CN113912842B

CN113912842B - Ligand, conductive early-strength polycarboxylate superplasticizer, conductive early-strength graphene dispersion slurry and preparation method thereof

Info

Publication number: CN113912842B
Application number: CN202111076864.8A
Authority: CN
Inventors: 邵幼哲; 李格丽; 吴传灯; 林志群; 方云辉; 钟丽娜
Original assignee: Hunan Kezhijie New Material Co ltd; Kezhijie New Material Group Co Ltd
Current assignee: Hunan Kezhijie New Material Co ltd; Kezhijie New Material Group Co Ltd
Priority date: 2021-09-14
Filing date: 2021-09-14
Publication date: 2023-10-24
Anticipated expiration: 2041-09-14
Also published as: CN113912842A

Abstract

The invention relates to the field of polycarboxylate water reducers, and provides a ligand, a conductive early-strength polycarboxylate water reducer, conductive early-strength graphene dispersion slurry and a preparation method thereof. The ligand is formed by polycondensing a first polymer, thionyl chloride, 4-hydroxy-2, 2':6', 2' -terpyridine and dichloromethane. The first polymer is formed by free radical polymerization of methoxy polyethylene glycol acrylate, unsaturated monocarboxylic acid and acrylamide monomers. The conductive early-strength polycarboxylate water reducer is prepared from a ligand, zinc nitrate and deionized water. The conductive early-strength graphene dispersion slurry is prepared by mixing graphene, graphene oxide, a conductive early-strength polycarboxylate water reducer and deionized water. The conductive early-strength polycarboxylate water reducer and the conductive early-strength graphene dispersion slurry prepared by the method have excellent conductive performance and early-strength performance.

Description

Ligand, conductive early-strength polycarboxylate superplasticizer, conductive early-strength graphene dispersion slurry and preparation method thereof

Technical Field

The invention relates to the field of polycarboxylate water reducers, in particular to a ligand, a conductive early-strength polycarboxylate water reducer, conductive early-strength graphene dispersion slurry and a preparation method thereof.

Background

The polycarboxylate water reducer has the characteristics of high water reducing rate, high slump retaining property, low alkali, green environmental protection and the like, and has been widely applied to concrete engineering. However, the early strength of the common polycarboxylate water reducer is slow to develop, and particularly under the low-temperature condition, the common polycarboxylate water reducer is limited in winter construction and use in cold environment, so that early hydration of cement is promoted, and the development of the early-strength polycarboxylate water reducer has remarkable technical and economic benefits.

In recent years, along with the rapid development of economy in China, in many projects, in order to accelerate the project progress and shorten the construction period, an early strength water reducer is required to be used for accelerating the hydration speed of cement, increasing the early strength of concrete and ensuring the successful completion of the projects.

Conductive concrete is a concrete with conductive properties, which is made by adding conductive components to ordinary concrete, and generally has a conductive mechanism that a network is formed by conductive component materials dispersed in a matrix, and is conducted by tunneling to connect insulators between the networks. The conductive concrete has very wide application in the aspects of snow melting and deicing of cold area engineering (such as road engineering, reservoir dams, airport runways and the like), engineering piezoelectric sensor manufacturing, thermal parameter monitoring and the like.

At present, the high conductivity and the high strength of the concrete are difficult to be organically combined in the preparation of the conductive concrete, the conductivity of the concrete is emphasized, the strength of the concrete is emphasized, and the key technical bottleneck for limiting the development of the conductive concrete is also realized.

The existing conductive concrete is prepared by compounding conductive materials in the concrete, such as iron slag, steel fibers, carbon nanotubes, graphite powder, graphene and the like, but because the substances are dispersed in the concrete and the contact conductivity is low, the iron slag and the steel fibers are easy to rust in the concrete, and the carbon fibers, the carbon nanotubes, the graphite powder and the graphene are easy to agglomerate or are incompatible with the concrete, so that the conductivity of the concrete and even the mechanical property of the concrete are further influenced.

The existing concrete with the functions of conductivity and early strength is mostly compounded by adopting a polycarboxylate water reducer with the functions of early strength and non-conductivity and a conductive component with the function of conductivity, wherein the conductive component is dispersed in the concrete, the contact conductivity probability is low, and the conductivity is poor.

The prior Chinese patent with reference to publication number CN103304181A discloses an early-strength polycarboxylic acid high-performance water reducer which comprises the following components in percentage by weight: 10-20% of polycarboxylate water reducer, 10-17% of calcium chloride, 10-20% of sodium nitrite, 1-3% of triethanolamine and the balance of water. However, the calcium chloride in the concrete can aggravate the reaction between alkali and aggregate, so that the corrosion of the concrete is aggravated, in addition, the calcium ions in the concrete are increased by adding the calcium chloride, the probability of producing calcium sulfate by the reaction of the calcium ions and sulfate is increased, and therefore, the concrete is cracked, and the sulfate corrosion resistance of the concrete is reduced. And the concrete is not conductive.

