High performance modified bitumen based on nanocomposites

Abstract

The high-performance modified asphalt based on nanocomposite belongs to the technical field of modified asphalt materials, and is characterized in that the raw material weight parts composition comprises: 100 parts of base asphalt, 1.5-3 parts of SBS, 1-5 parts of hydroxyl-modified nanometer powder composite polyester, 0.1-2 parts of stabilizer and 0.01-0.5 parts of crosslinking agent.The nanometer powder is compounded with the polyester material through hydrogen bond or polymer bond in advance, the good lipophilicity of the polyester is utilized, good compatibility of the SBS and the asphalt is realized, the dispersibility and the compatibility of the powder in the asphalt are optimized, and the performance of the modified asphalt is obviously improved.

Description

TECHNICAL FIELD

[0001] The high-performance modified asphalt based on nanocomposites belongs to the technical field of modified asphalt materials. BACKGROUND

[0002] In the field of road engineering, the performance improvement of asphalt materials has always been the focus of research. With the development of nanotechnology, nanocomposite modified asphalt has received widespread attention due to its unique physical and chemical properties. The high specific surface area and high activity of nanomaterials enable them to exhibit excellent performance in modified asphalt, including improving the high-temperature stability, low-temperature crack resistance, and aging resistance of asphalt.

[0003] Chinese patent CN104559263A discloses a kind of nanometer / polymer composite modified asphalt material and its preparation method. The patent discloses a kind of nanometer / polymer composite modified asphalt material composed of nanomaterials, polymers and matrix asphalt. This material provides a kind of composite modified asphalt with good high-temperature rutting resistance and low-temperature crack resistance by combining nano-ZnO, nano-TiO2 or nano-CaCO3 with polymers and matrix asphalt. However, this technology has serious deficiencies in actual use. Because of its large specific surface area and high surface energy, nanomaterials are prone to spontaneous agglomeration and difficult to disperse uniformly in asphalt, which limits their performance in asphalt modification. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the deficiencies of the prior art and provide a high-performance modified asphalt based on nanocomposites with uniform dispersion of nanomaterials.

[0005] The technical solution adopted by the present application to solve its technical problem is: the high-performance modified asphalt based on nanocomposites, characterized in that the raw material weight composition includes: 100 parts of matrix asphalt, 1.5-3 parts of SBS, 1-5 parts of hydroxylated modified nanometer powder composite polyester, 0.1-2 parts of stabilizer, and 0.01-0.5 parts of crosslinking agent.

[0006] The present application utilizes the high specific surface area and high activity of nanomaterials to improve the high-temperature rutting resistance and low-temperature crack resistance of modified asphalt through physical and chemical interactions with asphalt. The present application pre-complexes nanomaterials with polyester materials through hydrogen bonds or polymer bonds, utilizes the good lipophilicity of polyester itself to achieve good compatibility with SBS and asphalt, optimizes the dispersibility and compatibility of the powder in asphalt, and significantly improves the performance of modified asphalt.

[0007] Preferably, the raw material weight parts composition is: 100 parts of base pitch, 2.0~2.5 parts of SBS, 2~4 parts of hydroxyl-modified nano-powder composite polyester, 0.5~1 part of stabilizer, and 0.1~0.2 part of cross-linking agent. The modified pitch of the application shows more excellent comprehensive performance under the preferred weight parts composition.

[0008] Optionally, the stabilizer in the application can use the commonly used stabilizer modified by SBS, preferably a sulfur compound stabilizer, such as diphenyl disulfide, difurfuryl disulfide, ethyl sulfide, dimethyl isooctyl tin mercaptoacetate, and di-n-octyl tin mercaptoacetate. These stabilizers crosslink and graft with the SBS polymer molecular chain and the active functional groups of pitch, so that the polymer and pitch form a stable colloidal system, thereby improving the thermal stability of the modified pitch.

[0009] Specifically, the preparation method of the hydroxyl-modified nano-powder composite polyester is as follows:

[0010] 1) Copolymerization of the copolymer monomers of the polyester under the conditions of a catalyst and heating to prepare a glue solution;

[0011] 2) While maintaining the heating state, 5%~10% of hydroxyl-modified nano-powder by mass of the glue solution is added to the glue solution, and stirring is continued for 2h~4h;

[0012] 3) The product is decontaminated, washed, dried, and formed to obtain the product.

