CN112708060B - Novel anti-corrosion polycarboxylate superplasticizer and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of building materials, in particular to a novel anticorrosive polycarboxylate superplasticizer and a preparation method thereof, wherein the novel anticorrosive polycarboxylate superplasticizer is prepared by carrying out polymerization reaction on a small monomer with an anticorrosive function, an unsaturated macromonomer, unsaturated carboxylic acid and/or unsaturated carboxylic anhydride under the action of an initiator and a molecular weight regulator to generate the novel anticorrosive polycarboxylate superplasticizer with a small monomer with the anticorrosive function linked on a molecular main chain; the unsaturated macromonomer is at least one of ethylene glycol monovinyl polyglycol ether and 4-hydroxybutyl vinyl polyoxyethylene ether. The novel anticorrosive polycarboxylate superplasticizer provided by the invention is an ether superplasticizer with an anticorrosive effect, has excellent anticorrosive and water-reducing effects, and the finally obtained novel anticorrosive polycarboxylate superplasticizer product has a stable high molecular structure, can tolerate high temperature higher than 50 ℃, has more excellent high-temperature anticorrosive performance, is simple in preparation process, and has important practical application value.

Description

Novel anti-corrosion polycarboxylate superplasticizer and preparation method thereof

Technical Field

The invention relates to the technical field of building materials, in particular to a novel anticorrosive polycarboxylate superplasticizer and a preparation method thereof.

Background

With the development and progress of modern science and technology, the scale of basic engineering construction is gradually enlarged, modern construction engineering is developed to high-rise, super high-rise and large-span frame engineering, the demand on concrete is gradually increased, and the performance requirements on pumping, segregation resistance and the like of the concrete are gradually increased.

In concrete materials, admixtures, such as water reducing agents, are often used. The conventional method for solving the problem of mildew and odor of the polycarboxylate superplasticizer is a compound preservative, and some people research novel anti-corrosion polycarboxylate superplasticizers.

The novel polycarboxylate superplasticizer prepared from vinyl ether macromonomers has excellent water reducing performance and low sensitivity, and is already applied to some key projects as a high-end polycarboxylate superplasticizer product, and the key projects have strict requirements on high-temperature resistance and corrosion resistance stability.

The method for adding the preservative in the compounding process is the method which is the most widely applied in the prior art, but the compounded preservative generally has a small molecular weight, so that on one hand, the problem that the preservative is not uniformly dispersed in the polycarboxylic acid water reducing agent can exist, and on the other hand, the conventional compound preservative used in the prior art can be decomposed and lose efficacy in the environment of higher than 50 ℃, and the application of the preservative is limited to a certain extent.

CN110642996A, published in 2020, 01, 03 days, discloses a self-novel antiseptic polycarboxylic acid water reducing agent and a preparation method thereof, but the monomers used for the water reducing agent with antiseptic property are any one or more of polymethacrylic acid acyloxy ethyl trimethyl ammonium chloride, poly [2- (acryloyloxy) ethyl ] trimethyl ammonium bromide, poly benzyl ethyl trimethyl ammonium chloride, poly allyl trimethyl ammonium chloride and poly (3-acrylamide propyl) trimethyl ammonium bromide. However, these substances are already polymers, have no polymerization activity and cannot be connected into the molecular structure of the water reducing agent, so the method is also a method for compounding the preservative in nature.

CN110128048A, published in 2019, 08 and 16 months, discloses a corrosion-resistant slump-retaining polycarboxylic acid water reducer for summer and a preparation method thereof, and also realizes the corrosion resistance by a method of compounding a bactericide (polyhexamethylene guanidine phosphate).

CN110015857A, with the publication time of 2019, 07, 16, discloses a preparation method and application of a straw-starch-based mixed modified compound polycarboxylate water reducer, dimethyl fumarate is directly compounded into a patent product as a preservative, but the water solubility of dimethyl fumarate is not very good, a large amount of water is generally required to be compounded and added in the practical use process of the polycarboxylate water reducer, and the water content is often over 90%, so the effect of directly compounding and adding dimethyl fumarate is not ideal.

