Preparation method of antioxidant intercalated hydrotalcite modified asphalt

Abstract

The application discloses a preparation method of an antioxidant intercalated hydrotalcite modified asphalt, and the method comprises the following steps: dissolving the antioxidant in an organic solvent, mixing the organic solvent with a NaOH solution, and heating the mixture to 65-70 DEG C and refluxing for 24-48 hours; adding hydrochloric acid to neutralize the excessive NaOH and filtering; and crystallizing the filtered product after washing to obtain Na + Anchoring type antioxidant; Mg(NO3)2·6H2O and Al(NO3)3·9H2O are dissolved in ultrapure water, the antioxidant Na + is added, and stirring and dissolving are carried out; the temperature is increased to 90-110 DEG C, NaOH is added dropwise, and crystallization reaction is carried out for 24-72 hours; the antioxidant intercalated hydrotalcite is obtained through filtering, washing and drying; and the antioxidant intercalated hydrotalcite is mixed with asphalt to obtain the product through high-speed shearing; the one-step synthesis of the OLDHs avoids the complicated process of inserting the antioxidant into the hydrotalcite after the synthesis of the hydrotalcite and the influence of the properties of the hydrotalcite on the anti-aging effect of the OLDHs; the Na + Anchoring type antioxidant has excellent water solubility and affinity with the hydrotalcite, the Na + of the antioxidant can form an ionic bond with the interlayer anion to be stably anchored in the interlayer of the magnesium-aluminum hydrotalcite, and the stability of the general antioxidant intercalated hydrotalcite is improved.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to a method for preparing antioxidant-intercalated hydrotalcite-modified asphalt. Background Technology

[0002] Hydrotalcite (LDHs) is a layered inorganic functional material. As a bimetallic hydroxide with a layered structure, it possesses multiple functions such as flame retardancy, modification, adsorption, and anti-oxidation, and is widely used in industries such as plastics, rubber, coatings, and papermaking. As a novel anti-aging agent, hydrotalcite can effectively shield ultraviolet radiation and has shown significant advantages in improving the UV aging resistance of asphalt. However, its effect on the mixing and construction of asphalt concrete and on the thermo-oxidative aging problems during service is minimal.

[0003] Studies have shown that antioxidant-intercalated hydrotalcite (LDH) prepared by intercalating antioxidants into the LDH interlayer possesses both free radical scavenging and UV shielding capabilities, potentially improving the resistance of asphalt to thermo-oxidative aging and UV aging. However, the process of intercalating antioxidants after LDH synthesis is cumbersome, and the properties of LDHs themselves significantly affect the anti-aging effect of antioxidant-intercalated LDH. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a one-step synthesis method for antioxidant-intercalated layered double hydroxides (OLDHs). This method inserts antioxidants simultaneously with the synthesis of LDHs, avoiding the cumbersome process of inserting antioxidants after LDH synthesis and the influence of LDH's own properties on the anti-aging effect of LDHs. This not only improves the compatibility of LDH with asphalt, prevents the antioxidant from migrating to the asphalt surface, and avoids its decomposition and failure under ultraviolet light, but also enables structural regulation and agglomeration control of the antioxidant-intercalated LDH, further enhancing its anti-aging effect.

[0005] Meanwhile, further research by the inventors revealed that ordinary antioxidants intercalated into hydrotalcite also suffer from poor compatibility between the antioxidant and hydrotalcite, making it difficult to achieve uniform intercalation modification, causing the antioxidant to easily detach, and resulting in poor persistence. This invention provides a modified antioxidant with better water solubility and affinity for hydrotalcite, making the intercalation modification more uniform, and it can be stably anchored in the magnesium aluminum hydrotalcite interlayer by forming ionic bonds with interlayer anions.

[0006] A method for preparing antioxidant-intercalated hydrotalcite-modified asphalt includes the following steps:

[0007] (1) Dissolve the antioxidant in an organic solvent, mix it with NaOH solution, heat to 65-70℃ and reflux for 24-48 h; add hydrochloric acid dropwise to neutralize excess NaOH and filter; wash the filtered product and crystallize to obtain Na + - Anchored antioxidants;

[0008] (2) Dissolve Mg(NO3)2·6H2O and Al(NO3)3·9H2O in ultrapure water, and add the antioxidant-Na + Dissolve by stirring, heat to 90-110℃, add NaOH dropwise for crystallization reaction for 24-72 hours; after filtration, washing, and drying, obtain antioxidant intercalated hydrotalcite;

[0009] (3) After heating and dissolving the asphalt, add the antioxidant intercalated hydrotalcite and shear at high speed to obtain antioxidant intercalated hydrotalcite modified asphalt.

