Concrete anti-freezing water reducing agent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of concrete additives, in particular to a concrete anti-freezing water reducing agent and a preparation method and application thereof. The concrete anti-freezing water reducing agent comprises a compound A, a component B, a component C and a solvent D, wherein the component B comprises at least one organic acid; the component C comprises at least one fiber; the solvent D is a mixture of water and an organic solvent, and the compound A is selected from a compound represented by the following structural formula I; the concrete water reducing agent with good anti-freezing capability is prepared by the preparation method disclosed by the invention.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of concrete additives, and particularly relates to a concrete anti-freezing water reducing agent and a preparation method and application thereof. BACKGROUND

[0002] A water reducing agent is a kind of concrete additive which can reduce the amount of mixing water while maintaining the slump of concrete. Most of them are anionic surfactants, such as lignin sulfonate, naphthalene sulfonate formaldehyde polymer, etc. After being added to the concrete mixture, it has a dispersing effect on the cement particles, can improve the workability, reduce the unit water consumption, and improve the fluidity of the concrete mixture; or reduce the unit cement consumption, save cement. The appearance form is divided into water agent and powder. The solid content of water agent is generally 20%, 40%, 60%, and the solid content of powder is generally 98%. According to the water reducing and strengthening ability of the water reducing agent, it is divided into ordinary water reducing agent (also known as plasticizer, the water reducing rate is not less than 8%, represented by lignin sulfonate), high-efficiency water reducing agent (also known as superplasticizer, the water reducing rate is not less than 14%, including naphthalene, melamine, aminosulfonate, aliphatic, etc.) and high-performance water reducing agent (the water reducing rate is not less than 25%, represented by polycarboxylic acid type water reducing agent), and is further divided into early strength type, standard type and slow setting type.

[0003] The existing concrete water reducing agent has weak anti-freezing ability, which can cause the concrete to crack in winter in the north and affect the strength of the concrete. Therefore, it is urgent to develop a new type of concrete water reducing agent with good anti-freezing ability. SUMMARY

[0004] The present disclosure provides a concrete anti-freezing water reducing agent and a preparation method and application thereof to solve the problems in the related art.

[0005] According to a first aspect of the embodiments of the present disclosure, a concrete anti-freezing water reducing agent is provided, which comprises a compound A, a component B, a component C and a solvent D; wherein, The component B comprises the following: sodium lignosulfonate, sodium dodecyl sulfate, sodium gluconate and at least one organic acid; The component C comprises at least two of the following: borax, calcium silicate, magnesium sulfate and at least one fiber; The solvent D is a mixture of water and an organic solvent, wherein the organic solvent is selected from at least one of the following: ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, ethylene glycol, glycerol, diethyl ether, dimethyl ether, ethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, acetone; The compound A is selected from the compounds represented by the following structural formula I: ; Formula I-1 wherein R1is selected from a group represented by the following formula II-1 or II-2: , ; T1, T2, T3are each independently selected from a direct bond, a substituted or unsubstituted C1-C30alkyl, a substituted or unsubstituted C2-C30alkenyl, a substituted or unsubstituted C2-C30alkynyl, a substituted or unsubstituted C1-C30alkoxy, a substituted or unsubstituted C3-30cycloalkyl, a substituted or unsubstituted C6-C30aryl, a substituted or unsubstituted 3-30 membered heterocyclyl, a substituted or unsubstituted 5-30 membered heteroaryl; X1, X2, X3are each independently selected from CH or N; L1, L2, L3are each independently selected from a group comprising and ; R 11 , R 21 , R 31 are each independently selected from a group comprising a polyether segment.

[0006] In an aspect of the embodiments of the present disclosure, the organic acid is selected from citric acid, lactic acid, tartaric acid, salicylic acid, gallic acid, succinic acid, or malic acid.

[0007] In an aspect of the embodiments of the present disclosure, the fiber is selected from polypropylene fiber or a modified product thereof, polyvinyl alcohol fiber or a modified product thereof, glass fiber or a modified product thereof, hydroxypropyl cellulose or a modified product thereof, hydroxyethyl cellulose or a modified product thereof, brucite fiber or a modified product thereof, wollastonite fiber or a modified product thereof.

[0008] In an aspect of the embodiments of the present disclosure, in the solvent D, the mass ratio of water and organic solvent is selected from 1:(0.25-0.75); the organic solvent is selected from at least one of ethanol, n-propanol, diethyl ether, dimethyl ether, acetone.

