A graphene oxide-based long-side-chain polycarboxylate superplasticizer and its preparation method

Abstract

This invention relates to the field of water-reducing agent processing technology, and discloses a graphene oxide-based long-side-chain polycarboxylate water-reducing agent and its preparation method. The graphene oxide-based long-side-chain polycarboxylate water-reducing agent comprises, by weight, 0.1-0.15 parts graphene oxide, 3-5 parts hydroxyl polyethylene glycol succinimide, 5-7 parts dispersant, 0.03-0.12 parts catalyst, 100-150 parts polyether monomer, 10-13 parts unsaturated carboxylic acid monomer, 0.3-0.8 parts molecular weight regulator, 0.8-1.5 parts initiator, 0.1-0.4 parts reducing agent, and alkali solution. The graphene oxide-based long-side-chain polycarboxylate water-reducing agent prepared by this invention has better water-reducing and slump-retention properties than ordinary polycarboxylate water-reducing agents, making concrete less prone to bleeding and exhibiting higher compressive strength.

Description

Technical Field

[0001] This invention relates to the field of water-reducing agent processing technology, specifically to a graphene oxide-based long-side-chain polycarboxylate water-reducing agent and its preparation method. Background Technology

[0002] In recent years, nanotechnology has developed rapidly, showing promising application prospects in many fields such as chemical engineering, building materials, and biology. Graphene oxide (GO) is a graphene derivative composed of single or multiple layers of wrinkled two-dimensional carbon sheets, with oxygen-containing functional groups such as hydroxyl and carboxyl groups on the surface or between the layers. The hydration product of cement-based materials is nano-hydrated calcium silicate. Adding graphene oxide can improve the toughness of cement-based materials by utilizing its own two-dimensional grid structure, and can control the structure of cement hydration products to form multi-scale composite materials, thereby further strengthening and toughening cement-based materials.

[0003] Currently, researchers have used graphene oxide to regulate the cement hydration process, improving the morphology and quantity of hydration products in cement paste to enhance the performance of cement-based materials and solve problems such as low flexural and compressive strength and easy cracking during use. However, most studies are based on the physical mixing of graphene oxide and polycarboxylate superplasticizers, using chemical reactions to graft graphene oxide onto polyether macromonomers and increase the branch length of the polyether monomers. Research on synthesizing polycarboxylate superplasticizers in this way is limited. Therefore, this invention provides a method for producing a graphene oxide-based long-side-chain polycarboxylate superplasticizer. Summary of the Invention

[0004] The present invention aims to provide a graphene oxide-based long-side-chain polycarboxylate superplasticizer and its preparation method, so as to achieve better water reduction and slump retention performance, making concrete less prone to bleeding and having higher compressive strength.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a graphene oxide-based long-side-chain polycarboxylate superplasticizer, comprising, by weight, 0.1-0.15 parts of graphene oxide, 3-5 parts of hydroxyl polyethylene glycol succinimide ester, 5-7 parts of dispersant, 0.03-0.12 parts of catalyst, 100-150 parts of polyether monomer, 10-13 parts of unsaturated carboxylic acid monomer, 0.3-0.8 parts of molecular weight regulator, 0.8-1.5 parts of initiator, 0.1-0.4 parts of reducing agent, and alkali solution.

[0006] On the other hand, this technical solution provides a method for preparing a graphene oxide-based long-side-chain polycarboxylate superplasticizer, comprising the following steps:

[0007] Step 1: Preparation of graphene oxide / hydroxyl polyethylene glycol succinimide ester: Graphene oxide and hydroxyl polyethylene glycol succinimide ester react under the action of a catalyst to generate graphene oxide / hydroxyl polyethylene glycol succinimide ester;

[0008] Step 2, Preparation of graphene oxide-based long side-chain polyether: The graphene oxide / hydroxyl polyethylene glycol succinimide ester obtained in Step 1 is reacted with polyether monomers under heating conditions to generate graphene oxide-based polyether.

[0009] Step 3: Preparation of graphene oxide-based long-side-chain polycarboxylate superplasticizer, the method is as follows:

[0010] S1: Prepare the bottom solution A by mixing graphene oxide-based polyether with deionized water;

[0011] S2: Mix unsaturated carboxylic acid monomers, molecular weight regulators and deionized water to prepare dropwise solution B;

[0012] S3: Mix the reducing agent and deionized water to prepare the dropping solution C;

[0013] S4: Add the initiator to the bottom liquid A, and then add the B and C materials at a uniform rate. After the addition is completed, keep the temperature and adjust the pH value to neutral with an alkaline solution to obtain the graphene oxide-based long side chain polycarboxylate superplasticizer solution.

[0014] Preferably, as an improvement, the graphene oxide is a two-dimensional carbon nanosheet containing hydroxyl and carboxyl groups; the hydroxyl polyethylene glycol succinimide ester is at least one of hydroxyl polyethylene glycol succinimide acetate, hydroxyl polyethylene glycol succinimide propionate, and hydroxyl polyethylene glycol succinimide glutarate.

