ultraviolet reflection and free radical capture synergistically resist aging.

[0031] In addition, nano-titanium dioxide also has ultraviolet inhibition ability. Through the ultrasonic dispersion-melt grafting collaborative process, nano-titanium dioxide has achieved dual breakthroughs in photoactivity regulation and interface strengthening, and the ultraviolet shielding rate and pollutant degradation rate have been improved; the rutting factor has been improved and the storage segregation rate has been reduced.

[0032] In this embodiment, the grafting monomer is selected from one or both of glycidyl methacrylate and maleic anhydride. By selecting glycidyl methacrylate (GMA) or maleic anhydride (MAH) as the grafting monomer and combining it with the ultrasonic dispersion-melt grafting synergistic process, the interfacial bonding, functionalization, and performance synergy of the nanografted composite modifier can be significantly optimized. GMA is used as a grafting monomer. The epoxy group of GMA undergoes a ring-opening reaction with the nanomaterial (the hydroxyl groups of the nanomaterial are exposed by ultrasonic treatment or the amino groups are imparted by KH-550 surface modification), thereby improving the interfacial bonding energy. The polarity of the epoxy group enhances the compatibility of the nanomaterial with asphaltene and inhibits segregation. The unreacted epoxy group of GMA can serve as a subsequent crosslinking site and further undergo a ring-opening reaction with the active groups of asphalt (such as phenolic hydroxyl groups and carboxyl groups), thereby improving the dispersion of the polymer and nanomaterial in the asphalt matrix and forming a more complex crosslinked interpenetrating network. As a grafting monomer, MAH's anhydride groups increase the polarity of the SBS macromolecules, strengthening the polarity of the asphalt molecules and the SBS macromolecules, making it easier for the overall structure to present a network cross-linking structure. At the same time, the two carboxylic acid groups formed by the MAH anhydride group can simultaneously connect the asphalt molecules and the coupling agent nano-inorganic particles, which also increases the possibility of forming an internal network structure. At the same time, grafting MAH can improve the thermal oxidation stability of SBS. This is due to the relative reduction of C=C double bonds and the content of active α-H in its phase position, which increases the onset temperature of oxidation and prolongs the oxidation induction period.

[0033] GMA was grafted onto SBS as follows:

[0034] MAH was grafted onto SBS as follows:

[0035] In this embodiment, the polymer is a styrene-butadiene-styrene block copolymer. By selecting styrene-butadiene-styrene block copolymer (SBS) as the polymer matrix and combining it with an ultrasonic dispersion-melt grafting synergistic process, its unique microstructure and performance advantages can be fully utilized to achieve high performance of the nano-grafted composite modifier. The styrene hard segment (PS) provides rigid support, restricts the high-temperature flow of asphalt, and improves rutting resistance. The butadiene soft segment (PB) imparts elasticity, absorbs stress, and enhances low-temperature crack resistance. The two-phase separation structure forms a physically cross-linked network, achieving "rigid and flexible" mechanical properties. The unsaturated double bonds (C=C) of the butadiene segment can undergo free radical grafting reactions with grafting monomers (such as maleic anhydride MAH) to form chemical bonds. The benzene ring structure provides thermal stability, adapting to the high-temperature melt extrusion process. Ultrasonic dispersion optimizes the SBS / nanomaterial interface. Ultrasonic cavitation exfoliates nanomaterial agglomerates (such as OMMT) while simultaneously shearing SBS molecular chains, exposing more double bond reactive sites. Ultrasonic treatment in oil fractions promotes physical adsorption (van der Waals forces) and pre-grafting reactions between SBS and nanomaterials. Melt grafting strengthens multiscale bonding and chemical bonding between SBS and nanomaterials. During melt extrusion, screw shear forces induce the distribution of nanomaterials along the SBS interface, aligning OMMT flakes parallel to the flow direction, and SiO2 / TiO2 filling the interstitial spaces between the PS-PB phases. The SBS physical network, enhanced nanomaterial rigidity, and grafted chain interface toughening synergistically enhance mechanical properties. The nanomaterial's UV shielding, the grafting agent's antioxidant properties, and the SBS's elastic cushioning synergistically enhance durability. The ultrasonic dispersion-melt grafting synergistic process, using SBS as the polymer matrix, achieves breakthrough performance improvements in nanografted composite modifiers through multiscale interface design and functional synergy. The synergistic effect between SBS and nanomaterials / grafting agents reduces material usage while maintaining compatibility with existing asphalt processing equipment.