[0009] In an aspect of the embodiments of the present disclosure, the fiber is selected from a maleic anhydride modified polypropylene fiber; the maleic anhydride modified polypropylene fiber is prepared by the following steps: Step 1-a: polypropylene fiber, maleic anhydride, BPO, dimethylbenzene are added to a reaction container, then nitrogen is introduced for protection, then the temperature is raised to 50-55°C, and kept for 30-60 min to complete the swelling; Step 2-a: the temperature is raised to 80-90°C, and the reaction is carried out for 3-6 h; Step 3-a: the reaction product is extracted in a Soxhlet extractor using acetone for 10-20 h, and after drying, the maleic anhydride modified polypropylene fiber is obtained.

[0010] In one aspect of embodiments of the present disclosure, R1is selected from any one of the following groups:

[0011] In one aspect of embodiments of the present disclosure, compound A is selected from the following compounds represented by structural formula I-2: ; wherein L1is selected from the following groups represented by formula III-1: ; wherein T4and T5are each independently selected from a direct bond, substituted or unsubstituted C1-C10alkyl, substituted or unsubstituted C2-C10alkenyl, substituted or unsubstituted C2-C10alkynyl, substituted or unsubstituted C1-C10alkoxy, substituted or unsubstituted C3-8cycloalkyl; R 11 is selected from a group comprising a polyether segment.

[0012] In one aspect of embodiments of the present disclosure, L1is: .

[0013] In one aspect of embodiments of the present disclosure, R 11 comprises a polyethylene glycol segment.

[0014] In one aspect of embodiments of the present disclosure, R 11 is selected from any one of the following groups:

[0015] wherein i is selected from 13, 14, 15, or 16.

[0016] In one aspect of embodiments of the present disclosure, compound A is selected from one of the following two compounds: or .

[0017] According to a second aspect of embodiments of the present disclosure, there is provided a method for preparing the aforementioned concrete antifreeze water reducing agent, the method comprising the following steps: Step 1: preparing maleic anhydride modified polypropylene fibers; Step 2: preparing compound A; Step 3: adding compound A and component B into a stirring tank, keeping mechanical stirring, then slowly adding solvent D, continuing stirring for 60-90 min, then adding component C comprising the maleic anhydride modified polypropylene fibers, continuing stirring for 5-10 min; obtaining the concrete antifreeze water reducing agent.

[0018] According to a third aspect of the embodiments of the present disclosure, there is provided a use of the aforementioned concrete antifreeze water-reducing agent and / or the concrete antifreeze water-reducing agent prepared according to the aforementioned method in preparing a concrete base material.

[0019] The technical solutions provided by the embodiments of the present disclosure can include the following beneficial effects: As can be seen from the above embodiments, the present disclosure provides a concrete water-reducing agent with good antifreeze ability.

[0020] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and are not limiting to the present disclosure. DETAILED DESCRIPTION

[0021] For the purpose of making the purpose, technical solutions and advantages of the present application more clear, the technical solutions of the present application will be described clearly and completely in the following with embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. The embodiments described herein are illustrative and are used to provide a basic understanding of the present application. The embodiments of the present application should not be interpreted as a limitation to the present application.

[0022] For the sake of brevity, only some numerical ranges are specifically disclosed herein. However, any lower limit can be combined with any upper limit to form a range not explicitly recited; and any lower limit can be combined with any other lower limit to form a range not explicitly recited, and likewise any upper limit can be combined with any other upper limit to form a range not explicitly recited. Further, each individual disclosed point or singular numerical value can be combined with any other point or singular numerical value to form a range not explicitly recited, either as a lower or upper limit, or in combination with other lower or upper limits.

[0023] In this document, the terms "comprises", "comprising", or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element preceded by "comprises... a" does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.

[0024] In the description herein, unless otherwise specified, "above", "below" include the number itself.

[0025] Unless otherwise specified, the terms used in the present disclosure have the meanings commonly understood by those skilled in the art. Unless otherwise specified, the values of the parameters mentioned in the present disclosure can be measured by various measurement methods commonly used in the art (for example, the test can be carried out according to the method given in the embodiments of the present disclosure).

