Polymer cationic asphalt emulsifier as well as preparation method and application thereof

Abstract

The invention provides a polymer cationic asphalt emulsifier as well as a preparation method and application thereof. According to the preparation method of the polymer cationic asphalt emulsifier, three monomers including 9-octadecenoic acid methyl ester, maleic anhydride and p-vinyltoluene are utilized to react to obtain the polymer cationic asphalt emulsifier. Based on a free radical polymerization technology, various functional groups (long-chain alkyl, a methyl styrene chain, imidazoline and the like) are integrated into a single polymer skeleton, so that the interfacial activity of an emulsifier is expected to be improved, the stability and the use performance of emulsified asphalt are improved, high efficiency and economical efficiency are achieved, and the development trend of green road materials is met. Compared with a traditional asphalt emulsifier, the polymer cationic asphalt emulsifier has higher surface activity and excellent high and low temperature stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of asphalt emulsifier, in particular to a polymer cationic asphalt emulsifier and a preparation method and application thereof. BACKGROUND

[0002] The asphalt emulsifier is a key material for preparing emulsified asphalt, and its performance directly affects the storage stability, construction performance and road effect of the emulsified asphalt. The cationic asphalt emulsifier becomes the focus of current research and application due to its good adhesion, water damage resistance and compatibility with aggregate. The traditional cationic asphalt emulsifier has a simple molecular structure, and is difficult to form a dense adsorption layer at the asphalt-water interface, resulting in a large amount of emulsification required, and easy demulsification due to insufficient interface film strength, and easy particle aggregation or flocculation during storage. At the same time, the traditional emulsifier damages the low-temperature ductility of asphalt, so that the asphalt emulsion is difficult to meet the demand for high and low temperature performance. Many researchers try to improve the stability and performance of emulsified asphalt by compounding emulsifiers or polymer emulsions, but the compounded emulsifiers have problems such as poor compatibility between components and complex process, and the polymer modified emulsified asphalt has high cost and poor compatibility and stability.

[0003] At present, the asphalt emulsifier has insufficient surface activity and stability, and the low-temperature performance is difficult to meet the use requirements, and it is necessary to improve it. SUMMARY

[0004] Therefore, the present application provides a polymer cationic asphalt emulsifier and a preparation method and application thereof, to solve the problems of insufficient surface activity and stability of the asphalt emulsifier in the prior art, and difficult to meet the use requirements of low-temperature performance.

[0005] In order to solve the above problems, the present application adopts the following technical solutions:

[0006] In a first aspect, the present application provides a preparation method of a polymer cationic asphalt emulsifier, comprising the following steps:

[0007] S1, mixing part of 9-octadecenoic acid methyl ester, maleic anhydride and p-vinyl toluene to obtain a monomer mixture;

[0008] S2, mixing a chain initiator and a chain transfer agent with another part of 9-octadecenoic acid methyl ester to obtain a mixture;

[0009] S3, adding the mixture to the monomer mixture to obtain a polymer precursor;

[0010] S4, adding tetraethylenepentamine to the polymer precursor to obtain an amide intermediate;

[0011] S5, the intramolecular water molecule of the amidation intermediate is removed and imidazoline ring is generated, and the polymer cationic asphalt emulsifier is obtained.

[0012] Preferably, the chain initiator is cumene peroxide;

[0013] The chain transfer agent is 3-mercaptopropionic acid.

[0014] Preferably, a part of 9-octadecenoic acid methyl ester, maleic anhydride and p-vinyl toluene are mixed under inert atmosphere at 130-135℃ to obtain a monomer mixture.

[0015] Preferably, the mixture is added to the monomer mixture and reacted at 130-135℃ for 3-4h to obtain a polymer precursor.

[0016] Preferably, tetraethylenepentamine is added to the polymer precursor and reacted at 160-165℃ for 3-4h to obtain an amidation intermediate.

[0017] Preferably, the amidation intermediate is stirred at 220-225℃ for 3-4h to completely remove the intramolecular water molecule of the amidation intermediate and generate imidazoline ring, and the polymer cationic asphalt emulsifier is obtained.

[0018] Preferably, 9-octadecenoic acid methyl ester, maleic anhydride and p-vinyl toluene are weighed according to the molar ratio of 1.0:(0.7-1.3):(0.2-0.6);

[0019] 90-95% of 9-octadecenoic acid methyl ester, maleic anhydride and p-vinyl toluene are mixed to obtain a monomer mixture;

[0020] The chain initiator and the chain transfer agent are mixed with the rest of 9-octadecenoic acid methyl ester to obtain a mixture.