CN109796561A, with the publication time of 2019, 05, 24 days, discloses an aromatic ring polycarboxylic acid water reducer mother liquor, a preparation method and an application thereof, wherein an aryl conjugated unsaturated carboxylic acid is used as an anticorrosive monomer to prepare a polycarboxylic acid water reducer with a self-anticorrosive effect, but the aryl conjugated unsaturated carboxylic acid has the problems of large steric hindrance and undesirable polymerization effect during polymerization, and finally the performance of the product is influenced.

CN109400819A, published in 2019, 03, 01, discloses a viscosity-reduction-integrated antibacterial amphoteric polycarboxylic acid high-efficiency water reducing agent and a preparation method thereof, wherein guanidine hydrochloride and an alkyl compound with two amino groups at two ends are used for preparing an antibacterial monomer, and then are used for synthesizing the polycarboxylic acid water reducing agent, and the synthesis process is complex and has high energy consumption.

CN108373526A, published in 2018, 08.07.2018, discloses an antifouling and antibacterial polycarboxylate water reducer and a preparation method thereof, wherein the antibacterial effect is realized by adding (methyl) acrylic acid sulfobetaine and methacryloyloxyethyl trimethyl ammonium chloride during polymerization, but the two monomers are higher in cost.

CN107698721A, published in 2018, 16.02.2018, discloses a branched-chain antibacterial polycarboxylate superplasticizer, and a preparation method and application thereof, but the preparation process is too complex and the production efficiency is low.

CN107265907A, published for 10 months and 20 days in 2017, discloses an amphoteric antibacterial polycarboxylic acid high-efficiency water reducing agent and a preparation method thereof, wherein copolymerization is carried out firstly, and then the amphoteric antibacterial polycarboxylic acid high-efficiency water reducing agent is sequentially reacted with unsaturated polyester macromonomer and halogen-terminated polyether, the process is complex, and the product conversion rate is limited due to the reaction of large molecular weight and macromolecules, so that the product performance is influenced.

CN105621927A, published 2016 (06, 01), discloses a preparation method of an antibacterial preservative for a polycarboxylic acid water reducer, wherein betaine and dimethyl fumarate monomers with antibacterial functions are introduced into polyoxyethylene ether with a similar structure of the polycarboxylic acid water reducer for free radical copolymerization reaction, so that the preservative is compatible with the polycarboxylic acid water reducer with a similar molecular structure. However, the product of the patent only has an antiseptic effect and does not have a water reducing effect, and the polymerization efficiency is low because dimethyl fumarate monomer and unsaturated monomer are directly polymerized in a system, so that the water solubility is poor, and the phase separation problem exists in the polymerization process.

Disclosure of Invention

In order to solve the problem of how to provide a novel water reducing agent with excellent and stable anti-corrosion effect in the background art, the invention provides a novel anti-corrosion polycarboxylate water reducing agent, which is prepared by carrying out polymerization reaction on an anti-corrosion functional small monomer, an unsaturated macromonomer, unsaturated carboxylic acid and/or unsaturated carboxylic anhydride under the conditions of an initiator and a molecular weight regulator to generate a novel anti-corrosion polycarboxylate water reducing agent with a molecular main chain connected with the anti-corrosion functional small monomer;

the preservative functional small monomer is fumarate and/or maleate;

the unsaturated macromonomer is vinyl ether macromonomer;

on the basis of the technical scheme, the vinyl ether type macromonomer is at least one of ethylene glycol monovinyl polyethylene glycol ether and 4-hydroxybutyl vinyl polyoxyethylene ether.

On the basis of the technical scheme, the mass ratio range of the unsaturated macromonomer, the preservative functional small monomer, the unsaturated carboxylic acid and/or the unsaturated carboxylic anhydride is 180: (1-15): (5-30).

On the basis of the technical scheme, further, the using amount of the initiator is 0.5-3.0% of the total mass of the reactants; the dosage of the molecular weight regulator is 0.2-3.0% of the total mass of the reactants.