[0015] In this technical solution, the two-dimensional carbon nanosheets containing hydroxyl and carboxyl groups are represented by the following structure (I); the structural formula of hydroxyl polyethylene glycol succinimide ester is shown in formula (II).

[0016] Equation (I) Equation (II)

[0017] In formula (II), (a) is hydroxy polyethylene glycol succinimide acetate, (b) is hydroxy polyethylene glycol succinimide propionate, and (c) is hydroxy polyethylene glycol succinimide glutarate.

[0018] Preferably, as an improvement, the dispersant is at least one of N, N-dimethylformamide, and dimethyl sulfoxide; and the catalyst is p-toluenesulfonic acid.

[0019] Preferably, as an improvement, the polyether monomer is at least one of allyl polyethylene glycol ether (APEG), isobutylene polyethylene glycol ether (HPEG), and isopentenyl polyethylene glycol ether (TPEG).

[0020] Preferably, as an improvement, the unsaturated carboxylic acid monomer is at least one of maleic anhydride, acrylic acid, and methacrylic acid.

[0021] Preferably, as an improvement, the molecular weight regulator is at least one of sodium hypophosphite, mercaptoethanol, mercaptoacetic acid, or mercaptopropionic acid; the initiator is at least one of hydrogen peroxide, sodium persulfate, ammonium persulfate, or potassium persulfate; and the reducing agent is at least one of sodium sulfite, potassium sulfite, sodium bisulfite, vitamin C, ferrous sulfate, or sodium formaldehyde sulfoxylate.

[0022] Preferably, as an improvement, in step one, graphene oxide is first added to the dispersant and ultrasonically dispersed to form a graphene oxide dispersion, and then a catalyst and hydroxyl polyethylene glycol succinimide are added to react and generate graphene oxide / hydroxyl polyethylene glycol succinimide.

[0023] Preferably, as an improvement, in step two, the heating temperature is 55-65℃ and the reaction time is 4-6h.

[0024] Preferably, as an improvement, in step three, the addition time of component A in S4 is 2.5-3.5 hours, and the addition time of component B is 2.5-4 hours. After the addition is completed, the reaction is stopped by keeping the temperature for 1 hour, and the pH value is adjusted to neutral with an alkaline solution.

[0025] The principle and advantages of this solution are as follows: This technical solution overcomes the technical limitations of existing technologies based on the physical mixing of graphene oxide and polycarboxylate superplasticizers. It creatively employs grafting graphene oxide onto polyether macromonomers and increasing the branch chain length of the polyether monomers to synthesize polycarboxylate superplasticizers. During the research and development process, the preparation methods of graphene oxide / hydroxyl polyethylene glycol succinimide ester, the preparation methods of graphene oxide-based long-side-chain polyethers, and the selection of raw materials required for the above two reactions were the research and development challenges of this technical solution. During the research and development process, the inventors obtained graphene oxide / hydroxyl polyethylene glycol succinimide ester by reacting hydroxyl polyethylene glycol succinimide ester with graphene oxide, and then reacted it with polyether monomers to generate graphene oxide-based polyethers, achieving significant advantages. Compared with existing technologies, this technical solution has the following advantages:

[0026] 1. This technical solution uses graphene oxide and hydroxyl polyethylene glycol succinimide to react and obtain graphene oxide / hydroxyl polyethylene glycol succinimide. Further reaction with polyether macromonomer can effectively graft graphene oxide onto the polyether macromonomer, thereby obtaining a graphene-based polycarboxylate superplasticizer. It can form a hydrophilic-hydrophobic layer on the surface of cement particles by relying on the hydrophilic effect of polyethylene glycol and the hydrophobic effect of the two-dimensional grid of graphene oxide. This can increase the thickness of the adsorption layer on the surface of cement particles and improve the fluidity and retention performance of cement-based materials.

[0027] 2. This technical solution obtains a long-side-chain polyether by reacting graphene oxide / hydroxyl polyethylene glycol succinimide ester and polyether. The further obtained long-side-chain polycarboxylate superplasticizer can form a thicker adsorption layer on cement particles, fixing more free water molecules, which helps to reduce the bleeding phenomenon of concrete.

[0028] 3. The graphene oxide-based long-chain polycarboxylate superplasticizer obtained in this technical solution has the following advantages: First, graphene can exert a template effect and a nucleation effect on the surface of cement hydration products, thereby adjusting the interfacial microstructure of cement-based composite materials and improving the mechanical properties of cement-based materials. Second, the long-chain polycarboxylate superplasticizer can promote the hydration of C3A and C3S in cement hydration products, accelerate the formation of calcium hydroxide and ettringite, thereby promoting the improvement of strength.