[0036] In this embodiment, the surface treatment agent is a silane coupling agent, one of KH-550 and KH-570; and / or the cosolvent is cyclohexane oil. By selecting a silane coupling agent as the surface treatment agent and aromatic rubber oil as the cosolvent, combined with an ultrasonic dispersion-melt grafting synergistic process, the nanomaterial's dispersibility, interfacial bonding, and process stability can be significantly optimized. The siloxane groups (—Si—O—) of the silane coupling agent (e.g., KH550, KH570) condense with the surface hydroxyl groups (—OH) of the nanomaterial (e.g., nano-OMMT, nano-SiO2, nano-TiO2) to form Si—O—Si covalent bonds, reducing surface energy and enhancing hydrophobicity. The organic segments (e.g., amino groups, double bonds) of the silane chemically crosslink with asphalt molecules or GMA / MAH-grafted polymer monomers, further enhancing interfacial bonding energy. The absolute value of the zeta potential of the silane-modified nanomaterial in oil increases, inhibiting aggregation. The silane pre-activated surface provides more grafting sites, increasing the grafting rate; the silane layer blocks moisture and oxygen penetration, reducing the mass loss rate after UV aging. The low polarity of cycloalkane oil matches the hydrophobic end of silane, driving the silane molecules to form a dense monolayer arrangement on the surface of the nanomaterial, improving the interfacial binding energy; the flexible chain segments of cycloalkanes in cycloalkane oil are embedded in the silane network, forming a "elastic interfacial layer" that inhibits interfacial debonding caused by stress concentration; its low volatility ensures the integrity of the silane-nanomaterial bond during high-temperature extrusion, and the interfacial binding energy retention rate is increased after thermal oxidative aging; this system transforms the interfacial bonding between the nanofiller and the asphalt matrix from physical adsorption to chemical-mechanical interlocking through solvent-mediated interfacial topology reconstruction, achieving a synergistic leap in the toughness and durability of the composite material.

[0037] KH570 treats nano inorganic particles as follows:

[0038] KH550 treats nano inorganic particles as follows:

[0039] The nano-grafted composite modifier of this embodiment is prepared using the above-mentioned method for preparing the nano-grafted composite modifier.

[0040] The preparation method of the high-performance modified asphalt of this embodiment adopts the above-mentioned nano-grafted composite modifier, and includes the following steps: S500, high-speed shear blending the nano-grafted composite modifier with an ultraviolet absorber, a stabilizer and a molten matrix asphalt, the shear speed is 4000 rpm to 6000 rpm, and the mixing time is 30 minutes to 60 minutes; S600, the blended mixture prepared in S500 is subjected to performance development treatment to obtain a high-performance modified asphalt material. In step S500, high-speed shear blending at 4000-6000 rpm effectively breaks down residual agglomerates of the nanografted composite modifier (e.g., OMMT flakes and SiO2 / TiO2 particles), keeping the particle size within a specific range (e.g., 100-300 nm). Active groups of the grafting agent, such as anhydride and epoxy groups, chemically crosslink with the phenolic hydroxyl or carboxyl groups of the asphalt molecules, further enhancing interfacial bonding energy and improving the dispersibility of the polymer and nanomaterial. The UV absorber is evenly dispersed to form a molecular-level UV shielding layer, reducing the photooxidation rate of the asphalt. The stabilizer slows down thermal oxidative aging by capturing free radicals (e.g., quenching ·OH and ROO·). When using nano-OMMT, the uniformly distributed flake structure formed by the preparation process described herein inhibits oxygen infiltration and slows thermal oxidative aging. The molten asphalt system is optimized, and high-temperature shearing reduces the system viscosity, promoting physical and chemical reactions between the nanomaterial and the grafted segments or asphalt molecules, forming a physical-chemical crosslinked network. During the performance development process in step S600, the nanomaterials are aligned. During the development process, nanosheets (such as OMMT) are oriented along the stress relaxation direction, forming an ordered barrier network. Stabilizers and UV absorbers are evenly distributed through molecular diffusion, inhibiting macrophase separation between the modifier and the asphalt. The combination of high-speed shearing and development overcomes the dispersion-stabilization contradiction inherent in traditional step-by-step processes. Low-temperature treatment during the development phase reduces energy consumption compared to traditional high-temperature mixing. This method for preparing high-performance modified asphalt achieves uniform dispersion, interfacial strengthening, and long-term stabilization of the nanografted composite modifier, UV absorber, and stabilizer in the asphalt through the synergistic combination of high-speed shear blending and performance development.

