An asphaltene spherulite cluster / thermoplastic polymer composite with high gas barrier and anti-aging properties and a preparation method thereof

Abstract

An asphaltene spherulite / thermoplastic polymer composite with high gas barrier and anti-aging properties and its preparation method. In the present invention, asphaltene is selected as the raw material, and submicron-sized materials, i.e., asphaltene spherulites, are obtained through a hydrothermal method. Then, by using a solution method or a melt method, the asphaltene spherulites are filled into a thermoplastic polymer matrix to design a composite material with high gas barrier and anti-aging properties. The oxygen permeability of the composite film prepared by using the composite material of the present invention has decreased by 48.3%, and the carbon dioxide permeability has decreased by 33%. This is mainly because the filling of asphaltene spherulites increases the crystallinity of high-density polyethylene, and the good dispersion in the high-density polyethylene matrix makes the gas have a more tortuous permeation path in the composite film. At the same time, asphaltene spherulites can absorb ultraviolet light, thereby slowing down the aging effect of ultraviolet light on thermoplastic polymer materials.

Description

Technical Field

[0001] The present invention relates to a preparation method of a composite material, in particular to an asphaltene spherulite cluster / thermoplastic polymer composite material with high gas barrier performance and anti-aging performance and a preparation method thereof. Background Art

[0002] Under the background of "dual carbon", the natural gas industry has developed rapidly. With the continuous increase in the exploration and exploitation of natural gas, the natural gas pipeline transportation network has also developed rapidly. Steel pipes, as commonly used pipelines for long-distance transportation of natural gas, not only provide safety guarantees for natural gas transportation but also are one of the most economical ways. However, steel pipes are extremely vulnerable to corrosion. For example, some impurities (such as carbon dioxide, oxygen, etc.) in the transported natural gas will cause corrosion to the pipeline, resulting in perforation of the pipeline and thus leakage of natural gas. Among them, carbon dioxide corrosion (sweet corrosion) and hydrogen sulfide corrosion (acid corrosion) are the most common corrosion forms. At present, methods such as selecting appropriate anti-corrosion materials, using corrosion inhibitors, and lining or coating with metals and non-metals (including polymers and their composites) are used to alleviate pipeline corrosion. Among them, adding non-metallic lining materials to steel pipelines is becoming a feasible and reliable solution to alleviate corrosion. Polymer lining materials have the advantages of low cost and corrosion resistance. The materials most commonly used as lining pipes for oil and gas pipelines are high-density polyethylene, polyamide, polyvinylidene fluoride, etc. However, the penetration of gases (such as oxygen, carbon dioxide, etc.) under conditions such as pressure reduces the service life of the pipeline. A large number of studies have shown that the permeability of polymers can be effectively reduced by adding lamellar or granular nano-fillers, such as nano-particles of layered silicates (clays), graphene, graphene oxide, silica, titanium dioxide, etc. Among them, graphene and its derivatives have better filling effects, mainly because graphene has a lamellar structure and a very small geometric pore size (0.064 nanometers), which is very effective in improving the gas barrier performance of polymers and is considered to be one of the best nano-fillers for next-generation applications. However, graphene and its derivatives are mainly used to prepare high gas barrier performance composite materials by mixing with polymers as two-dimensional materials, but their preparation costs are relatively high and are not suitable for large-scale industrial applications. Summary of the Invention

[0003] The purpose of the present invention is to provide an asphaltene spherulite cluster / thermoplastic polymer composite material with high gas barrier and anti-aging performance and a preparation method thereof.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] 1) Preparation of asphaltene spherulite clusters:

[0006] Take 200 - 500 mg of asphaltene and 40 - 50 ml of organic solvent and add them to a reaction kettle for solvothermal reaction. After the reaction mixture cools to room temperature, use a filter membrane with a pore size of less than 0.5 microns to perform suction filtration on it, and rotary evaporate the filtrate to obtain asphaltene spherulite cluster powder;

[0007] 2) Prepare asphaltene spherulite cluster / thermoplastic polymer composites by solution method or melt method:

[0008] Solution method

[0009] Add 2 - 8 g of thermoplastic polymer powder and 80 - 150 ml of xylene, toluene or ortho - dichlorobenzene to a round - bottom flask, stir at 140 - 170 °C and 500 - 1200 revolutions per minute to obtain a thermoplastic polymer solution;

[0010] Add 20 - 120 mg of asphaltene spherulite cluster powder and 70 - 120 ml of xylene, toluene or ortho - dichlorobenzene to a beaker, stir at 500 - 1200 revolutions per minute at room temperature to obtain an asphaltene spherulite cluster dispersion;

[0011] Use a dropper to slowly add the asphaltene spherulite cluster dispersion to the thermoplastic polymer solution at 140 - 170 °C, stir evenly at 500 - 1200 revolutions per minute, pour it into 50 - 100 ml of acetone and stir for sedimentation. Remove the organic solvent from the precipitate at - 0.08 - 0.09 MPa and 70 - 80 °C by rotary evaporation or vacuum drying to obtain asphaltene spherulite cluster / thermoplastic polymer composites;

[0012] Melt method

[0013] Take 20 - 60 g of thermoplastic polymer particles and add them to the sample loading cavity of a torque rheometer. Raise the temperature to 150 - 170 °C. After the thermoplastic polymer particles are completely melted, add 200 - 1200 mg of asphaltene spherulite cluster powder, stir evenly at 10 - 30 revolutions per minute, and then lower the temperature to below 120 °C to obtain asphaltene spherulite cluster / thermoplastic polymer composites.

[0014] The asphaltene in step 1) is obtained from natural asphalt, petroleum asphalt, tar asphalt (i.e., coal tar pitch), shale asphalt or wood asphalt, and synthetic asphalt (i.e., synthetic asphalt with naphthalene, anthracene, methylnaphthalene aromatic hydrocarbons as raw materials).

[0015] The organic solvents in step 1) include alcohols: methanol, ethanol, isopropanol; esters: methyl acetate, ethyl acetate, propyl acetate; ethers: diethyl ether, propylene oxide; ketones: acetone, methyl butyl ketone, methyl isobutyl ketone; aromatic hydrocarbons: benzene, toluene, xylene; aliphatic hydrocarbons: pentane, hexane, octane; cycloaliphatic hydrocarbons: cyclohexane, cyclohexanone, toluene cyclohexanone; halogenated hydrocarbons: chlorobenzene, dichlorobenzene, dichloromethane; pyridine, phenol, or a mixture of one or more of them.

