Preparation method of epoxy resin modified asphalt based on DA reaction self-healing

Abstract

The invention discloses a preparation method of epoxy resin modified asphalt based on DA reaction self-healing, and belongs to the technical field of high polymer materials. The method comprises the following steps: reacting epoxy resin with furfuryl amine in a solvent to generate a linear prepolymer, then carrying out a DA reversible reaction on the linear prepolymer and a bismaleimide compound to form a self-healing epoxy resin solution, and finally mixing the self-healing epoxy resin solution with matrix asphalt to prepare the modified asphalt. Key process parameters include that the molar ratio of the epoxy resin to the furfuryl amine is (1-2): (2-3), the reaction temperature is 30-90 DEG C, and the doping amount of the self-healing epoxy resin is 20-70wt%. The prepared modified asphalt has high strength (the tensile strength is greater than or equal to 6MPa) and self-healing performance (the highest self-healing rate within one hour is 56.4%) through a DA dynamic cross-linked network, different road requirements can be flexibly met by adjusting the mixing amount of the resin, and the service life of a road surface is prolonged. The defect that traditional thermosetting resin modified asphalt has no self-healing ability is overcome, and a new scheme is provided for an intelligent long-service-life pavement material.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a method for preparing self-healing epoxy resin modified asphalt based on DA reaction. Background Art

[0002] Asphalt pavement has become the most widely used advanced pavement form in road engineering due to its advantages such as smoothness, wear resistance, and convenient construction. However, with the increasing traffic load and the impact of climate change, asphalt pavement inevitably develops cracks, rutting and other damage during service, resulting in a shortened service life. Although traditional thermosetting resin-modified asphalt (such as epoxy resin-modified asphalt) can improve mechanical strength and temperature stability through the polymer network, its highly cross-linked irreversible chemical network has fundamental defects:

[0003] 1. Lack of self-healing ability: Thermosetting resin networks cannot melt at high temperatures and cannot dissolve at room temperature, resulting in the inability of microcracks in the road surface to repair themselves through external stimuli (such as temperature changes). The damage will continue to expand until the structure fails.

[0004] 2. Significant brittleness: The three-dimensional rigid network limits the deformation capacity of the asphalt matrix, making the modified asphalt poor in impact resistance and prone to cracking due to sudden changes in load.

[0005] 3. Insufficient performance adjustability: Traditional modification processes are difficult to balance mechanical strength and self-healing properties. Functional improvements require complex formula design or the addition of additional healing agents. The process is costly and has limited effects.

[0006] In existing technologies, some studies have attempted to enhance the self-healing ability of materials by introducing reversible chemical bonds. However, applying this mechanism to epoxy resin-modified asphalt still faces the following challenges:

[0007] 1. The contradiction between reversible bond stability and mechanical properties: Conventional reversible bonds (such as dynamic covalent bonds) are easily broken under high temperature or load, resulting in a significant decrease in the mechanical strength of modified asphalt;

[0008] 2. Interface compatibility issues: The introduction of reversible groups may destroy the compatibility between epoxy resin and asphalt, causing phase separation and affecting the overall performance of the material.

[0009] The technical breakthrough of the present invention:

[0010] To address the above difficulties, the present invention innovatively introduces the reversible DA (Diels-Alder) reaction into the epoxy resin molecular design, and constructs a dynamically cross-linked self-healing epoxy resin network through the thermally reversible addition-decomposition reaction of furan groups and maleimide groups.

[0011] The essential difference from existing technologies:

[0012] Existing thermosetting resin modified asphalt relies on irreversible chemical cross-linking, while the present invention constructs a dynamic reversible cross-linking network through DA reaction, breaking through the "strength-self-healing" contradiction of traditional materials at the molecular structure level, and providing a new technical path for the design of long-life self-repairing pavement materials.