[0013] In the application, the polyester is used as a matrix to composite the hydroxyl-modified nano-powder. The hydroxyl-modified nano-powder is directly added to the reaction system of the polyester glue solution for continuous reaction. The hydroxyl groups of the polyester chain end and the hydroxyl groups of the hydroxyl-modified nano-powder form hydrogen bonds or even ether bonds for compounding, so that the stable hydroxyl-modified nano-powder composite polyester is obtained.

[0014] Preferably, the copolymer monomers in step 1) are polyol, epichlorohydrin, and dianhydride, and the molar ratio of polyol, epichlorohydrin, and dianhydride is 1:20~50:18~45. The polyester chain is polymerized from the epichlorohydrin and the dianhydride in the application. The polyester chain itself has high thermal stability, toughness, and strength, which can ensure the application requirements of pitch materials. The polyester material uses polyol as a starting agent, and a plurality of polyester chains copolymerized from epichlorohydrin and dianhydride are connected thereto. The polyester material can better form molecular entanglement with pitch and SBS, and the thermal stability, toughness, and strength of the modified pitch are higher. The ratio of the epichlorohydrin monomer is slightly higher than that of the dianhydride, so that the chain end of the polyester chain is as hydroxyl as possible, and the compounding with the hydroxyl-modified nano-powder is easier.

[0015] Preferably, the polyol is trimethylol ethane, glycerol, or pentaerythritol.

[0016] Meanwhile, the polyols can also be used as the cross-linking agent in the weight composition of the modified asphalt.

[0017] Preferably, the dianhydride is tetrabromophthalic anhydride, phthalic anhydride, 1,8-naphthalic anhydride or succinic anhydride.

[0018] Preferably, the catalyst in step 1) is sodium methoxide or sodium ethoxide, and the heating condition is heating to 50-90℃, and the reaction time is 4-8h.

[0019] More specifically, the preparation method of the hydroxylated modified nano-powder is as follows: adding nano-powder into NaOH aqueous solution with a concentration of 5-10mol / L, the mass ratio of the NaOH aqueous solution and the nano-powder being 100:1-5, heating to 120-140℃ for hydrothermal synthesis, and the hydrothermal synthesis time being 20-30h; and the product after the hydrothermal synthesis is repeatedly washed with water and acid, and then dried and ground to obtain the product.

[0020] The present application provides a simple preparation method of the hydroxylated modified nano-powder, which can efficiently and at low cost prepare the hydroxylated modified nano-powder, and can be suitable for large-scale use of the modified asphalt.

[0021] Preferably, the nano-powder comprises one or more of nano-ZnO, nano-TiO2 and nano-CaCO3.

[0022] Preferably, in the preparation method of the hydroxylated modified nano-powder, the material before the hydrothermal synthesis is stirred at room temperature for 60-100min.

[0023] The preparation steps of the high-performance modified asphalt based on the nano-composite material are as follows:

[0024] 1) mixing the hydroxylated modified nano-powder, the polyester and the cross-linking agent in a proportion at 200-250℃ to obtain a premix;

[0025] 2) Mix the base asphalt, SBS, stabilizer and premix in the proportion, heat to 170-180℃, stir and mix evenly, then shear with a high-speed shearing machine for 50-90 minutes, cool and store, and develop for 1-2 hours.

[0026] Stirring the mixed raw materials at a temperature of 200-250℃ can promote the cross-linking reaction and increase the cross-linking density of the material. Mix the base asphalt, SBS (styrene-butadiene-styrene block copolymer), stabilizer and premix in the proportion, and heat to 170-180℃, which is beneficial to the compatibility of SBS and asphalt, and can also ensure the effective action of the stabilizer. Shearing the mixture with a high-speed shearing machine can further disperse the nanomaterial and SBS, improve the uniformity of the mixture, and enhance the stability and performance of the modified asphalt. The process can produce high-performance modified asphalt with excellent high and low temperature performance, aging resistance and durability, which is suitable for various harsh road engineering environments.

[0027] Preferably, the stirring and mixing in step 1) is performed in a twin-screw extruder, and the speed of the high-speed shearing machine in step 2) is 600-800 rpm. Using a twin-screw extruder for stirring and mixing and controlling the speed of the high-speed shearing machine can improve the production efficiency and product quality of the modified asphalt, reduce production costs, and ensure the consistency and uniformity of the product.