Another chinese patent with publication number CN112708048A discloses an ester anti-mud type super-early-strength polycarboxylate superplasticizer and a preparation method thereof, wherein the ester anti-mud type super-early-strength polycarboxylate superplasticizer comprises the following preparation raw materials: methoxy polyethylene glycol acrylate, 3-chloro-1-propanol, N-methylallylamine, unsaturated carboxylic acid, allylamine, acrylamide, oxidant, reducing agent, chain transfer agent, methanol. The ester mud-resistant super-early-strength polycarboxylate water reducer has good workability, and the short side chains have high density of early-strength groups, so that the early strength of concrete is greatly improved, and the mud-resistant super-early-strength polycarboxylate water reducer has good mud resistance. However, the concrete is not conductive, and the reaction of 3-chloro-1-propanol and amine substances can generate quaternary ammonium salt, which makes the synthetic reaction process more complex, increases the uncertainty of the synthetic result and weakens the water reducing capability of the polycarboxylate water reducing agent, and in fact, the steps are very complex in terms of the reaction steps disclosed by the patent, and involve multiple temperature changes and multiple addition of reaction components, which simultaneously lead to increased side reactions and uncertainty of the synthetic result.

Another chinese patent with publication number CN111268978A discloses a carbon fiber doped conductive cement-based material, which comprises, by weight, 85-90 parts of cement, 125-200 parts of sand, 10-15 parts of mineral powder, 1-3 parts of redispersible latex powder, 40-50 parts of water, 0.5-0.8 part of water reducer, and 0.03-0.06 part of defoamer; and the carbon fiber accounts for 0.6-1% of the volume of the mixture. S1, preparing a carbon fiber dispersion liquid; s2, preparing cement-based mortar; s3, forming the conductive cement-based material. The conductive cement-based material has the performance of early strength and quick hardening, and is suitable for repair engineering; the durability, toughness and resistivity are higher, and the shrinkage of the cement-based material is effectively reduced; has the functions of repairing and conducting electricity. However, the water reducer and the conductive carbon fiber are compounded into the material by adopting a compounding means, the conductive component is dispersed in the cement-based material, the contact conductivity is low, and the conductive performance is poor.

Disclosure of Invention

In order to solve the defect of poor conductive capability of the concrete with early strength performance in the prior art, the invention provides a ligand which is formed by polycondensing a first polymer, thionyl chloride, 4-hydroxy-2, 2':6',2 '-terpyridine and methylene dichloride, wherein the mass ratio of the first polymer to the 4-hydroxy-2, 2':6', 2' -terpyridine is (10-12): (1-1.5); the first polymer is formed by free radical polymerization of methoxy polyethylene glycol acrylate, unsaturated monocarboxylic acid and acrylamide monomers, the molecular weight of the methoxy polyethylene glycol acrylate is 2000-5000, and the mass ratio of the methoxy polyethylene glycol acrylate to the unsaturated monocarboxylic acid to the acrylamide monomers is (110-120): (10-15): (1-1.5).

In one embodiment, the preparation method of the first polymer comprises the following specific steps in parts by weight:

80 to 100 parts of deionized water, 110 to 120 parts of methoxy polyethylene glycol acrylate and 0.15 to 0.25 part of oxidant are put into a reaction kettle, and are stirred and dissolved uniformly, and the reaction temperature is 25 to 60 ℃; dissolving 10-15 parts of unsaturated monocarboxylic acid and 1-1.5 parts of acrylamide monomer in 40 parts of deionized water to prepare a material A for standby, and dissolving 0.5-0.8 part of chain transfer agent in 20 parts of deionized water to prepare a material B for standby; dissolving 0.15-0.2 part of reducing agent in 20 parts of deionized water to prepare a material C for standby;

Simultaneously dripping the prepared materials A, B and C into a reaction kettle, wherein the dripping time of the materials A is 3.5-4 hours, the dripping time of the materials B is 3.5-4 hours, the dripping time of the materials C is 3-3.5 hours, and the heat preservation reaction is carried out for 1-2 hours; neutralizing until the pH value is 6-7, and distilling under reduced pressure to remove water to obtain a first polymer.

In one embodiment, the unsaturated monocarboxylic acid is one or all of methacrylic acid and acrylic acid; the acrylamide monomer is one or more of N, N-dimethylacrylamide, N-isopropyl acrylamide and acrylamide.

In one embodiment, the oxidant is one or more of ammonium persulfate, potassium persulfate, sodium persulfate and hydrogen peroxide; the chain transfer agent is one or more of 3-mercaptopropionic acid, mercaptoacetic acid, mercaptoethanol, thioglycerol and dodecyl mercaptan; the reducing agent is one or more of L-ascorbic acid, sodium bisulfite, sodium hypophosphite and formaldehyde sodium bisulfite; the pH was neutralized with sodium hydroxide.