[0029] 4. The graphene oxide-based polycarboxylate superplasticizer prepared by the chemical reaction method in this technical solution has better water reduction and slump retention properties than the graphene oxide-polycarboxylate superplasticizer mixture obtained by physical mixing, and also has an advantage in compressive strength. Detailed Implementation

[0030] The following detailed description provides further details on specific embodiments, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the technical means used in the following embodiments are conventional means well known to those skilled in the art; the experimental methods used are all conventional methods; and the materials and reagents used are all commercially available.

[0031] Overview of the plan:

[0032] A graphene oxide-based long-side-chain polycarboxylate superplasticizer, comprising, by weight, 0.1-0.15 parts graphene oxide, 3-5 parts hydroxyl polyethylene glycol succinimide, 5-7 parts dispersant, 0.03-0.12 parts catalyst, 100-150 parts polyether monomer, 10-13 parts unsaturated carboxylic acid monomer, 0.3-0.8 parts molecular weight regulator, 0.8-1.5 parts initiator, 0.1-0.4 parts reducing agent, and alkali solution.

[0033] A method for preparing a graphene oxide-based long-side-chain polycarboxylate superplasticizer includes the following steps:

[0034] Step 1: Preparation of graphene oxide / hydroxyl polyethylene glycol succinimide ester: The raw materials include, by mass, 0.1-0.15 parts of graphene oxide, 3-5 parts of hydroxyl polyethylene glycol succinimide ester, 5-7 parts of dispersant, and 0.03-0.12 parts of catalyst.

[0035] Among them, graphene oxide is a two-dimensional carbon nanosheet containing hydroxyl and carboxyl groups; hydroxyl polyethylene glycol succinimide ester is at least one of hydroxyl polyethylene glycol succinimide acetate, hydroxyl polyethylene glycol succinimide propionate, and hydroxyl polyethylene glycol succinimide glutarate; the dispersant is at least one of N,N-dimethylformamide and dimethyl sulfoxide; and the catalyst is p-toluenesulfonic acid.

[0036] The preparation process of graphene oxide / hydroxyl-modified polyethylene glycol succinimide ester is as follows:

[0037] (1) Weigh 0.1-0.15 parts of graphene oxide powder and add it to 5-7 parts of dispersant. Disperse it ultrasonically for 2 hours to form a uniform graphene oxide dispersion.

[0038] (2) Transfer the above graphene dispersion to a three-necked flask, add 0.03-0.12 parts of catalyst, stir until the catalyst dissolves, and heat to 100°C. Slowly add 3-5 parts of hydroxyl polyethylene glycol succinimide ester, continue stirring for 5-6 hours, cool to room temperature, centrifuge the above liquid at 10000 rpm for 30 minutes, remove the supernatant, and obtain graphene oxide / hydroxyl polyethylene glycol succinimide ester.

[0039] Step 2: Preparation of graphene oxide-based long side-chain polyether: The raw materials include 3.1-5.15 parts by weight of graphene oxide / hydroxyl polyethylene glycol succinimide ester and 100-150 parts by weight of polyether monomer.

[0040] The graphene oxide / hydroxy polyethylene glycol succinimide ester is at least one of graphene oxide / hydroxy polyethylene glycol succinimide acetate, graphene oxide / hydroxy polyethylene glycol succinimide propionate, and graphene oxide / hydroxy polyethylene glycol succinimide glutarate; the polyether monomer is at least one of allyl polyethylene glycol ether (APEG), isobutylene polyethylene glycol ether (HPEG), and isopentenyl polyethylene glycol ether (TPEG).

[0041] The preparation process of graphene oxide-based long-side-chain polyether is as follows: Weigh 3.1-5.15 parts of graphene oxide / hydroxyl polyethylene glycol succinimide ester and 80-100 parts of deionized water into a three-necked flask, start stirring and heat to 55-65℃, add 100-150 parts of polyether monomer, react for 4-6 h, and cool to room temperature to obtain graphene oxide-based polyether. The reaction formulas are as follows: Formula (III) and Formula (IV):

[0042] Equation (III)

[0043]

[0044] Formula (IV)

[0045] In equation (IV), (d) is APEG, (e) is HPEG, and (f) is TPEG.

[0046] Step 3: Preparation of graphene oxide-based long-side-chain polycarboxylate superplasticizer: The raw materials include, by mass, 100-150 parts of graphene oxide long-side-chain polyether monomer, 10-13 parts of unsaturated carboxylic acid monomer, 0.3-0.8 parts of molecular weight regulator, 0.8-1.5 parts of initiator, and 0.1-0.4 parts of reducing agent.

[0047] The graphene oxide-based long-side-chain polyether monomer is at least one of graphene oxide-based long-side-chain allyl polyethylene glycol ether, graphene oxide-based long-side-chain isobutylene polyethylene glycol ether, and graphene oxide-based long-side-chain isopentenene polyethylene glycol ether; the unsaturated carboxylic acid monomer is at least one of maleic anhydride, acrylic acid, and methacrylic acid; the molecular weight regulator is at least one of sodium hypophosphite, mercaptoethanol, mercaptoacetic acid, or mercaptopropionic acid; the initiator is at least one of hydrogen peroxide, sodium persulfate, ammonium persulfate, or potassium persulfate; and the reducing agent is at least one of sodium sulfite, potassium sulfite, sodium bisulfite, vitamin C, ferrous sulfate, or sodium formaldehyde sulfoxylate.