[0010] According to the above scheme, the antioxidant in step (1) is a water-soluble antioxidant.

[0011] In the optimized scheme, the antioxidant in step (1) is one of antioxidant 1222, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, and sodium β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0012] According to the above scheme, the organic solvent in step (1) is a small molecule alcohol.

[0013] According to the above scheme, the concentration of the NaOH solution in step (1) is 8-30 wt%.

[0014] According to the above scheme, in step (1), the filtered product is washed with n-heptane and then crystallized with water to obtain antioxidant-Na. + .

[0015] According to the above scheme, the molar ratio of Mg(NO3)2·6H2O and Al(NO3)3·9H2O in step (2) is (2~4):1.

[0016] According to the above scheme, in step (2), the antioxidant-Na + With Al 3+ The molar ratio is 1:1.

[0017] According to the above scheme, the asphalt heating temperature in step (3) is 140-150℃, the shearing speed is 2000-3000r / min, and the shearing time is 30-40min.

[0018] According to the above scheme, in step (3) by weight: 100 parts asphalt, and 2 to 4 parts of the antioxidant intercalated hydrotalcite.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] This invention provides a one-step synthesis of OLDHs, avoiding the cumbersome process of inserting antioxidants after LDH synthesis and the influence of the properties of LDHs themselves on the anti-aging effect of OLDHs.

[0021] By adjusting the synthesis parameters, the morphology, structure, and size of hydrotalcite can be controlled, reducing surface defects and agglomeration problems, and improving the storage stability of OLDHs modified asphalt.

[0022] Na + - Anchored antioxidants possess excellent water solubility and affinity for hydrotalcite, resulting in more uniform insertion and modification. The Na+ in the antioxidant... + It can form ionic bonds with interlayer anions and be stably anchored between magnesium aluminum layer double hydroxides, improving the stability of general antioxidant intercalated layer double hydroxides. Detailed Implementation

[0023] The following embodiments further illustrate the technical solution of the present invention, but are not intended to limit the scope of protection of the present invention.

[0024] A specific embodiment provides a method for preparing antioxidant-intercalated hydrotalcite-modified asphalt:

[0025] (1) Antioxidant hydrolysis: Dissolve the antioxidant in methanol and mix with an equal volume of NaOH solution. Heat the mixture to 65-70℃ under a nitrogen atmosphere and reflux for 24-48 hours. Then add hydrochloric acid to adjust the pH to about 7. Filter out the generated NaCl, wash with n-heptane, filter, and crystallize with water to obtain Na. + - Anchored antioxidants;

[0026] (2) Synthesis of antioxidant-intercalated hydrotalcite: Mg(NO3)2·6H2O and Al(NO3)3·9H2O were dissolved in ultrapure water, and hydrolyzed antioxidants were added. The mixture was stirred under a nitrogen atmosphere to completely dissolve the antioxidants. Then, NaOH was added dropwise to the mixed solution and the pH of the solution was adjusted to about 9 by rapid stirring. At the same time, the temperature was raised to 90-110℃ and the crystallization reaction was carried out for 24-72 hours. After filtration, circulating washing and vacuum drying, antioxidant-intercalated OLDHs were obtained.

[0027] (3) Preparation of aging resistant asphalt: Using a high-speed shearing machine, 100 parts by weight of asphalt and 2-4 parts by weight of antioxidant intercalated hydrotalcite are mixed evenly to obtain aging resistant asphalt.

[0028] Example 1

[0029] (1) Dissolve 10-14g of antioxidant 1222 in 20-40mL of methanol solvent, mix with an equal volume of NaOH solution, reflux the mixture under nitrogen atmosphere to dissolve, then add hydrochloric acid to adjust the pH to about 7, filter out the generated NaCl, add 10-20mL of n-heptane to wash and filter, and crystallize to obtain antioxidant 1222-Na + .