[0026] The term "about" is used to describe and account for small variations. When used in connection with a quantity, the term can refer to a range of variation less than or equal to ±10% of the quantity, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05% of the quantity. Additionally, quantities, ratios, and other numerical values are sometimes presented herein in a range format. It is to be understood that such range format is used for convenience and brevity and should be taken as a literal disclosure of all individual values and subranges falling within the range. Any numerical value, however, can inherently contain undesirable tolerances.

[0027] A list of items joined by "at least one of" or "one or more of" can mean any combination of the listed terms. For example, if a list of items includes A, B, and C, then "at least one of A, B, and C" or "one or more of A, B, and C" can mean A alone; B alone; C alone; A and B together; A and C together; B and C together; or A, B, and C together. An item can be included in a list of items even if the item is not expressly listed. A list of items can include one or more instances of an item. An item can be included in a list of items even if the item is not expressly listed.

[0028] In the present disclosure, the term "alkyl" refers to an aliphatic hydrocarbon group that can be straight-chain or branched. Branched is meant one or more lower alkyl groups, such as methyl, ethyl, or propyl, attached to the linear alkyl chain. "Lower alkyl" refers to a group having from about 1 to about 6 carbon atoms in the chain, which can be straight or branched.

[0029] In the present disclosure, the term "alkenyl" refers to an aliphatic hydrocarbon group that contains at least one carbon-carbon double bond, which can be straight-chain or branched. Branched is meant one or more lower alkyl groups, such as methyl, ethyl, or propyl, attached to the linear alkenyl chain. "Lower alkenyl" refers to a group having from about 2 to about 6 carbon atoms in the chain, which can be straight or branched.

[0030] In the present disclosure, the term "alkynyl" refers to an aliphatic hydrocarbon group containing at least one carbon-carbon triple bond, which can be straight-chain or branched. Branched refers to one or more lower alkyl groups, such as methyl, ethyl, or propyl, attached to the linear alkynyl chain. "Lower alkynyl" refers to an alkynyl group containing from about 2 to about 6 carbon atoms, which can be straight-chain or branched. Non-limiting examples of alkynyl groups include ethynyl, propynyl, 2-butynyl, 3-methylbutynyl, n-pentynyl, and decynyl.

[0031] In the present disclosure, the term "aryl" refers to an aromatic monocyclic or polycyclic ring system. The aryl group can be optionally substituted with one or more "ring system substituents," which can be the same or different, as defined herein. Non-limiting examples of suitable aryl groups include phenyl and naphthyl.

[0032] In the present disclosure, the term "heteroaryl" refers to an aromatic monocyclic or polycyclic ring system in which one or more of the ring atoms is an element other than carbon, such as nitrogen, oxygen, or sulfur, alone or in combination. Preferred heteroaryls contain from about 5 to about 6 ring atoms. The "heteroaryl" group can be optionally substituted with one or more "ring system substituents," which can be the same or different, as defined herein. The prefix naphtho-, oxazepin-, thiazepin-, or oxazocin- before a heteroaryl group name indicates the presence of at least one nitrogen, oxygen, or sulfur atom, respectively, as a ring atom. The nitrogen atom of a heteroaryl group can optionally be oxidized to the corresponding N-oxide. Non-limiting examples of suitable heteroaryl groups include pyridyl, pyrazinyl, furanyl, thiophenyl, pyrimidinyl, isoxazolyl, isothiazolyl, oxazolyl, thiazolyl, pyrazolyl, furazanyl, pyrrolyl, pyrazolyl, triazolyl, 1,2,4-thiadiazolyl, pyrazinyl, pyridazinyl, quinoxalinyl, phthalazinyl, imidazo[l,2-a]pyridyl, imidazo[2,l-b]thiazolyl, benzofurazanyl, indolyl, azaindolyl, benzimidazolyl, benzothiophenyl, quinolinyl, imidazolyl, thienopyridyl, quinazolinyl, thienopyrimidinyl, pyrrolopyridyl, imidazopyridyl, isoquinolinyl, benzoazaindolyl, 1,2,4-triazinyl, benzothiazolyl, and the like.