On the basis of the technical scheme, in the polymerization reaction process, an initiator aqueous solution, a molecular weight regulator aqueous solution and an unsaturated carboxylic acid and/or unsaturated carboxylic anhydride aqueous solution are dropwise added within 0.5-2 h, the reaction temperature is 10-40 ℃, the temperature is kept for 0-2 h after the dropwise addition, and alkali is added to adjust the pH value of the product to 5-7.

On the basis of the technical scheme, the initiator further comprises a water-soluble redox initiation system reagent; specifically, hydrogen peroxide-ascorbic acid-ferrous sulfate, hydrogen peroxide-sodium formaldehyde sulfoxylate-ferrous sulfate can be adopted;

the molecular weight regulator comprises at least one of thioglycolic acid, mercaptoethanol, mercaptopropionic acid, sulfonated mercaptopropionic acid and sodium hypophosphite.

On the basis of the technical scheme, the fumaric acid ester comprises monomethyl fumarate and monoethyl fumarate.

On the basis of the technical scheme, the maleate further comprises diethyl maleate, dimethyl maleate and dipropyl maleate.

On the basis of the technical scheme, the molecular weight of the unsaturated macromonomer is 600-6000.

In addition to the above technical solution, the unsaturated carboxylic acid and/or unsaturated carboxylic acid anhydride is at least one of acrylic acid, methacrylic acid, and maleic anhydride.

The invention also provides a preparation method of the novel anticorrosive polycarboxylate superplasticizer, which comprises the following steps:

adding an unsaturated macromonomer, an anticorrosive small monomer and water into a reactor for stirring, after the materials are uniformly mixed, dropwise adding unsaturated carboxylic acid and/or unsaturated carboxylic anhydride, an initiator and a molecular weight regulator for 0.5-2 h at the reaction temperature of 10-40 ℃; after the dropwise addition is finished, preserving the heat for 0-2 hours to obtain a copolymerization product;

and adding alkali into the obtained copolymerization product to adjust the pH value of the product to 5-7, thus obtaining the novel anticorrosive polycarboxylate superplasticizer.

According to the novel anticorrosive polycarboxylate water reducer provided by the invention, at least one monomer unit of fumarate and maleate is introduced into a product molecular structure in a copolymerization mode of an unsaturated macromonomer, an anticorrosive functional small monomer, unsaturated carboxylic acid and/or unsaturated carboxylic anhydride, so that the novel anticorrosive polycarboxylate water reducer with anticorrosive performance is obtained, a small-molecular preservative does not need to be compounded, the problem of uneven distribution caused by poor compatibility of the preservative and the polycarboxylate water reducer is solved, the formed final product is a stable high-molecular structure, the high temperature higher than 50 ℃ can be tolerated, and the high-temperature anticorrosive performance is more excellent.

The novel anti-corrosion polycarboxylate water reducer provided by the invention is suitable for application occasions with high requirements on sensitivity and anti-corrosion of the polycarboxylate water reducer, the used raw materials are wide in source, the price is low, the preparation process is simple, the cost of the project product is enabled to better meet the application requirements of the polycarboxylate water reducer, and the novel anti-corrosion polycarboxylate water reducer has important practical application value.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the following description will clearly and completely describe the embodiments of the present invention, and obviously, the described embodiments are a part of the embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention also provides a preparation example of the novel anticorrosive polycarboxylate superplasticizer as shown in the following:

example 1

(1) Adding 180.00g of ethylene glycol monovinyl polyglycol ether with the molecular weight of 3500, 3.00g of monomethyl fumarate, 0.006g of ferrous sulfate and 145.00g of water into a reactor, starting a stirrer and a temperature control device, starting dropwise adding an acrylic acid aqueous solution (15.00 g of acrylic acid and 20.00g of water), a hydrogen peroxide aqueous solution (1.50 g of hydrogen peroxide and 20.00g of water), a mercaptopropionic acid aqueous solution (0.80 g of mercaptopropionic acid and 20.00g of water) and an ascorbic acid aqueous solution (0.40 g of ascorbic acid and 20.00g of water) when the materials are uniformly mixed, wherein the initial reaction temperature is 15 ℃, the dropwise adding time is 0.5h, the temperature of the materials in the dropwise adding process is controlled to be less than or equal to 30 ℃, and keeping the temperature for 1h after the dropwise adding is finished to obtain a copolymerization product;

(2) and (2) adding 7g of 32% sodium hydroxide aqueous solution into the copolymerization product prepared in the step (1) to obtain the novel anticorrosive polycarboxylate superplasticizer KZJ-1.