The invention also provides a preparation method of the ligand, which comprises the following specific steps in parts by mass:

weighing 100-120 parts of first polymerAdding the compound into a first reaction vessel, adding 150-250 parts of thionyl chloride, dropwise adding 0.5-1 part of N, N-dimethylformamide, heating and refluxing, and reacting t ₁ Distilling to remove unreacted thionyl chloride, adding 100-200 parts of redistilled toluene, and distilling under reduced pressure to remove residual thionyl chloride; weighing 10-15 parts of 4-hydroxy-2, 2':6', 2' -terpyridine, adding into a second reaction vessel, adding 10-30 parts of dry dichloromethane and 2-5 parts of triethylamine, stirring and heating to reflux to obtain a material D;

diluting the material D with 400-500 parts of dry dichloromethane, and at t ₂ Is added into the first reaction vessel by internal dripping, and reaction t is continued ₃ The method comprises the steps of carrying out a first treatment on the surface of the The solvent was removed by rotary evaporation to give the ligand.

In one embodiment, t ₁ For 5 to 7 hours, t ₂ 1 to 1.5h, t ₃ 20-28 h.

The invention also provides a conductive early-strength polycarboxylate water reducer, which is prepared from the ligand, zinc nitrate and deionized water according to the technical scheme, wherein the mass ratio of the ligand to the zinc nitrate is 15: (2-3).

The invention also provides a preparation method of the conductive early-strength polycarboxylate superplasticizer, which comprises the following specific preparation steps in parts by mass:

and (3) weighing 150 parts of the ligand in a third reaction container, dissolving the ligand in equal amount of deionized water to prepare an E material, weighing 20-30 parts of zinc nitrate in a fourth reaction container, adding equal amount of deionized water to dissolve the E material, transferring the solution into a fifth reaction container, stirring the solution for 5-10 min, adding the E material drop into the fifth reaction container, and supplementing water until the solid content is 35-45%, thereby preparing the conductive early-strength polycarboxylate water reducer.

The invention also provides a conductive early-strength type graphene dispersion slurry, which is prepared by mixing graphene, graphene oxide, the conductive early-strength type polycarboxylate superplasticizer and deionized water in the technical scheme, wherein the mass ratio of the graphene to the graphene oxide to the conductive early-strength type polycarboxylate superplasticizer to the deionized water is (1-4): (1-4): 5:50.

The invention also provides a preparation method of the conductive early-strength graphene dispersion slurry, which comprises the following specific steps: mixing graphene, graphene oxide, the conductive early-strength type polycarboxylate superplasticizer and deionized water, stirring at a speed of 500-540 r/min for 1-2 min, and then performing ultrasonic treatment for 20-60 min to obtain the conductive early-strength type graphene dispersion slurry.

Based on the above, compared with the prior art, the ligand provided by the invention introduces terpyridine groups, and because of the high conjugation and stability of terpyridine, the N atom on the ring is very active and is easy to react with Zn ²⁺ And (3) coordinating the metal ions to form a complex with novel and stable structure. The metal supermolecular polymer generated by coordination complexing of the organic macromolecule containing the ligand and the metal ion can not only have the property of the polymer, but also can obtain the special optical, electric, magnetic and other properties of the metal ion, and the electric activity is obviously improved. The invention innovatively applies the principle of free radical polymerization activity matching, and introduces polyether macromonomer with ultra-high molecular weight, so that the synthesized polymer has a molecular structure with long side chain and short main chain, the shape of the molecule is changed into an inverted T shape from a traditional comb shape, the length of the side chain is far beyond the main chain, the structure has strong steric hindrance dispersing effect, has better hydrophilicity, accelerates the hydration process, and simultaneously can greatly promote the development of early strength of concrete.

The invention adopts nitrate which can accelerate the hydration speed of cement, introduces acrylamide functional small monomers with early strength effect into the polycarboxylic acid structure, and coordinates with the nitrate to further promote the development of early strength on coagulation.

According to the invention, the conductive early-strength type polycarboxylate water reducer, the graphene oxide and the graphene are mixed and a dispersion process is combined, so that the prepared conductive early-strength type graphene dispersion slurry is high in stability, has excellent conductive performance and early-strength performance, has a steric hindrance effect due to a long side chain structure of the conductive early-strength type polycarboxylate water reducer, and can prevent aggregation of graphene particles, and the electrostatic repulsion force provided by anionic polar groups such as carboxyl groups can improve the dispersion effect.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments; the technical features designed in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other; all other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the description of the present invention, it should be noted that all terms used in the present invention (including technical terms and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs and are not to be construed as limiting the present invention; it will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

The present invention provides the following examples and comparative examples:

example 1

1. First Polymer Synthesis

80 parts of deionized water, 110 parts of methoxypolyethylene glycol acrylate (molecular weight is 5000) and 0.15 part of ammonium persulfate are put into a reaction kettle, stirred and dissolved uniformly, and the reaction temperature is 25 ℃;

10 parts of methacrylic acid and 1 part of N, N-dimethylacrylamide are dissolved in 40 parts of deionized water to prepare a material A for standby, and 0.5 part of 3-mercaptopropionic acid is dissolved in 20 parts of deionized water to prepare a material B for standby; 0.15 part of L-ascorbic acid is dissolved in 20 parts of deionized water to prepare a C material for standby.