[0030] (2) Dissolve 4-6 g of Mg(NO3)2·6H2O and 2-3 g of Al(NO3)3·9H2O in 100-200 mL of ultrapure water, and add 50-100 mL of antioxidant 1222-Na. + The solution was stirred under a nitrogen atmosphere until completely dissolved. Then, NaOH was added dropwise to adjust the pH of the solution to around 9. After stirring rapidly for 1 hour, the mixture was transferred to a hydrothermal reactor at 100–120°C for crystallization for 8–10 hours. After filtration, circulating washing, and vacuum drying, antioxidant 1222-Na was obtained. + Intercalated hydrotalcite.

[0031] (3) Using a high-speed shearing machine, mix 100 parts of asphalt with 2-4 parts of antioxidant 1222-Na + The intercalated hydrotalcite is mixed evenly to obtain aging-resistant asphalt.

[0032] Comparative Example 1

[0033] (1) Dissolve 10-14g of antioxidant 1222 in 20-40mL of methanol solvent, mix with an equal volume of NaOH solution, reflux the mixture under nitrogen atmosphere to dissolve, then add hydrochloric acid to adjust the pH to about 7, filter out the generated NaCl, add 10-20mL of n-heptane to wash and filter, and crystallize to obtain antioxidant 1222-Na + .

[0034] (2) Dissolve 4–6 g of Mg(NO3)2·6H2O and 2–3 g of Al(NO3)3·9H2O in 100–200 mL of ultrapure water. Stir under a nitrogen atmosphere until completely dissolved. Then, add NaOH dropwise to the mixed solution to adjust the pH to about 9. After stirring rapidly for 1 hour, transfer the mixture to a hydrothermal reactor at 100–120 °C for crystallization for 8–10 hours. After filtration, circulating washing, and vacuum drying, obtain hydrotalcite. Then add 10–14 g of antioxidant 1222-Na + Mix 5-7g of hydrotalcite into 200-300mL of ultrapure water to allow the antioxidant to penetrate between the hydrotalcite layers.

[0035] (3) Using a high-speed shearing machine, mix 100 parts of asphalt with 2-4 parts of antioxidant 1222-Na + The intercalated hydrotalcite is mixed evenly to obtain aging-resistant asphalt.

[0036] Example 2:

[0037] (1) Dissolve 10–14 g of the antioxidant sodium β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate in 20–40 mL of methanol solvent, mix with an equal volume of high-concentration NaOH solution, reflux the mixture under a nitrogen atmosphere, then add hydrochloric acid to adjust the pH to about 7, filter out the generated NaCl, add 10–20 mL of n-heptane to wash and filter, and crystallize to obtain the antioxidant sodium β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate-Na + .

[0038] (2) Dissolve 4–6 g of Mg(NO3)2·6H2O and 2–3 g of Al(NO3)3·9H2O in 100–200 mL of ultrapure water, and add 100–150 mL of the antioxidant sodium β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate-Na + The solution was stirred under a nitrogen atmosphere until completely dissolved. Then, NaOH was added dropwise to adjust the pH to approximately 9. After rapid stirring for 1 hour, the mixture was transferred to a hydrothermal reactor at 100–120°C for crystallization for 8–10 hours. After filtration, circulating washing, and vacuum drying, the antioxidant sodium β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate was obtained. + Intercalated hydrotalcite.

[0039] (3) Using a high-speed shearing machine, 100 parts of asphalt and 2-4 parts of antioxidant β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate sodium-Na + The intercalated hydrotalcite is mixed evenly to obtain aging-resistant asphalt.

[0040] Comparative Example 2:

[0041] (1) Dissolve 4-6g Mg(NO3)2·6H2O and 2-3g Al(NO3)3·9H2O in 100-200mL of ultrapure water, add 100-150mL of antioxidant sodium β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, stir under nitrogen atmosphere until completely dissolved, then add NaOH dropwise to the mixed solution to adjust the pH of the solution to about 10, stir rapidly for 1 hour, then transfer the mixed system to a hydrothermal reactor at 110-130℃ for crystallization for 6-8 hours, filter, wash in circulation, and dry under vacuum to obtain the one-step synthesized antioxidant sodium β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate intercalated hydrotalcite.

[0042] (2) Using a high-speed shearing machine, 100 parts of asphalt and 2 to 4 parts of one-step synthesized antioxidant β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate sodium intercalated hydrotalcite are mixed evenly to obtain aging-resistant asphalt.