[0041] In this embodiment, the performance development treatment in step S600 specifically includes: continuing to maintain the blended mixture prepared in S500 at 170°C to 180°C for performance development treatment, and continuously stirring for 20 minutes to 30 minutes, so that the nano-grafted composite modifier can further diffuse in the asphalt matrix and fully integrate with the matrix, ensuring that the composite structure of the nanomaterial and the polymer reaches the optimal distribution state in the asphalt system, so that the various properties of the prepared modified asphalt material can be fully improved and stabilized, and finally a high-performance modified asphalt material with excellent performance is obtained.

[0042] In this embodiment, the UV absorber is selected from at least one of nano-titanium dioxide and nano-zinc oxide; and / or the stabilizer is sulfur. In the nano-grafted composite modified asphalt, nano-titanium dioxide (TiO2) and nano-zinc oxide (ZnO) are selected as UV absorbers, and sulfur is used as a stabilizer to synergistically improve the material's anti-aging properties, durability, and chemical stability. Nano-titanium dioxide (TiO2) generates hydroxyl radicals (·OH) and superoxide radicals (·O2 - ), decomposing asphalt aging products (such as carbonyl compounds). Nano-zinc oxide (ZnO) nanoparticles capture photogenerated electron-hole pairs through surface defects, inhibiting photocatalytic side reactions. The synergistic effect of TiO2 and ZnO is that ZnO inhibits the photocatalytic activity of TiO2 (via an electron transfer mechanism), protecting asphalt components from degradation.

[0043] The high-performance modified asphalt of this embodiment is prepared using the above-mentioned method for preparing high-performance modified asphalt.

[0044] During implementation, a high-performance modified asphalt material and its preparation method are provided, specifically a preparation method based on the synergistic modification of nanomaterial ultrasonic dispersion and polymer grafting reaction extrusion technology, firstly, the nanomaterial and the surface treatment agent are ultrasonically dispersed in a cosolvent, and then melt-grafted with the grafting monomer and the polymer through a reaction extrusion device to prepare a nano-grafted composite modifier, which is then shear-mixed with the matrix asphalt, ultraviolet absorber and stabilizer at high speed, and subjected to performance development treatment, to finally prepare a high-performance modified asphalt. The present invention combines physical ultrasonic dispersion with chemical grafting reaction to achieve deep dispersion and long-term stability of nanomaterials in the asphalt system, significantly improving the high and low temperature performance, anti-ultraviolet aging performance and storage stability of the modified asphalt, and is suitable for road engineering applications under extreme environmental conditions such as severe cold and high ultraviolet. Specifically comprising the following steps: (1) Ultrasonic dispersion pretreatment of nanomaterials: Nanomaterials (such as organic montmorillonite, nanosilica, or nanotitanium dioxide) are added to a cosolvent (such as aromatic rubber oil) and subjected to high-power ultrasonic dispersion treatment at a temperature of 70°C to 90°C (with an ultrasonic power of at least 1000W for 30 to 40 minutes) to form a uniformly distributed emulsion. The emulsion is then modified with a surface treatment agent. The temperature is maintained at 70°C to 90°C, and the ultrasonic power is ≥1000W for 60 to 90 minutes to prepare a uniform and stable nanomaterial suspension dispersion system. This effectively breaks down the initial agglomeration structure of the nanoparticles, resulting in a highly dispersed nanosuspension system that provides excellent primary dispersion for subsequent reactions.

[0045] (2) Polymer grafting reaction extrusion modification: The grafting monomer (such as glycidyl methacrylate (GMA) or maleic anhydride (MAH)) and the polymer (such as SBS elastomer) are premixed in proportion and then fed into a twin-screw reaction extruder for melt grafting reaction. The reaction temperature is controlled at 160°C to 200°C, the screw speed is controlled at 150rpm to 300rpm, and the extrusion reaction time is 3 minutes to 8 minutes. The primary extruded material is then mixed at high speed with the nano-ultrasonic dispersion slurry obtained in step (1) and then extruded for a second time. During the extrusion process, the grafting monomer is covalently bonded to the polymer chain segment and further anchored on the surface of the nanomaterial, significantly improving the interfacial bonding ability between the nanomaterial and the polymer. In addition, the high shear effect applied during the extrusion process also achieves a secondary deep dispersion of the nanomaterial, further improving the uniform distribution and interfacial stability of the nanoparticles.