[0033] In the present disclosure, the term "amino" refers to a -NR'R" group. The amino group can optionally be substituted. In an unsubstituted amino group, R' and R" are hydrogen. In a substituted amino group, R' and R" can each independently be, but are not limited to, hydrogen, alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, alkylcycloalkyl, alkylheterocycloalkyl, alkoxy, sulfonyl, alkenyl, alkylcarbonyl, aryl, arylalkyl, or heteroaryl, provided that R' and R" are not both hydrogen. In a substituted amino group, R' and R" can cyclize to form a cyclic amino group, such as pyrrolidinyl or piperidinyl. Such cyclic amino groups can incorporate additional heteroatoms, such as to form a piperazinyl or morpholinyl group. Such cyclic amino groups can optionally be substituted, such as with amino, hydroxy, or oxo.

[0034] In the present disclosure, the term "alkoxy" refers to -O-alkyl. Alkoxy can refer to straight-chained, branched, or cyclic, saturated or unsaturated oxy-hydrocarbon chains, including, for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, t-butoxy, and pentoxy. Alkoxy can be optionally substituted with one or more alkoxy substituents ("substituted alkoxy").

[0035] In the present disclosure, the term "cycloalkyl" refers to non-aromatic mono- or polycyclic ring systems, with preferred cycloalkyl rings containing from about 5 to about 7 ring atoms. Cycloalkyl can be optionally substituted with one or more "ring system substituents," which can be the same or different, as defined above. Non-limiting examples of suitable monocyclic cycloalkyl groups include cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, and the like. Non-limiting examples of suitable polycyclic cycloalkyl groups include 1-decalinyl, norbornyl, adamantyl, and the like. In the present disclosure, the term "cycloalkoxy" refers to a group in which one or more of the carbon atoms of a mono- or polycyclic ring system of "cycloalkyl" is replaced with an oxygen atom.

[0036] In the present disclosure, the term "heterocyclyl" refers to a non-aromatic saturated monocyclic or polycyclic ring system in which one or more of the ring atoms is an element other than carbon, such as nitrogen, oxygen, or sulfur, alone or in combination. There are no adjacent oxygen and / or sulfur atoms in the ring system, with preferred heterocycles containing from about 5 to about 6 ring atoms. The prefix n-, o-, or s-hetero in the name of a heterocyclyl group indicates the presence of at least one nitrogen, oxygen, or sulfur atom, respectively, as a ring atom. Heterocyclyl can be optionally substituted with one or more "ring system substituents," which can be the same or different, as defined herein. The nitrogen or sulfur atom of a heterocyclyl group can be optionally oxidized to the corresponding N-oxide, S-oxide, or S,S-dioxide. Non-limiting examples of suitable monocyclic heterocyclyl rings include piperidinyl, pyrrolidinyl, piperazinyl, morpholinyl, thiomorpholinyl, thiazolidinyl, 1,3-dioxolanyl, 1,4-dioxanyl, tetrahydrofuranyl, tetrahydrothiophenyl, tetrahydrothiopyranyl, and the like.

[0037] The present disclosure is further illustrated in the following non-limiting examples. The various chemical reagents used in the examples of the present disclosure are obtained from common commercial sources unless otherwise specified. The amounts described hereinafter are mass amounts unless otherwise specified. Room temperature is understood to mean, unless otherwise specified, the temperature at which the reaction is carried out.

[0038] Examples and Comparative Examples: Example

[0039] Example 1 includes the following steps: 1. Preparation of maleic anhydride-modified polypropylene fibers: Polypropylene fibers (length about 40 mm, particle size 6-9, porosity 0.06) were provided, 100 g of polypropylene fibers, 35 g of maleic anhydride, 5 g of BPO and 250 mL of xylene were added into a reaction vessel, then nitrogen was introduced for protection, then the temperature was raised to 55 °C and maintained for 45 min to complete the swelling; the temperature was raised to 90 °C and reacted for 4 h; the reaction product was extracted with acetone in a Soxhlet extractor for 12 h, and after drying, maleic anhydride modified polypropylene fibers were obtained.

