Method for modifying nano-zinc oxide and colored asphalt

Abstract

The application discloses a modification method of nano zinc oxide and colored asphalt, and belongs to the technical field of asphalt modifier. In order to improve the oxidation resistance and high and low temperature performance of the colored asphalt, the nano modification material added in the prior art may cause the increase of the viscosity of the asphalt. The modification method of the nano zinc oxide comprises the following steps: 1) the nano zinc oxide is subjected to low-temperature plasma surface treatment; 2) a polyacrylamide aqueous solution with a weight concentration of 0.5-1% is added into the nano zinc oxide under the condition of a rotating speed of 4000-6000 rpm, and stirring is carried out for 30-60 min; and 3) the modified nano zinc oxide is obtained through separation, washing and drying. By increasing the number of surface functional groups of the nano zinc oxide and solving the problem of difficult dispersion of the nano zinc oxide caused by the increase of the number of the functional groups, the increase of the viscosity of the asphalt after the addition of the asphalt is avoided, the high temperature performance and the aging resistance of the colored asphalt are improved, the elastic performance of the modified colored asphalt is improved, and the low temperature self-healing property of the modified colored asphalt is improved.

Description

Technical Field

[0001] A method for modifying nano zinc oxide and colored asphalt, belonging to the field of asphalt modifier technology. Background Technology

[0002] Colored asphalt is a binder with properties similar to petroleum asphalt, prepared from base oil, petroleum resin, and modifiers. Due to the high proportion of low-viscosity base oil in colored asphalt, its high-temperature performance is poor. Furthermore, petroleum resin, being a C5-C9 copolymer, contains a certain amount of unsaturated bonds, which are prone to oxidation at high temperatures, forming free radicals and reducing the antioxidant properties of the modified colored asphalt. Additionally, petroleum resin is a brittle solid at room temperature with low elasticity, resulting in poor elasticity of the modified colored asphalt at low temperatures and consequently poor self-healing properties. The base oil also contains some unsaturated components, which also undergo oxidation, leading to poor anti-aging properties in the colored asphalt. Existing technologies using modifiers in the preparation of colored asphalt all involve polymers, whose unsaturated components undergo partial thermal degradation with increasing temperature, further degrading the high-temperature performance of the colored asphalt.

[0003] Because nano-zinc oxide has a certain number of surface-active groups on its surface, adding it to modified asphalt can improve the high-temperature performance and anti-aging properties of the asphalt. This is because nanomaterials are inorganic materials and cannot be completely dissolved in asphalt. They can only improve the performance of asphalt by undergoing physical and chemical reactions with the components in the asphalt through their surface functional groups, forming compounds. Therefore, the modification effect of nanomaterials is closely related to the number of functional groups on their surface; the more functional groups, the better the modification effect. However, as the number of surface functional groups increases, the surface energy of nanomaterials increases, leading to poor dispersibility. This causes nanomaterials to agglomerate in modified asphalt, significantly increasing the viscosity of the modified asphalt and thus reducing the modification effect, limiting the application of nanomaterials in modified asphalt.

[0004] Patent CN116376304A discloses a modified asphalt and its preparation method and application. The asphalt modifier used in the modified asphalt increases the low-temperature ductility, low-temperature crack resistance and aging resistance of the asphalt. However, the zinc oxide used in the asphalt modifier is only used as a stabilizer and mainly utilizes the modification effect of rubber. The nano calcium carbonate used in the modified asphalt will also increase the viscosity of the asphalt, and fails to solve the problem of increased viscosity caused by nanomaterial modification. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for modifying asphalt with nano zinc oxide and colored asphalt that can improve the oxidation resistance and high and low temperature performance of asphalt without increasing the viscosity of asphalt.

[0006] The technical solution adopted by this invention to solve its technical problem is: a method for modifying nano-zinc oxide, characterized by comprising the following steps:

[0007] 1) Nano zinc oxide undergoes low-temperature plasma surface treatment;

[0008] 2) Add nano zinc oxide to a 0.5-1% (w / w) polyacrylamide aqueous solution at 4000-6000 rpm and stir for 30-60 min;

[0009] 3) Separate, wash and dry to obtain modified nano zinc oxide.

[0010] By increasing the number of functional groups on the surface of nano zinc oxide and solving the problem of difficulty in dispersing nano zinc oxide due to the increase in the number of functional groups, the increase in asphalt viscosity after addition to asphalt can be avoided. This can improve the high-temperature performance and anti-aging performance of colored asphalt, as well as the elastic properties of modified colored asphalt and enhance its low-temperature self-healing properties.