Simultaneously dripping the prepared materials A, B and C into the reaction kettle at a constant speed, dripping the materials A for 3.5 hours, dripping the materials B for 3 hours, and carrying out heat preservation reaction for 1 hour; the mixture was neutralized to pH 6 by the addition of 32% sodium hydroxide solution, and the water was removed by distillation under reduced pressure to give a first polymer.

2. Ligand preparation

100 parts of the first polymer was weighed into a 1000ml three-necked flask, 200 parts of thionyl chloride was added thereto, 0.5 parts of N, N-dimethylformamide was added dropwise thereto, and the mixture was refluxed with heating and reacted for 5 hours. Unreacted thionyl chloride is distilled off, 150 parts of distilled toluene is added, and residual thionyl chloride is distilled off under reduced pressure.

10 parts of 4-hydroxy-2, 2':6', 2' -terpyridine are weighed, added into a 100ml three-necked flask, 20 parts of dry dichloromethane and 3 parts of triethylamine are added, and stirred and heated to reflux, so as to obtain a material D. The resulting material D was diluted with 400 parts of dry dichloromethane and slowly added dropwise over 1h to a 1000ml three-necked flask at a constant speed, and the reaction was continued for 24h. The solvent was removed by rotary evaporation to give the ligand.

3. Preparation of conductive early-strength polycarboxylate water reducer

150 parts of ligand is weighed into a 500ml beaker and is dissolved by using equal amount of deionized water to prepare an E material, 20 parts of zinc nitrate is weighed into a 100ml beaker, equal amount of deionized water is added to dissolve the E material, the solution is transferred into the 100ml beaker, a rotating magnet is placed on a magnetic stirrer to magnetically stir the solution, the E material is added into the zinc nitrate solution in the flask at a constant speed for 5min, and water is added until the solid content is 40%, so that the conductive early-strength polycarboxylate water reducer is prepared.

4. Preparation of conductive early-strength graphene dispersion slurry

Mixing 1 part of graphene, 4 parts of graphene oxide, 5 parts of conductive early-strength polycarboxylate superplasticizer and 50 parts of deionized water, mechanically stirring at a speed of 500r/min for 1min, and then moving into an ultrasonic instrument for ultrasonic treatment for 30min to obtain conductive early-strength graphene dispersion slurry.

Example 2

1. First Polymer Synthesis

90 parts of deionized water, 110 parts of methoxypolyethylene glycol acrylate (molecular weight 3000) and 0.2 part of sodium persulfate are put into a reaction kettle, stirred and dissolved uniformly, and the reaction temperature is 40 ℃;

dissolving 6 parts of methacrylic acid, 6 parts of acrylic acid and 1.2 parts of N-isopropyl acrylamide in 40 parts of deionized water to prepare a material A for standby, and dissolving 0.6 part of mercaptoethanol in 20 parts of deionized water to prepare a material B for standby; 0.18 part of sodium hypophosphite is dissolved in 20 parts of deionized water to prepare a material C for standby.

Simultaneously dripping the prepared materials A, B and C into the reaction kettle at a constant speed, dripping the materials A for 3.5 hours, dripping the materials B for 3 hours, and carrying out heat preservation reaction for 1.5 hours; the mixture was neutralized to pH 6 by the addition of 32% sodium hydroxide solution, and the water was removed by distillation under reduced pressure to give a first polymer.

2. Ligand preparation

110 parts of the first polymer are weighed into a 1000ml three-necked flask, 200 parts of thionyl chloride are added, 0.8 part of N, N-dimethylformamide is added dropwise, and the mixture is heated and refluxed and reacted for 6 hours. Unreacted thionyl chloride is distilled off, 150 parts of distilled toluene is added, and residual thionyl chloride is distilled off under reduced pressure.

12 parts of 4-hydroxy-2, 2':6', 2' -terpyridine are weighed, added into a 100ml three-necked flask, 20 parts of dry dichloromethane and 3 parts of triethylamine are added, and stirred and heated to reflux, so as to obtain a material D. The resulting material D was diluted with 400 parts of dry dichloromethane and slowly added dropwise over 1.5h to a 1000ml three-necked flask at a constant speed, and the reaction was continued for 24h. The solvent was removed by rotary evaporation to give the ligand.

3. Preparation of conductive early-strength polycarboxylate water reducer

150 parts of ligand is weighed into a 500ml beaker and is dissolved by using equal amount of deionized water to prepare an E material, 25 parts of zinc nitrate is weighed into a 100ml beaker, equal amount of deionized water is added to dissolve the E material, the solution is transferred into the 100ml beaker, a rotating magnet is placed on a magnetic stirrer to magnetically stir the solution, the E material is added into the zinc nitrate solution in the flask at a constant speed for 7min, and water is added until the solid content is 40%, so that the conductive early-strength polycarboxylate water reducer is prepared.