[0021] Preferably, the mass of the chain initiator is 0.2-0.3% of the sum of the masses of 9-octadecenoic acid methyl ester, maleic anhydride and p-vinyl toluene;

[0022] The mass of the chain transfer agent is 0.2-0.3% of the sum of the masses of 9-octadecenoic acid methyl ester, maleic anhydride and p-vinyl toluene;

[0023] The molar amount of the tetraethylenepentamine is (0.6-1.0):1.0 of the sum of the molar amounts of 9-octadecenoic acid methyl ester and maleic anhydride.

[0024] In the second aspect, the application further provides a polymer cationic asphalt emulsifier prepared by the preparation method.

[0025] In a third aspect, the application further provides the polymer cationic asphalt emulsifier prepared by the preparation method or the use of the polymer cationic asphalt emulsifier in preparing emulsified asphalt.

[0026] The polymer cationic asphalt emulsifier, the preparation method and the use thereof have the following beneficial effects compared with the prior art:

[0027] 1. The preparation method of the polymer cationic asphalt emulsifier utilizes three monomers, i.e., 9-octadecenoic acid methyl ester, maleic anhydride and p-vinyl toluene, to obtain the polymer cationic asphalt emulsifier. The free radical polymerization technology is used to integrate various functional groups (long-chain alkyl, methyl styrene chain, imidazoline, etc.) in a single polymer skeleton, which is expected to improve the interfacial activity of the emulsifier, improve the stability and use performance of the emulsified asphalt, and has high efficiency and economy, which meets the development trend of green road materials. The polymer cationic asphalt emulsifier has stronger surface activity than the traditional asphalt emulsifier and has excellent high and low temperature stability.

[0028] 2. The critical micelle concentration of the polymer cationic asphalt emulsifier is 0.492-1.078 g / L, and the surface tension is 32.2-37.6 mN / m. Compared with the existing cationic asphalt emulsifier, the polymer cationic asphalt emulsifier has a significantly smaller critical micelle concentration and surface tension, which indicates that the polymer cationic asphalt emulsifier has stronger surface activity and is expected to prepare asphalt emulsion with smaller and more uniform particle size and improve the storage stability of the asphalt emulsion. The glass transition temperature of the polymer cationic asphalt emulsifier is lower than-60℃, which shows excellent low temperature performance, which will help to solve the problem of insufficient deformation performance of the traditional emulsified asphalt in low temperature environment. The decomposition temperature of the polymer cationic asphalt emulsifier is greater than 300℃, which is much higher than the preparation temperature of the emulsified asphalt and the service temperature of the emulsified asphalt mixture, which ensures that the polymer cationic asphalt emulsifier can always play its role in improving the low temperature performance of the asphalt. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0030] Figure 1 The critical micelle concentration and the corresponding surface tension of the polymer cationic asphalt emulsifier prepared in Example 1 are shown in the following table.

[0031] Figure 2Critical micelle concentration and corresponding surface tension of the polymer cationic asphalt emulsifier prepared in Example 1;

[0032] Figure 3 Critical micelle concentration and corresponding surface tension of the polymer cationic asphalt emulsifier prepared in Example 2;

[0033] Figure 4 Critical micelle concentration and corresponding surface tension of the polymer cationic asphalt emulsifier prepared in Example 3;

[0034] Figure 5 Critical micelle concentration and corresponding surface tension of the polymer cationic asphalt emulsifier prepared in Example 4;

[0035] Figure 6 Critical micelle concentration and corresponding surface tension of the polymer cationic asphalt emulsifier prepared in Example 5;

[0036] Figure 7 Critical micelle concentration and corresponding surface tension of the polymer cationic asphalt emulsifier prepared in Example 6;

[0037] Figure 8 Critical micelle concentration and corresponding surface tension of the polymer cationic asphalt emulsifier prepared in Example 7;

[0038] Figure 9 Critical micelle concentration and corresponding surface tension of the polymer cationic asphalt emulsifier prepared in Comparative Example 1;

[0039] Figure 10 Critical micelle concentration and corresponding surface tension of the polymer cationic asphalt emulsifier prepared in Comparative Example 2;

[0040] Figure 11 Glass transition temperature test results of the polymer cationic asphalt emulsifiers prepared in Examples 1 to 7;

[0041] Figure 12 Decomposition temperature test results of the polymer cationic asphalt emulsifier prepared in Example 1;

[0042] Figure 13 Decomposition temperature test results of the polymer cationic asphalt emulsifier prepared in Example 2;

[0043] Figure 14 Decomposition temperature test results of the polymer cationic asphalt emulsifier prepared in Example 3;

[0044] Figure 15 Decomposition temperature test results of the polymer cationic asphalt emulsifier prepared in Example 4;

[0045] Figure 16 Decomposition temperature test results for the polymer cationic asphalt emulsifier prepared in Example 5;

[0046] Figure 17 Decomposition temperature test results for the polymer cationic asphalt emulsifier prepared in Example 6;

[0047] Figure 18 Decomposition temperature test results for the polymer cationic asphalt emulsifier prepared in Example 7;