[0011] Preferably, the conditions for the low-temperature plasma surface treatment in step 1) are: nitrogen to oxygen in a volume ratio of 1.5 to 9:1, gas flow rate of 15 to 30 L / min, voltage of 20 to 30 kV, and frequency of 6 to 10 kHz.

[0012] Preferably, the low-temperature plasma surface treatment in step 1) lasts for 1 to 5 minutes.

[0013] Preferably, the nano zinc oxide is first soaked in deionized water for 60-100 minutes before undergoing the low-temperature plasma surface treatment in step 1).

[0014] Preferably, the preparation method of the polyacrylamide aqueous solution in step 2) is as follows: after mixing water and polyacrylamide, the mixture is kept at a constant temperature of 50~70℃ for 20~40 minutes to obtain the polyacrylamide aqueous solution.

[0015] A colored asphalt, characterized in that: the raw materials, by weight, include 57-68 parts of petroleum resin, 24-32 parts of base oil, 5-10 parts of SBS polymer, and 1-4 parts of the aforementioned nano zinc oxide.

[0016] Preferably, the petroleum resin is one or more of coumarone resin, terpene resin, and semi-hydrogenated petroleum resin.

[0017] Preferably, the base oil is one or both of naphthenic oil and high aromatic oil.

[0018] Preferably, the preparation method includes the following steps:

[0019] 1) After mixing the base oil and SBS polymer, maintain a constant temperature of 130~140℃ for 40~60 minutes, then heat to 150~160℃ and add nano zinc oxide while stirring at 1000~2000 rpm, continuing to stir for 30~50 minutes.

[0020] 2) Add petroleum resin. After the petroleum resin dissolves, continue stirring for 30-40 minutes, and then place it in an environment of 140-150℃ for constant temperature development for 60-100 minutes.

[0021] Premixing SBS polymers with base oils allows the SBS polymers to absorb light components from the base oils and swell, opening up the intertwined polymer chains and facilitating the rapid formation of a three-dimensional network structure, thus enhancing the modification effect. Premixing modified nano-zinc oxide with base oils allows the thickeners encapsulated in the modified nano-zinc oxide to dissolve in low-viscosity base oils, promoting the performance of the modified nano-zinc oxide. The addition of petroleum resins can appropriately increase the viscosity of colored asphalt to a certain extent (unlike the sudden increase in viscosity caused by nanomaterials), improving the high-temperature performance of colored asphalt.

[0022] Compared with existing technologies, the beneficial effects of this invention are as follows: The surface of nano-zinc oxide is activated by plasma discharge treatment, generating numerous activation reaction sites. Simultaneously, under plasma treatment, hydrogen and oxygen donors react at these activation sites to generate highly reactive hydroxyl groups, increasing the number of active hydroxyl groups on the nano-zinc oxide surface. This increased number of active groups gives the nano-zinc oxide higher reactivity. At high temperatures and in air, it can preferentially replace unsaturated bonds in base oils and petroleum resins, combining with oxygen to undergo oxidation reactions. This prevents the oxidation of components in colored asphalt, improving the anti-aging properties of the colored asphalt. Furthermore, the increased number of active functional groups on the nano-zinc oxide surface allows it to insert into the molecular chains of polymer modifiers and undergo physicochemical reactions with the polymer molecules, forming a compact structure within the polymer molecules. This prevents thermal decomposition of the polymer at high temperatures, thereby improving the anti-aging properties of the colored asphalt. Furthermore, the increased number of surface-active functional groups in nano-zinc oxide not only increases the contact area between nano-zinc oxide and asphalt, but also fosters molecular bonding between nano-zinc oxide, asphalt, and polymer modifier molecular chains. This results in a dense structure, allowing nano-zinc oxide to absorb more external force, thus providing reinforcement and improving the low-temperature ductility of colored asphalt. Simultaneously, the increased surface-active groups enhance the self-aggregation of nano-zinc oxide particles, improving the elasticity of colored asphalt and giving it self-healing properties. In the preparation of modified asphalt, nano-zinc oxide coated with thickener prevents agglomeration caused by a large number of active groups on its surface, which would otherwise lead to a poor modification effect. At the same time, the thickener dissolves in the modified asphalt, releasing the surface-modified nano-zinc oxide, resulting in uniform dispersion and improved modification effects. Detailed Implementation

[0023] The present invention will be further described below with reference to the embodiments, wherein Embodiment 2 is the preferred embodiment of the present invention.

