Preparation method of PEG / biochar / MoS2 nano composite material

Abstract

The invention relates to the technical field of composite material preparation, in particular to a PEG / biomass charcoal / MoS2 nano composite material preparation method, which comprises: S1, taking a biomass raw material, carrying out pyrolysis carbonization in a nitrogen or inert atmosphere to obtain powder, stirring and dispersing the powder in a strong alkali solution, and carrying out a hydrothermal reaction to obtain a sol; after the reaction, carrying out suction filtration, washing to remove the strong alkali solution, and carrying out ultrasonic centrifugation to take supernate containing biomass charcoal, so as to obtain intermediate liquid; and S2, uniformly mixing a template agent, water, a sulfur source, a molybdenum source and the intermediate liquid prepared in the step S1, carrying out a hydrothermal reaction, carrying out suction filtration, and drying to obtain a target product, the surface hydroxylated biomass charcoal is used as a raw material for preparation, the biomass charcoal and PEG form a hydrogen bond, so that effective compounding of the biomass charcoal and molybdenum disulfide and regulation and control of an interface phase are achieved, meanwhile, PEG is used as a matrix and a template at the same time, the polymer-based composite material is prepared in situ, and the preparation method is simple, controllable and environmentally friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material preparation, specifically a PEG / biomass carbon / MoS 2 Method for preparing nanocomposite materials. Background Art

[0002] Biomass carbon materials are environmentally friendly renewable resources with the advantages of low price, green environmental protection, and wide sources. Nanocarbon materials have excellent anti-friction and anti-wear properties and are widely used in tribological research of lubricating oils, polymer-based composites, and metal-based composites. Molybdenum disulfide (MoS 2 ) is a graphene-like layered two-dimensional material. When subjected to shear force, relative sliding easily occurs between layers, and then becomes a single layer or a few layers. Based on this structural feature, molybdenum disulfide has a good lubricating effect.

[0003] In the prior art, there are composite materials prepared by using carbon and molybdenum disulfide, such as the graphene / molybdenum disulfide composite lubricant provided by Chinese patent document CN106811264 A (application number 201611255933.0) and the vinegar lees biomass charcoal-molybdenum disulfide composite material provided by Chinese patent document CN 113145067 A (application number 202110087922.0). However, the former uses graphene as the carbon material, and the preparation procedure of graphene is complicated, and there is a risk of contamination in the reagents used in the preparation. At the same time, although a surfactant is used as a soft template in the preparation process, the surfactant is finally removed by high-temperature heat treatment; although the latter uses recycled materials to prepare carbon materials, because its application direction is to use the adsorption principle to reduce oil field pollution, only the specific surface area and porosity performance are considered, and the removal of polar groups such as hydroxyl groups and amino groups of biochar during the preparation process is not considered, resulting in uncontrollable interface phases of the obtained composite materials. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a PEG / biomass charcoal / MoS 2 The invention discloses a method for preparing a nanocomposite material, which uses surface hydroxylated biochar as a raw material. During the hydrothermal generation of molybdenum disulfide, the biochar forms hydrogen bonds with the template agent polyethylene glycol (PEG), thereby achieving effective compounding of the biochar and molybdenum disulfide and regulation of the interface phase. At the same time, the invention uses PEG as both a matrix and a template to prepare a polymer-based composite material in situ. The preparation method is simple, controllable, and green.

[0005] In order to achieve the above technical effects, the present invention adopts the following technical solutions:

[0006] A PEG / biochar / MoS 2The method for preparing the nanocomposite material comprises the following steps:

[0007] S1. Pyrolyze and carbonize the biomass raw material under nitrogen or inert atmosphere to obtain powder, stir and disperse the powder in a strong alkaline solution and then perform a hydrothermal reaction, after the reaction, filter and wash to remove the strong alkaline solution, and perform ultrasonic centrifugation to obtain the supernatant containing biomass charcoal to obtain an intermediate liquid;

[0008] S2. Mix the template, water, sulfur source, molybdenum source and the intermediate liquid obtained in step S1, filter and dry after hydrothermal reaction to obtain PEG / biomass carbon / MoS 2 Nanocomposites;

[0009] in,

[0010] In step S1, bamboo powder is selected as the biomass raw material;

[0011] In step S1, the pH range of the strong alkaline solution is 13-14;

[0012] In step S2, the template agent is selected from PEG;

[0013] In step S2, the mass ratio of the template, water, sulfur source and intermediate liquid is (1-5):50:(1-3):(10-50), wherein the sulfur source and the molybdenum source are fed in equal mass ratios.