[0040] 2. Preparation of a monocarboxyl-terminated polyether compound: The reaction steps for preparing the monocarboxyl-terminated polyether compound in Example 1 are shown below:

[0041] mPEG (molecular weight 750) 19 g was dissolved in 120 mL of water, 20 mL of 40% KOH solution was added, stirred for 30 min, cooled to about 0 °C in an ice water bath, and 10 mL of acrylonitrile was slowly added dropwise. After dropping, continue stirring under ice water bath for 24 h. Add 40 mL of 20% NaCl solution, adjust pH to 7, extract with dichloromethane, and dry with anhydrous sodium sulfate. Evaporate the solvent, dissolve the residue in 80 mL of 5 mol / L HCl, stir at 25 °C for 24 h, then neutralize with NaOH, adjust the pH to about 10.0, then extract with dichloromethane, dry with anhydrous sodium sulfate, evaporate the solvent, dissolve the residue in 100 mL of 8% NaOH aqueous solution, stir at 25 °C for 24 h. Neutralize with concentrated hydrochloric acid, adjust pH to 7, extract with dichloromethane, dry with anhydrous sodium sulfate, remove the solvent by rotary evaporation, and dry under vacuum to obtain a colorless transparent oil (i.e. the monocarboxyl-terminated polyether compound prepared in Example 1), yield 71%, conversion rate 90%. The above steps can be repeated to prepare sufficient amount of monocarboxyl-terminated polyether compound for the following reaction.

[0042] 3. Preparation of Compound A: 3.1. The monocarboxyl-terminated polyether compound was subjected to an amination reaction, and the reaction steps are shown below:

[0043] Take 15 g of the mono-carboxyl end group polyether compound prepared in Example 1 in a round bottom flask, then add 30 mL of thionyl chloride as a reaction solvent, 1 mL of DMF as a catalyst, heat and reflux for 12 h, after the reaction is completed, cool to room temperature, remove the remaining solvent by vacuum distillation. Then slowly add 20 mL of methanol under ice bath conditions, heat and reflux for 5 h, then cool to room temperature, at this time a large amount of white crystalline solid is precipitated, filter and dry at room temperature to obtain the methylation product, the yield is 87%. Put all the methylation product into a round bottom flask, add hydrazine hydrate as a reaction reagent, heat and reflux for 12 h, cool to room temperature, remove the solvent by rotary evaporation, and vacuum dry to obtain the amination product, the yield is 79%.

[0044] React the amination product with trimesaldehyde, the reaction steps are as follows:

[0045] Put the amination product and trimesaldehyde into a round bottom flask according to the molar ratio of 3:1, then add xylene as a reaction solvent, disperse uniformly by ultrasonic, slowly add glacial acetic acid as a catalyst, then react at room temperature for 12 h under nitrogen protection, filter to obtain yellow solid product compound A.

[0046] 4. Preparation of the anti-freezing water reducing agent of Example 1: Take 30 parts by weight of compound A, 8 parts by weight of sodium lignosulfonate, 4 parts by weight of sodium dodecyl sulfate, 1 part by weight of sodium gluconate, 2 parts by weight of tartaric acid into a stirring tank, keep mechanical stirring, then slowly add 80 parts by weight of water and 40 parts by weight of ethanol, continue stirring for 80 min, then add 5 parts by weight of borax, 5 parts by weight of calcium silicate, 15 parts by weight of maleic anhydride modified polypropylene fiber, 2 parts by weight of magnesium sulfate, continue stirring for 10 min, to obtain the concrete anti-freezing water reducing agent of Example 1.

[0047] Example 2: Example 2 includes the following steps: 1. Preparation of maleic anhydride modified polypropylene fiber: Provide polypropylene fiber (length about 40 mm, particle size 6-9, porosity 0.06), add 100 g of polypropylene fiber, 35 g of maleic anhydride, 5 g of BPO and 250 mL of xylene into a reaction container, then introduce nitrogen protection, then heat to 55 ℃, keep for 45 min, complete swelling; heat to 90 ℃, react for 4 h; extract the reaction product with acetone in a Soxhlet extractor for 12 h, dry to obtain maleic anhydride modified polypropylene fiber.

[0048] 2. Preparation of compound A: 2.1. Commercially available polycaprolactone-polyethylene glycol-carboxylic acid (molecular weight 750) is used as the monocarboxyl-terminated polyether compound of Example 2, which has the following structural formula:

[0049] 2.2. The polycaprolactone-polyethylene glycol-carboxylic acid is subjected to an amination reaction, the reaction steps of which are shown below:

[0050] 15 g of polycaprolactone-polyethylene glycol-carboxylic acid is weighed into a round-bottom flask, followed by the addition of 35 mL of thionyl chloride as a reaction solvent, 1.5 mL of DMF as a catalyst, and heating under reflux for 12 h. After the reaction is complete, the mixture is cooled to room temperature, and the remaining solvent is removed by distillation under reduced pressure. Then 5 mL of methanol is slowly added under ice-bath conditions, and heating under reflux is carried out for 5 h. The mixture is then cooled to room temperature, at which point a large amount of white crystalline solid precipitates. After filtration and drying at room temperature, the methylation product is obtained in a yield of 82%. The entire methylation product is placed in a round-bottom flask, and hydrazine hydrate is added as a reaction reagent. After heating under reflux for 12 h, the mixture is cooled to room temperature, the solvent is removed by rotary evaporation, and the amination product is obtained after vacuum drying in a yield of 71%.