[0013] Therefore, it is necessary to provide a preparation method of self-healing epoxy resin modified asphalt based on DA reaction to solve the above problems. Summary of the Invention

[0014] In view of the shortcomings of the existing technology, the purpose of the embodiments of the present invention is to provide a preparation method of self-healing epoxy resin modified asphalt based on DA reaction, so as to solve the problem that the epoxy resin modified asphalt network in the above background technology does not have self-healing properties.

[0015] To achieve the above object, the present invention provides the following technical solutions:

[0016] A method for preparing self-healing epoxy resin modified asphalt based on DA reaction, characterized by comprising the following steps:

[0017] Step S1, adding epoxy resin and furfurylamine in a molar ratio of 1-2:2-3 into a three-necked flask containing dimethylformamide or dimethylacetamide;

[0018] Step S2, stirring at 300 r / min, heating to 30-90° C., reacting for 4-12 hours to obtain a linear prepolymer;

[0019] Step S3, adding 1.5-3.0 g of bismaleimide diphenylmethane or bismaleimide diphenyl ether to a beaker, and adding 10-30 mL of dimethylformamide (DMF), and stirring the bismaleimide diphenylmethane or bismaleimide diphenyl ether at 30-90° C. until dissolved;

[0020] Step S4: dripping the solution in the beaker into a three-necked flask, and reacting with the prepolymer at a constant temperature of 30-90° C. for 10-60 minutes to obtain a self-healing epoxy resin solution;

[0021] Step S5, pouring the self-healing epoxy resin solution obtained by the reaction into a mold, placing it in a 30-90° C. forced air oven for 72 hours to remove the solvent, and obtaining a polymer EP-DA;

[0022] Step S6: placing the matrix asphalt in an oven and heating it to 50-110° C., adding different mass fractions of self-healing epoxy resin solution, and stirring with a shearing machine at 5000 r / min for 10-60 min;

[0023] Step S7: The mixed modified asphalt is poured into a mold to be cooled, placed at room temperature for 24 hours, and then cured in an oven at 30-90° C. to obtain self-healing epoxy resin modified asphalt with different mass fractions.

[0024] Furthermore, the molar ratio of the epoxy resin to the furfurylamine in step S1 is 1:3.

[0025] Furthermore, the temperature in steps S2 and S3 is both 60° C., and the reaction time in step S2 is 8 hours.

[0026] Furthermore, the reaction temperature in step S4 is 60° C. and the reaction time is 30 min.

[0027] Furthermore, the mass fraction of the self-healing epoxy resin in step S6 ranges from 20 to 70 wt%, and is respectively 40 wt%, 45 wt%, 50 wt%, 55 wt%, and 60 wt%, preferably 45 wt%. By adjusting the resin dosage, the mechanical properties and self-healing ability of the modified asphalt can be flexibly adjusted.

[0028] Furthermore, the stirring time in step S6 is 10 minutes.

[0029] Furthermore, the cooling time in step S7 is 72 hours, and the oven temperature is 60°C.

[0030] In summary, the embodiments of the present invention have the following beneficial effects compared with the prior art:

[0031] 1. Utilizing the thermally reversible DA reaction between furan and maleimide groups, the cracks are self-healed. Experiments show that the self-healing rate reaches up to 56.4% within one hour, and the tensile strength recovers to 6.43 MPa after healing. Repeatable healing is possible, significantly slowing the spread of pavement damage.

[0032] 2. The dynamic network exhibits thermosetting high-strength characteristics at room temperature (tensile strength is above 8MPa when the dosage is 45wt%). At high temperatures, the DA bond reversibly fractures and absorbs energy, which improves toughness and significantly enhances impact resistance.

[0033] 3. By adjusting the resin content (20-70wt%), a precise balance between strength and self-healing efficiency can be achieved. Low content is suitable for lightly loaded pavements, medium content (45wt%) provides the best overall performance, and high content meets the needs of heavy-load traffic.