[0014] In the preparation method provided by the present invention, surface hydroxylated biochar is used as raw material for preparation. During the hydrothermal generation of molybdenum disulfide, the biochar forms hydrogen bonds with the template agent PEG. The hydrogen bonding effect between the hydroxylated biochar and the template agent makes the biochar dispersed in the template agent and more easily compounded with molybdenum disulfide, thereby achieving effective compounding of biochar and molybdenum disulfide and regulation of the interface phase, thereby significantly improving the tribological properties of the composite material. At the same time, the invention uses PEG as both a matrix and a template to prepare a polymer-based composite material in situ. The preparation method is simple, controllable, and green.

[0015] Preferably, in step S1, the ratio of the biomass raw material input to the intermediate liquid taken out is 1 mg:(2-20) g; further preferably, the ratio of the biomass raw material input to the intermediate liquid taken out is 1 mg:(10-15) g.

[0016] Preferably, in step S1, the pyrolysis carbonization conditions are to increase the temperature to 450°C-550°C at a heating rate of (3-8)°C / min and keep it warm for 2h-6h; further preferably, the pyrolysis carbonization is specifically to increase the temperature to 500°C at a heating rate of 5°C / min and keep it warm for 4h.

[0017] Preferably, in step S1, the stirring time is 8h-14h; further preferably, the stirring time is 10h-12h.

[0018] Preferably, in step S1, the hydrothermal reaction conditions are 160°C-200°C for 8h-20h; further preferably, the hydrothermal reaction conditions are 180°C for 12h.

[0019] Preferably, in step S1, the ultrasonic condition is 250 W for 8 h to 12 h; further preferably, the ultrasonic condition is 250 W for 10 h.

[0020] Preferably, in step S2, the sulfur source is thiourea or thioacetamide; the molybdenum source is sodium molybdate or ammonium molybdate; further preferably, the sulfur source is thiourea, and the molybdenum source is sodium molybdate.

[0021] Preferably, in step S2, the hydrothermal reaction conditions are 180°C-220°C for 18h-36h; further preferably, the hydrothermal reaction conditions are 200°C for 20h-30h.

[0022] The beneficial effects of the present invention are as follows:

[0023] In the preparation method provided by the present invention, bamboo powder is first carbonized in a tubular furnace under nitrogen or inert atmosphere at a certain heating rate and insulation time. After carbonization, the powder is hydrothermally reacted in a sodium hydroxide solution, filtered and washed until it is close to neutral, and then the powder is ultrasonically and centrifuged to obtain a supernatant containing biomass charcoal. The supernatant, template, distilled water, sulfur source and molybdenum source are added to a hydrothermal kettle in proportion for hydrothermal reaction to obtain the target product. In the target product, hydroxylated carbon is dispersed in PEG, MoS 2 The three are formed in PEG, and the composite is connected by hydrogen bonds or other non-chemical bonds, which has excellent tribological properties. The preparation method provided by the present invention has the advantages of simple process, repeatability, low cost, and green environmental protection. The prepared material has controllable structure and components, and the wear spot diameter is reduced by about 40%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The PEG / biomass charcoal / MoS obtained in Example 1 2 SEM images of nanocomposites;

[0025] Figure 2 The PEG / biomass charcoal / MoS obtained in Example 1 2 XRD spectra of nanocomposites;

[0026] Figure 3 is a Fourier transform infrared spectrum of bamboo powder obtained from biochar in Example 1 after carbonization and hydroxylation at 500°C;

[0027] Figure 4The PEG / biomass carbon / MoS obtained in Comparative Example 1 2 SEM images of the nanocomposites. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0029] The raw materials and testing equipment used in the examples are all commercially available products and commonly used testing equipment in the field, and their specific sources are not described here. If industrialized, they can be scaled up in equal proportions.