Example 2

(1) Adding 180.00g of 4-hydroxybutyl vinyl polyoxyethylene ether with the molecular weight of 3000, 4.00g of diethyl maleate, 0.005g of ferrous sulfate and 145.00g of water into a reactor, starting a stirrer and a temperature control device, starting dropwise adding an acrylic acid aqueous solution (wherein 18.00g of acrylic acid and 20.00g of water), a hydrogen peroxide aqueous solution (wherein 1.80g of hydrogen peroxide and 20.00g of water), a thioglycolic acid aqueous solution (wherein 0.90g of thioglycolic acid and 20.00g of water), a rongalite aqueous solution (wherein 0.30 g of rongalite and 20.00g of water), starting the reaction temperature of 10 ℃, dropwise adding time of 0.75h, controlling the material temperature to be less than or equal to 30 ℃ in the dropwise adding process, and preserving heat for 1h after the dropwise adding is finished to obtain a copolymerization product;

(2) and (2) adding 9g of 32% sodium hydroxide aqueous solution into the copolymerization product prepared in the step (1) to obtain the novel anticorrosive polycarboxylate superplasticizer KZJ-2.

Example 3:

(1) adding 180.00g of ethylene glycol monovinyl polyglycol ether with the molecular weight of 4000, 0.50g of monomethyl fumarate, 1.50g of diethyl maleate, 2.50g of sodium hypophosphite, 0.005g of ferrous sulfate and 150.00g of water into a reactor, starting a stirrer and a temperature control device, starting dropwise adding a mixed aqueous solution of acrylic acid and maleic anhydride (wherein 12.00g of acrylic acid, 2.00g of maleic anhydride and 20.00g of water), a hydrogen peroxide aqueous solution (1.50 g of hydrogen peroxide and 20.00g of water), an ascorbic acid aqueous solution (wherein 0.40 g of ascorbic acid and 20.00g of water), starting the reaction at 10 ℃, dropwise adding time for 1h, controlling the temperature of the materials in the dropwise adding process to be less than or equal to 30 ℃, and preserving heat for 1h after the dropwise adding is finished to obtain a copolymerization product;

(2) and (2) adding 6g of 32% sodium hydroxide aqueous solution into the copolymerization product prepared in the step (1) to obtain the novel anticorrosive polycarboxylate superplasticizer KZJ-3.

Example 4:

(1) adding 180.00g of ethylene glycol monovinyl polyglycol ether with the molecular weight of 3000, 1.50g of monomethyl fumarate, 1.50g of diethyl maleate, 3.00g of sodium hypophosphite, 0.005g of ferrous sulfate and 150.00g of water into a reactor, starting a stirrer and a temperature control device, starting to dropwise add an acrylic acid mixed aqueous solution (wherein 14.00g of acrylic acid and 20.00g of water), a hydrogen peroxide aqueous solution (wherein 1.20g of hydrogen peroxide and 20.00g of water), a rongalite aqueous solution (wherein 0.50g of rongalite and 20.00g of water), starting the reaction temperature of 15 ℃, the dropwise adding time of 1.0h, controlling the temperature of the materials to be less than or equal to 30 ℃ in the dropwise adding process, and keeping the temperature for 0.5h after the dropwise adding is finished to obtain a copolymerization product;

(2) and (2) adding 11g of 32% sodium hydroxide aqueous solution into the copolymerization product prepared in the step (1) to obtain the novel anticorrosive polycarboxylate superplasticizer KZJ-4.