[0048] Figure 19 Decomposition temperature test results for the cationic asphalt emulsifier in Comparative Example 1;

[0049] Figure 20 Decomposition temperature test results for the cationic asphalt emulsifier in Comparative Example 2;

[0050] Figure 21 Decomposition temperature test results for the cationic asphalt emulsifier in Comparative Example 3. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be clearly and completely described in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0052] It should be noted that the sequence of the following embodiments is not limited as the preferred sequence of the embodiments. In addition, in the description of the present application, the term "comprising" means "including but not limited to". Various embodiments of the present application can exist in the form of a range; it should be understood that the description in the form of a range is only for the convenience and brevity, and should not be understood as a hard limitation on the scope of the present application; therefore, it should be considered that the described range has been specifically disclosed all possible sub-ranges and single values within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, regardless of the range. In addition, whenever a numerical range is indicated in this text, it means that any cited number (fraction or integer) within the indicated range is included.

[0053] The present application provides a preparation method of a polymer cationic asphalt emulsifier, comprising the following steps:

[0054] S1, mixing part of methyl 9-octadecenoate, maleic anhydride and p-vinyl toluene to obtain a monomer mixture;

[0055] S2, mixing the chain initiator, the chain transfer agent and another part of 9-octadecenoic acid methyl ester to obtain a mixture;

[0056] S3, adding the mixture to the monomer mixture, and reacting to obtain a polymer precursor;

[0057] S4, adding tetraethylenepentamine to the polymer precursor, and reacting to obtain an amidation intermediate;

[0058] S5, removing the intramolecular water molecules of the amidation intermediate and generating an imidazoline ring, so as to obtain the polymer cationic asphalt emulsifier.

[0059] The preparation method of the polymer cationic asphalt emulsifier of the present application utilizes three monomers, 9-octadecenoic acid methyl ester (CAS No.: 112-62-9, molecular formula C 19 H 36 O2), maleic anhydride (alias: maleic anhydride, chemical formula: C4H2O3), and p-vinyl toluene (i.e. 4-vinyl toluene, molecular formula C9H 10 ), to perform a polymerization reaction; the present application integrates various functional groups (long-chain alkyl, methyl styrene chain, imidazoline, etc.) in a single polymer skeleton based on free radical polymerization technology, which is expected to improve the interfacial activity of the emulsifier, and improve the stability and performance of the emulsified asphalt, which is both efficient and economical, and meets the development trend of green road materials. The polymer cationic asphalt emulsifier of the present application has stronger surface activity than traditional asphalt emulsifiers, and has excellent high and low temperature stability, and the specific preparation process is as follows:

[0060]

[0061] Specifically, the first step (1) reaction is that 9-octadecenoic acid methyl ester (a), maleic anhydride (b), and p-vinyl toluene (c) generate a polymer precursor under the action of a chain initiator, i.e. cumene hydroperoxide, and a chain transfer agent, i.e. 3-mercapto propionic acid; the chemical structural formula of the polymer precursor is:

[0062] The second step (2) reaction is that the polymer precursor reacts with tetraethylenepentamine to obtain an amidation intermediate, and the chemical structural formula of the amidation intermediate is:

[0063] The third step (3) reaction is that the amidation intermediate is dehydrated intramolecularly to obtain a polymer cationic asphalt emulsifier, and the chemical structural formula of the polymer cationic asphalt emulsifier is:

[0064]

[0065] In some embodiments, the chain initiator is cumene hydroperoxide (i.e., cumene hydroperoxide, chemical formula: C9H 12 O2);

[0066] The chain transfer agent is 3-mercaptopropionic acid (structural formula: HS-CH2 CH2COOH).

[0067] In some embodiments, a part of the methyl 9-octadecenoate, maleic anhydride, p-vinyl toluene is mixed under an inert atmosphere at 130-135°C to obtain a monomer mixture.

[0068] In some embodiments, the inert atmosphere comprises at least one of nitrogen, helium, neon, argon.

[0069] In some embodiments, the mixture is added to the monomer mixture and reacted at 130-135°C for 3-4h to obtain a polymer precursor, which is reaction step (1).

[0070] In some embodiments, tetraethylenepentamine (i.e., tetraethylenyl pentamine, molecular formula: C8H 23 N5) is added to the polymer precursor and reacted at 160-165°C for 3-4h to obtain an amidated intermediate, which is reaction step (2).

[0071] In some embodiments, the amidated intermediate is stirred at 220-225°C for 3-4h to completely remove the water molecules in the amidated intermediate and generate imidazoline ring, so as to obtain a polymer cationic asphalt emulsifier, which is reaction step (3).