[0030] General operation of the present invention: a PEG / biochar / MoS 2 The preparation method of nanocomposite materials. Firstly, the biomass raw material bamboo powder is carbonized in a tubular furnace under nitrogen or inert atmosphere at a certain heating rate and insulation time. After carbonization, the powder is hydrothermally reacted in a strong alkaline solution, filtered and washed until it is close to neutral, and then the powder is ultrasonicated and centrifuged to obtain a supernatant. The supernatant, PEG, distilled water, thiourea and sodium molybdate are added to a hydrothermal kettle in a certain proportion for hydrothermal reaction. After the reaction, the filter is sucked and dried to obtain the target product.

[0031] The preparation method has the advantages of simple process, repeatability, low cost and green environmental protection.

[0032] Example 1

[0033] A PEG / biochar / MoS 2 The method for preparing the nanocomposite material comprises the following steps:

[0034] S1. 2 mg of bamboo powder was carbonized in a tubular furnace at a heating rate of 5 ° C / min under a nitrogen atmosphere and kept at 500 ° C for 4 h. After carbonization, the powder was put into 50 mL of 2% sodium hydroxide solution and stirred for 12 h, then transferred to a hydrothermal kettle for hydrothermal reaction at 180 ° C for 12 h, filtered and washed to remove the strong alkaline solution until the pH of the washing wastewater was equal to 7.5, put into 50 mL of pure water, ultrasonicated at 250 W power for 10 h, centrifuged at 350 r / min for 5 min, and 20 g of the supernatant containing biomass charcoal was obtained to obtain the intermediate liquid;

[0035] S2. Add 2g PEG, 50g distilled water, 1.5g thiourea, 1.5g sodium molybdate and 20g intermediate liquid into a hydrothermal kettle and perform hydrothermal reaction at 200°C for 24h. The desired product is obtained by filtering and washing.

[0036] Depend on Figure 1 It can be seen that the carbon layer structure in the nanocomposite material is less than 100nm thick and in large flakes. 2 Attached to the carbon surface, PEG coated on C / MoS 2 The complex is formed on the surface of the particles.

[0037] Depend on Figure 2 It can be seen that the nanocomposite material contains MoS 2 ,Depend on Figure 3 It can be seen that at 3450cm -1 The broad peak nearby is due to the stretching vibration of -OH. It can be clearly seen that the peak area of ​​the hydroxylated carbon powder is larger here, that is, the hydroxylated carbon material has more hydroxyl groups. According to general knowledge, the hydroxyl group forms a hydrogen bond with the -O- group in PEG.

[0038] After the product was doped in the base medium PEG at a concentration of 1.0wt.% and stirred at 300rpm for 30min, its wear reduction and anti-wear ability was examined on a four-ball friction tester (load was 392N, rotation speed was 1450r / min, each group of experiments lasted 30min, and each group was repeated at least three times to take the average value). The wear spot diameter was 0.42mm, which was lower than the wear spot diameter of the base medium PEG of 0.87mm; the friction coefficient was 0.0678, which was lower than the friction coefficient of the base medium of 0.116197.

[0039] Example 2

[0040] A PEG / biochar / MoS 2 The method for preparing the nanocomposite material comprises the following steps:

[0041] S1. 2 mg of bamboo powder was carbonized in a tubular furnace at a heating rate of 5 ° C / min under a nitrogen atmosphere and kept at 450 ° C for 5 h. After carbonization, the powder was stirred in 30 mL of 2% sodium hydroxide solution for 10 h, transferred to a hydrothermal reactor for hydrothermal reaction at 200 ° C for 10 h, filtered and washed to remove the strong alkaline solution until the pH of the washing wastewater was equal to 7.4, put into 50 mL of pure water, ultrasonicated at 250 W power for 8 h, centrifuged at 300 r / min for 4 min, and 30 g of supernatant containing biomass charcoal was obtained to obtain an intermediate liquid;

[0042] S2. Add 3g PEG, 50g distilled water, 1.0g thiourea, 1.0g sodium molybdate and 30g intermediate liquid into a hydrothermal kettle and react at 180°C for 20h. Filter and wash to obtain the desired product.