Comparative example 1:

(1) adding 180.00g of ethylene glycol monovinyl polyglycol ether with the molecular weight of 3500, 0.006g of ferrous sulfate and 145.00g of water into a reactor, starting a stirrer and a temperature control device, starting dropwise adding an acrylic acid aqueous solution (wherein 15.00g of acrylic acid and 20.00g of water), a hydrogen peroxide aqueous solution (wherein 1.50g of hydrogen peroxide and 20.00g of water), a mercaptopropionic acid aqueous solution (wherein 0.80g of mercaptopropionic acid and 20.00g of water) and an ascorbic acid aqueous solution (wherein 0.40 g of ascorbic acid and 20.00g of water) when the materials are uniformly mixed, controlling the temperature of the materials to be less than or equal to 30 ℃ in the dropwise adding process, and preserving the temperature for 1h after the dropwise adding is finished to obtain a copolymerization product;

(2) and (2) adding 7g of 32% sodium hydroxide aqueous solution into the copolymerization product prepared in the step (1) to obtain a comparison sample PCE-1.

Comparative example 2:

and mixing PCE-1 and monomethyl fumarate according to a mass ratio of 143: 1, and compounding to obtain a comparison sample PCE-2.

Comparative example 3:

PCE-1 and

the K350 preservative is 143: 1, and compounding to obtain a comparative sample PCE-3.

Comparative example 4:

(1) adding 180.00g of ethylene glycol monovinyl polyglycol ether with the molecular weight of 3500, 3.32g of dimethyl fumarate, 0.006g of ferrous sulfate and 145.00g of water into a reactor, starting a stirrer and a temperature control device, starting dropwise adding an acrylic acid aqueous solution (15.00 g of acrylic acid and 20.00g of water), a hydrogen peroxide aqueous solution (1.50 g of hydrogen peroxide and 20.00g of water), a mercaptopropionic acid aqueous solution (0.80 g of mercaptopropionic acid and 20.00g of water) and an ascorbic acid aqueous solution (0.40 g of ascorbic acid and 20.00g of water) when the materials are uniformly mixed, wherein the initial reaction temperature is 15 ℃, the dropwise adding time is 0.5h, the temperature of the materials is controlled to be less than or equal to 30 ℃ in the dropwise adding process, and preserving heat for 1h after the dropwise adding is finished to obtain a copolymerization product;

(2) and (2) adding 7g of 32% sodium hydroxide aqueous solution into the copolymerization product prepared in the step (1) to obtain the novel anticorrosive polycarboxylate superplasticizer PCE-4.

And (3) performance detection:

1. testing of concrete Properties

The novel anti-corrosive polycarboxylic acid water reducing agents prepared in examples 1 to 4 and the polycarboxylic acid water reducing agents prepared in comparative examples 1, 2, 3 and 4 were subjected to a performance test according to GB/T8076-2008 with a folding content of 0.18%, and the test results are shown in Table 1:

TABLE 1 concrete test results

As shown in Table 1, the comparison result of PCE-1 and KZJ-1 shows that after monomethyl fumarate in KZJ-1 is removed, the water reducing rate and the compressive strength ratios of 3d, 7d and 28d of the product are not affected basically, and the comparison result of PCE-4 and KZJ-1 shows that the water reducing rate and the compressive strength ratios of 3d, 7d and 28d of the product are reduced slightly after the monomethyl fumarate and other substances in KZJ-1 are changed into dimethyl fumarate, and the product synthesized according to the technical scheme of the patent has higher water reducing rate and compressive strength ratios of 3d, 7d and 28 d.

2. Test of Corrosion resistance

The novel anti-corrosive polycarboxylate water reducers prepared in examples 1 to 4 and the polycarboxylate water reducers prepared in comparative examples 1, 2, 3 and 4 are diluted to be 15% in concentration, 1% of white sugar and 2% of sodium gluconate are added to be compounded to obtain finished water reducer products, 300g of each finished product sample is placed in an open glass container with the same volume of 500m l, the finished product samples are heated to 50 ℃ and are kept at the constant temperature for 12 hours, then the finished product samples are placed in a constant temperature cabinet with the temperature of 30 ℃ for 15 days (d), 30d, 60d, 90d and 120d, the state of the samples (whether peculiar smell, turbidity or mildew exists or not) is observed at corresponding time, so that the anti-corrosive performance of the samples is compared, and the specific test results are shown in table 2.