[0072] In some embodiments, the methyl 9-octadecenoate, maleic anhydride, p-vinyl toluene are weighed according to the molar ratio of 1.0:(0.7-1.3):(0.2-0.6);

[0073] 90-95% of the mass of the methyl 9-octadecenoate, maleic anhydride, p-vinyl toluene are mixed to obtain a monomer mixture;

[0074] The chain initiator and the chain transfer agent are mixed with the remaining methyl 9-octadecenoate to obtain a mixture.

[0075] In some embodiments, the mass of the chain initiator is 0.2-0.3% of the sum of the masses of the methyl 9-octadecenoate, maleic anhydride, p-vinyl toluene;

[0076] The mass of the chain transfer agent is 0.2-0.3% of the sum of the masses of the methyl 9-octadecenoate, maleic anhydride, p-vinyl toluene;

[0077] The molar amount of tetraethylenepentamine is (0.6-1.0):1.0 of the sum of the molar amounts of methyl 9-octadecenoate and maleic anhydride, that is, if the tetraethylenepentamine is 0.6-1.0 mol, the sum of the molar amounts of methyl 9-octadecenoate and maleic anhydride is 1.0 mol.

[0078] The critical micelle concentration of the polymer cationic asphalt emulsifier is 0.492-1.078 g / L, and the surface tension is 32.2-37.6 mN / m, which is obviously smaller than that of the existing cationic asphalt emulsifier, which shows that the polymer cationic asphalt emulsifier has stronger surface activity, and is expected to prepare asphalt emulsion with smaller and more uniform particle size and improve the storage stability of the asphalt emulsion.

[0079] The glass transition temperature of the polymer cationic asphalt emulsifier is lower than-60 DEG C, which shows excellent low-temperature performance, which will help to solve the problem of insufficient deformation performance of traditional emulsified asphalt in low-temperature environment.

[0080] The decomposition temperature of the polymer cationic asphalt emulsifier is greater than 300 DEG C, which is much higher than the preparation temperature of emulsified asphalt and the service temperature of emulsified asphalt mixture, which ensures that the polymer cationic asphalt emulsifier can always play its role in improving the low-temperature performance of asphalt.

[0081] Based on the same inventive concept, the application further provides a polymer cationic asphalt emulsifier prepared by the preparation method.

[0082] Based on the same inventive concept, the application further provides a polymer cationic asphalt emulsifier prepared by the preparation method or the application of the polymer cationic asphalt emulsifier in preparing emulsified asphalt.

[0083] The polymer cationic asphalt emulsifier, the preparation method and the application thereof are further illustrated by specific examples below. This part further illustrates the content of the application in combination with specific examples, but should not be understood as limiting the application. If not specifically stated, the technical means adopted in the examples are conventional means familiar to those skilled in the art. Unless specifically stated, the reagents, methods and equipment adopted in the application are conventional reagents, methods and equipment in the art.

[0084] Example 1

[0085] The application provides a preparation method of a polymer cationic asphalt emulsifier, which comprises the following steps:

[0086] S1, 9-octadecenoic acid methyl ester, maleic anhydride and p-vinyl toluene are weighed according to the molar ratio of 1.0:0.7:0.4;

[0087] 90% by mass of 9-octadecenyl acid methyl ester, all of maleic anhydride and p-vinyl toluene are added into a three-necked flask, nitrogen is introduced to exhaust the air in the flask, then the temperature is continuously increased to 130°C at a rotation speed of 200 rpm, so that the monomers are uniformly dissolved, to obtain a monomer mixture;

[0088] S2, isopropylbenzene peroxide hydrogen chain initiator, 3-mercaptopropionic acid chain transfer agent and the remaining 10% by mass of 9-octadecenyl acid methyl ester are uniformly shaken to obtain a mixture;

[0089] S3, the mixture is slowly dropped into the three-necked flask through a dropping funnel, and the reaction is continued at 130°C for 3h to obtain a polymer precursor; wherein the amount of chain initiator and chain transfer agent is 0.2wt% of the total mass of the three monomers;

[0090] S4, the temperature is increased to 160°C, tetraethylenepentamine is added into the three-necked flask through a dropping funnel, and the reaction is carried out at a stirring speed of 200 rpm for 3h to obtain an amidation intermediate; wherein the molar amount of tetraethylenepentamine is 0.8:1.0 of the sum of the molar amounts of 9-octadecenyl acid methyl ester and maleic anhydride;

[0091] S5, the temperature is increased to 220°C, the rotation speed is kept at 200 rpm, and the intramolecular water molecules of the amidation intermediate are completely removed for 3h to form an imidazoline ring, so that the polymer cationic asphalt emulsifier is obtained.