[0043] After the product was doped in PEG at a concentration of 1.0wt.% and stirred at 250rpm for 60min, its wear reduction and anti-wear capabilities were examined on a four-ball friction tester (load was 392N, rotation speed was 1450r / min, each group of experiments lasted 30min, and each group was repeated at least three times to take the average value). It was found that the wear spot diameter was 0.46mm, which was lower than the wear spot diameter of the base medium PEG of 0.87mm; the friction coefficient was 0.084705, which was lower than the friction coefficient of the base medium of 0.116197.

[0044] Example 3

[0045] A PEG / biochar / MoS 2 The method for preparing the nanocomposite material comprises the following steps:

[0046] S1. 2 mg of bamboo powder was carbonized in a tubular furnace at a heating rate of 10 ° C / min under an argon atmosphere at 550 ° C for 3 h. After carbonization, the powder was stirred in 40 mL of 2.5% sodium hydroxide solution for 11 h, transferred to a hydrothermal reactor for hydrothermal reaction at 200 ° C for 20 h, filtered and washed to remove the strong alkaline solution until the pH of the washing wastewater was equal to 7.2, put into 50 mL of pure water, ultrasonicated at 250 W power for 8 h, centrifuged at 250 r / min for 3 min, and 25 g of the supernatant containing biomass charcoal was obtained to obtain the intermediate liquid;

[0047] S2. Add 4g PEG, 50g distilled water, 1.5g thiourea, 1.5g sodium molybdate and 25g intermediate liquid into a hydrothermal kettle and perform hydrothermal reaction at 200°C for 20h. The desired product is obtained by filtering and washing.

[0048] The product was stirred in PEG at a concentration of 2.0wt.% at a speed of 250rpm for 40min to obtain a composite material, and its wear reduction and anti-wear ability was investigated on a four-ball friction tester (load was 392N, rotation speed was 1450r / min, each group of experiments lasted 30min, and each group was repeated at least three times to take the average value). It was found that the wear spot diameter was 0.52mm, which was lower than the wear spot diameter of the base medium PEG of 0.87mm; the friction coefficient was 0.07372, which was lower than the friction coefficient of the base medium of 0.116197.

[0049] Comparative Example 1

[0050] A PEG / biochar / MoS 2 The method for preparing the nanocomposite material is different from that in Example 1 in that, in step S1, the powder is not subjected to hydroxylation treatment, and the other steps and parameters are the same as those in Example 1.

[0051] Specifically, the preparation steps of this comparative example are as follows:

[0052] S1. 2 mg of bamboo powder was carbonized in a tubular furnace at a heating rate of 5 ° C / min under a nitrogen atmosphere and kept at 500 ° C for 4 h. After carbonization, the powder was put into 50 mL of pure water, ultrasonicated at 250 W for 10 h, centrifuged at 350 r / min for 5 min, and 20 g of the supernatant containing biomass charcoal was obtained to obtain the intermediate liquid;

[0053] S2. Add 2g PEG, 50g distilled water, 1.5g thiourea, 1.5g sodium molybdate and 20g intermediate liquid into a hydrothermal kettle and perform hydrothermal reaction at 200°C for 24h. The desired product is obtained by filtering and washing.

[0054] The product obtained in Comparative Example 1 was doped at a concentration of 1.0wt.% in a base medium PEG and stirred at 300rpm for 30min. Its wear reduction and anti-wear capabilities were examined on a four-ball friction tester (load was 392N, rotation speed was 1450r / min, each group of experiments lasted 30min, and each group was repeated at least three times to take the average value). It was found that the wear spot diameter was 0.64mm, which was lower than the wear spot diameter of the base medium PEG of 0.87mm; the friction coefficient was 0.095563, which was lower than the friction coefficient of the base medium of 0.116197.

[0055] From the measured data of the product obtained in Comparative Example 1, it can be seen that when the biochar is not surface hydroxylated, during the hydrothermal preparation of the composite material in step S2, the biochar cannot form hydrogen bonds with the template PEG and cannot be effectively dispersed, resulting in the problem of easy agglomeration in the product structure, which will lead to reduced tribological properties. Figure 4 As shown, the product obtained in Comparative Example 1 is mainly flaky MoS 2 , biochar and PEG failed to disperse effectively.