[0034] 4. The self-healing function is integrated into the molecular structure, eliminating the need for additional additives and allowing for recyclable solvents, in line with the concept of green materials. Compared to traditional processes, the modified asphalt produced by this invention can extend the service life of pavement by 30%-50%, significantly reducing maintenance costs, demonstrating both scientific value and promising engineering applications.

[0035] In order to more clearly illustrate the structural features and effects of the present invention, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a flow chart of the preparation method of self-healing epoxy resin modified asphalt based on DA reaction in the invention embodiment.

[0037] Figure 2 This is the fluorescence microscopy result of the self-healing epoxy resin modified asphalt based on DA reaction in the embodiment of the invention.

[0038] Figure 3 This is a graph showing the tensile strength and self-healing rate of the self-healing epoxy resin modified asphalt after healing based on DA reaction in the embodiment of the invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0040] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0041] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the field or according to the product instructions.

[0042] The technical solution of the present invention will be described in detail below with reference to the embodiments, but the protection scope is not limited thereto. The specific implementation of the present invention will be described in detail below with reference to the specific embodiments.

[0043] Example 1:

[0044] In this embodiment, see Figure 1 The method for preparing a self-healing epoxy resin modified asphalt based on DA reaction comprises the following steps:

[0045] Step 1: add epoxy resin and furfurylamine in a ratio of 1:3 into a three-necked flask containing dimethylformamide;

[0046] Step 2: stirring the solution in the three-necked flask at a speed of 300 r / min, slowly heating to 60° C., and reacting for 8 hours to obtain a linear prepolymer;

[0047] Step 3: Add 2.0 g of bismaleimide diphenylmethane to a beaker, add 30 mL of DMF, and stir at 60° C. until the bismaleimide diphenylmethane is fully dissolved;

[0048] Step 4: slowly add the solution in the beaker dropwise to the three-necked flask, and continue to react with the prepolymer at a constant temperature of 60° C. for 30 minutes to obtain a self-healing epoxy resin solution;

[0049] Step 5: Pour the self-healing epoxy resin solution obtained by the reaction into a special mold, place it in a blast oven at 60° C. for 72 hours to remove the solvent, and obtain the polymer EP-DA;

[0050] Step 6: Heat the matrix asphalt in an oven to 90-100°C, add self-healing epoxy resin solutions with mass fractions of 40wt%, 45wt%, 50wt%, 55wt%, and 60wt%, respectively, at this temperature, and stir at a speed of 5000r / min for ten minutes using a shearing machine;

[0051] Step 7: Pour the mixed modified asphalt into a mold, cool it, place it at room temperature for 24 hours, and then put it into a 60°C forced air oven for curing for 72 hours to obtain self-healing epoxy resin modified asphalt with different mass fractions.

[0052] In this embodiment, the self-healing epoxy resin modified asphalt produced based on the DA reaction comprises an internal epoxy resin network structure based on the furan-maleimide DA reaction as its backbone, with dispersed asphalt particles serving as the network filler. The three-dimensional self-healing epoxy resin network provides the modified asphalt with excellent mechanical strength and self-healing properties, ensuring the modified asphalt's mechanical strength and healing properties during use. The continuous resin phase structure, encapsulating the asphalt particles within the self-healing epoxy resin network, imparts enhanced mechanical strength and self-healing properties to the modified asphalt. By adjusting the self-healing epoxy resin dosage, self-healing epoxy resin modified asphalts with varying mechanical strength, self-healing properties, and toughness can be prepared to meet the paving requirements of various road surfaces. The solvent is dimethylformamide, and the modified asphalt exhibits optimal overall performance when the self-healing epoxy resin dosage is 45 wt% of the asphalt mass.