[0048] The preparation process of graphene oxide-based long-side-chain polycarboxylate superplasticizer is as follows:

[0049] S1: Weigh 100-150 parts of graphene oxide-based long side-chain polyether and 20-50 parts of deionized water into a three-necked flask to prepare bottom solution A;

[0050] S2: Prepare dropwise solution B by placing 10-13 parts of unsaturated carboxylic acid monomers, 0.3-0.8 parts of molecular weight regulator and 8-11 parts of deionized water in a beaker;

[0051] S3: Prepare dropwise solution C by placing 0.1-0.4 parts of reducing agent and 20-25 parts of deionized water in a beaker;

[0052] S4: At room temperature, add 0.8-1.5 parts of initiator to the bottom liquid A. After 5-10 minutes, add the above-mentioned materials B and C dropwise at a uniform rate. The dropwise addition time of material A is 2.5-3.5 hours, and the dropwise addition time of material B is 2.5-4 hours. After the dropwise addition is completed, keep warm for 1 hour to end the reaction. Adjust the pH value to neutral with an alkaline solution to obtain the graphene oxide-based long side chain polycarboxylic acid water-reducing agent solution. The alkaline solution is at least one of NaOH or KOH solution.

[0053] Example 1

[0054] A method for preparing a graphene oxide-based long-side-chain polycarboxylate superplasticizer includes the following steps:

[0055] Step 1: Preparation of graphene oxide / hydroxyl-containing polyethylene glycol succinimide glutarate

[0056] Weigh 0.12 parts of graphene oxide powder and add it to 5.5 parts of N,N-dimethylformamide. Disperse the mixture ultrasonically for 2 hours to form a uniform graphene oxide dispersion. Transfer the graphene dispersion to a three-necked flask, add 0.1 parts of p-toluenesulfonic acid, stir until the p-toluenesulfonic acid dissolves, and heat to 100°C. Slowly add 4 parts of hydroxyl polyethylene glycol succinimide glutarate, continue stirring for 5 hours, cool to room temperature, and centrifuge the liquid at 10,000 rpm for 30 minutes. Remove the supernatant to obtain graphene oxide / hydroxyl polyethylene glycol succinimide glutarate.

[0057] Step 2: Preparation of graphene oxide-based long-side-chain APEG

[0058] Weigh 4.12 parts of graphene oxide / hydroxyl polyethylene glycol succinimide glutarate and 80 parts of deionized water into a three-necked flask, start stirring and heat to 60°C, add 100 parts of allyl polyethylene glycol ether (APEG), react for 5 h, cool to room temperature, and obtain graphene oxide-based long side chain APEG.

[0059] Step 3: Preparation of graphene oxide-based long-side-chain APEG polycarboxylate superplasticizer

[0060] Weigh 100 parts of graphene oxide-based long-side-chain polycarboxylate superplasticizer (APEG) and 20 parts of deionized water into a three-necked flask to prepare bottom solution A. Prepare dropwise solution B by adding 13 parts of maleic anhydride, 0.7 parts of mercaptoacetic acid, and 11 parts of deionized water into a beaker. Prepare dropwise solution C by adding 0.3 parts of sodium formaldehyde sulfoxylate and 23 parts of deionized water into a beaker. At room temperature, add 1.5 parts of potassium persulfate to bottom solution A. After 5-10 minutes, add dropwise solutions B and C at a uniform rate. The dropwise addition time for solution A is 3 hours, and for solution B is 3.5 hours. After the addition is complete, maintain the temperature for 1 hour to stop the reaction. Adjust the pH to neutral with KOH solution to obtain the graphene oxide-based APEG long-side-chain polycarboxylate superplasticizer solution.

[0061] Example 2

[0062] A method for preparing a graphene oxide-based long-side-chain polycarboxylate superplasticizer includes the following steps:

[0063] Step 1: Preparation of graphene oxide / hydroxyl-modified polyethylene glycol succinimide acetate

[0064] Weigh 0.1 parts of graphene oxide powder and add it to 5 parts of N,N-dimethylformamide. Disperse the mixture ultrasonically for 2 hours to form a uniform graphene oxide dispersion. Transfer the graphene dispersion to a three-necked flask, add 0.05 parts of p-toluenesulfonic acid, stir until the p-toluenesulfonic acid dissolves, and heat to 100°C. Slowly add 3 parts of hydroxyl polyethylene glycol succinimide acetate and continue stirring for 6 hours. After cooling to room temperature, centrifuge the liquid at 10,000 rpm for 30 minutes and remove the supernatant to obtain graphene oxide / hydroxyl polyethylene glycol succinimide acetate.