[0028] Compared with the prior art, the present application has the beneficial effects that: the present application provides a high-performance modified asphalt technology based on nanocomposite materials, which optimizes the dispersibility and compatibility of nanomaterials in asphalt by pre-combining nanometer powder with polyester material, significantly improving the high-temperature rutting resistance and low-temperature cracking resistance of the modified asphalt. The simple hydroxyl-modified nanometer powder preparation method realizes efficient, low-cost mass production, and the use of sulfur compound stabilizer improves the thermal stability. The preferred raw material ratio and preparation conditions further improve the comprehensive performance of the modified asphalt. In addition, the use of a twin-screw extruder and the control of the speed of the high-speed shearing machine improves the production efficiency, reduces the cost, and ensures the consistency and uniformity of the product. The modified asphalt of the present application is not only suitable for various harsh road engineering environments, but also has environmental protection and economic benefits, providing a longer service life and lower maintenance cost solution for road construction. DETAILED DESCRIPTION

[0029] The present application will be further described below in conjunction with specific examples, of which Example 1 is the best mode. The following raw materials are all commercially available.

[0030] Preparation of hydroxyl-modified nanometer ZnO

[0031] The nano-ZnO is added into the aqueous solution of NaOH with a concentration of 7 mol / L, the mass ratio of the aqueous solution of NaOH and the nano-ZnO is 100:3, the material is stirred at room temperature for 80 min, then heated to 130 DEG C for hydrothermal synthesis, the time of hydrothermal synthesis is 25 h; the product after hydrothermal synthesis is repeatedly washed with water, washed with acid, then dried and ground to obtain.

[0032] Preparation of hydroxylated modified nano-TiO2

[0033] The nano-TiO2 is added into the aqueous solution of NaOH with a concentration of 5 mol / L, the mass ratio of the aqueous solution of NaOH and the nano-TiO2 is 100:5, the material is stirred at room temperature for 100 min, then heated to 120 DEG C for hydrothermal synthesis, the time of hydrothermal synthesis is 20 h; the product after hydrothermal synthesis is repeatedly washed with water, washed with acid, then dried and ground to obtain.

[0034] Preparation of hydroxylated modified nano-CaCO3

[0035] The nano-CaCO3 is added into the aqueous solution of NaOH with a concentration of 10 mol / L, the mass ratio of the aqueous solution of NaOH and the nano-CaCO3 is 100:1, the material is stirred at room temperature for 60 min, then heated to 140 DEG C for hydrothermal synthesis, the time of hydrothermal synthesis is 30 h; the product after hydrothermal synthesis is repeatedly washed with water, washed with acid, then dried and ground to obtain.

[0036] Preparation of hydroxylated modified nano-TiO2 composite polyester A

[0037] 1) glycerol, epichlorohydrin, tetrabromophthalic anhydride and sodium methoxide are added into a polymerization kettle according to a molar ratio of 1:35:30:0.0005, the stirring is started and heated to 65 DEG C for copolymerization reaction for 6 h to prepare a glue solution;

[0038] 2) under the heating condition, the prepared hydroxylated modified nano-TiO2 is added into the glue solution with a mass of 8% of the glue solution, the stirring is continued for 3 h;

[0039] 3) the product is decontaminated, washed, dried and formed to obtain.

[0040] Preparation of hydroxylated modified nano-TiO2 composite polyester B

[0041] 1) glycerol, epichlorohydrin, succinic anhydride and sodium methoxide are added into a polymerization kettle according to a molar ratio of 1:35:30:0.0005, the stirring is started and heated to 65 DEG C for copolymerization reaction for 6 h to prepare a glue solution;

[0042] 2) under the heating condition, the prepared hydroxylated modified nano-TiO2 is added into the glue solution with a mass of 8% of the glue solution, the stirring is continued for 3 h;

[0043] 3) The product is obtained by removing impurities, washing, drying and molding.

[0044] Preparation of hydroxyl-modified nano-ZnO composite polyester

[0045] 1) Add trimethylol ethane, epichlorohydrin, phthalic anhydride and sodium methoxide in a molar ratio of 1:20:18:0.0001 into a polymerization kettle, start stirring and heat to 90℃ for 4h to prepare a glue solution;

[0046] 2) Keep heating, add 5% of the prepared hydroxyl-modified nano-ZnO to the glue solution, and continue stirring for 2h;

[0047] 3) The product is obtained by removing impurities, washing, drying and molding.