4. Preparation of conductive early-strength graphene dispersion slurry

Mixing 2 parts of graphene, 3 parts of graphene oxide, 5 parts of conductive early-strength type polycarboxylate superplasticizer and 50 parts of deionized water, mechanically stirring at the speed of 520r/min for 1.5min, and then moving into an ultrasonic instrument for ultrasonic treatment for 40min to obtain conductive early-strength type graphene dispersion slurry.

Example 3

1. First Polymer Synthesis

100 parts of deionized water, 120 parts of methoxypolyethylene glycol acrylate (molecular weight 2000) and 0.25 part of hydrogen peroxide are put into a reaction kettle, stirred and dissolved uniformly, and the reaction temperature is 60 ℃;

15 parts of acrylic acid and 1.5 parts of acrylamide are dissolved in 40 parts of deionized water to prepare a material A for standby, and 0.8 part of dodecyl mercaptan is dissolved in 20 parts of deionized water to prepare a material B for standby; 0.2 part of formaldehyde sodium bisulphite is dissolved in 20 parts of deionized water to prepare a material C for standby.

Simultaneously dripping the prepared materials A, B and C into the reaction kettle at a constant speed, dripping the materials A for 4 hours, dripping the materials B for 3.5 hours, and reacting for 2 hours under heat preservation; 32% sodium hydroxide solution was added to neutralize to pH 7, and water was removed by distillation under reduced pressure to give a first polymer.

2. Ligand preparation

120 parts of the first polymer were weighed into a 1000ml three-necked flask, 200 parts of thionyl chloride was added thereto, 1 part of N, N-dimethylformamide was added dropwise thereto, and the mixture was refluxed with heating and reacted for 7 hours. Unreacted thionyl chloride is distilled off, 150 parts of distilled toluene is added, and residual thionyl chloride is distilled off under reduced pressure.

15 parts of 4-hydroxy-2, 2':6', 2' -terpyridine are weighed, added into a 100ml three-necked flask, 20 parts of dry dichloromethane and 3 parts of triethylamine are added, and stirred and heated to reflux, so as to obtain a material D. The resulting material D was diluted with 400 parts of dry dichloromethane and slowly added dropwise over 1.5h to a 1000ml three-necked flask at a constant speed, and the reaction was continued for 24h. The solvent was removed by rotary evaporation to give the ligand.

3. Preparation of conductive early-strength polycarboxylate water reducer

150 parts of ligand is weighed into a 500ml beaker and is dissolved by using equal amount of deionized water to prepare E material, 30 parts of zinc nitrate is weighed into a 100ml beaker, equal amount of deionized water is added to dissolve, the solution is transferred into the 100ml beaker, a rotating magnet is placed on a magnetic stirrer to magnetically stir, the E material is added into the zinc nitrate solution in the flask at a constant speed within 10min, and water is added until the solid content is 40%, thus the conductive early-strength polycarboxylate water reducer is prepared.

4. Preparation of conductive early-strength graphene dispersion slurry

Mixing 2.5 parts of graphene, 2.5 parts of graphene oxide, 5 parts of conductive early-strength type polycarboxylate superplasticizer and 50 parts of deionized water, mechanically stirring at the speed of 540r/min for 2min, and then moving into an ultrasonic instrument to carry out ultrasonic treatment for 60min to obtain the conductive early-strength type graphene dispersion slurry.

Example 4

1. First Polymer Synthesis

2. Ligand preparation

15 parts of 4-hydroxy-2, 2':6', 2' -terpyridine are weighed, added into a 100ml three-necked flask, 20 parts of dry dichloromethane and 3 parts of triethylamine are added, and stirred and heated to reflux, so as to obtain a material D. The resulting material D was diluted with 400 parts of dry dichloromethane and slowly added dropwise over 1h to a 1000ml three-necked flask at a constant speed, and the reaction was continued for 24h. The solvent was removed by rotary evaporation to give the ligand.

3. Preparation of conductive early-strength polycarboxylate water reducer

4. Preparation of conductive early-strength graphene dispersion slurry

Example 5

1. First Polymer Synthesis

2. Ligand preparation

3. Preparation of conductive early-strength polycarboxylate water reducer

150 parts of ligand is weighed into a 500ml beaker and is dissolved by using equal amount of deionized water to prepare an E material, 30 parts of zinc nitrate is weighed into a 100ml beaker, equal amount of deionized water is added to dissolve the E material, the solution is transferred into the 100ml beaker, a rotating magnet is placed on a magnetic stirrer to magnetically stir the solution, the E material is added into the zinc nitrate solution in the flask at a constant speed for 5min, and water is added until the solid content is 40%, so that the conductive early-strength polycarboxylate water reducer is prepared.

4. Preparation of conductive early-strength graphene dispersion slurry

Example 6

1. First Polymer Synthesis

2. Ligand preparation

3. Preparation of conductive early-strength polycarboxylate water reducer

4. Preparation of conductive early-strength graphene dispersion slurry

Comparative example 1

1 part of graphene, 4 parts of graphene oxide, 5 parts of a commercially available early-strength water reducer (with a solid content of 40%) and 50 parts of deionized water are mixed, mechanically stirred at a speed of 500r/min for 1min, and then transferred into an ultrasonic instrument for ultrasonic treatment for 30min, so that the slurry is prepared.