[0092] Example 2 (the difference from Example 1 is that the molar ratio of 9-octadecenyl acid methyl ester, maleic anhydride and p-vinyl toluene is 1.0:1.0:0.4)

[0093] The embodiment of the present application provides a preparation method of a polymer cationic asphalt emulsifier, which comprises the following steps:

[0094] S1, 9-octadecenyl acid methyl ester, maleic anhydride and p-vinyl toluene are weighed according to a molar ratio of 1.0:1.0:0.4;

[0095] 90% by mass of 9-octadecenyl acid methyl ester, all of maleic anhydride and p-vinyl toluene are added into a three-necked flask, nitrogen is introduced to exhaust the air in the flask, then the temperature is continuously increased to 130°C at a rotation speed of 200 rpm, so that the monomers are uniformly dissolved, to obtain a monomer mixture;

[0096] S2, isopropylbenzene peroxide hydrogen chain initiator, 3-mercaptopropionic acid chain transfer agent and the remaining 10% by mass of 9-octadecenyl acid methyl ester are uniformly shaken to obtain a mixture;

[0097] S3, the mixture is slowly added to the three-necked flask through a dropping funnel, and the reaction is continued at 130 DEG C for 3h to obtain a polymer precursor; wherein the amount of the chain initiator and the chain transfer agent is 0.2wt% of the total mass of the three monomers;

[0098] S4, the temperature is raised to 160 DEG C, tetraethylenepentamine is added to the three-necked flask through a dropping funnel, and the reaction is carried out at a stirring speed of 200 rpm for 3h to obtain an amidation intermediate; wherein the molar amount of tetraethylenepentamine is 0.8:1.0 of the sum of the molar amounts of methyl 9-octadecenoate and maleic anhydride;

[0099] S5, the temperature is raised to 220 DEG C, the stirring speed is kept at 200 rpm, and the amidation intermediate is completely dehydrated for 3h to form an imidazoline ring, and a polymer cationic asphalt emulsifier is obtained.

[0100] Example 3 (the difference from Example 1 is that the molar ratio of methyl 9-octadecenoate, maleic anhydride and p-vinyl toluene is 1.0:1.3:0.4)

[0101] The embodiment of the present application provides a preparation method of a polymer cationic asphalt emulsifier, comprising the following steps:

[0102] S1, three monomers of methyl 9-octadecenoate, maleic anhydride and p-vinyl toluene are weighed according to a molar ratio of 1.0:1.3:0.4;

[0103] 90% of the mass of methyl 9-octadecenoate, all of maleic anhydride and p-vinyl toluene are added to a three-necked flask, nitrogen is introduced to exhaust the air in the flask, then the temperature is continuously raised to 130 DEG C at a speed of 200 rpm, and the monomers are uniformly dissolved to obtain a monomer mixture;

[0104] S2, the isopropylbenzene hydrogen peroxide chain initiator, the 3-mercaptopropionic acid chain transfer agent and the remaining 10% of the mass of methyl 9-octadecenoate are uniformly shaken to obtain a mixture;

[0105] S3, the mixture is slowly added to the three-necked flask through a dropping funnel, and the reaction is continued at 130 DEG C for 3h to obtain a polymer precursor; wherein the amount of the chain initiator and the chain transfer agent is 0.2wt% of the total mass of the three monomers;

[0106] S4, the temperature is raised to 160 DEG C, tetraethylenepentamine is added to the three-necked flask through a dropping funnel, and the reaction is carried out at a stirring speed of 200 rpm for 3h to obtain an amidation intermediate; wherein the molar amount of tetraethylenepentamine is 0.8:1.0 of the sum of the molar amounts of methyl 9-octadecenoate and maleic anhydride;

[0107] S5. Raise the temperature to 220°C and maintain the rotation speed at 200 rpm. After 3 hours, the water molecules in the amidation intermediate molecule are completely removed to generate an imidazoline ring, thereby obtaining a polymer cationic asphalt emulsifier.

[0108] Example 4 (The difference from Example 1 is that the molar amount of tetraethylenepentamine is 0.6:1.0 of the sum of the molar amounts of 9-octadecenoic acid methyl ester and maleic anhydride)

[0109] The present invention provides a method for preparing a polymer cationic asphalt emulsifier, comprising the following steps:

[0110] S1. Weigh 9-octadecenoic acid methyl ester, maleic anhydride, and p-vinyl toluene in a molar ratio of 1.0:0.7:0.4;

[0111] 90% by weight of methyl 9-octadecenoate, all of the maleic anhydride, and p-vinyltoluene were added to a three-necked flask, nitrogen was introduced to evacuate the air in the flask, and then the temperature was continuously raised to 130° C. at a speed of 200 rpm to allow the monomers to be uniformly dissolved in each other, thereby obtaining a monomer mixture;

[0112] S2, the isopropylbenzene hydroperoxide chain initiator, the 3-mercaptopropionic acid chain transfer agent and the remaining 10% by weight of 9-octadecenoic acid methyl ester are shaken evenly to obtain a mixture;