[0048] Preparation of hydroxyl-modified nano-CaCO3 composite polyester

[0049] 1) Add pentaerythritol, epichlorohydrin, 1,8-naphthalene anhydride and sodium ethoxide in a molar ratio of 1:50:45:0.001 into a polymerization kettle, start stirring and heat to 50℃ for 8h to prepare a glue solution;

[0050] 2) Keep heating, add 10% of the prepared hydroxyl-modified nano-CaCO3 to the glue solution, and continue stirring for 4h;

[0051] 3) The product is obtained by removing impurities, washing, drying and molding. Example 1

[0052] Prepare raw materials by weight parts: base asphalt 100 parts, SBS 2.2 parts, hydroxyl-modified nano-ZnO composite polyester A 3 parts, diphenyl disulfide 0.8 parts, pentaerythritol 0.15 parts.

[0053] 1) Put the hydroxyl-modified nano-ZnO composite polyester A and pentaerythritol into a twin-screw extruder, control the mixing temperature at 230℃, and get the premix;

[0054] 2) According to the proportion, heat the base asphalt, SBS, diphenyl disulfide and premix to 175℃ and stir evenly, then use a high-speed shearing machine for shearing for 70min, the speed of the high-speed shearing machine is 700r / min; cool and store, and develop for 1.5h later. Example 2

[0055] Prepare raw materials by weight parts: base asphalt 100 parts, SBS 2.2 parts, hydroxyl-modified nano-ZnO composite polyester B 3 parts, diphenyl disulfide 0.8 parts, pentaerythritol 0.15 parts.

[0056] 1) Hydroxyl-modified nano-ZnO composite polyester B and pentaerythritol were fed into a twin-screw extruder, and the mixing temperature was controlled at 230℃, and a premix was obtained by discharging;

[0057] 2) The matrix asphalt, SBS, diphenyl disulfide and the premix were mixed uniformly at 175℃ according to the ratio, and then sheared by a high-speed shearing machine for 70 min at a speed of 700 rpm; after cooling and storage, it was developed for 1.5 h. Example 3

[0058] The raw materials were prepared according to the weight parts: matrix asphalt 100 parts, SBS 2.0 parts, hydroxyl-modified nano-ZnO composite polyester A 2 parts, diphenyl disulfide 0.5 parts, and pentaerythritol 0.1 part.

[0059] 1) Hydroxyl-modified nano-ZnO composite polyester A and crosslinking agent were fed into a twin-screw extruder, and the mixing temperature was controlled at 220℃, and a premix was obtained by discharging;

[0060] 2) The matrix asphalt, SBS, stabilizer and the premix were mixed uniformly at 175℃ according to the ratio, and then sheared by a high-speed shearing machine for 80 min at a speed of 700 rpm; after cooling and storage, it was developed for 1.5 h. Example 4

[0061] The raw materials were prepared according to the weight parts: matrix asphalt 100 parts, SBS 2.5 parts, hydroxyl-modified nano-ZnO composite polyester A 4 parts, diphenyl disulfide 1 part, and pentaerythritol 0.2 part.

[0062] 1) Hydroxyl-modified nano-ZnO composite polyester A and crosslinking agent were fed into a twin-screw extruder, and the mixing temperature was controlled at 240℃, and a premix was obtained by discharging;

[0063] 2) The matrix asphalt, SBS, stabilizer and the premix were mixed uniformly at 175℃ according to the ratio, and then sheared by a high-speed shearing machine for 60 min at a speed of 700 rpm; after cooling and storage, it was developed for 1.5 h. Example 5

[0064] The raw materials were prepared according to the weight parts: matrix asphalt 100 parts, SBS 1.5 parts, hydroxyl-modified nano-ZnO composite polyester 5 parts, ethyl sulfide 0.1 part, and trimethylol ethane 0.5 part.

[0065] 1) Hydroxyl-modified nano-ZnO composite polyester A and crosslinking agent were fed into a twin-screw extruder, and the mixing temperature was controlled at 240℃, and a premix was obtained by discharging;

[0066] 2) The matrix asphalt, SBS, stabilizer and premix are mixed uniformly at 170°C by stirring, and then sheared by a high-speed shearing machine for 90 minutes at a speed of 600 revolutions per minute. After cooling and storage, the product is ready for use after 2 hours of post-development. Example 6

[0067] The raw materials are prepared in parts by weight: 100 parts of matrix asphalt, 3 parts of SBS, 1 part of the prepared hydroxyl-modified nano-CaCO3 composite polyester, 2 parts of dimethyl dithioethyltin isooctyl, and 0.01 parts of pentaerythritol.