[0065] Step 2: Preparation of graphene oxide-based long-side-chain HPEG

[0066] Weigh 3.1 parts of graphene oxide / hydroxy polyethylene glycol succinimide acetate and 90 parts of deionized water into a three-necked flask, start stirring and heat to 60°C, add 100 parts of isobutylene-based polyethylene glycol ether (HPEG), react for 4 h, and cool to room temperature to obtain graphene oxide-based long side chain HPEG.

[0067] Step 3: Preparation of graphene oxide-based long-side-chain HPEG polycarboxylate superplasticizer

[0068] Weigh 100 parts of graphene oxide-based long-side-chain HPEG and 20 parts of deionized water into a three-necked flask to prepare bottom solution A. Prepare dropwise solution B by placing 11 parts of methacrylic acid, 0.3 parts of mercaptoacetic acid, and 10 parts of deionized water into a beaker. Prepare dropwise solution C by placing 0.3 parts of vitamin C and 20 parts of deionized water into a beaker. At room temperature, add 0.9 parts of hydrogen peroxide (27.5% by mass) to bottom solution A. After 5-10 minutes, add the above-mentioned solutions B and C dropwise at a uniform rate. The dropwise addition time for solution A is 2.5 hours, and the dropwise addition time for solution B is 3 hours. After the addition is complete, keep the temperature for 1 hour to stop the reaction. Adjust the pH value to neutral with NaOH solution to obtain the graphene oxide-based long-side-chain HPEG polycarboxylate superplasticizer solution.

[0069] Example 3

[0070] A method for preparing a graphene oxide-based long-side-chain polycarboxylate superplasticizer includes the following steps:

[0071] Step 1: Preparation of graphene oxide / hydroxyl-modified polyethylene glycol succinimide propionate

[0072] Weigh 0.1 parts of graphene oxide powder and add it to 5 parts of N,N-dimethylformamide. Disperse the mixture ultrasonically for 2 hours to form a uniform graphene oxide dispersion. Transfer the graphene dispersion to a three-necked flask, add 0.06 parts of p-toluenesulfonic acid, stir until the p-toluenesulfonic acid dissolves, and heat to 100°C. Slowly add 3 parts of hydroxyl polyethylene glycol succinimide propionate and continue stirring for 6 hours. After cooling to room temperature, centrifuge the liquid at 10,000 rpm for 30 minutes and remove the supernatant to obtain graphene oxide / hydroxyl polyethylene glycol succinimide propionate.

[0073] Step 2: Preparation of graphene oxide-based long-side-chain HPEG

[0074] Weigh 3.1 parts of graphene oxide / hydroxyl polyethylene glycol succinimide propyl ester and 130 parts of deionized water into a three-necked flask, start stirring and heat to 60°C, add 150 parts of isobutylene-based polyethylene glycol ether (HPEG), react for 4 h, cool to room temperature, and obtain graphene oxide-based long side chain HPEG.

[0075] Step 3: Preparation of graphene oxide-based long-side-chain HPEG polycarboxylate superplasticizer

[0076] Weigh 150 parts of graphene oxide-based long-side-chain HPEG and 20 parts of deionized water into a three-necked flask to prepare bottom solution A; prepare dropping solution B by placing 10 parts of acrylic acid, 0.5 parts of mercaptoethanol, and 9 parts of deionized water into a beaker; prepare dropping solution C by placing 0.4 parts of sodium bisulfite and 24 parts of deionized water into a beaker. At room temperature, add 1.5 parts of sodium persulfate to bottom solution A. After 5-10 minutes, add the above-mentioned solutions B and C dropwise at a uniform rate. The dropping time for solution A is 2.5 hours, and the dropping time for solution B is 2.5 hours. After the dropping is completed, keep the temperature for 1 hour to stop the reaction. Adjust the pH value to neutral with NaOH solution to obtain the graphene oxide-based long-side-chain HPEG polycarboxylate superplasticizer solution.

[0077] Example 4

[0078] A method for preparing a graphene oxide-based long-side-chain polycarboxylate superplasticizer includes the following steps:

[0079] Step 1: Preparation of graphene oxide / hydroxyl-modified polyethylene glycol succinimide acetate

[0080] Weigh 0.13 parts of graphene oxide powder and add it to 6 parts of dimethyl sulfoxide. Disperse the mixture ultrasonically for 2 hours to form a uniform graphene oxide dispersion. Transfer the graphene dispersion to a three-necked flask, add 0.06 parts of p-toluenesulfonic acid, stir until the p-toluenesulfonic acid dissolves, and heat to 100°C. Slowly add 3 parts of hydroxyl polyethylene glycol succinimide acetate and continue stirring for 6 hours. After cooling to room temperature, centrifuge the liquid at 10,000 rpm for 30 minutes and remove the supernatant to obtain graphene oxide / hydroxyl polyethylene glycol succinimide acetate.

[0081] Step 2: Preparation of graphene oxide-based long-side-chain TPEG

[0082] Weigh 3.13 parts of graphene oxide / hydroxy polyethylene glycol succinimide acetate and 90 parts of deionized water into a three-necked flask, start stirring and heat to 60°C, add 110 parts of isopentenyl polyethylene glycol ether (TPEG), react for 4 h, cool to room temperature, and obtain graphene oxide-based long side chain TPEG.