[0053] The self-healing epoxy resin modified asphalt based on DA reaction prepared in this example was observed by fluorescence microscopy to characterize its phase structure. Figure 2 As shown by Figure 2 It can be seen that when the EP-DA content is 40wt%, the asphalt phase and the EP-DA phase form an interpenetrating network structure, but the asphalt phase is still dominant. At this time, SEPA still exhibits some properties of thermoplastic asphalt, that is, it still has a certain fluidity at higher temperatures. When the EP-DA phase content reaches 45wt%, the resin phase forms a continuous three-dimensional network structure. The resin phase acts as a reinforcing phase and is distributed in the resin phase in the form of spherical particles. At this time, SEPA has thermosetting properties. As the resin content is further increased, the resin phase network structure is further improved and densified, which helps the modified asphalt to exert the physical and chemical properties of the resin phase.

[0054] The tensile healing test of the self-healing epoxy resin modified asphalt based on DA reaction prepared in this embodiment was carried out, and the results are as follows: Figure 3 As shown by Figure 3 It can be seen that thermosetting self-healing epoxy resin modified asphalt can heal after fracture, and temperature will affect the healing efficiency; in addition, healing basically occurs in the early stage of fracture, with the highest self-healing rate of 56.4% after healing for 1 hour, and the tensile strength after healing is 6.43 MPa.

[0055] Example 2:

[0056] In this embodiment, the preparation method of the self-healing epoxy resin modified asphalt based on DA reaction includes the following steps:

[0057] Step 1: Add epoxy resin and furfurylamine in a ratio of 1.1:3 into a three-necked flask containing dimethylformamide;

[0058] Step 2: stirring the solution in the three-necked flask at a speed of 300 r / min, slowly heating to 60° C., and reacting for 8 hours to obtain a linear prepolymer;

[0059] Step 3: Add 2.0 g of bismaleimide diphenylmethane to a beaker, add 30 mL of DMF, and stir at 60° C. until the bismaleimide diphenylmethane is fully dissolved;

[0060] Step 4: slowly add the solution in the beaker dropwise to the three-necked flask, and continue to react with the prepolymer at a constant temperature of 60° C. for 30 minutes to obtain a self-healing epoxy resin solution;

[0061] Step 5: Pour the self-healing epoxy resin solution obtained by the reaction into a special mold, place it in a blast oven at 60° C. for 72 hours to remove the solvent, and obtain the polymer EP-DA;

[0062] Step 6: Heat the matrix asphalt in an oven to 90-100°C, add 40 wt% of a self-healing epoxy resin solution at this temperature, and stir at a speed of 5000 r / min for ten minutes using a shearing machine;

[0063] Step 7: Pour the mixed modified asphalt into a mold, cool it, place it at room temperature for 24 hours, and then place it in a 60°C forced air oven for curing for 72 hours to obtain a self-healing epoxy resin modified asphalt.

[0064] In this embodiment, the DA reaction-based self-healing epoxy resin modified asphalt prepared in this embodiment was self-healed for 24 hours after being damaged, and its self-healing rate was 21.74%, and the tensile strength after healing was 2.13 MPa.

[0065] Example 3:

[0066] In one embodiment of the present invention, in step 1, epoxy resin and furfurylamine are added to a three-necked flask containing dimethylformamide in a ratio of 1.1:3;

[0067] Step 2: stirring the solution in the three-necked flask at a speed of 300 r / min, slowly heating to 60° C., and reacting for 8 hours to obtain a linear prepolymer;

[0068] Step 3: Add 2.0 g of bismaleimide diphenylmethane to a beaker, add 30 mL of DMF, and stir at 60° C. until the bismaleimide diphenylmethane is fully dissolved;

[0069] Step 4: slowly add the solution in the beaker dropwise to the three-necked flask, and continue to react with the prepolymer at a constant temperature of 60° C. for 30 minutes to obtain a self-healing epoxy resin solution;

[0070] Step 5: Pour the self-healing epoxy resin solution obtained by the reaction into a special mold, place it in a blast oven at 60° C. for 72 hours to remove the solvent, and obtain the polymer EP-DA;

[0071] Step 6: Heat the matrix asphalt in an oven to 90-100°C, add 45 wt% of a self-healing epoxy resin solution at this temperature, and stir at a speed of 5000 r / min for ten minutes using a shearing machine;

[0072] Step 7: Pour the mixed modified asphalt into a mold, cool it, place it at room temperature for 24 hours, and then place it in a 60°C forced air oven for curing for 72 hours to obtain a self-healing epoxy resin modified asphalt.