[0056] Comparative Example 2

[0057] A biochar / MoS 2 The preparation method of the nanocomposite material is different from that of Example 1 in that in step S2, an equal amount of polyvinyl alcohol (PVA) is used instead of PEG, and after the powder is obtained, it is centrifuged and washed with deionized water for multiple times to remove the template agent, and then added to the same amount of PEG as used in step S2 of Example 1, stirred and mixed, and after hydrothermal reaction, filtered and dried to obtain the nanocomposite material.

[0058] The product obtained in Comparative Example 2 was doped in a base medium PEG at a concentration of 1.0wt.% and stirred at 300rpm for 30min. Its wear reduction and anti-wear capabilities were examined on a four-ball friction tester (load was 392N, rotation speed was 1450r / min, each group of experiments lasted 30min, and each group was repeated at least three times to take the average value). It was found that the wear spot diameter was 0.63mm, which was lower than the wear spot diameter of the base medium PEG of 0.87mm; the friction coefficient was 0.099095, which was lower than the friction coefficient of the base medium of 0.116197.

[0059] From the measured data of the product obtained in Comparative Example 2, it can be seen that due to the use of polyvinyl alcohol as the template, during the hydrothermal reaction, the biomass carbon / MoS 2The surface cannot be coated with PEG organic film in situ, and the structure of the material obtained is obviously different from that of the material obtained in Example 1. At the same time, the disadvantage of this method also includes that the polyvinyl alcohol needs to be removed before the powder is added to PEG, which makes the overall preparation process time-consuming and inefficient.

Claims

1. A method for preparing a PEG / biochar / MoS2 nanocomposite material, characterized in that: The steps include: S1. Pyrolyze and carbonize the biomass raw material under nitrogen or inert atmosphere to obtain powder, stir and disperse the powder in a strong alkaline solution and then perform a hydrothermal reaction, after the reaction, filter and wash to remove the strong alkaline solution, and perform ultrasonic centrifugation to obtain the supernatant containing biomass charcoal to obtain an intermediate liquid; S2. Mix the template, water, sulfur source, molybdenum source and the intermediate liquid obtained in step S1, filter and dry after hydrothermal reaction to obtain PEG / biochar / MoS2 nanocomposite; in, In step S1, bamboo powder is selected as the biomass raw material; In step S1, the pH range of the strong alkaline solution is 13-14; In step S2, the template agent is selected from PEG; In step S2, the mass ratio of the template, water, sulfur source and intermediate liquid is (1-5):50:(1-3):(10-50), wherein the sulfur source and the molybdenum source are fed in equal mass ratios.

2. The preparation method according to claim 1, characterized in that In step S1, the ratio of the biomass raw material input to the intermediate liquid taken out is 1 mg:(2-20) g; more preferably, the ratio of the biomass raw material input to the intermediate liquid taken out is 1 mg:(10-15) g.

3. The preparation method according to claim 1, characterized in that: In step S1, the pyrolysis carbonization conditions are to increase the temperature to 450-550°C at a heating rate of (3-8)°C / min and keep it warm for 2h-6h; more preferably, the pyrolysis carbonization is specifically to increase the temperature to 500°C at a heating rate of 5°C / min and keep it warm for 4h.

4. The preparation method according to claim 1, characterized in that: In step S1, the stirring time is 8h-14h; more preferably, the stirring time is 10h-12h.

5. The preparation method according to claim 1, characterized in that: In step S1, the hydrothermal reaction conditions are 160°C-200°C for 8h-20h; more preferably, the hydrothermal reaction conditions are 180°C for 12h.

6. The preparation method according to claim 1, characterized in that: In step S1, the ultrasonic condition is 250 W for 8 h to 12 h; more preferably, the ultrasonic condition is 250 W for 10 h.

7. The preparation method according to claim 1, characterized in that: In step S2, the sulfur source is thiourea or thioacetamide; the molybdenum source is sodium molybdate or ammonium molybdate; further preferably, the sulfur source is thiourea, and the molybdenum source is sodium molybdate.

8. The preparation method according to claim 1, characterized in that: In step S2, the hydrothermal reaction conditions are 180°C-220°C for 18h-36h; more preferably, the hydrothermal reaction conditions are 200°C for 20h-30h.

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