[0016] The solvothermal reaction in step 1) is carried out at 200 °C - 285 °C for 2 h - 3 h.

[0017] The diameter of the asphaltene spherulite cluster powder obtained in step 1) is 2 - 4 microns.

[0018] The thermoplastic polymers in step 2) include low-density polyethylene, high-density polyethylene, polypropylene, polystyrene, polyvinyl alcohol, polymethyl methacrylate, polyvinyl chloride, acrylonitrile-butadiene-styrene, polyoxymethylene, nylon, polycarbonate, polyphenylene ether, polysulfone, polyphenylene sulfide, polyethylene terephthalate, polybutylene terephthalate, or polypropylene terephthalate.

[0019] The asphaltene spherulite / thermoplastic polymer composite prepared by the above method has high gas barrier and anti-aging properties, can absorb ultraviolet light, and has an absorption response to ultraviolet light with a wavelength of 200 - 400 nanometers.

[0020] Considering that the filler-polymer interaction and the preparation method of polymer nanocomposites play a great role in controlling the dispersion of nanofillers in the matrix and affecting the control of composite material properties. In the present invention, asphaltene is selected as the raw material, and submicron materials - asphaltene spherulites are obtained by the solvothermal method, and they are filled into the thermoplastic polymer matrix by the solution method or the melt method to obtain an asphaltene spherulite / thermoplastic polymer composite with high gas barrier and anti-aging properties. Compared with the high-density polyethylene film, the oxygen permeability of the film made of the asphaltene spherulite / thermoplastic polymer composite decreased by 48.3%, and the carbon dioxide permeability decreased by 33%. This is mainly because the filling of asphaltene spherulites improves the crystallinity of the thermoplastic polymer, and the good dispersion in the thermoplastic polymer matrix makes the gas have a more tortuous permeation path in the composite film. Dynamic mechanical analysis shows that the addition of asphaltene spherulites makes the rigidity of the thermoplastic polymer film better, and the glass transition temperature increases, and it is not easy to be deformed by heat. This result shows that asphaltene can be used as a high-performance gas barrier material with high added value and has potential application prospects in the long-term safe service of oil and gas pipelines.

[0021] In addition, the surface of the prepared asphaltene spherulites contains multiple functional groups, such as alkanes, amorphous carbon, carbonyl groups, carboxyl groups, nitro groups, esters, amines, amides and their combinations. The asphaltene spherulites are associated with the polymer composite. The asphaltene spherulites are associated with the polymer through at least one of hydrogen bond interaction, van der Waals interaction, adsorption, physical adsorption, self-assembly and their combinations. The asphaltene spherulites are used in the fields of oil and gas storage and transportation, food packaging, electronic packaging, tires, inflatable medical devices, inflatable daily necessities, etc. Description of the Drawings

[0022] Figure 1Using ethanol as the solvent, the sample preparation concentrations of asphaltene and asphaltene clusters are both 100 ppm. a Scanning electron microscope image of asphaltene deposited on a silicon wafer; b Scanning electron microscope image of asphaltene clusters deposited on a silicon wafer; c High-resolution image of b; d Atomic force microscope image of asphaltene clusters deposited on a mica sheet;

[0023] Figure 2 Sample preparation of asphaltene cluster powder. a Scanning electron microscope image of asphaltene deposited on a silicon wafer; b High-resolution image of a;

[0024] Figure 3 X-ray diffraction spectrograms of asphaltene and asphaltene clusters;

[0025] Figure 4 a Full spectrum of X-ray photoelectron spectroscopy of asphaltene, b and c are the C1s and O1s spectra of asphaltene respectively; d Full spectrum of X-ray photoelectron spectroscopy of asphaltene clusters, e and f are the C1s and O1s spectra of asphaltene clusters respectively

[0026] Figure 5 a and b respectively represent the trend graphs of oxygen and carbon dioxide permeabilities of high-density polyethylene composite films with different fillers varying with the filling ratio and preparation method;

[0027] Figure 6 a Differential scanning calorimetry analysis graph of asphaltene cluster / high-density polyethylene composite films with different filling ratios prepared by the melting method; b Trend graph of the relative crystallinity change of asphaltene cluster / high-density polyethylene composite films with different filling ratios prepared by the melting method;

[0028] Figure 7 Film quenched by liquid nitrogen freezing. a Cross-sectional scanning electron microscope image of a high-density polyethylene film; b Cross-sectional scanning electron microscope image of a 3wt% asphaltene cluster / high-density polyethylene composite film prepared by the melting method; c, d High-resolution images of a 3wt% asphaltene cluster / high-density polyethylene composite film prepared by the melting method;

[0029] Figure 8 Film treated by liquid nitrogen freezing. a Cross-sectional scanning electron microscope image of a 3wt% asphaltene cluster / high-density polyethylene composite film prepared by the solution method; b High-resolution image of a;

[0030] Figure 9 a Particle size distribution graph of asphaltene clusters with different concentrations; b Zeta potential distribution graph of asphaltene clusters with a concentration of 500 ppm;

[0031] Figure 10 Performance comparison of high-density polyethylene and asphaltene cluster / high-density polyethylene composite films. a Stress-strain curve; b Variation of storage modulus with temperature; c Variation of loss modulus with temperature; d Variation of damping factor with temperature;

[0032] Figure 11 Asphaltene clusters are dispersed in ethanol at a concentration of 50 ppm. a Ultraviolet absorption spectra of asphaltene clusters and high-density polyethylene composite films, b Stress-strain curves of high-density polyethylene and its composite films before and after aging. Detailed implementation manners

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0034] Embodiment 1:

[0035] 1) Preparation of asphaltene clusters:

[0036] Take 200 mg of natural asphalt and 40 ml of methanol and add them to a reaction kettle for solvothermal reaction at 200 °C for 3 h. After the reaction mixture cools to room temperature, filter it through a filter membrane with a pore size of less than 0.5 microns, and rotary evaporate the filtrate to obtain asphaltene cluster powder;

[0037] 2) Preparation of asphaltene cluster / thermoplastic polymer composite by solution method:

[0038] Add 2 g of low-density polyethylene powder and 80 ml of xylene to a round-bottom flask and stir at 140 °C and 500 revolutions per minute to obtain a low-density polyethylene solution;

[0039] Add 20 mg of asphaltene cluster powder and 70 ml of xylene to a beaker and stir at room temperature at 500 revolutions per minute to obtain an asphaltene cluster dispersion;

[0040] Use a dropper to slowly add the asphaltene cluster dispersion to the low-density polyethylene solution at 140 °C, stir evenly at 500 revolutions per minute, pour it into 50 ml of acetone and stir for sedimentation. The precipitate is dried by rotary evaporation or vacuum drying at -0.08 MPa and 70 °C to remove the organic solvent to obtain asphaltene cluster / low-density polyethylene composite.