[0046] (3) High-speed shear blending of nano-grafted composite modifier and asphalt: The nano-grafted composite modifier prepared in step (2) is mixed with the pre-heated molten matrix asphalt (such as No. 70 asphalt), and an appropriate amount of ultraviolet absorber (such as nano titanium dioxide or zinc oxide) and stabilizer (such as sulfur) are added at the same time. The mixture is mixed using a high-speed shearing device at a speed of 4000 rpm to 6000 rpm. The shear mixing time is 30 minutes to 60 minutes, so that the composite modifier is fully and evenly dispersed in the asphalt matrix and a stable multi-phase composite system is formed.

[0047] (4) Performance development process of high-performance modified asphalt: The mixed system after high-speed shear blending is continued to be maintained at 170°C to 180°C for performance development treatment, and is continuously stirred for 20 to 30 minutes to allow the nano-grafted composite modifier to further diffuse in the asphalt matrix and fully integrate with the matrix, ensuring that the composite structure of the nanomaterial and the polymer reaches the optimal distribution state in the asphalt system, so that the various properties of the prepared modified asphalt material can be fully improved and stabilized, and finally a high-performance modified asphalt material with excellent performance is obtained.

[0048] The present invention uses ultrasonic dispersion and grafting reaction extrusion technology in synergy to innovatively achieve the "double dispersion" effect of nanomaterials, that is, primary ultrasonic physical dispersion and subsequent chemical-mechanical coupling secondary dispersion. Specifically, the first ultrasonic treatment significantly reduces the degree of agglomeration of nanomaterials, and the second grafting extrusion process uses mechanical shear and chemical reaction to further reduce the size of nanoparticles, enhance dispersion uniformity and interface stability, and ultimately construct a stable nanomaterial-polymer covalent network structure. This structure effectively improves the high and low temperature performance, resistance to ultraviolet aging and storage stability of modified asphalt materials, and is particularly suitable for road engineering applications under high-cold and strong ultraviolet environmental conditions. It has outstanding innovation and technical advantages in solving the problem of nanomaterial dispersion, optimizing the interface structure of modifiers and improving the performance of asphalt materials, and can effectively meet the comprehensive performance requirements of high-performance asphalt materials in the field of road engineering.

[0049] The present invention achieves primary dispersion of nanomaterials through ultrasonic treatment, breaks up agglomerate structures, and increases the specific surface area of materials; during the grafting extrusion process, the grafting reaction not only achieves chemical bonding, but also further promotes the "redispersion" of nanomaterials due to shear and hot melting, thereby constructing a stable interface structure; nanomaterials are evenly distributed in asphalt, enhancing barrier properties, reflectivity and anti-aging capabilities; the softening point of modified asphalt is significantly improved, low-temperature ductility is improved, and performance retention after aging is increased; the grafted composite modifier has good compatibility with asphalt and excellent storage stability, and is suitable for application in complex environments such as plateaus and severe cold; while achieving dispersion uniformity, the present invention establishes "structural locking" through grafting reactions.

[0050] Example 1 Weigh 100 parts of matrix asphalt (70#), 3 parts of organic montmorillonite, 0.3 parts of silane coupling agent KH-550 or KH-570 as surface treatment agent, 15 parts of cyclohexane oil, 10 parts of SBS polymer, 1 part of grafting monomer GMA (glycidyl methacrylate) or MAH (maleic anhydride), 1 part of nano-TiO2 (UV absorber), and 0.8 parts of sulfur (stabilizer).