[0051] The amination product is reacted with trimesic aldehyde, the reaction steps of which are shown below:

[0052] The amination product and trimesic aldehyde are placed in a round-bottom flask in a molar ratio of 3:1, followed by the addition of xylene as a reaction solvent, and the mixture is uniformly dispersed by ultrasonic dispersion. Then glacial acetic acid is slowly added dropwise as a catalyst, and the mixture is reacted at room temperature for 12 h under nitrogen protection. After filtration, the yellow solid product of Example 2, compound A, is obtained.

[0053] 4. Preparation of the antifreeze water-reducing agent of Example 2: 30 parts by weight of compound A, 8 parts by weight of sodium lignosulfonate, 4 parts by weight of sodium dodecyl sulfate, 1 part by weight of sodium gluconate, 2 parts by weight of tartaric acid, 80 parts by weight of water, and 40 parts by weight of ethanol are added to a stirring tank, mechanical stirring is maintained, and then 5 parts by weight of borax, 5 parts by weight of calcium silicate, 15 parts by weight of maleic anhydride-modified polypropylene fiber, and 2 parts by weight of magnesium sulfate are slowly added. After stirring for 10 min, the concrete antifreeze water-reducing agent of Example 2 is obtained.

[0054] Example 3: The steps of Example 3 are the same as those of Example 1, except that 2 parts by weight of citric acid is used instead of the tartaric acid used in Example 1.

[0055] Example 4: Example 4 includes the following steps: 1. Preparation of mono-carboxyl terminated polyether compound: The reaction steps of Example 4 to prepare the mono-carboxyl terminated polyether compound are shown as follows:

[0056] mPEG (molecular weight 750) 19 g was dissolved in 120 mL of water, 20 mL of 40% KOH solution was added, stirred for 30 min, and cooled to about 0°C in an ice water bath. 10 mL of acrylonitrile was slowly added dropwise. After the dropwise addition was completed, the reaction was continued to stir for 24 h in an ice water bath. 40 mL of 20% NaCl solution was added to adjust the pH to 7, and dichloromethane was used for extraction, and anhydrous sodium sulfate was used for drying. The solvent was removed by evaporation, and the residue was dissolved in 80 mL of 5 mol / L HCl, stirred at 25°C for 24 h, then neutralized with NaOH to adjust the pH to about 10.0, and then extracted with dichloromethane, dried with anhydrous sodium sulfate, and the solvent was removed by evaporation. The residue was dissolved in 100 mL of 8% NaOH aqueous solution, stirred at 25°C for 24 h. Neutralized with concentrated hydrochloric acid, adjust the pH to 7, use dichloromethane for extraction, use anhydrous sodium sulfate for drying, remove the solvent by rotary evaporation, and vacuum dry to obtain a colorless transparent oily liquid (i.e. the mono-carboxyl terminated polyether compound prepared in Example 1), the yield is 71%, and the conversion rate is 90%. The above steps can be repeated to prepare sufficient mono-carboxyl terminated polyether compound for the following reaction.

[0057] 2. Preparation of compound A: 2.1. The mono-carboxyl terminated polyether compound was subjected to an amination reaction, and the reaction steps are shown as follows:

[0058] 15 g of the mono-carboxyl terminated polyether compound prepared in Example 4 was weighed into a round-bottom flask, then 30 mL of thionyl chloride was added as a reaction solvent, 1 mL of DMF was added as a catalyst, and heated to reflux for 12 h. After the reaction was completed, it was cooled to room temperature, and the remaining solvent was removed by reduced pressure distillation. Then 20 mL of methanol was slowly added under ice bath conditions, and heated to reflux for 5 h. After cooling to room temperature, a large amount of white crystalline solid was precipitated, which was filtered and dried at room temperature to obtain the methylation product, with a yield of 87%. The entire methylation product was placed in a round-bottom flask, and hydrazine hydrate was added as a reaction reagent. After heating to reflux for 12 h, it was cooled to room temperature, the solvent was removed by rotary evaporation, and vacuum dried to obtain the amination product, with a yield of 79%.