[0041] Embodiment 2:

[0042] 1) Preparation of asphaltene clusters:

[0043] Take 400 mg of petroleum asphalt and 48 ml of methyl acetate and add them to a reaction kettle for solvothermal reaction at 220 °C for 2 h. After the reaction mixture cools to room temperature, filter it through a filter membrane with a pore size of less than 0.5 microns, and rotary evaporate the filtrate to obtain asphaltene cluster powder;

[0044] 2) Preparation of asphaltene cluster / thermoplastic polymer composite by solution method:

[0045] Solution method

[0046] Add 5 g of high-density polyethylene powder and 120 ml of toluene into a round-bottom flask, and stir at 150 °C and 1000 revolutions per minute to obtain a high-density polyethylene solution;

[0047] Add 100 mg of asphaltene spherulite powder and 110 ml of toluene into a beaker, and stir at room temperature and 1000 revolutions per minute to obtain an asphaltene spherulite dispersion;

[0048] Slowly add the asphaltene spherulite dispersion into the high-density polyethylene solution at 150 °C using a dropper, stir evenly at 1000 revolutions per minute, pour it into 60 ml of acetone and stir for sedimentation. The precipitate is dried by rotary evaporation or vacuum drying at -0.09 MPa and 75 °C to remove the organic solvent to obtain an asphaltene spherulite / high-density polyethylene composite.

[0049] Example 3:

[0050] 1) Preparation of asphaltene spherulites:

[0051] Take 300 mg of coal tar pitch and 43 ml of diethyl ether and add them into a reaction kettle, carry out a solvothermal reaction at 240 °C for 2.5 h. After the reaction mixture cools to room temperature, filter it using a filter membrane with a pore size of less than 0.5 microns, and rotary evaporate the filtrate to obtain asphaltene spherulite powder;

[0052] 2) Preparation of asphaltene spherulite / thermoplastic polymer composite by solution method:

[0053] Add 3 g of polypropylene powder and 90 ml of ortho-dichlorobenzene into a round-bottom flask, and stir at 160 °C and 800 revolutions per minute to obtain a polypropylene solution;

[0054] Add 80 mg of asphaltene spherulite powder and 100 ml of ortho-dichlorobenzene into a beaker, and stir at room temperature and 800 revolutions per minute to obtain an asphaltene spherulite dispersion;

[0055] Slowly add the asphaltene spherulite dispersion into the polypropylene solution at 160 °C using a dropper, stir evenly at 800 revolutions per minute, pour it into 70 ml of acetone and stir for sedimentation. The precipitate is dried by rotary evaporation or vacuum drying at -0.08 MPa and 72 °C to remove the organic solvent to obtain an asphaltene spherulite / polypropylene composite.

[0056] Example 4:

[0057] 1) Preparation of asphaltene spherulites:

[0058] Take 280 mg of wood tar pitch and 42 ml of acetone and add them into a reaction kettle, carry out a solvothermal reaction at 260 °C for 3 h. After the reaction mixture cools to room temperature, filter it using a filter membrane with a pore size of less than 0.5 microns, and rotary evaporate the filtrate to obtain asphaltene spherulite powder;

[0059] 2) Preparation of asphaltene spherulite / thermoplastic polymer composite by solution method:

[0060] Add 6 g of polystyrene powder and 130 ml of xylene into a round-bottom flask, stir at 145 °C and 600 rpm to obtain a polystyrene solution;

[0061] Add 60 mg of asphaltene spherulite powder and 90 ml of xylene into a beaker, stir at room temperature and 600 rpm to obtain an asphaltene spherulite dispersion;

[0062] Slowly add the asphaltene spherulite dispersion into the polystyrene solution at 145 °C using a dropper, stir evenly at 600 rpm, pour it into 80 ml of acetone and stir for sedimentation. Remove the organic solvent from the precipitate at -0.09 MPa and 78 °C by rotary evaporation or vacuum drying to obtain the asphaltene spherulite / polystyrene composite.

[0063] Example 5:

[0064] 1) Preparation of asphaltene spherulite:

[0065] Take 350 mg of asphaltene obtained from synthetic asphalt with naphthalene as the raw material and 45 ml of benzene, add them into a reaction kettle, carry out a solvothermal reaction at 280 °C for 2 h. After the reaction mixture cools to room temperature, filter it through a filter membrane with a pore size of less than 0.5 microns, and carry out rotary evaporation on the filtrate to obtain asphaltene spherulite powder;

[0066] 2) Preparation of asphaltene spherulite / thermoplastic polymer composite by solution method:

[0067] Add 4 g of polyvinyl alcohol powder and 100 ml of toluene into a round-bottom flask, stir at 165 °C and 1200 rpm to obtain a polyvinyl alcohol solution;

[0068] Add 40 mg of asphaltene spherulite powder and 80 ml of toluene into a beaker, stir at room temperature and 1200 rpm to obtain an asphaltene spherulite dispersion;

[0069] Slowly add the asphaltene spherulite dispersion into the polyvinyl alcohol solution at 165 °C using a dropper, stir evenly at 1200 rpm, pour it into 90 ml of acetone and stir for sedimentation. Remove the organic solvent from the precipitate at -0.09 MPa and 80 °C by rotary evaporation or vacuum drying to obtain the asphaltene spherulite / polyvinyl alcohol composite.