Comparative example 2

2 parts of graphene, 3 parts of graphene oxide, 5 parts of a commercially available early-strength water reducer (with a solid content of 40%) and 50 parts of deionized water are mixed, mechanically stirred at a speed of 520r/min for 1.5min, and then transferred into an ultrasonic instrument for ultrasonic treatment for 40min, so that the slurry is prepared.

Comparative example 3

2.5 parts of graphene, 2.5 parts of graphene oxide, 5 parts of a commercially available early-strength water reducer (with a solid content of 40%) and 50 parts of deionized water are mixed, mechanically stirred at a speed of 540r/min for 2min, and then transferred into an ultrasonic instrument for ultrasonic treatment for 60min, so that the slurry is prepared.

Comparative example 4

1. First Polymer Synthesis

2. Ligand preparation

100 parts of the first polymer was weighed into a 1000ml three-necked flask, 200 parts of thionyl chloride was added thereto, 0.5 parts of N, N-dimethylformamide was added dropwise thereto, and the mixture was refluxed with heating and reacted for 5 hours. Unreacted thionyl chloride is distilled off, 150 parts of distilled toluene is added, and residual thionyl chloride is distilled off under reduced pressure to obtain the ligand.

3. Preparation of conductive early-strength polycarboxylate water reducer

4. Preparation of conductive early-strength graphene dispersion slurry

Comparative example 5

1. First Polymer Synthesis

2. Ligand preparation

Weighing 20 parts of 4-hydroxy-2, 2':6', 2' -terpyridine, adding into a 100ml three-necked flask, adding 20 parts of dry dichloromethane and 3 parts of triethylamine, stirring and heating to reflux to obtain a material D. The resulting material D was diluted with 400 parts of dry dichloromethane and slowly added dropwise over 1h to a 1000ml three-necked flask at a constant speed, and the reaction was continued for 24h. The solvent was removed by rotary evaporation to give the ligand.

3. Preparation of conductive early-strength polycarboxylate water reducer

4. Preparation of conductive early-strength graphene dispersion slurry

Comparative example 6

1. First Polymer Synthesis

2. Ligand preparation

7 parts of 4-hydroxy-2, 2':6', 2' -terpyridine are weighed, added into a 100ml three-necked flask, 20 parts of dry dichloromethane and 3 parts of triethylamine are added, and stirred and heated to reflux, so as to obtain a material D. The resulting material D was diluted with 400 parts of dry dichloromethane and slowly added dropwise over 1h to a 1000ml three-necked flask at a constant speed, and the reaction was continued for 24h. The solvent was removed by rotary evaporation to give the ligand.

3. Preparation of conductive early-strength polycarboxylate water reducer

4. Preparation of conductive early-strength graphene dispersion slurry

Comparative example 7

1. First Polymer Synthesis

2. Ligand preparation

3. Preparation of conductive early-strength polycarboxylate water reducer

150 parts of ligand is weighed into a 500ml beaker and is dissolved by using equal amount of deionized water to prepare an E material, 10 parts of zinc nitrate is weighed into a 100ml beaker, equal amount of deionized water is added to dissolve the E material, the solution is transferred into the 100ml beaker, a rotating magnet is placed on a magnetic stirrer to magnetically stir the solution, the E material is added into the zinc nitrate solution in the flask at a constant speed for 5min, and water is added until the solid content is 40%, so that the conductive early-strength polycarboxylate water reducer is prepared.

4. Preparation of conductive early-strength graphene dispersion slurry

Comparative example 8

1. First Polymer Synthesis

2. Ligand preparation

3. Preparation of conductive early-strength polycarboxylate water reducer

150 parts of ligand is weighed into a 500ml beaker and is dissolved by using equal amount of deionized water to prepare an E material, 40 parts of zinc nitrate is weighed into a 100ml beaker, equal amount of deionized water is added to dissolve the E material, the solution is transferred into the 100ml beaker, a rotating magnet is placed on a magnetic stirrer to magnetically stir the solution, the E material is added into the zinc nitrate solution in the flask at a constant speed for 5min, and water is added until the solid content is 40%, so that the conductive early-strength polycarboxylate water reducer is prepared.

4. Preparation of conductive early-strength graphene dispersion slurry

Comparative example 9

1. First Polymer Synthesis

2. Ligand preparation

3. Preparation of polycarboxylate water reducer

150 parts of ligand is weighed in a 500ml beaker, and water is added until the solid content is 40%, so that the polycarboxylate superplasticizer is prepared.

4. Preparation of conductive early-strength graphene dispersion slurry

Comparative example 10

1. First Polymer Synthesis

2. Ligand preparation

3. Preparation of conductive early-strength polycarboxylate water reducer

4. Preparation of conductive early-strength graphene dispersion slurry

8 parts of graphene, 4 parts of graphene oxide, 5 parts of conductive early-strength polycarboxylate superplasticizer and 50 parts of deionized water are mixed, mechanically stirred at the speed of 500r/min for 1min, and then transferred into an ultrasonic instrument for ultrasonic treatment for 30min, so that the conductive early-strength graphene dispersion slurry is prepared.