[0073] In this embodiment, the DA reaction-based self-healing epoxy resin modified asphalt prepared in this embodiment was self-healed for 1 hour after being damaged, and its self-healing rate was 42.71%, and the tensile strength after healing was 4.17 MPa.

[0074] In summary, the self-healing modified asphalt prepared by the present invention not only possesses a high-strength resin network structure compared to existing modified asphalt, but also innovatively introduces self-healing groups, giving the modified asphalt excellent self-healing properties and good toughness. This allows the self-healing modified asphalt to maintain excellent mechanical properties while also possessing self-healing properties, effectively healing microcracks in the pavement and, on a macro level, extending the service life of the pavement.

[0075] The present invention can adjust the ratio of polyepoxy resin to asphalt to flexibly prepare modified asphalt with different road performance and self-healing performance.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing self-healing epoxy resin modified asphalt based on DA reaction, characterized in that: The following steps are involved: Step S1, adding epoxy resin and furfurylamine in a molar ratio of 1-2:2-3 into a three-necked flask containing dimethylformamide or dimethylacetamide; Step S2, stirring at 300 r / min, heating to 30-90° C., reacting for 4-12 hours to obtain a linear prepolymer; Step S3, adding a certain amount of bismaleimide diphenylmethane or bismaleimide diphenyl ether to a beaker, and adding 10-30 mL of dimethylformamide (DMF), stirring the bismaleimide diphenylmethane or bismaleimide diphenyl ether at 30-90° C. until dissolved; Step S4: dripping the solution in the beaker into a three-necked flask, and reacting with the prepolymer at a constant temperature of 30-90° C. for 10-60 minutes to obtain a self-healing epoxy resin solution; Step S5, pouring the self-healing epoxy resin solution obtained by the reaction into a mold, placing it in a 30-90° C. forced air oven for 72 hours to remove the solvent, and obtaining a polymer EP-DA; Step S6: placing the matrix asphalt in an oven and heating it to 50-110° C., adding different mass fractions of self-healing epoxy resin solution, and stirring with a shearing machine at 5000 r / min for 10-60 min; Step S7: The mixed modified asphalt is poured into a mold to be cooled, placed at room temperature for 24 hours, and then cured in an oven at 30-90° C. to obtain self-healing epoxy resin modified asphalt with different mass fractions.

2. The method for preparing self-healing epoxy resin modified asphalt based on DA reaction according to claim 1, characterized in that: The molar ratio of the epoxy resin to furfurylamine in step S1 is 1:

3.

3. The method for preparing self-healing epoxy resin modified asphalt based on DA reaction according to claim 1, characterized in that: The temperature in steps S2 and S3 is both 60° C., and the reaction time in step S2 is 8 h.

4. The method for preparing self-healing epoxy resin modified asphalt based on DA reaction according to claim 1, characterized in that: The reaction temperature in step S4 is 60° C. and the reaction time is 30 min.

5. The method for preparing self-healing epoxy resin modified asphalt based on DA reaction according to claim 1, characterized in that: The mass fractions of the self-healing epoxy resin in step S6 are 40 wt %, 45 wt %, 50 wt %, 55 wt % and 60 wt % respectively.

6. The method for preparing self-healing epoxy resin modified asphalt based on DA reaction according to claim 1, characterized in that: The stirring time in step S6 is 10 minutes.

7. The method for preparing self-healing epoxy resin modified asphalt based on DA reaction according to claim 1, characterized in that: The cooling time in step S7 is 72 hours, and the oven temperature is 60°C.

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