[0070] Example 6:

[0071] 1) Preparation of asphaltene spherulite:

[0072] 220 mg of anthracene was used as the raw material to obtain asphaltene in the synthetic asphalt, and 41 ml of a mixed solution of pentane, toluene, and cyclohexanone was added to the reaction kettle. The solvothermal reaction was carried out at 210 °C for 2.5 h. After the reaction mixture was cooled to room temperature, it was filtered by suction using a filter membrane with a pore size of less than 0.5 microns, and the filtrate was rotary evaporated to obtain asphaltene nanosphere cluster powder;

[0073] 2) Preparation of asphaltene nanosphere cluster / thermoplastic polymer composite by solution method:

[0074] 8 g of polymethyl methacrylate powder and 150 ml of o-dichlorobenzene were added to a round-bottom flask and stirred at 155 °C and 900 rpm to obtain a polymethyl methacrylate solution;

[0075] 120 mg of asphaltene nanosphere cluster powder and 120 ml of o-dichlorobenzene were added to a beaker and stirred at room temperature at 900 rpm to obtain an asphaltene nanosphere cluster dispersion;

[0076] The asphaltene nanosphere cluster dispersion was slowly added to the polymethyl methacrylate solution at 155 °C using a dropper, stirred evenly at 900 rpm, poured into 85 ml of acetone, stirred and settled, and the precipitate was rotary evaporated or vacuum dried at -0.09 MPa and 75 °C to remove the organic solvent to obtain asphaltene nanosphere cluster / polymethyl methacrylate composite.

[0077] Example 7:

[0078] 1) Preparation of asphaltene nanosphere cluster:

[0079] 340 mg of methylnaphthalene aromatic hydrocarbon was used as the raw material to obtain asphaltene in the synthetic asphalt, and 44 ml of chlorobenzene was added to the reaction kettle. The solvothermal reaction was carried out at 230 °C for 3 h. After the reaction mixture was cooled to room temperature, it was filtered by suction using a filter membrane with a pore size of less than 0.5 microns, and the filtrate was rotary evaporated to obtain asphaltene nanosphere cluster powder;

[0080] 2) Preparation of asphaltene nanosphere cluster / thermoplastic polymer composite by solution method:

[0081] 7 g of polyvinyl chloride powder and 140 ml of xylene were added to a round-bottom flask and stirred at 170 °C and 1100 rpm to obtain a polyvinyl chloride solution;

[0082] 50 mg of asphaltene nanosphere cluster powder and 85 ml of xylene were added to a beaker and stirred at room temperature at 1100 rpm to obtain an asphaltene nanosphere cluster dispersion;

[0083] Slowly add the asphaltene spherulite dispersion to the polyvinyl chloride solution at 170 °C using a dropper, stir evenly at 1100 revolutions per minute, pour it into 100 ml of acetone, stir and settle, and remove the organic solvent from the precipitate at -0.08 MPa and 78 °C by rotary evaporation or vacuum drying to obtain the asphaltene spherulite / polyvinyl chloride composite material.

[0084] Example 8:

[0085] 1) Preparation of asphaltene spherulites:

[0086] Take 260 mg of natural asphalt and 42 ml of isopropanol and add them to a reaction kettle for solvothermal reaction at 250 °C for 3 h. After the reaction mixture cools to room temperature, filter it through a filter membrane with a pore size of less than 0.5 microns by suction filtration, and rotary evaporate the filtrate to obtain asphaltene spherulite powder;

[0087] 2) Preparation of asphaltene spherulite / thermoplastic polymer composite by melting method:

[0088] Take 20 g of acrylonitrile-butadiene-styrene particles and add them to the sample loading cavity of a torque rheometer. Raise the temperature to 140 °C. After the acrylonitrile-butadiene-styrene particles are completely melted, add 200 mg of asphaltene spherulite powder, stir evenly at 10 revolutions per minute, and then lower the temperature to below 120 °C to obtain asphaltene spherulite / acrylonitrile-butadiene-styrene composite material.

[0089] Example 9:

[0090] 1) Preparation of asphaltene spherulites:

[0091] Take 380 mg of petroleum asphalt and 47 ml of ethyl acetate and add them to a reaction kettle for solvothermal reaction at 270 °C for 2 h. After the reaction mixture cools to room temperature, filter it through a filter membrane with a pore size of less than 0.5 microns by suction filtration, and rotary evaporate the filtrate to obtain asphaltene spherulite powder;

[0092] 2) Preparation of asphaltene spherulite / thermoplastic polymer composite by melting method:

[0093] Take 30 g of nylon particles and add them to the sample loading cavity of a torque rheometer. Raise the temperature to 150 °C. After the nylon particles are completely melted, add 400 mg of asphaltene spherulite powder, stir evenly at 20 revolutions per minute, and then lower the temperature to below 120 °C to obtain asphaltene spherulite / nylon composite material.

[0094] Example 10:

[0095] 1) Preparation of asphaltene spherulites:

[0096] Take 430 mg of coal tar pitch and 48 ml of propylene oxide and add them to a reaction kettle. Perform solvothermal reaction at 285 °C for 2.5 h. After the reaction mixture cools to room temperature, use a filter membrane with a pore size of less than 0.5 microns to perform suction filtration on it, and perform rotary evaporation on the filtrate to obtain asphaltene sphere cluster powder;

[0097] 2) Preparation of asphaltene sphere cluster / thermoplastic polymer composite by melt method:

[0098] Take 40 g of polycarbonate particles and add them to the sample loading cavity of a torque rheometer. Raise the temperature to 160 °C. After the polycarbonate particles are completely melted, add 600 mg of asphaltene sphere cluster powder. After stirring evenly at 15 revolutions per minute, lower the temperature to below 120 °C to obtain asphaltene sphere cluster / polycarbonate composite.

[0099] Example 11:

[0100] 1) Preparation of asphaltene sphere clusters:

[0101] Take 450 mg of shale asphalt and 49 ml of methyl isobutyl ketone and add them to a reaction kettle. Perform solvothermal reaction at 265 °C for 2.5 h. After the reaction mixture cools to room temperature, use a filter membrane with a pore size of less than 0.5 microns to perform suction filtration on it, and perform rotary evaporation on the filtrate to obtain asphaltene sphere cluster powder;

[0102] 2) Preparation of asphaltene sphere cluster / thermoplastic polymer composite by melt method:

[0103] Take 50 g of polyphenylene ether particles and add them to the sample loading cavity of a torque rheometer. Raise the temperature to 1405 °C. After the polyphenylene ether particles are completely melted, add 1000 mg of asphaltene sphere cluster powder. After stirring evenly at 25 revolutions per minute, lower the temperature to below 120 °C to obtain asphaltene sphere cluster / polyphenylene ether composite.