[0113] S3. Slowly add the mixture dropwise into the three-necked flask through a dropping funnel, and continue to react at 130° C. for 3 h to obtain a polymerization precursor; wherein the amount of the chain initiator and the chain transfer agent is 0.2 wt% of the total mass of the three monomers;

[0114] S4. Raise the temperature to 160° C., add tetraethylenepentamine dropwise to the three-necked flask through a dropping funnel, and react for 3 hours at a stirring speed of 200 rpm to prepare an amidated intermediate; wherein the molar weight of tetraethylenepentamine is 0.6:1.0 of the sum of the molar weights of 9-octadecenoic acid methyl ester and maleic anhydride;

[0115] S5. Raise the temperature to 220°C and maintain the rotation speed at 200 rpm. After 3 hours, the water molecules in the amidation intermediate molecule are completely removed to generate an imidazoline ring, thereby obtaining a polymer cationic asphalt emulsifier.

[0116] Example 5 (The difference from Example 1 is that the molar amount of tetraethylenepentamine is 1.0:1.0 of the sum of the molar amounts of 9-octadecenoic acid methyl ester and maleic anhydride)

[0117] The present invention provides a method for preparing a polymer cationic asphalt emulsifier, comprising the following steps:

[0118] S1, 9-octadecenyl acid methyl ester, maleic anhydride and p-vinyl toluene were weighed according to a molar ratio of 1.0:0.7:0.4;

[0119] 90% of 9-octadecenyl acid methyl ester, all maleic anhydride and p-vinyl toluene were added into a three-necked flask, nitrogen was introduced to remove air in the flask, then the temperature was continuously increased to 130°C at a rotation speed of 200 rpm, so that the monomers were uniformly dissolved, and a monomer mixture was obtained;

[0120] S2, isopropylbenzene peroxide hydrogen chain initiator and 3-mercapto propionic acid chain transfer agent were added into the remaining 10% of 9-octadecenyl acid methyl ester, and shaken to obtain a mixture;

[0121] S3, the mixture was slowly added into the three-necked flask through a dropping funnel, and the reaction was continued at 130°C for 3h to obtain a polymer precursor; wherein the amount of the chain initiator and the chain transfer agent was 0.2wt% of the total mass of the three monomers;

[0122] S4, the temperature was increased to 160°C, tetraethylenepentamine was added into the three-necked flask through a dropping funnel, and the reaction was carried out at a stirring speed of 200 rpm for 3h to obtain an amidation intermediate; wherein the molar amount of tetraethylenepentamine was 1.0:1.0 of the sum of the molar amounts of 9-octadecenyl acid methyl ester and maleic anhydride;

[0123] S5, the temperature was increased to 220°C, the rotation speed was kept at 200 rpm, and the amidation intermediate was completely dehydrated for 3h to form an imidazoline ring, and a polymer cationic asphalt emulsifier was obtained.

[0124] Example 6 (the difference from Example 1 is that the molar ratio of 9-octadecenyl acid methyl ester, maleic anhydride and p-vinyl toluene is 1.0:0.7:0.2)

[0125] The application provides a preparation method of a polymer cationic asphalt emulsifier, which comprises the following steps:

[0126] S1, 9-octadecenyl acid methyl ester, maleic anhydride and p-vinyl toluene were weighed according to a molar ratio of 1.0:0.7:0.2;

[0127] 90% of 9-octadecenyl acid methyl ester, all maleic anhydride and p-vinyl toluene were added into a three-necked flask, nitrogen was introduced to remove air in the flask, then the temperature was continuously increased to 130°C at a rotation speed of 200 rpm, so that the monomers were uniformly dissolved, and a monomer mixture was obtained;

[0128] S2, the isopropyl benzene peroxide hydrogen chain initiator, 3-mercapto propionic acid chain transfer agent and the remaining 10% of the mass of 9-octadecene acid methyl ester are shaken uniformly to obtain a mixture;

[0129] S3, the mixture is slowly added to a three-necked flask through a dropping funnel, and the reaction is continued at 130°C for 3h to obtain a polymer precursor; wherein the amount of chain initiator and chain transfer agent is 0.2wt% of the total mass of the three monomers;

[0130] S4, the temperature is raised to 160°C, and tetraethylenepentamine is added to the three-necked flask through a dropping funnel, and the reaction is carried out at a stirring speed of 200rpm for 3h to obtain an amidation intermediate; wherein the molar amount of tetraethylenepentamine is 0.8:1.0 of the sum of the molar amounts of 9-octadecene acid methyl ester and maleic anhydride;

[0131] S5, the temperature is raised to 220°C, the stirring speed is kept at 200rpm, and the amidation intermediate is completely dehydrated for 3h to form an imidazoline ring, and a polymer cationic asphalt emulsifier is obtained.