[0051] First, the organic montmorillonite was mixed with naphthenic oil and ultrasonically dispersed at 80°C for 40 minutes (power 1200W) to obtain a uniformly distributed emulsion. The obtained emulsion was then mixed with a silane coupling agent and ultrasonically dispersed at 80°C for another 90 minutes (power 1200W) to prepare a uniform and stable nano-dispersed slurry. After SBS and the grafting monomer are homogenized at high speed, they are melt-grafted through a twin-screw extruder. The extruder barrel includes a feed section, an initial feed section, and seven intermediate sections. The temperatures of each section are: 170°C, 175°C, 175°C, 175°C, 175°C, 175°C, 180°C, 185°C, and 190°C, and the screw speed is 200 rpm. Then, the above materials were premixed evenly with the nano-dispersed slurry, and then melt grafted by a twin-screw reaction extruder. The temperatures of each section of the extruder were 170° C., 175° C., 175° C., 175° C., 175° C., 175° C., 175° C., 180° C., and 180° C. from the feed end to the discharge end, and the screw speed was 170 rpm to obtain a nano-grafted composite modifier. ① KH550 plus GMA. The epoxy groups in GMA can be opened by the amino groups to form β-hydroxyamine bonds, which crosslink the montmorillonite with the SBS chains (1). In addition, GMA grafted SBS can also crosslink with asphalt molecules (2). The amino groups on the surface of KH550-treated nanomaterials can also crosslink with asphalt molecules to form amide bonds or imine bonds (3). The details are as follows: (1) (2) (3) ②KH-550 (γ-aminopropyltriethoxysilane) + MAH (maleic anhydride): After hydrolysis, KH-550 can bond with the hydroxyl groups on the surface of montmorillonite, leaving the terminal amino group (-NH2) fixed on the surface of nano-montmorillonite. After MAH is grafted onto SBS, the anhydride ring and the amino group open to form an amide / imide structure, achieving covalent cross-linking (4). At the same time, MAH-grafted SBS can also cross-link with asphalt molecules (5), and the amino groups on the surface of KH550-treated nanomaterials can also cross-link with asphalt molecules to form amide bonds or imide bonds (6). The details are as follows: (4) (5) (6) ③KH-570 + GMA: The double bonds of GMA copolymerize with the double bonds on the surface of SBS and KH-570 to form a bridging structure (7), and the epoxy groups can participate in further cross-linking in the asphalt (8). The details are as follows: (7) (8) ④KH-570 + MAH: (SBS-g-MAH), (KH570-nanomaterial) MAH is difficult to copolymerize with the methacryloyl group in KH-570, but under the action of residual initiator, KH-570 can crosslink with SBS through free radical polymerization like GMA (9). MAH-g-SBS that does not participate in secondary crosslinking can react with asphalt or have a weak polar effect (10). The details are as follows: (9) (10) The obtained modifier is mixed with pre-heated melted asphalt, and nano-TiO2 and sulfur are added. It is shear-mixed at 170°C and 5000 rpm for 45 minutes. Then, the temperature is maintained at 170°C and stirring is continued for 30 minutes to develop the properties, so that the modifier is fully stabilized and evenly distributed in the asphalt matrix, and finally high-performance modified asphalt with excellent performance is prepared.

[0052] Example 2 The steps are the same as those in Example 1, except that nano-SiO2 is used instead of organic montmorillonite.

[0053] Example 3 The steps are the same as those in Example 1, but nano-TiO2 is used instead of organic montmorillonite.

[0054] The following comparative examples are used to clarify the effect of the synergistic mechanism of "nano-ultrasonic dispersion + polymer grafting reaction extrusion" on the modification of the present invention: Comparative Example 1 (traditional physical blending, no ultrasound, no grafting) All the raw materials in Example 1 were directly added to a molten asphalt matrix (170°C). No ultrasonic treatment or grafting extrusion was performed. Instead, the modified asphalt was subjected to high-speed shearing at 5000 rpm for 60 minutes and performance development for 30 minutes. The resulting softening point was 69.8°C, the ductility at 5°C was only 14.7 cm, and the ductility decreased by a whopping 38.6% after aging. The storage stability difference reached 5.6°C, indicating poor performance.

[0055] Comparative Example 2 (ultrasound only, no grafting extrusion) The nanomaterials in Example 1 were subjected to ultrasonic dispersion treatment but were not grafted and extruded. The ultrasonic slurry was directly mixed with the other materials in Example 1 in asphalt and then subjected to high-speed shearing and performance development conditions similar to those in Example 1.

[0056] Comparative Example 3 (graft extrusion only, no ultrasonic dispersion) The nanomaterials in Example 1 were not ultrasonically dispersed, and the other components in Example 1 were directly melt-grafted and extruded, and then blended with asphalt. Other process conditions were the same as in Example 1.

[0057] Comparative Example 4 (ultrasound and grafting were performed separately without co-extrusion) The nanomaterials were first ultrasonically dispersed, and then melt-extruded with the other components in Example 1 to prepare a grafted polymer. Finally, the two were added to the asphalt and mixed without extrusion grafting together. The other process conditions were the same as in Example 1.