[0104] Example 12:

[0105] 1) Preparation of asphaltene sphere clusters:

[0106] Take 480 mg of asphaltene obtained from synthetic asphalt with naphthalene as the raw material and 47 ml of xylene and add them to a reaction kettle. Perform solvothermal reaction at 235 °C for 2.5 h. After the reaction mixture cools to room temperature, use a filter membrane with a pore size of less than 0.5 microns to perform suction filtration on it, and perform rotary evaporation on the filtrate to obtain asphaltene sphere cluster powder;

[0107] 2) Preparation of asphaltene sphere cluster / thermoplastic polymer composite by melt method:

[0108] Add 60 g of polyphenylene sulfide particles into the sample loading cavity of a torque rheometer. Raise the temperature to 165 °C. After the polyphenylene sulfide particles are completely melted, add 1,200 mg of asphaltene cluster powder. After stirring evenly at 30 revolutions per minute, lower the temperature to below 120 °C to obtain an asphaltene cluster / polyphenylene sulfide composite material.

[0109] Example 13:

[0110] 1) Preparation of asphaltene clusters:

[0111] Take 500 mg of asphaltene obtained from synthetic asphalt with anthracene as the raw material and 50 ml of octane and add them into a reaction kettle. Carry out a solvothermal reaction at 275 °C for 3 h. After the reaction mixture cools to room temperature, select a filter membrane with a pore size of less than 0.5 microns to carry out suction filtration on it, and perform rotary evaporation on the filtrate to obtain asphaltene cluster powder;

[0112] 2) Preparation of asphaltene cluster / thermoplastic polymer composite material by the melting method:

[0113] Take 45 g of polyethylene terephthalate particles and add them into the sample loading cavity of a torque rheometer. Raise the temperature to 155 °C. After the polyethylene terephthalate particles are completely melted, add 800 mg of asphaltene cluster powder. After stirring evenly at 20 revolutions per minute, lower the temperature to below 120 °C to obtain an asphaltene cluster / polyethylene terephthalate composite material.

[0114] Example 14:

[0115] 1) Preparation of asphaltene clusters:

[0116] Take 320 mg of asphaltene obtained from synthetic asphalt with methylnaphthalene aromatic hydrocarbon as the raw material and 45 ml of a mixed solution of dichloromethane and phenol and add them into a reaction kettle. Carry out a solvothermal reaction at 255 °C for 2.5 h. After the reaction mixture cools to room temperature, select a filter membrane with a pore size of less than 0.5 microns to carry out suction filtration on it, and perform rotary evaporation on the filtrate to obtain asphaltene cluster powder;

[0117] 2) Preparation of asphaltene cluster / thermoplastic polymer composite material by the melting method:

[0118] Take 35 g of polytrimethylene terephthalate particles and add them into the sample loading cavity of a torque rheometer. Raise the temperature to 170 °C. After the polytrimethylene terephthalate particles are completely melted, add 500 mg of asphaltene cluster powder. After stirring evenly at 30 revolutions per minute, lower the temperature to below 120 °C to obtain an asphaltene cluster / polytrimethylene terephthalate composite material.

[0119] Mechanical property test

[0120] The stress-strain test was carried out using a dynamic thermomechanical analyzer (TA Instruments, USA) of model DMA 850. The test of the curves of damping factor, storage modulus, and loss modulus with temperature change was performed using a dynamic thermomechanical analyzer (NETZSCH, Germany) of model DMA 242. The composite material prepared by the present invention was made into a film sample in the shape of a rectangle with a cutting size of 30 mm × 6 mm × 0.1 mm. The temperature was raised from -130 °C to 100 °C at a rate of 2 °C / minute, a frequency of 1 Hz, and a strain of 1%. The static force was set to 0.01 N, and the dynamic force was set to 0.1 N.

[0121] Gas barrier property test

[0122] The gas (carbon dioxide, oxygen) permeability test of the film was carried out using a differential pressure method gas permeation meter (Labthink Instruments Co., Ltd., Jinan, China) of model VAC-V2. Unless otherwise specified, the gas permeability was tested at 23 °C and 0% relative humidity. The film thickness was measured using an EVERETT digital thickness gauge. The diameter of the film was 10 cm, and the thickness was 100 ± 7 μm. The reported effective gas permeability represents the average value of three independent experiments for each sample.

[0123] Advantages of the present invention:

[0124] The present invention discloses a process for preparing asphaltene-based spheres and forming a composite film with high-density polyethylene. The main advantages are as follows:

[0125] 1. Asphaltene was selected as the raw material, improving the high-value utilization of asphalt;

[0126] 2. Ethanol was selected as the solvent in the supercritical process and can be reused, saving resources and being environmentally friendly;

[0127] 3. The doping of asphaltene-based sphere clusters sets up "roadblocks" for the free movement of gas molecules, effectively extending the gas permeation path and increasing the crystallinity of the high-density polyethylene material, thereby improving the gas barrier property of the high-density polyethylene film;

[0128] 4. The preparation method is simple. The melting method is selected for the preparation method, which can effectively reduce the use of solvents, is environmentally friendly, and is suitable for industrial production.

[0129] Microstructure and composition analysis of asphaltene sphere clusters

[0130] The shape of the asphaltene sphere clusters obtained after the solvent heat treatment of asphaltene is completely different from that of the raw material asphaltene. The microstructure of asphaltene is an irregular block structure ( Figure 1 a); while the microstructure of the asphaltene sphere clusters dispersed in ethanol is a flaky structure with an average diameter of 130 nm and an average thickness of 15.5 nm ( Figure 1b–d), the microstructure in powder form is micron-sized spheres ( Figure 2 a, b). Asphaltene is a synthetic asphalt with pure aromatic compound naphthalene as raw material. The X-ray diffraction characterization results of asphaltene and asphaltene spherulites prove their layered aromatic hydrocarbon structure. The X-ray diffraction spectra ( Figure 3 ) of both have two obvious broad peaks (about 24° and 44°), corresponding to the (002) peak with an ordered arrangement structure similar to graphite and the stacking degree (100) peak of the hexagonal ordered structure respectively. In addition, the elemental composition in asphaltene and asphaltene spherulites was studied by X-ray photoelectron spectroscopy. The X-ray photoelectron spectroscopy measurement scanning spectra ( Figure 4 a, d) of both show two characteristic peaks of C1s and O 1s, and the positions of the characteristic peaks hardly change, indicating that the elemental composition of asphaltene and asphaltene spherulites is the same; however, the C content of asphaltene decreases and the O content increases. It may be that some aromatic hydrocarbon molecules are oxidized during the reaction, resulting in an increase in the O content of asphaltene; the high-resolution C1s spectra and O1s spectra of asphaltene and asphaltene spherulites both show C–C / C═C, C–O ( Figure 4 b, e) and C–O, C═O ( Figure 4 c, f) characteristic peaks, among which the C–C / C═C content is the highest, which corresponds to the aromatic ring structure in asphaltene and asphaltene spherulites.