[0083] Step 3: Preparation of graphene oxide-based long-side-chain TPEG polycarboxylate superplasticizer.

[0084] Weigh 110 parts of graphene oxide-based long-side-chain TPEG and 30 parts of deionized water into a three-necked flask to prepare bottom solution A. Prepare dropwise solution B by placing 13 parts of acrylic acid, 0.4 parts of mercaptopropionic acid, and 8 parts of deionized water into a beaker. Prepare dropwise solution C by placing 0.4 parts of sodium formaldehyde sulfoxylate and 25 parts of deionized water into a beaker. At room temperature, add 1.3 parts of ammonium persulfate to bottom solution A. After 5-10 minutes, add the above-mentioned solutions B and C dropwise at a uniform rate. The dropwise addition time for solution A is 3 hours, and the dropwise addition time for solution B is 3.5 hours. After the addition is complete, keep the temperature for 1 hour to stop the reaction. Adjust the pH value to neutral with NaOH solution to obtain the graphene oxide-based TPEG long-side-chain polycarboxylate superplasticizer solution.

[0085] Example 5

[0086] A method for preparing a graphene oxide-based long-side-chain polycarboxylate superplasticizer includes the following steps:

[0087] Step 1: Preparation of graphene oxide / hydroxyl-modified polyethylene glycol succinimide acetate

[0088] Weigh 0.1 parts of graphene oxide powder and add it to 7 parts of dimethyl sulfoxide. Disperse the mixture ultrasonically for 2 hours to form a uniform graphene oxide dispersion. Transfer the graphene dispersion to a three-necked flask, add 0.12 parts of p-toluenesulfonic acid, stir until the p-toluenesulfonic acid dissolves, and heat to 100°C. Slowly add 4 parts of hydroxyl polyethylene glycol succinimide acetate and continue stirring for 6 hours. After cooling to room temperature, centrifuge the liquid at 10,000 rpm for 30 minutes and remove the supernatant to obtain graphene oxide / hydroxyl polyethylene glycol succinimide acetate.

[0089] Step 2: Preparation of graphene oxide-based long-side-chain TPEG

[0090] Weigh 4.1 parts of graphene oxide / hydroxy polyethylene glycol succinimide acetate and 100 parts of deionized water into a three-necked flask, start stirring and heat to 60°C, add 130 parts of isopentenyl polyethylene glycol ether (TPEG), react for 4 h, cool to room temperature, and obtain graphene oxide-based long side chain TPEG.

[0091] Step 3: Preparation of graphene oxide-based long-side-chain TPEG polycarboxylate superplasticizer.

[0092] Weigh 150 parts of graphene oxide-based long-side-chain TPEG and 30 parts of deionized water into a three-necked flask to prepare bottom solution A; prepare dropping solution B by placing 11 parts of acrylic acid, 0.3 parts of mercaptoethanol, and 11 parts of deionized water into a beaker; prepare dropping solution C by placing 0.35 parts of sodium formaldehyde sulfoxylate and 22 parts of deionized water into a beaker. At room temperature, add 1.0 part of hydrogen peroxide (mass concentration of 27.5%) to bottom solution A. After 5-10 minutes, add the above-mentioned solutions B and C dropwise at a uniform rate. The dropping time for solution A is 3 hours, and the dropping time for solution B is 3 hours. After the dropping is completed, keep the temperature for 1 hour to end the reaction. Adjust the pH value to neutral with NaOH solution to obtain the graphene oxide-based TPEG long-side-chain polycarboxylate superplasticizer solution.

[0093] Comparative Example 1

[0094] Preparation of APEG-type polycarboxylate superplasticizer

[0095] Weigh 100 parts APEG and 100 parts deionized water into a three-necked flask to prepare bottom solution A; prepare dropping solution B by placing 13 parts maleic anhydride, 0.7 parts mercaptoacetic acid, and 11.5 parts deionized water into a beaker; prepare dropping solution C by placing 0.3 parts sodium formaldehyde sulfoxylate and 23 parts deionized water into a beaker. At room temperature, add 1.5 parts potassium persulfate to bottom solution A. After 5-10 minutes, add the above-mentioned solutions B and C dropwise at a uniform rate. The dropping time for solution A is 3 hours, and the dropping time for solution B is 3.5 hours. After the dropping is completed, keep the temperature for 1 hour to stop the reaction. Adjust the pH value to neutral with KOH solution to obtain the APEG polycarboxylate superplasticizer solution.

[0096] Comparative Example 2

[0097] Preparation of graphene oxide-APEG polycarboxylate superplasticizer

[0098] Weigh 0.12 parts of graphene oxide powder and add it to 250 parts of the APEG polycarboxylate superplasticizer described in Comparative Example 1. Disperse the mixture ultrasonically for 2 hours to form a uniform graphene oxide dispersion, thus obtaining the physically mixed graphene oxide-APEG polycarboxylate superplasticizer.