[0059] The amination product was reacted with triformylphenol, and the reaction steps are shown as follows:

[0060] The amination product and trimesic aldehyde were put into a round-bottom flask at a molar ratio of 3:1, then dimethylbenzene was added as a reaction solvent, and then the mixture was uniformly dispersed by ultrasonic, and then ice acetic acid was slowly added as a catalyst, and then the mixture was reacted at room temperature for 12 h under nitrogen protection, and then a yellow solid product compound A was obtained by filtration.

[0061] 4. Preparation of the anti-freezing water-reducing agent of Example 4: 30 parts by weight of compound A, 8 parts by weight of sodium lignosulfonate, 4 parts by weight of sodium dodecyl sulfate, 1 part by weight of sodium gluconate, 2 parts by weight of tartaric acid were weighed into a stirring tank, mechanical stirring was maintained, then 80 parts by weight of water and 40 parts by weight of ethanol were slowly added, and stirring was continued for 80 min, then 10 parts by weight of borax, 10 parts by weight of calcium silicate, and 7 parts by weight of magnesium sulfate were added, and stirring was continued for 10 min, to obtain the concrete anti-freezing water-reducing agent of Example 4.

[0062] The main difference between Example 4 and Example 1 is that Example 4 does not include modified polypropylene fibers.

[0063] Comparative Example 1: Comparative Example 1 includes the following steps: 1. Preparation of maleic anhydride modified polypropylene fibers: Polypropylene fibers (length about 40 mm, particle size 6-9, porosity 0.06) were provided, 100 g of polypropylene fibers, 35 g of maleic anhydride, 5 g of BPO, and 250 mL of dimethylbenzene were added to a reaction container, then nitrogen was introduced for protection, then the temperature was raised to 55°C and maintained for 45 min to complete swelling, then the temperature was raised to 90°C and reacted for 4 h; the reaction product was extracted with acetone in a Soxhlet extractor for 12 h, and then dried to obtain maleic anhydride modified polypropylene fibers.

[0064] 2. Preparation of compound A: 2.1. Commercially available hydroxyl polyethylene glycol (molecular weight 750) was used as the carboxyl-terminated polyether compound of Example 3, which has the following structural formula: .

[0065] The reaction steps for preparing compound A in Comparative Example 1 are as follows: .

[0066] Compound A of Comparative Example 1 was prepared by putting hydroxyl polyethylene glycol (molecular weight 750) and trimesic acid in a round bottom flask in a molar ratio of 3:1 (0.15 mol:0.05 mol), adding 0.8 g of p-TSA, and then adding 100 mL of toluene; passing nitrogen gas for 10 min, and then raising the temperature to 110°C while maintaining a nitrogen atmosphere; refluxing for 6 h, and then stopping the reflux, recovering the toluene by distillation under reduced pressure, dissolving the residue in 200 mL of dichloromethane, washing twice with saturated NaHCO3 to remove the catalyst, drying with anhydrous sodium sulfate, filtering, and evaporating the solvent to obtain the product, Compound A of Comparative Example 1, as a yellowish viscous oil.

[0067] 3. Preparation of the antifreeze water-reducing agent of Comparative Example 1 30 parts by weight of Compound A, 8 parts by weight of sodium lignosulfonate, 4 parts by weight of sodium dodecyl sulfate, 1 part by weight of sodium gluconate, and 2 parts by weight of tartaric acid were weighed into a stirring tank, mechanical stirring was maintained, and then 80 parts by weight of water and 40 parts by weight of ethanol were slowly added, stirring was continued for 80 min, and then 5 parts by weight of borax, 5 parts by weight of calcium silicate, 15 parts by weight of maleic anhydride-modified polypropylene fiber, and 2 parts by weight of magnesium sulfate were added, and stirring was continued for 10 min to obtain the concrete antifreeze water-reducing agent of Comparative Example 1.

[0068] Comparative Example 2 Comparative Example 2 was prepared in the same way as Comparative Example 1, except that equimolar nitrilotriacetic acid was used instead of trimesic acid in Comparative Example 1, and the reaction steps for preparing Compound A are shown below. .