[0024] Example 1

[0025] A method for modifying nano-zinc oxide includes the following steps:

[0026] 1) After soaking nano zinc oxide in deionized water for 70 minutes, it was filtered and then surface-treated using a low-temperature plasma reactor. The conditions for low-temperature plasma treatment were: nitrogen to oxygen at a volume ratio of 5:1, gas flow rate of 20 L / min, voltage of 25 kV, frequency of 7 kHz, and treatment time of 5 minutes.

[0027] 2) Mix water and polyacrylamide to prepare a 1% polyacrylamide solution by weight, and then incubate at 60℃ for 30 minutes to obtain a polyacrylamide solution.

[0028] 3) Add nano zinc oxide powder slowly to the polyacrylamide solution at a speed of 4000~6000 rpm and stir for 50 min.

[0029] 4) Centrifuge, rinse with deionized water, and dry in an 80℃ oven for 80 minutes to obtain modified nano zinc oxide.

[0030] A type of colored asphalt, the raw materials of which include: 67 kg of petroleum resin, 28 kg of base oil, 4 kg of SBS polymer and 1 kg of modified nano zinc oxide.

[0031] Its preparation method is as follows:

[0032] 1) After mixing the base oil and SBS polymer, place it in a 135℃ oven for constant temperature development for 50 minutes, then heat it to 155℃, add modified nano zinc oxide at a stirring speed of 1500 rpm, and continue stirring for 40 minutes.

[0033] 2) Add petroleum resin. After the petroleum resin dissolves, continue stirring for 35 minutes. Place it in a 145℃ oven for constant temperature development for 80 minutes to obtain modified colored asphalt.

[0034] Example 2

[0035] A colored asphalt, based on Example 1, uses the following raw materials: 68 kg of petroleum resin, 24 kg of base oil, 6 kg of SBS polymer, and 2 kg of modified nano-zinc oxide. Other conditions are the same as in Example 1.

[0036] Example 3

[0037] A colored asphalt, based on Example 1, uses the following raw materials: 57 kg of petroleum resin, 30 kg of base oil, 10 kg of SBS polymer, and 3 kg of modified nano-zinc oxide. Other conditions are the same as in Example 1.

[0038] Example 4

[0039] A colored asphalt, based on Example 1, uses the following raw materials: 64 kg of petroleum resin, 26 kg of base oil, 8 kg of SBS polymer, and 2 kg of modified nano-zinc oxide. Other conditions are the same as in Example 1.

[0040] Example 5

[0041] A colored asphalt, based on Example 1, uses the following raw materials: 59 kg of petroleum resin, 31 kg of base oil, 6 kg of SBS polymer, and 4 kg of modified nano-zinc oxide. Other conditions are the same as in Example 1.

[0042] Example 6

[0043] A colored asphalt, based on Example 1, uses the following raw materials: 63 kg of petroleum resin, 32 kg of base oil, 5 kg of SBS polymer, and 1 kg of modified nano-zinc oxide. Other conditions are the same as in Example 1.

[0044] Example 7

[0045] A method for modifying nano-zinc oxide, based on Example 1, wherein in step 1), the nitrogen and oxygen volume ratio is set to 1.5:1, the gas flow rate is set to 30 L / min, the voltage is set to 30 kV, the frequency is set to 10 kHz, and the time is set to 1 min. Other conditions are the same as in Example 1.

[0046] Example 8

[0047] A method for modifying nano-zinc oxide, based on Example 1, wherein step 1) the nano-zinc oxide is soaked in deionized water for 100 min; step 2) the concentration of the polyacrylamide aqueous solution is set to 0.5%, and the isothermal development time is set to 50°C for 20 min. Other conditions are the same as in Example 1.

[0048] Comparative Example 1

[0049] A colored asphalt, based on Example 1, except that the modified nano-zinc oxide in the raw materials is replaced with ordinary nano-zinc oxide without any surface treatment. Other conditions and the method for preparing the colored asphalt are the same as in Example 1.

[0050] Comparative Example 2

[0051] A method for modifying nano-zinc oxide, based on Example 1, involves only step 1) of the treatment, omitting steps 2) to 4). Other conditions and the method for preparing colored asphalt are the same as in Example 1.

[0052] Comparative Example 3

[0053] A method for modifying nano-zinc oxide, based on Example 1, involves only performing steps 2) to 4), omitting step 1). Other conditions and the method for preparing colored asphalt are the same as in Example 1.