[0131] Gas barrier properties of asphaltene spherulite / high-density polyethylene composite films

[0132] Currently, more research is focused on using two-dimensional materials such as layered silicates, graphene and its derivatives as fillers to improve the gas barrier properties of polymers. In this paper, montmorillonite in layered silicates and graphene oxide in graphene and its derivatives are selected as fillers, and high-density polyethylene is used as the matrix to form a composite film, which is used as a control group to study the influence of asphaltene spherulites on the oxygen and carbon dioxide permeabilities of high-density polyethylene films. As Figure 5As shown in the figure, the changing trends of the oxygen and carbon dioxide permeabilities of the composite films prepared by the solution method are related to the types and proportions of the fillers. The oxygen and carbon dioxide permeabilities of the graphene oxide / high-density polyethylene composite films prepared by the solution method first decrease and then increase with the increase of the filling ratio. This is mainly because with the increase of the filling ratio, the aggregation of graphene oxide becomes more obvious, resulting in more defects in the high-density polyethylene film, causing the increase of the oxygen and carbon dioxide permeabilities. The oxygen and carbon dioxide permeabilities of the montmorillonite / high-density polyethylene composite films prepared by the ball milling method continuously decrease with the increase of the filling ratio. When the filling ratio is 3wt%, the oxygen permeability of the composite film decreases by about 22.3%, and the carbon dioxide permeability decreases by about 2%. The oxygen and carbon dioxide permeabilities of the asphaltene clusters / high-density polyethylene composite films prepared by the solution method also continuously decrease with the increase of the filling ratio, but the decreasing trend is greater. When the filling ratio is 3wt%, the oxygen permeability of the composite film decreases by about 33.2%, and the carbon dioxide permeability decreases by about 24%. In this paper, the raw material asphaltene was also selected as the filler to study the oxygen and carbon dioxide permeabilities of the asphaltene / high-density polyethylene composite films. The results show that when the filling ratio is low, its oxygen and carbon dioxide permeabilities decrease to a certain extent and are better than those of graphene oxide. However, with the increase of the filling ratio, its oxygen and carbon dioxide permeabilities do not decrease but increase instead. This is mainly because with the increase of the filling ratio, the aggregation of asphaltene becomes more obvious, resulting in more defects in the high-density polyethylene film, causing the increase of the oxygen and carbon dioxide permeabilities. Through the above comparison, the filling of asphaltene clusters has a good effect on reducing the oxygen and carbon dioxide permeabilities of high-density polyethylene films. Although the asphaltene cluster powder can be well dispersed in organic solvents, the uniformity of the composite films prepared by the solution method is poor. This may be due to the weak interfacial binding force between asphaltene clusters and high-density polyethylene, and the better dispersion effect of asphaltene clusters in organic substances. However, the uniformity of the asphaltene clusters / high-density polyethylene composite films prepared by the melting method is good, and their oxygen and carbon dioxide permeabilities were studied. The results show that when the filling ratio is 3wt%, the oxygen permeability of the composite film decreases by about 48.3%, and the carbon dioxide permeability decreases by about 33%. Comparing the oxygen and carbon dioxide permeabilities of the asphaltene clusters / high-density polyethylene composite films prepared by the melting method and the solution method, the oxygen and carbon dioxide permeabilities of the composite films prepared by the melting method decrease more. The main reason is that at high temperatures, the fluidity of high-density polyethylene is better, and the asphaltene cluster powder continuously diffuses in the high-density polyethylene matrix through stirring, resulting in better uniformity of the composite film.The oxygen permeability of the high-density polyethylene composite film is lower than that of carbon dioxide, mainly because the kinetic diameter of oxygen (the diameter of oxygen is 0.346 nm) is higher than that of carbon dioxide (the diameter of carbon dioxide is 0.330 nm). During the diffusion process, the energy required for oxygen is higher than that of carbon dioxide, resulting in a smaller diffusion coefficient of oxygen than that of carbon dioxide. According to the solution-diffusion mechanism, the permeability coefficient is equal to the product of the solubility coefficient and the diffusion coefficient. Therefore, the oxygen permeability is less than the carbon dioxide permeability.

[0133] The gas barrier performance of the polymer film reflects the ability of the film to hinder the penetration of gas molecules. Whether a gas can pass through the film is determined by the diffusion rate of gas molecules, which depends on the crystallinity of the polymer film, the size of gas molecules, the aspect ratio of the filler, etc. According to the differential scanning calorimetry scanning curve of the asphalt spherulite / high-density polyethylene composite film prepared by the melting method with different filling ratios ( Figure 6 a), its relative crystallinity can be analyzed, and the relative crystallinity is calculated according to the following formula:

[0134]

[0135] where ΔH m is the heat of fusion of the polymer, is the heat of fusion of 100% crystallization of the polymer, with the unit of joule / gram. The theoretical heat of fusion of 100% crystallization of polyethylene is 286.7 joules / gram. With the increase of the filling ratio of asphalt spherulites, the relative crystallinity of the asphalt spherulite / high-density polyethylene composite film prepared by the melting method also increases continuously ( Figure 6 b), indicating that the addition of asphalt spherulites increases the crystallinity of the high-density polyethylene film. This is consistent with the reported literature that the increase in the crystallinity of the polymer can reduce its gas permeability. It may be that during the film pressing process, the chain segment orientation arrangement introduced by the extension of high-density polyethylene from the center to the outside and the addition of asphalt spherulites make the molecular chains of high-density polyethylene more ordered. From a microscopic perspective, the high-density polyethylene film is a disordered network structure ( Figure 7 a), and the asphalt spherulites in the 3wt% asphalt spherulite / high-density polyethylene composite film prepared by the melting method are wrapped by high-density polyethylene chains ( Figure 7 b, d), making the high-density polyethylene film denser to a certain extent, and micron-sized asphalt spherulite particles can also be observed ( Figure 7 c). Comparing the dispersion of asphalt spherulites in the 3wt% asphalt spherulite / high-density polyethylene prepared by the melting method and the solution method ( Figure 8 a, b), the asphalt spherulites are more evenly dispersed in the composite film prepared by the melting method. According to the analysis of the nanoparticle size analyzer, the particle size of asphalt spherulites increases with the increase of concentration ( Figure 9a), the average zeta potential of the asphaltene spherulite suspension (using ethanol as the solvent and with a concentration of 500 ppm) is 7.8 mV ( Figure 9 b), some of the asphaltene spherulite surfaces are negatively charged. Therefore, under the action of electrostatic force, the asphaltene spherulite molecules will attract each other and self-assembly will occur. Therefore, during the preparation of the asphaltene spherulite / high-density polyethylene composite film by the melting method, as the filling ratio of the asphaltene spherulites increases, the possibility of their self-assembly becomes greater.