[0132] Example 7 (the difference from Example 1 is that the molar ratio of 9-octadecene acid methyl ester, maleic anhydride and p-vinyl toluene is 1.0:0.7:0.6)

[0133] The embodiment of the present application provides a preparation method of a polymer cationic asphalt emulsifier, which comprises the following steps:

[0134] S1, 9-octadecene acid methyl ester, maleic anhydride and p-vinyl toluene are weighed according to a molar ratio of 1.0:0.7:0.6;

[0135] 90% of the mass of 9-octadecene acid methyl ester, all of the maleic anhydride and the p-vinyl toluene are added to a three-necked flask, nitrogen is introduced to exhaust the air in the flask, then the temperature is continuously raised to 130°C at a stirring speed of 200rpm, the monomers are uniformly dissolved, and a monomer mixture is obtained;

[0136] S2, the isopropyl benzene peroxide hydrogen chain initiator, 3-mercapto propionic acid chain transfer agent and the remaining 10% of the mass of 9-octadecene acid methyl ester are shaken uniformly to obtain a mixture;

[0137] S3, the mixture is slowly added to a three-necked flask through a dropping funnel, and the reaction is continued at 130°C for 3h to obtain a polymer precursor; wherein the amount of chain initiator and chain transfer agent is 0.2wt% of the total mass of the three monomers;

[0138] S4. Raise the temperature to 160° C., add tetraethylenepentamine dropwise to the three-necked flask through a dropping funnel, and react for 3 hours at a stirring speed of 200 rpm to prepare an amidated intermediate; wherein the molar weight of tetraethylenepentamine is 0.8:1.0 of the sum of the molar weights of 9-octadecenoic acid methyl ester and maleic anhydride;

[0139] S5. Raise the temperature to 220°C and maintain the rotation speed at 200 rpm. After 3 hours, the water molecules in the amidation intermediate molecule are completely removed to generate an imidazoline ring, thereby obtaining a polymer cationic asphalt emulsifier.

[0140] Comparative Example 1

[0141] This comparative example provides a cationic asphalt emulsifier, specifically SBT cationic asphalt emulsifier, which is an emulsifier sold and widely used in the market, and its appearance is a brown-black liquid.

[0142] Comparative Example 2

[0143] This comparative example provides a cationic asphalt emulsifier, specifically SHLH cationic asphalt emulsifier, which is an emulsifier sold and widely used in the market, and its appearance is a dark brown liquid.

[0144] Comparative Example 3

[0145] This comparative example provides a cationic asphalt emulsifier, specifically KZW cationic asphalt emulsifier, which is an emulsifier sold and widely used in the market, and its appearance is a brown viscous liquid.

[0146] The surface tension of the cationic asphalt emulsifiers in Examples 1 to 7 and Comparative Examples 1 to 3 in aqueous solutions of different concentrations was tested using a fully automatic tensiometer to obtain the critical micelle concentration and the corresponding surface tension to evaluate the surface activity of the emulsifier. The test results are as follows: Figures 1-10 The glass transition temperature and decomposition temperature of the asphalt emulsifier were tested by differential calorimetry and thermogravimetric analysis respectively, and the low-temperature and high-temperature stability of the emulsifier were characterized. The test results are shown as follows: Figure 11 and Figures 12-21 All test results are summarized in Table 1.

[0147] Table 1 - Performance index test results of different cationic asphalt emulsifiers

[0148]

[0149]

[0150] As can be seen from the test results in Table 1, compared with all the comparative examples, the polymeric cationic asphalt emulsifiers of Examples 1 to 7 have significantly lower critical micelle concentrations and surface tensions. This indicates that the polymeric cationic asphalt emulsifiers have stronger surface activity and are expected to produce asphalt emulsions with smaller and more uniform particle sizes and improve the storage stability of asphalt emulsions. Since the three emulsifiers in Comparative Examples 1 to 3 have relatively small molecular weights, no obvious glass transition temperature is found on the DSC curve. The glass transition temperatures of all polymeric cationic asphalt emulsifiers in Examples 1 to 7 are below -40°C, showing excellent low-temperature performance, which will help solve the problem of insufficient deformation performance of traditional emulsified asphalt in low-temperature environments. According to the thermogravimetric analysis results, the decomposition temperatures of all polymeric cationic asphalt emulsifiers in Examples 1 to 7 are greater than 300°C, which is much higher than the preparation temperature of the emulsified asphalt and the service temperature of the emulsified asphalt mixture. This ensures that the polymeric cationic asphalt emulsifier can always play its role in improving the low-temperature performance of asphalt. The decomposition temperature of the emulsifier in the comparative example is about 57° C., which will cause it to volatilize and decompose significantly during the emulsification process, thereby affecting the emulsification effect.