The above preparation methods, the brands of the raw materials and other technical indexes adopted in the examples and comparative examples can be selected according to the prior art, and if the technical indexes are specified in the invention, the technical indexes are selected within the specified range of the invention, so that the technical effects of the invention are not affected.

The conductive early-strength polycarboxylate water reducer synthesized in examples 1 to 3 was compared with the commercial early-strength water reducer (solid content: 40%) and the water reducer obtained in comparative examples 4 to 9, and the water reducer was prepared from red lion cement in an amount of 0.40% by mass of cement (folded into solid content) and was measured for water reduction rate, air content and strength according to GB 8076-2008 concrete admixture. And after the test piece is maintained to the corresponding age, the resistivity of the test piece is directly tested by using a resistivity meter. The test method comprises the following steps: and (3) selecting a certain non-molding surface of the test piece as a test surface, wetting the molding surface by using wet cloth, simultaneously plugging wetted sponge into an electrode of the resistivity instrument, opening a switch of the resistivity instrument, and tightly attaching the electrode of the resistivity instrument to the test surface for testing. The concrete mixing ratio is as follows: 360kg/m of cement ³ 790kg/m sand ³ Stone 1060kg/m ³ 175kg/m of water ³ The results obtained are shown in the accompanying table 1. The conductive early-strength graphene dispersion slurry obtained by compounding the examples 1 to 3 is subjected to performance comparison with the comparative examples 1 to 10, the mixing amount of the water reducer is kept to be 0.38% of the cement mass (folded into solid matters), the mixing amount of the slurry is 0.5% of the cement mass, and the mixing ratio of concrete is as follows: 360kg/m of cement ³ 790kg/m sand ³ Stone 1060kg/m ³ 173.5kg/m of water ³ The concrete air content, strength and resistivity test results are shown in the attached table 2.

Table 1 water reducer performance comparison

Table 2 comparative slurry properties

The test results of examples 1 to 3 and the commercial early strength type water reducing agent in the attached table 1 show that the conductive early strength type polycarboxylate water reducing agent of the invention has the conductive effect while maintaining excellent water reducing and early strength properties; examples 4 to 6, comparative example 4 (no terpyridyl group) and comparative example 9 (no zinc nitrate) demonstrate that terpyridyl groups and zinc nitrate mutually support the conductivity of the water reducer and interact with each other, resulting in a conductivity better than that achieved when terpyridyl groups and zinc nitrate are used alone; and when no zinc nitrate exists, the synergistic effect of the zinc nitrate and the acrylamide monomer disappears, so that the early strength performance of the conductive early strength polycarboxylate water reducer is reduced. Comparative examples 5 to 8 illustrate that the content of terpyridyl groups and zinc nitrate is not within the scope of the technical scheme of the invention, and the conductive effect of the water reducer is reduced. The test results of examples 1-3 and comparative examples 1-3 in the attached table 2 show that the conductive early-strength graphene dispersion slurry can further improve early-strength and later-strength of concrete and enhance the conductive performance of the concrete; examples 4 to 6, comparative example 4 and comparative example 9 illustrate that the terpyridyl group and zinc nitrate mutually support the conductivity of the conductive early strength graphene dispersion slurry, and interact with each other to produce a conductive effect superior to that of the terpyridyl group and zinc nitrate alone; comparative examples 5 to 8 illustrate that the contents of terpyridyl groups and zinc nitrate do not fall within the scope of the technical scheme disclosed by the invention, and comparative example 10 illustrates that the conductive early-strength type graphene dispersion slurry has a dispersion effect on graphene, and when the content of graphene is increased, graphene cannot be effectively dispersed due to the reduction of the mass ratio of the conductive early-strength type polycarboxylate water reducer to the graphene, so that graphene agglomeration is caused, and the conductivity is reduced.

It will be appreciated by those skilled in the art that when the technical scheme of the present invention is changed within the following range, the technical effects similar to or the same as those of the above embodiments can still be obtained, and the technical scheme still falls within the protection scope of the present invention.

In conclusion, compared with the prior art, the ligand provided by the invention introduces terpyridine groups, and because terpyridine has high conjugation and stability, and the N atom on the ring is very active, the ligand is easy to react with Zn ²⁺ And (3) coordinating the metal ions to form a complex with novel and stable structure. The metal supermolecular polymer generated by coordination complexing of the organic macromolecule containing the ligand and the metal ion can not only have the property of the polymer, but also can obtain the special optical, electric, magnetic and other properties of the metal ion, and the electric activity is obviously improved. The invention innovatively applies the principle of free radical polymerization activity matching, and introduces polyether macromonomer with ultra-high molecular weight, so that the synthesized polymer has a molecular structure with long side chain and short main chain, the shape of the molecule is changed into an inverted T shape from a traditional comb shape, the length of the side chain is far beyond the main chain, the structure has strong steric hindrance dispersing effect, has better hydrophilicity, accelerates the hydration process, and simultaneously can greatly promote the development of early strength of concrete.