[0099] Comparative Example 3

[0100] Preparation of HPEG-type polycarboxylate superplasticizer

[0101] Weigh 100 parts HPEG and 110 parts deionized water into a three-necked flask to prepare bottom solution A; prepare drop solution B by placing 11 parts methacrylic acid, 0.3 parts mercaptoacetic acid, and 10 parts deionized water into a beaker; prepare drop solution C by placing 0.3 parts vitamin C and 20 parts deionized water into a beaker. At room temperature, add 0.9 parts hydrogen peroxide (mass concentration of 27.5%) to bottom solution A. After 5-10 minutes, add the above-mentioned components B and C dropwise at a uniform rate. The dropwise addition time for component A is 2.5 hours, and the dropwise addition time for component B is 3 hours. After the dropwise addition is completed, keep the temperature for 1 hour to end the reaction. Adjust the pH value to neutral with NaOH solution to obtain the HPEG polycarboxylate superplasticizer solution.

[0102] Comparative Example 4

[0103] Preparation of graphene oxide-HPEG polycarboxylate superplasticizer

[0104] Weigh 0.1 parts of graphene oxide powder and add it to 252.5 parts of the HPEG polycarboxylate superplasticizer described in Comparative Example 3. Disperse the mixture ultrasonically for 2 hours to form a uniform graphene oxide dispersion, thus obtaining the physically mixed graphene oxide-HPEG polycarboxylate superplasticizer.

[0105] Comparative Example 5

[0106] Preparation of TPEG polycarboxylate superplasticizer

[0107] Weigh 110 parts of TPEG and 120 parts of deionized water into a three-necked flask to prepare bottom solution A; prepare drop solution B by placing 13 parts of acrylic acid, 0.4 parts of mercaptopropionic acid, and 8 parts of deionized water into a beaker; prepare drop solution C by placing 0.4 parts of sodium formaldehyde sulfoxylate and 25 parts of deionized water into a beaker. At room temperature, add 1.3 parts of ammonium persulfate to bottom solution A. After 5-10 minutes, add the above-mentioned B and C solutions dropwise at a uniform rate. The dropwise addition time for A is 3 hours, and the dropwise addition time for B is 3.5 hours. After the dropwise addition is completed, keep the temperature for 1 hour to stop the reaction. Adjust the pH value to neutral with NaOH solution to obtain the graphene oxide-based TPEG polycarboxylate superplasticizer solution.

[0108] Comparative Example 6

[0109] Preparation of graphene oxide-TPEG polycarboxylate superplasticizer

[0110] Weigh 0.13 parts of graphene oxide powder and add it to 278.1 parts of the TPEG polycarboxylate superplasticizer described in Comparative Example 3. Disperse the mixture ultrasonically for 2 hours to form a uniform graphene oxide dispersion, thus obtaining the physically mixed graphene oxide-TPEG polycarboxylate superplasticizer.

[0111] Experimental Example

[0112] According to the method of GB / 8076-2008 "Concrete Admixtures", the samples prepared in Examples 1-5 and Comparative Examples 1-6 were compared with commercially available polycarboxylate superplasticizers in concrete performance testing. The workability of concrete was judged by human observation and perception, which included three aspects: fluidity, cohesiveness and water retention. Flowability was indicated by slump / spread, while cohesiveness and water retention were judged by visual observation. The results are shown in Table 1.

[0113] Table 1. Performance test results of concrete with different types of polycarboxylate superplasticizers (constituent dosage: 0.16%)

[0114]

[0115] As shown in Table 1, under the same folded solid dosage (0.16%), compared with the graphene oxide-based long-side-chain polycarboxylate superplasticizer prepared in this invention (Examples 1-5), ordinary polycarboxylate superplasticizer (Comparative Examples 1, 3, 5), and commercially available polycarboxylate superplasticizer, the graphene oxide-based long-side-chain polycarboxylate superplasticizer prepared in this invention has better water reduction and slump retention properties, and also higher 3-day and 28-day compressive strengths. Compared with the graphene oxide-based long-side-chain polycarboxylate superplasticizer prepared in this invention (Examples 1-5) and physically mixed graphene oxide-polycarboxylate superplasticizer (Comparative Examples 2, 4, 6), the water reduction and slump retention properties of the graphene oxide-based long-side-chain polycarboxylate superplasticizer are significantly better than those of the physically mixed graphene oxide-polycarboxylate superplasticizer, and the 3-day and 28-day compressive strengths are also superior.

[0116] The admixture dosage was increased to 0.19%, and concrete performance tests and working conditions were compared for Examples 2 and 4, and Comparative Examples 3, 4, 5 and 6. The results are shown in Table 2.