[0151] From the comparison of the results of Examples 1 to 3, it can be seen that with the increase in the amount of maleic anhydride used, the surface activity of the asphalt emulsifier changes slightly, while the low-temperature deformation ability decreases and the high-temperature stability decreases. It is appropriate to select a maleic anhydride molar ratio of 0.7.

[0152] Comparing the results of Examples 1 and 4-5, it can be seen that the surface activity of the polymeric cationic asphalt emulsifier decreases with increasing tetraethylene pentamine dosage. When the tetraethylene pentamine molar ratio reaches 1.0, the high and low temperature stability of the emulsifier decreases significantly. Tetraethylene pentamine is the main polarity contributing group in the emulsifier's molecular structure. The enhanced overall hydrophilicity of the emulsifier makes it more difficult to transfer from the aqueous phase to the liquid-air interface. To ensure the hydrophilic-lipophilic balance and stability of the polymeric emulsifier, the tetraethylene pentamine molar ratio was set to 0.8.

[0153] Comparing the results of Examples 1 and 6-7 shows that the surface activity of the polymeric cationic asphalt emulsifier first increases and then decreases with increasing p-vinyltoluene content. This is primarily due to p-vinyltoluene's hydrophobicity. Excessive use results in poor water solubility in the emulsifier, slowing molecular diffusion to the interface. Furthermore, due to the rigidity and stability of p-vinyltoluene's structure, this increases the emulsifier's low-temperature brittleness but improves its high-temperature stability. Taking both surface activity and stability into account, the optimal molar ratio of p-vinyltoluene monomer is 0.4.

[0154] The above merely provides the preferred embodiment of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a polymer cationic asphalt emulsifier, characterized in that: The following steps are involved: S1, mixing portions of methyl 9-octadecenoate, maleic anhydride, and p-vinyltoluene to obtain a monomer mixture; S2, mixing the chain initiator, the chain transfer agent and another portion of 9-octadecenoic acid methyl ester to obtain a mixture; S3, adding the mixed material to the monomer mixture, reacting to obtain a polymerization precursor; S4, adding tetraethylenepentamine to the polymerization precursor to react and obtain an amidated intermediate; S5. The water molecules in the amidation intermediate molecule are removed to generate an imidazoline ring, thereby obtaining a polymer cationic asphalt emulsifier.

2. The method for preparing a polymer cationic asphalt emulsifier according to claim 1, wherein: The chain initiator is cumene hydroperoxide; The chain transfer agent is 3-mercaptopropionic acid.

3. The method for preparing a polymer cationic asphalt emulsifier according to claim 1, wherein: Parts of methyl 9-octadecenoate, maleic anhydride and p-vinyltoluene are mixed under an inert atmosphere at 130-135° C. to obtain a monomer mixture.

4. The method for preparing a polymer cationic asphalt emulsifier according to claim 1, wherein: The mixed material is added to the monomer mixture, and the mixture is reacted at 130-135° C. for 3-4 hours to obtain a polymerization precursor.

5. The method for preparing a polymer cationic asphalt emulsifier according to claim 1, wherein: Tetraethylenepentamine is added to the polymerization precursor and reacted at 160-165° C. for 3-4 hours to obtain an amidation intermediate.

6. The method for preparing a polymer cationic asphalt emulsifier according to claim 1, wherein: The amidated intermediate is stirred at 220-225° C. for 3-4 hours to completely remove the water molecules in the amidated intermediate molecule and generate an imidazoline ring, thereby obtaining a polymer cationic asphalt emulsifier.

7. The method for preparing a polymer cationic asphalt emulsifier according to claim 1, wherein: Weigh methyl 9-octadecenoate, maleic anhydride, and p-vinyltoluene in a molar ratio of 1.0:(0.7-1.3):(0.2-0.6); Mixing 90-95% by weight of methyl 9-octadecenoate, maleic anhydride, and p-vinyltoluene to obtain a monomer mixture; The chain initiator, the chain transfer agent and the remaining 9-octadecenoic acid methyl ester are mixed to obtain a mixture.

8. The method for preparing a polymer cationic asphalt emulsifier according to claim 1, wherein: The mass of the chain initiator is 0.2-0.3% of the sum of the mass of 9-octadecenoic acid methyl ester, maleic anhydride and p-vinyl toluene; The mass of the chain transfer agent is 0.2-0.3% of the sum of the mass of 9-octadecenoic acid methyl ester, maleic anhydride and p-vinyl toluene; The molar amount of the tetraethylenepentamine is (0.6-1.0):1.0 of the sum of the molar amounts of 9-octadecenoic acid methyl ester and maleic anhydride.

9. A polymer cationic asphalt emulsifier, characterized in that: The preparation method is as described in any one of claims 1 to 8.

10. Use of the polymer cationic asphalt emulsifier prepared by the preparation method according to any one of claims 1 to 8 or the polymer cationic asphalt emulsifier according to claim 9 in the preparation of emulsified asphalt.

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