[0136] Based on the above analysis, the filling of asphaltene spherulites can not only extend the gas transport path and play a physical barrier role, but also improve the relative crystallinity of the high-density polyethylene film. At the same time, the self-assembly of asphaltene spherulites forms an irregular rough surface, which can adsorb gas to a certain extent, thereby further reducing the gas permeability of the film. It can be known from the specific surface area and porosity analyzer that the surface pore diameter of the asphaltene spherulites is 14.36 nm and the surface area is 1.37 m² / g. Therefore, the filling of asphaltene spherulites can significantly reduce the oxygen and carbon dioxide permeabilities of the high-density polyethylene film, and has a good effect at a low filling ratio: the oxygen permeability of the 1wt% asphaltene spherulite / high-density polyethylene composite film prepared by the melting method is about 41.8% lower than that of the high-density polyethylene film, and the carbon dioxide permeability is reduced by about 24.9%.

[0137] Mechanical properties of the asphaltene spherulite / high-density polyethylene composite

[0138] Figure 10 are the stress-strain curve (a) of the asphaltene spherulite / high-density polyethylene prepared by the melting method and the curves of storage modulus (b), loss modulus (c) and loss factor (d) changing with temperature. It can be seen from the stress-strain curve that as the filling ratio of the asphaltene spherulites increases, the maximum stress of the composite film continuously increases, and the maximum strain first increases and then decreases ( Figure 10 a). This is mainly due to the interfacial bonding between the asphaltene spherulites and the high-density polyethylene, which restricts the movement of the high-density polyethylene molecular chains, similar to the "second-phase doping" in alloys, thus resulting in the continuous increase of its maximum stress. The maximum strain of the 0.5wt% asphaltene spherulite / high-density polyethylene composite film prepared by the melting method increases. The main reason may be that during the melting and mixing, only a small amount of high-density polyethylene molecular chains bind to the asphaltene spherulites, and the movement ability of most high-density polyethylene molecular chains increases under high-temperature conditions, reducing the restriction between the high-density polyethylene molecular chains, thereby leading to an increase in the maximum strain.

[0139] From the curve of storage modulus changing with temperature ( Figure 10b) It can be seen that in the range of -130 to 100 degrees Celsius, the storage modulus of the composite film decreases with increasing temperature, mainly because when the ambient temperature is lower than the glass transition temperature of high-density polyethylene, the mobility of the high-density polyethylene molecular chain is weak; when the temperature reaches the glass transition temperature of high-density polyethylene, its molecular chain mobility becomes stronger, and the thermal expansion and contraction of high-density polyethylene during the heating process weakens its intermolecular force, destroying part of the interface layer between the asphaltene clusters and high-density polyethylene. Therefore, the storage modulus of the asphaltene clusters / high-density polyethylene composite film prepared by the melt method gradually decreases and tends to be consistent with the increase of temperature. The higher the storage modulus of the asphaltene clusters / high-density polyethylene composite film prepared by the melt method, the better the rigidity and the stronger the structural stability under the action of dynamic load. This is because with the addition of asphaltene clusters, the stress is effectively transferred between the interfaces. The filling ratio of asphaltene clusters continues to increase, and the efficiency of stress transfer between the interfaces is higher, resulting in the higher storage modulus, better rigidity and stronger stability of the asphaltene clusters / high-density polyethylene composite film prepared by the melt method.

[0140] From the loss modulus and temperature variation curve ( Figure 10 c) Analysis shows that the loss modulus of the asphaltene spheroid cluster / high-density polyethylene composite film prepared by the melting method shows two mechanical relaxation processes as the temperature rises. The range of -130 to 100 degrees Celsius is the γ relaxation process related to the movement of short branches on the main chain, and the range of 0 to 60 degrees Celsius is the α relaxation process related to the orientation and formation of the molecular chain folding part of the polyethylene crystal region and the wafer surface, which reflects the glass transition temperature of the material to a certain extent. Compared with high-density polyethylene, the height and amplitude of the γ relaxation peak of the asphaltene spheroid cluster / high-density polyethylene composite film prepared by the melting method are both increased, indicating that the constraint on the movement of the molecular chain segments and the number of molecules of the molecular chain that undergoes transformation in the amorphous region are increased. In the range of 0 to 100 degrees Celsius, the composite material shows an obvious α mechanical relaxation process, and the peak value drifts to high temperature, indicating that the asphaltene spheroid clusters enhance the crystallinity of high-density polyethylene, which is consistent with the results of differential scanning calorimetry analysis.

[0141] From the loss factor and temperature change curve ( Figure 10d) Analysis shows that as the temperature increases, the loss factor of the asphaltene cluster / high-density polyethylene composite film prepared by the melting method gradually increases. The reason is that at lower temperatures, the molecular chains of high-density polyethylene are in a frozen state, with small intermolecular forces. The segmental motion can follow the changes in external forces, resulting in low internal friction and a small loss factor. The filling ratio of asphaltene clusters has no obvious effect on this value. When the temperature is higher than the glass transition temperature of high-density polyethylene, high-density polyethylene reaches the viscous flow state, and the entire macromolecule can move. At this time, the storage modulus drops significantly, and the loss factor value rises sharply. Moreover, at this time, the interference of asphaltene clusters on the molecular chain motion increases, and the difference in the loss factors of the asphaltene cluster / high-density polyethylene composite films with different filling ratios prepared by the melting method becomes larger.