[0058] The modified asphalts produced in the above examples and comparative examples were tested for performance according to the "Testing Procedures for Asphalt and Asphalt Mixtures for Highway Engineering" (JTG E20-2011), including high-temperature softening point (T 0606-2011), low-temperature ductility (T 0605-2011), and storage stability of polymer-modified asphalt (T 0661-2011). UV aging was conducted according to ASTM D4799 / D4799M, with experimental conditions based on existing literature on UV simulation of asphalt in Tibetan areas. Specifically, the UV aging test chamber was equipped with six 40W high-pressure mercury lamps with a wavelength of 320nm. The distance between the asphalt sample and the lamps was controlled at 300mm, and UV aging simulation was conducted at 60°C for six days. Finally, residual penetration was tested (JTG E20-2011 T0604-2011). A comparison of the performance tests for each sample is shown in Table 1. Table 1 Performance test data of different embodiments and comparative examples

[0059] The above results fully demonstrate that the synergistic technology of ultrasonic dispersion of nanomaterials and polymer grafting reactive extrusion of the present invention significantly improves the dispersion uniformity and interfacial stability of nanomaterials in asphalt, thereby greatly improving the high and low temperature performance, anti-ultraviolet aging ability and long-term storage stability of modified asphalt, and is particularly suitable for use in road projects in severely cold and strong ultraviolet environment areas.

[0060] The reasons for the differences in various performance indicators are analyzed as follows: 1. From the performance of Examples 1-3, it can be seen that Example 1 is superior to Examples 2-3 in terms of softening point, i.e., high-temperature stability of modified asphalt. This is because the nanomaterial in Example 1 uses organic montmorillonite, which has a typical layered silicate structure. After ultrasonic pretreatment, the interlayer structure is optimized, including: the interlayer spacing is expanded and the interlayer peeling degree is increased. In addition, Example 1 is second only to Example 2 in terms of anti-ultraviolet aging performance. It can be concluded that the organic montmorillonite in this example not only serves as an anchor point for polymer grafting modification, but also the intercalation and peeling structure after ultrasonic optimization further enhances its role in limiting the movement and penetration of polymers and oxygen, thereby improving high-temperature stability and anti-ultraviolet aging performance.

[0061] 2. In the present invention, each Example and Comparative Example contains secondary cases regarding different combinations of silane coupling agents / chemical grafting agents, distinguished by ①, ②, ③, and ④. As can be seen from Examples 1-3, ③ exhibits superior high-temperature stability, UV aging resistance, and storage stability. Components ①, ②, ③, and ④ were analyzed separately: ① is characterized by KH-550 + GMA. In this combination, KH-550 undergoes an epoxy ring-opening reaction with GMA, which renders GMA incapable of crosslinking with asphalt. ② is characterized by KH-550 + MAH, but the amino group readily reacts with the anhydride ring, resulting in a poorer grafting effect compared to ①. ③ is characterized by KH-570 + GMA. In this combination, KH-570 and GMA do not react with each other, but both KH-570 and GMA undergo a polymerization grafting reaction with SBS under the action of an initiator, forming a complex crosslinking system. ④ is characterized by KH-570 + MAH. These two components do not react with each other, but compared to ③, the MAH backbone is shorter, relying on ester bonds for crosslinking. This reduces the molecular distance between asphalt and SBS, increases the molecular interaction, and negatively impacts the low-temperature rheological properties of the modified asphalt. Due to the high degree of crosslinking, ③ and ④ exhibit inferior low-temperature rheological properties to ① and ②.

[0062] 3. According to the data analysis of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4, it can be seen that the comprehensive performance of Comparative Examples 1-4 is worse than that of Example 1. Through analysis, we can find that ①, ②, ③, and ④ in Comparative Examples 1-4 reflect different rules compared with Example 1.

[0063] (1) Comparative Examples 1-2 are characterized by not using a melt grafting process. The difference between the two lies in whether the nanomaterials are ultrasonically pretreated. Compared with Example 1, in terms of high-temperature stability, due to the lack of melt grafting treatment, a large amount of free KH-550 reacts with GMA and MAH, resulting in a large consumption, which cannot play the role of chemical cross-linking in improving the rheological properties and storage stability of asphalt. In particular, after ultrasonic treatment, the organic montmorillonite and SBS are severely agglomerated and poorly dispersed, resulting in poor high and low temperature rheological properties, UV aging resistance, and storage stability.