The synthetic method of the first polymer is simple, the side reaction is less, and the water reducing agent synthesized by the first polymer does not contain interference components such as quaternary ammonium salt and the like, so that the water reducing rate is high.

In addition, it should be understood by those skilled in the art that although many problems exist in the prior art, each embodiment or technical solution of the present invention may be modified in only one or several respects, without having to solve all technical problems listed in the prior art or the background art at the same time. Those skilled in the art will understand that nothing in one claim should be taken as a limitation on that claim.

Although terms such as the first polymer, unsaturated monocarboxylic acid, ligand, conductive early strength polycarboxylate water reducer, conductive early strength graphene dispersion paste, acrylamide-based monomer, etc. are more used herein, the possibility of using other terms is not excluded. These terms are used merely for convenience in describing and explaining the nature of the invention; they are to be interpreted as any additional limitation that is not inconsistent with the spirit of the present invention; the terms first, second, and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims

1. A ligand, characterized in that:

the catalyst is formed by polycondensing a first polymer, thionyl chloride, 4-hydroxy-2, 2':6',2 '-terpyridine and methylene dichloride, wherein the mass ratio of the first polymer to the 4-hydroxy-2, 2':6',2' -terpyridine is (10-12): (1-1.5);

the first polymer is formed by free radical polymerization of methoxy polyethylene glycol acrylate, unsaturated monocarboxylic acid and acrylamide monomers, the molecular weight of the methoxy polyethylene glycol acrylate is 2000-5000, and the mass ratio of the methoxy polyethylene glycol acrylate to the unsaturated monocarboxylic acid to the acrylamide monomers is (110-120): (10-15): (1-1.5);

the acrylamide monomer is one or more of N, N-dimethylacrylamide, N-isopropyl acrylamide and acrylamide.

2. A ligand according to claim 1, wherein:

the preparation method of the first polymer comprises the following specific steps in parts by weight:

3. A ligand according to claim 2, wherein: the unsaturated monocarboxylic acid is one or all of methacrylic acid and acrylic acid.

4. A ligand according to claim 2, wherein: the oxidant is one or more of ammonium persulfate, potassium persulfate, sodium persulfate and hydrogen peroxide; the chain transfer agent is one or more of 3-mercaptopropionic acid, mercaptoacetic acid, mercaptoethanol, thioglycerol and dodecyl mercaptan; the reducing agent is one or more of L-ascorbic acid, sodium bisulfite, sodium hypophosphite and formaldehyde sodium bisulfite; the pH was neutralized with sodium hydroxide.

5. A method of preparing a ligand according to any one of claims 1 to 4, wherein:

the method comprises the following specific steps of:

weighing 100-120 parts of a first polymer, adding the first polymer into a first reaction container, adding 150-250 parts of thionyl chloride, dropwise adding 0.5-1 part of N, N-dimethylformamide, heating and refluxing, and reacting t ₁ The method comprises the steps of (1) distilling to remove unreacted thionyl chloride, adding 100-200 parts of redistilled toluene, distilling under reduced pressure to remove residual thionyl chloride, weighing 10-15 parts of 4-hydroxy-2, 2':6',2' -terpyridine, adding into a second reaction vessel, adding 10-30 parts of dry dichloromethane and 2-5 parts of triethylamine, stirring and heating to reflux to obtain a material D;

6. The method for preparing a ligand according to claim 5, wherein: t is t ₁ Is 5 to 7 hours, t ₂ 1 to 1.5 h, t ₃ 20-28 h.

7. The utility model provides a conductive early-strength polycarboxylate water reducer which characterized in that: prepared from the ligand according to any one of claims 1 to 4, zinc nitrate and deionized water, wherein the mass ratio of the ligand to the zinc nitrate is 15: (2-3).

8. A method for preparing the conductive early-strength polycarboxylate superplasticizer according to claim 7, wherein:

the preparation method comprises the following specific preparation steps in parts by mass:

9. The conductive early-strength graphene dispersion slurry is characterized in that: the conductive early-strength polycarboxylate superplasticizer is prepared by mixing graphene, graphene oxide, the conductive early-strength polycarboxylate superplasticizer of claim 7 and deionized water, wherein the mass ratio of the graphene to the graphene oxide to the conductive early-strength polycarboxylate superplasticizer to the deionized water is (1-4): (1-4): 5:50.

10. A method for preparing the conductive early-strength graphene dispersion slurry according to claim 9, which is characterized in that:

the method comprises the following specific steps:

mixing graphene, graphene oxide, the conductive early-strength type polycarboxylate superplasticizer and deionized water, stirring at a speed of 500-540 r/min for 1-2 min, and then performing ultrasonic treatment for 20-60 min to obtain the conductive early-strength type graphene dispersion slurry.