[0142] In summary, in the range of -130 to 100 degrees Celsius, compared with the high-density polyethylene film, the dynamic mechanical properties of the 3wt% asphaltene cluster / high-density polyethylene composite film prepared by the melting method are better. The material has good rigidity, a high glass transition temperature, and is not easily deformed by heat. Therefore, it is more suitable for pipeline transportation in service environments at higher temperatures. The anti-aging performance of the asphaltene cluster / high-density polyethylene composite film

[0143] An ultraviolet irradiation accelerated aging experiment was used to measure the mechanical properties of the asphaltene cluster / high-density polyethylene composite film prepared by the melting method to reveal its anti-aging performance. Asphaltene clusters can absorb ultraviolet light with a wavelength range of 200 - 400 nm, and the asphaltene cluster / high-density polyethylene composite film prepared by the melting method can also absorb ultraviolet light with a wavelength range of 200 - 400 nm ( Figure 11 a). Compared with the asphaltene cluster solution, a red shift phenomenon occurs in the absorption peak of the asphaltene cluster / high-density polyethylene composite film prepared by the melting method. This may be due to the change in the intermolecular interaction after the asphaltene clusters are dispersed in high-density polyethylene compared with the solution state, resulting in relatively better molecular planarity. As the filling ratio of asphaltene clusters increases, the red shift phenomenon of the absorption peak of the asphaltene cluster / high-density polyethylene composite film prepared by the melting method becomes more obvious. This may be because as the filling ratio of asphaltene clusters increases, the probability of self-assembly becomes larger, leading to the expansion of the molecular π-conjugated system of asphaltene clusters and the influence of the conjugated structure of unsaturated C-H bonds in high-density polyethylene on asphaltene clusters. When the filling ratio of asphaltene clusters is 3wt%, the tensile strength of the high-density polyethylene film is increased by 10.89%. After 60 hours of ultraviolet aging, compared with the unaged film, the tensile strength of the pure high-density polyethylene film drops by 74.77%, while the tensile strength of the 3wt% asphaltene cluster / high-density polyethylene composite film prepared by the melting method only drops by 33.74%. This may be because asphaltene clusters can absorb part of the ultraviolet light, reducing the intensity of ultraviolet radiation on high-density polyethylene. Figure 11 b).

[0144] In summary, the filling of asphaltene clusters can not only improve the tensile strength of high-density polyethylene composite films, but also enhance the anti-aging performance of the films, thereby extending their service life and reducing their maintenance costs, so it can be better applied in the engineering field.

Claims

1. Preparation method of asphaltene spherulite cluster / thermoplastic polymer composite with high gas barrier and anti-aging properties, characterized in that: 1) Preparation of asphaltene spherulite clusters: Take 200 - 500 mg of asphaltene and 40 - 50 ml of organic solvent methanol or ethanol and add them to a reaction kettle for solvothermal reaction at 285 °C for 2 - 3 h. Wait for the reaction mixture to cool to room temperature, select a filter membrane with a pore size below 0.5 microns to perform suction filtration on it, and perform rotary evaporation on the filtrate to obtain asphaltene spherulite cluster powder; 2) Preparation of asphaltene spherulite cluster / thermoplastic polymer composite by solution method or melting method: Solution method Add 2 - 8 g of thermoplastic polymer powder and 80 - 150 ml of xylene, toluene or ortho-dichlorobenzene to a round-bottom flask and stir at 140 - 170 °C and 500 - 1200 revolutions per minute to obtain a thermoplastic polymer solution; Add 20 - 120 mg of asphaltene spherulite cluster powder and 70 - 120 ml of xylene, toluene or ortho-dichlorobenzene to a beaker and stir at 500 - 1200 revolutions per minute at room temperature to obtain an asphaltene spherulite cluster dispersion; Use a dropper to slowly add the asphaltene spherulite cluster dispersion to the thermoplastic polymer solution at 140 - 170 °C, stir evenly at 500 - 1200 revolutions per minute and pour it into 50 - 100 ml of acetone for stirring and sedimentation. The precipitate is dried by rotary evaporation or vacuum drying at -0.08 - 0.09 MPa and 70 - 80 °C to remove the organic solvent to obtain asphaltene spherulite cluster / thermoplastic polymer composite; Melting method Take 20 - 60 g of thermoplastic polymer particles and add them to the sample loading cavity of a torque rheometer. Raise the temperature to 150 - 170 °C. After the thermoplastic polymer particles are completely melted, add 200 - 1200 mg of asphaltene spherulite cluster powder, stir evenly at 10 - 30 revolutions per minute and then lower the temperature to below 120 °C to obtain asphaltene spherulite cluster / thermoplastic polymer composite.

2. The preparation method of the asphaltene spherulite / thermoplastic polymer composite material with high gas barrier and anti-aging properties according to claim 1, characterized in that: The asphaltene in step 1) includes asphaltene obtained from natural asphalt, petroleum asphalt, tar asphalt (i.e., coal tar asphalt), shale asphalt or wood asphalt, and synthetic asphalt (i.e., synthetic asphalt with naphthalene, anthracene, methylnaphthalene aromatic hydrocarbons as raw materials).

3. The preparation method of the asphaltene spherulite / thermoplastic polymer composite material with high gas barrier and anti-aging properties according to claim 1, characterized in that, The diameter of the asphaltene spherulite cluster powder obtained in step 1) is 2 - 4 microns.

4. The preparation method of the high-resistance gas and anti-aging performance asphaltene spherulite / thermoplastic polymer composite according to claim 1, characterized in that: The thermoplastic polymer in step 2) includes low-density polyethylene, high-density polyethylene, polypropylene, polystyrene, polyvinyl alcohol, polymethyl methacrylate, polyvinyl chloride, acrylonitrile-butadiene-styrene, polyoxymethylene, nylon, polycarbonate, polyphenylene ether, polysulfone, polyphenylene sulfide, polyethylene terephthalate, polybutylene terephthalate or polypropylene terephthalate.

5. The asphaltene sphere cluster / thermoplastic polymer composite prepared by the method according to claim 1, characterized in that, The asphaltene spherulite cluster / thermoplastic polymer composite can absorb ultraviolet light.

6. The asphaltene spherulite / thermoplastic polymer composite with high gas barrier and anti-aging properties as described in claim 5, characterized in that, The asphaltene spherulite cluster / thermoplastic polymer composite has an absorption response to ultraviolet light with a wavelength of 200 - 400 nanometers.

Images