[0054] Comparative Example 4

[0055] A colored asphalt, based on Example 1, is prepared by adding petroleum resin, SBS polymer, and modified nano-zinc oxide sequentially to base oil, then heating to 150°C, maintaining the temperature for 50 minutes, stirring at 1500 rpm for 40 minutes, and maintaining the temperature for 80 minutes to obtain the colored asphalt. Other conditions are the same as in Example 1.

[0056] Comparative Example 5

[0057] A colored asphalt, based on Example 1, without the addition of modified nano zinc oxide, with other conditions being the same as in Example 1.

[0058] Performance testing

[0059] The colored asphalt obtained in the above examples and comparative examples was subjected to performance tests. Penetration was determined according to GB / T 4509-2010. Softening point was determined according to GB / T 4507-2010. Aging was determined according to SH / T 0736-2003. Rotational viscosity at 135℃ was determined according to T0625-2011. Elastic recovery was tested according to NB / SH / T 0816-2010.

[0060] The test results are shown in Table 1 below.

[0061] Table 1 Performance Test Results

[0062] .

[0063] Based on the performance test results of the above embodiments and comparative examples, by increasing the number of functional groups on the surface of nanomaterials and solving the problem of difficulty in dispersing nanomaterials due to the increased number of functional groups, it is possible to improve both the high-temperature performance and anti-aging performance of colored asphalt, as well as the elastic properties and low-temperature self-healing properties of modified colored asphalt. Modification of nano-zinc oxide reveals that the addition of modified nano-zinc oxide particles significantly increases the softening point and ductility at 5°C of colored asphalt, indicating that the addition of modified nano-zinc oxide can significantly improve the high and low-temperature performance of colored asphalt. The increase in surface active groups of modified nano-zinc oxide can significantly improve the elastic recovery at 5°C of modified colored asphalt, giving it good self-healing ability. The residual ductility after aging shows that modified nano-zinc oxide can significantly improve the anti-aging performance of modified colored asphalt and further avoid a significant increase in viscosity due to the addition of nanomaterials. Furthermore, it is found that the above modification method and the colored asphalt preparation method have a synergistic and interrelated effect, jointly improving the performance of colored asphalt.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A type of colored asphalt, characterized in that: The raw materials, by weight, include 57-68 parts of petroleum resin, 24-32 parts of base oil, 5-10 parts of SBS polymer, and 1-4 parts of nano zinc oxide; The colored asphalt is prepared by the following steps: 1) After mixing the base oil and SBS polymer, maintain a constant temperature of 130~140℃ for 40~60 minutes, then heat to 150~160℃ and add nano zinc oxide while stirring at 1000~2000 rpm, continuing to stir for 30~50 minutes. 2) Add petroleum resin. After the petroleum resin dissolves, continue stirring for 30-40 minutes, and then place it in an environment of 140-150℃ for constant temperature development for 60-100 minutes. The modification method for nano-zinc oxide includes the following steps: S1, nano zinc oxide undergoes low-temperature plasma surface treatment; S2. Add nano zinc oxide to a 0.5-1% (w / w) polyacrylamide aqueous solution at 4000-6000 rpm and stir for 30-60 min. S3. Separation, washing, and drying yield modified nano-zinc oxide; The conditions for the low-temperature plasma surface treatment described in step S1 are: nitrogen to oxygen in a volume ratio of 1.5 to 9:1, gas flow rate of 15 to 30 L / min, voltage of 20 to 30 kV, and frequency of 6 to 10 kHz. The method for preparing the polyacrylamide aqueous solution in step S2 is as follows: after mixing water and polyacrylamide, the mixture is kept at a constant temperature of 50~70℃ for 20~40 minutes to obtain the polyacrylamide aqueous solution.

2. The colored asphalt according to claim 1, characterized in that: The low-temperature plasma surface treatment described in step S1 lasts for 1 to 5 minutes.

3. The colored asphalt according to claim 1, characterized in that: Before the low-temperature plasma surface treatment of nano zinc oxide described in step S1, it is first soaked in deionized water for 60-100 minutes.

4. The colored asphalt according to claim 1, characterized in that: The petroleum resin is one or more of coumarone resin, terpene resin, and semi-hydrogenated petroleum resin.

5. The colored asphalt according to claim 1, characterized in that: The base oil is one or both of naphthenic oil and high aromatic oil.