[0117] Table 2. Performance test results of concrete with different types of polycarboxylate superplasticizers (constituent solid dosage: 0.19%)

[0118]

[0119] As shown in Table 2, when the dosage is increased to 0.19%, the concrete with graphene oxide-based long-side-chain polycarboxylate superplasticizer (Examples 2 and 4) has better concrete condition, while ordinary polycarboxylate superplasticizer (Comparative Examples 3 and 5) and physically mixed graphene oxide-polycarboxylate superplasticizer (Comparative Examples 4 and 6) both show water bleeding. Therefore, it can be seen that the graphene oxide-based long-side-chain polycarboxylate superplasticizer prepared in this invention can make concrete less prone to water bleeding.

[0120] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A graphene oxide-based long-side-chain polycarboxylate superplasticizer, characterized in that: The composition, by weight, includes 0.1-0.15 parts graphene oxide, 3-5 parts hydroxyl polyethylene glycol succinimide, 5-7 parts dispersant, 0.03-0.12 parts catalyst, 100-150 parts polyether monomer, 10-13 parts unsaturated carboxylic acid monomer, 0.3-0.8 parts molecular weight regulator, 0.8-1.5 parts initiator, 0.1-0.4 parts reducing agent, and alkali solution. The graphene oxide / hydroxyl polyethylene glycol succinimide is obtained by reacting hydroxyl polyethylene glycol succinimide with graphene oxide, and then graphene oxide-based polyether is generated by reacting the graphene oxide / hydroxyl polyethylene glycol succinimide with the polyether monomer.

2. The graphene oxide-based long-side-chain polycarboxylate superplasticizer according to claim 1, characterized in that: The graphene oxide is a two-dimensional carbon nanosheet containing hydroxyl and carboxyl groups; the hydroxyl polyethylene glycol succinimide ester is at least one of hydroxyl polyethylene glycol succinimide acetate, hydroxyl polyethylene glycol succinimide propionate, and hydroxyl polyethylene glycol succinimide glutarate.

3. The graphene oxide-based long-side-chain polycarboxylate superplasticizer according to claim 2, characterized in that: The dispersant is at least one of N, N-dimethylformamide, and dimethyl sulfoxide; the catalyst is p-toluenesulfonic acid.

4. The graphene oxide-based long-side-chain polycarboxylate superplasticizer according to claim 3, characterized in that: The polyether monomer is at least one of allyl polyethylene glycol ether (APEG), isobutylene polyethylene glycol ether (HPEG), and isopentenyl polyethylene glycol ether (TPEG).

5. The graphene oxide-based long-side-chain polycarboxylate superplasticizer according to claim 4, characterized in that: The unsaturated carboxylic acid monomer is at least one of maleic anhydride, acrylic acid, and methacrylic acid.

6. The graphene oxide-based long-side-chain polycarboxylate superplasticizer according to claim 5, characterized in that: The molecular weight regulator is at least one of sodium hypophosphite, mercaptoethanol, mercaptoacetic acid, or mercaptopropionic acid; the initiator is at least one of hydrogen peroxide, sodium persulfate, ammonium persulfate, or potassium persulfate; and the reducing agent is at least one of sodium sulfite, potassium sulfite, sodium bisulfite, vitamin C, ferrous sulfate, or sodium formaldehyde sulfoxylate.

7. A method for preparing a graphene oxide-based long-side-chain polycarboxylate superplasticizer according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Preparation of graphene oxide / hydroxyl polyethylene glycol succinimide ester: Graphene oxide and hydroxyl polyethylene glycol succinimide ester react under the action of a catalyst to generate graphene oxide / hydroxyl polyethylene glycol succinimide ester; Step 2, Preparation of graphene oxide-based long side-chain polyether: The graphene oxide / hydroxyl polyethylene glycol succinimide ester obtained in Step 1 is reacted with polyether monomers under heating conditions to generate graphene oxide-based polyether. Step 3: Preparation of graphene oxide-based long-side-chain polycarboxylate superplasticizer, the method is as follows: S1: Dissolve graphene oxide-based polyether in deionized water to prepare bottom solution A; S2: Mix unsaturated carboxylic acid monomers, molecular weight regulators and deionized water to prepare dropwise solution B; S3: Mix the reducing agent and deionized water to prepare the dropping solution C; S4: Add the initiator to the bottom liquid A, and then add the B and C materials at a uniform rate. After the addition is completed, keep the temperature and adjust the pH value to neutral with an alkaline solution to obtain the graphene oxide-based long side chain polycarboxylate superplasticizer solution.

8. The method for preparing a graphene oxide-based long-side-chain polycarboxylate superplasticizer according to claim 7, characterized in that: In step one, graphene oxide is first added to the dispersant and ultrasonically dispersed to form a graphene oxide dispersion. Then, a catalyst and hydroxyl polyethylene glycol succinimide are added to react and generate graphene oxide / hydroxyl polyethylene glycol succinimide.

9. The method for preparing a graphene oxide-based long-side-chain polycarboxylate superplasticizer according to claim 8, characterized in that: In step two, the temperature is raised to 55-65℃, and the reaction time is 4-6 hours.

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