[0064] (2) In Comparative Examples 3-4, the characteristics are that they have all been melt-grafted, and the difference lies in whether the organic montmorillonite has been ultrasonically pretreated. Unlike Comparative Examples 1-2, the residual GMA and MAH after melt grafting are less, and the SBS is well dispersed. At the same time, after melt grafting, a stable network structure can be formed to improve the high and low temperature rheological properties and storage stability of asphalt, and reduce the sensitivity to ultraviolet radiation. Compared with Example 1, the nanomaterial in Comparative Example 3 has not been ultrasonically treated, and the content of free silane coupling agent is high. At the same time, the nanomaterial has natural agglomeration, and the asphalt modification efficiency is not as good as that of Example 1. The nanomaterial in Comparative Example 4 has not been melt-extruded, and is only secondary dispersed during the asphalt preparation process. At the same time, the "vacuum reactor" effect of melt extrusion is lacking, and the three-phase cross-linking system of organic montmorillonite, SBS, and asphalt is not fully formed.

[0065] Matters not covered by the present invention are known technologies.

[0066] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0067] The above-described embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that a person skilled in the art would be able to make numerous modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

[0068] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a nano-grafted composite modifier, characterized in that: The following steps are involved: S100, using ultrasonic equipment to disperse the nanomaterial in the cosolvent, maintaining the temperature at 70°C to 90°C, and performing ultrasonic dispersion treatment in the oil using the ultrasonic equipment, with an ultrasonic power of ≥1000W and an ultrasonic time of 30 minutes to 40 minutes, to form a uniformly distributed emulsion; The nanomaterial is selected from one or more of organic montmorillonite, nano silicon dioxide, and nano titanium dioxide; S200, modifying the emulsion with a surface treatment agent, maintaining the temperature at 70°C to 90°C, ultrasonic power ≥ 1000W, and ultrasonic time for 60 minutes to 90 minutes to form a uniform and stable nanomaterial dispersion slurry; The surface treatment agent is KH-550 or KH-570; S300, the grafting monomer and the polymer are uniformly mixed at high speed, and then fed into a twin-screw extruder for melt extrusion, the reaction temperature is 160° C. to 200° C., and the screw speed is 150 rpm to 300 rpm to obtain polymer grafted particles; The grafting monomer is selected from one or both of glycidyl methacrylate and maleic anhydride; The polymer is a styrene-butadiene-styrene block copolymer; S400, the nano material dispersion slurry and the polymer grafted particles are uniformly mixed at high speed, and then fed into a twin-screw extruder for melt extrusion to obtain a nano-grafted composite modifier.

2. The preparation method of the nano-grafted composite modifier according to claim 1, characterized in that: The cosolvent is naphthenic oil.

3. A nano-grafted composite modifier, characterized in that: The nano-grafted composite modifier is prepared by the preparation method of the nano-grafted composite modifier according to claim 1 or 2.

4. A method for preparing high-performance modified asphalt, using the nano-grafted composite modifier according to claim 3, characterized in that: The following steps are involved: S500, high-speed shear blending of the nano-grafted composite modifier, an ultraviolet absorber, a stabilizer, a rubber oil with aromatic hydrocarbons as the main component, and a molten matrix asphalt, with a shear speed of 4000 rpm to 6000 rpm and a mixing time of 30 minutes to 60 minutes; S600: performing a performance development treatment on the blended mixture prepared in S500 to prepare a high-performance modified asphalt material.

5. The method for preparing high-performance modified asphalt according to claim 4, characterized in that: The performance development process in step S600 specifically includes: The blended mixture prepared in S500 is continued to be maintained at 170°C to 180°C for performance development treatment, and is continuously stirred for 20 to 30 minutes to allow the nano-grafted composite modifier to diffuse in the asphalt matrix and fully integrate with the matrix, ensuring that the composite structure of the nanomaterial and the polymer reaches the optimal distribution state in the asphalt system, so that the various properties of the prepared modified asphalt material can be fully improved and stabilized, and ultimately a high-performance modified asphalt material with excellent performance is obtained.

6. The method for preparing high-performance modified asphalt according to claim 4 or 5, characterized in that: The ultraviolet absorber is selected from at least one of nano titanium dioxide and nano zinc oxide; and the stabilizer is sulfur.

7. A high performance modified asphalt, characterized in that: The high-performance modified asphalt is prepared by the preparation method of any one of claims 4 to 6.

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