Table 2 corrosion resistance test results

As can be seen from Table 2, PCE-1 has begun to appear heterogeneous by 30 daysThe flavor and the mildew phenomenon are generated, the antiseptic effect of the PCE-2 directly compounded with the monomethyl fumarate is slightly better than that of the PCE-1, but the peculiar smell and the mildew phenomenon are generated at 60 days, and the compound is compounded

The amount of PCE-3 of K350 preservative is equivalent to that of PCE-2 by replacing the amount of materials such as monomethyl fumarate and the like in synthesis with dimethyl fumarate PCE-4, while the novel anticorrosive polycarboxylate water reducer prepared in the embodiments 1 to 4 of the invention has obviously better anticorrosive effect than the comparative example in the environment of 50 ℃, which shows that the prepared novel anticorrosive polycarboxylate water reducer has a highly stable structure, can resist high temperature higher than 50 ℃ and has more excellent high-temperature anticorrosive performance by introducing monomethyl fumarate and/or maleic acid ester into a molecular structure of a product in a polymerization mode through specific raw material and proportion matching.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (6)

1. An anticorrosive polycarboxylate water reducing agent which is characterized in that: the anticorrosion polycarboxylate superplasticizer with a molecule main chain connected with the anticorrosion small monomer is generated by the polymerization reaction of the anticorrosion small monomer and the unsaturated macromonomer as well as the unsaturated carboxylic acid and/or the unsaturated carboxylic anhydride under the action of an initiator and a molecular weight regulator;

the preservative functional small monomer only contains fumarate or simultaneously contains fumarate and maleate;

the unsaturated macromonomer is vinyl ether macromonomer;

the mass ratio of the unsaturated macromonomer to the preservative functional small monomer to the unsaturated carboxylic acid and/or unsaturated carboxylic acid anhydride is in the range of 180: (1-15): (5-30);

the fumarate is one or two of monomethyl fumarate and monoethyl fumarate;

the vinyl ether macromonomer is at least one of ethylene glycol monovinyl polyglycol ether and 4-hydroxybutyl vinyl polyoxyethylene ether.

2. The anti-corrosion polycarboxylate water reducer according to claim 1, characterized in that: the amount of the initiator is 0.5-3.0% of the total mass of the reactants; the dosage of the molecular weight regulator is 0.2-3.0% of the total mass of the reactants.

3. The anti-corrosion polycarboxylate water reducer according to claim 1, characterized in that: in the polymerization reaction process, an initiator aqueous solution, a molecular weight regulator aqueous solution and an unsaturated carboxylic acid and/or unsaturated carboxylic acid anhydride aqueous solution are dropwise added within 0.5-2 h, the reaction temperature is 10-40 ℃, the temperature is kept for 0-2 h after the dropwise addition, and alkali is added to adjust the pH value of the product to 5-7.

4. The anticorrosive polycarboxylate water reducer according to claim 1, characterized in that: the maleic acid ester is at least one of diethyl maleate, dimethyl maleate and dipropyl maleate.

5. The anti-corrosion polycarboxylate water reducer according to claim 1, characterized in that: the unsaturated carboxylic acid and/or unsaturated carboxylic acid anhydride is at least one of acrylic acid, methacrylic acid and maleic anhydride.

6. The preparation method of the anticorrosive polycarboxylate water reducer according to any one of claims 1 to 5, characterized by comprising the following steps:

adding an unsaturated macromonomer, an anticorrosive small monomer and water into a reactor for stirring, after the materials are uniformly mixed, dropwise adding unsaturated carboxylic acid and/or unsaturated carboxylic anhydride, an initiator and a molecular weight regulator for 0.5-2 h at the reaction temperature of 10-40 ℃; after the dropwise addition is finished, preserving the heat for 0-2 hours to obtain a copolymerization product;

and adding alkali into the obtained copolymerization product to adjust the pH value of the product to 5-7, thus obtaining the anticorrosive polycarboxylate superplasticizer.