[0043] Example 3:

[0044] (1) Dissolve 10–14 g of antioxidant β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid in 20–40 mL of methanol solvent, mix with an equal volume of high-concentration NaOH solution, reflux the mixture under a nitrogen atmosphere, then add hydrochloric acid to adjust the pH to about 7, filter out the generated NaCl, add 10–20 mL of n-heptane to wash and filter, and crystallize to obtain antioxidant β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid-Na + .

[0045] (2) Dissolve 4–6 g of Mg(NO3)2·6H2O and 2–3 g of Al(NO3)3·9H2O in 100–200 mL of ultrapure water, and add 100–150 mL of hydrolyzed antioxidant β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid-Na. + The solution was stirred under a nitrogen atmosphere until completely dissolved. Then, NaOH was added dropwise to adjust the pH to approximately 9. After rapid stirring for 1 hour, the mixture was transferred to a hydrothermal reactor at 100–120°C for crystallization for 8–10 hours. After filtration, circulating washing, and vacuum drying, the antioxidant β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid-Na was obtained. + Intercalated hydrotalcite.

[0046] (3) Using a high-speed shearing machine, 100 parts of asphalt and 2-4 parts of antioxidant β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid-Na + The intercalated hydrotalcite is mixed evenly to obtain aging-resistant asphalt.

[0047] The performance characterization of the aging-resistant asphalt prepared in the above embodiments and comparative examples is shown in Table 1.

[0048] Table 1

[0049]

[0050] A comparison between Example 1 and Comparative Example 1 shows that, using the same antioxidant, the antioxidant 1222-Na synthesized in the one-step method in Example 1... + The intercalated hydrotalcite showed better results compared to the scheme in Comparative Example 1.

[0051] As can be seen from the schemes of Example 2 and Comparative Example 2, when a one-step intercalation method is used simultaneously, the antioxidant sodium β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate-Na prepared in Example 2... + The antioxidant sodium β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate used in Comparative Example 2 showed better results.

Claims

1. A method for improving the anti-aging properties of antioxidant-intercalated hydrotalcite-modified asphalt, characterized in that... Includes the following steps: (1) Dissolve the antioxidant in an organic solvent, mix it with NaOH solution, heat to 65-70℃ and reflux for 24-48 h; add hydrochloric acid dropwise to neutralize excess NaOH and filter. After washing the filtered product, crystallize to obtain antioxidant-Na + The antioxidant is one of antioxidant 1222, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, and sodium β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. (2) Dissolve Mg(NO3)2·6H2O and Al(NO3)3·9H2O in ultrapure water, and add the antioxidant-Na + Dissolve by stirring, heat to 90-110℃, add NaOH dropwise for crystallization reaction for 24-72 hours; after filtration, washing, and drying, obtain antioxidant intercalated hydrotalcite; the molar ratio of Mg(NO3)2·6H2O and Al(NO3)3·9H2O is (2-4):1; antioxidant-Na + With Al 3+ The molar ratio is 1:1; (3) After heating and dissolving the asphalt, add the antioxidant intercalated hydrotalcite and shear at high speed to obtain antioxidant intercalated hydrotalcite modified asphalt.

2. The method for improving the anti-aging properties of antioxidant-intercalated hydrotalcite-modified asphalt as described in claim 1, characterized in that... The organic solvent in step (1) is a small molecule alcohol.

3. The method for improving the anti-aging properties of antioxidant-intercalated hydrotalcite-modified asphalt as described in claim 1, characterized in that... The concentration of the NaOH solution in step (1) is 8-30 wt%.

4. The method for improving the anti-aging properties of antioxidant-intercalated hydrotalcite-modified asphalt as described in claim 1, characterized in that... Step (1) The filtered product was washed with n-heptane and crystallized with water to obtain antioxidant-Na. + .

5. The method for improving the anti-aging properties of antioxidant-intercalated hydrotalcite-modified asphalt as described in claim 1, characterized in that... Step (3) The asphalt heating temperature is 140-150 ℃, the shearing speed is 2000-3000 r / min, and the shearing time is 30-40 min.

6. The method for improving the anti-aging properties of antioxidant-intercalated hydrotalcite-modified asphalt as described in claim 1, characterized in that... In step (3), by weight: 100 parts asphalt and 2-4 parts of the antioxidant intercalated hydrotalcite.

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