[0068] 1) The hydroxyl-modified nano-powder composite polyester and the crosslinking agent are fed into a twin-screw extruder, and the mixing temperature is controlled at 250°C. The premix is obtained after discharging;

[0069] 2) The matrix asphalt, SBS, stabilizer and premix are mixed uniformly at 180°C by stirring, and then sheared by a high-speed shearing machine for 50 minutes at a speed of 800 revolutions per minute. After cooling and storage, the product is ready for use after 1 hour of post-development.

[0070] Comparative Example 1

[0071] The raw material formula and process are basically the same as those of Example 1, except that no pentaerythritol as a crosslinking agent is added to the raw materials.

[0072] Comparative Example 2

[0073] The raw material formula and process are basically the same as those of Example 1, except that no SBS and no diphenyl disulfide as a stabilizer are added to the raw materials.

[0074] Comparative Example 3

[0075] The raw material formula and process are basically the same as those of Example 1, except that no premix is prepared in the preparation process, and the raw materials are directly mixed by stirring in step 2).

[0076] The heating aging test and BBR test are performed on each example and comparative example. The experimental results are shown in Tables 1 and 2, respectively.

[0077] Table 1: Results of heating aging test

[0078]

[0079] As can be seen from Table 1, the modified asphalt of the present application has good anti-aging performance, and the formula and method of the present application significantly improve the anti-aging performance of the matrix asphalt.

[0080] Table 2: Results of BBR test

[0081]

[0082] As can be seen from Table 1, the modified asphalt of the embodiment of the present application significantly improves the low-temperature performance of the base asphalt.

[0083] The above description is merely preferred embodiments of the present application, but not a limitation of the present application. Any modification, equivalent replacement and improvement made by any person skilled in the art based on the above description should be within the scope of the present application.

Claims

1. High performance modified bitumen based on nanocomposite, characterized in that, The raw material weight parts composition comprises: base pitch 100 parts, SBS 1.5-3 parts, hydroxyl modified nano powder composite polyester 1-5 parts, stabilizer 0.1-2 parts, crosslinking agent 0.01-0.5 parts; The preparation steps are: 1) hydroxyl modified nano powder composite polyester and crosslinking agent are mixed at 230 DEG C under stirring according to the proportion to obtain a premix; 2) base pitch, SBS, stabilizer and premix are heated to 170 DEG C-180 DEG C under stirring according to the proportion, then sheared by a high-speed shearing machine for 50 min-90 min, cooled and stored, and developed for 1 h-2 h later; The preparation method of the hydroxyl modified nano powder composite polyester is: 1) glycerol, epichlorohydrin and tetrabromophthalic anhydride are mixed according to a molar ratio of 1:35:30, and then copolymerized under the action of a catalyst and heating to form a glue solution; 2) under the heating condition, 5%-10% of hydroxyl modified nano powder by mass of the glue solution is added into the glue solution, and stirring is continued for 2 h-4 h; 3) the product is decontaminated, washed, dried and formed to obtain the product; The catalyst in step 1) is sodium methoxide or sodium ethoxide, and the heating condition is heating to 50 DEG C-90 DEG C; The preparation method of the hydroxyl modified nano powder is: nano powder is added into a NaOH aqueous solution with a concentration of 5 mol / L-10 mol / L, and the mass ratio of the NaOH aqueous solution to the nano powder is 100:1-5, the material is stirred at room temperature for 60 min-100 min, then heated to 120 DEG C-140 DEG C for hydrothermal synthesis, the hydrothermal synthesis time is 20 h-30 h, and the product after hydrothermal synthesis is washed repeatedly with water and acid, and then dried and ground to obtain the product; the nano powder comprises one or more of nano ZnO and nano TiO2.

2. The nanocomposite based high performance modified bitumen according to claim 1, characterized in that, The raw material weight parts composition comprises: base pitch 100 parts, SBS 1.5-3 parts, hydroxyl modified nano powder composite polyester 1-5 parts, stabilizer 0.1-2 parts, crosslinking agent 0.01-0.5 parts; 3. The nanocomposite based high performance modified asphalt as claimed in claim 1 wherein: The stirring and mixing in step 1) is carried out in a double screw extruder; and the rotating speed of the high-speed shearing machine in step 2) is 600-800 rpm.

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