[0069] Performance testing Water-reducing and antifreeze ability testing The specific water-reducing performance testing method was to test the water-reducing ability of the sample in ordinary concrete (in which the weight ratio of Portland cement was 30%, fly ash was 15%, machine-made sand was 25%, gravel was 25%, and water was 5%) at 25°C according to the method specified in GB8076-2008, and the results are shown in Table 1.

[0070] Specific anti-freezing performance test method is to test the sample incorporated into ordinary concrete (in which Portland cement is 30% by weight, fly ash is 15%, machine-made sand is 25%, stone is 25%, and water is 5%) according to the method specified in GB / T50082-2009, the concrete mixtures of Examples 1-2 and Comparative Examples 1-2 are made into test samples, the same batch of molded test samples are evenly divided into two groups, one group is a standard curing test sample, and the other group is a freeze-thaw test sample, which is cured according to the operation process of the slow freezing method, and after reaching the specified age (28d), it is subjected to 100 freeze-thaw cycles. After the freeze-thaw cycle is completed, the average compressive strength of each proportion corresponding to the standard curing test sample and the freeze-thaw test sample is detected and calculated according to the method of GB / T50081-2019, the difference between the average compressive strength of the standard curing test sample and the freeze-thaw test sample is calculated to obtain the strength loss rate (the calculation method is the difference between the average compressive strength / the average compressive strength of the standard curing test sample), and then the ratio between the strength loss rate of the examples and the strength loss rate of the comparative examples is calculated, which is defined as the relative frost damage rate, and the results are shown in Table 1.

[0071] Table 1:

[0072] It can be seen that the anti-freezing performance of Comparative Example 1 is obviously not as good as that of Examples 1-4, because Examples 1-4 form -C=N-NH-CO- groups in the molecular structure of Compound A through reaction; which forms a double-site hydrogen bond with Si-OH / Al-OH on the surface of cement, reduces the adsorption free energy; when at subzero temperature, the interface desorption rate decreases significantly, the water reducer molecules are still firmly “nailed” on the particle surface, preventing agglomeration due to desorption. The π-conjugated plane of -C=N-NH-CO- group increases the chain segment, and when at subzero temperature, the branched chain still maintains an expanded conformation, the steric hindrance does not shrink, the spacing between cement particles is maintained, and the frozen water content is relatively reduced. In addition, the -NH- group can act as a proton relay in a high-alkali pore solution, buffering the pH mutation at the interface; therefore, the anti-freezing performance of Example 1 is significantly better than that of Comparative Example 1.

[0073] And the anti-freezing ability of Examples 1-4 and Comparative Example 1 is better than that of Comparative Example 2, because the rigid skeleton of the aromatic ring makes the three branched arms still maintain a radial conformation below zero degrees, and the chain segment does not collapse due to shrinkage; the effective hydration layer thickness at low temperature remains basically unchanged, continuing to provide stable steric repulsion. The rigid aromatic surface can lie flat on the cement crystal face (especially C-S-H), forming a multi-point adsorption of π-π stacking + carboxylic bidentate coordination; further reducing the interface binding free energy, reducing the low-temperature desorption rate, and making the water reducer “anchored more firmly”.

[0074] Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the features disclosed herein. It is intended that the disclosure be construed as including any patents, patent applications, publications, publications, or other disclosure of the prior art that may be related to the disclosure, in their entirety.

Claims

1. A concrete freeze resistant water reducing agent, characterized by, The concrete antifreeze water reducing agent comprises compound A, component B, component C and solvent D; wherein, Component B comprises the following: sodium lignosulfonate, sodium dodecyl sulfate, sodium gluconate and at least one organic acid; Component C comprises at least two of the following: borax, calcium silicate, magnesium sulfate and at least one fiber; Solvent D is a mixture of water and an organic solvent, wherein the organic solvent is selected from at least one of the following: ethanol, n-propanol, isopropanol, n-butanol, tert-butanol, ethylene glycol, glycerol, diethyl ether, dimethyl ether, acetone; Compound A is selected from the group consisting of compounds represented by the following structural Formula I: ; wherein R1is selected from a group represented by the following formula II-1 or II-2: ; ; each of T1, T2, T3is independently selected from a direct bond, a substituted or unsubstituted C1-C30alkyl, a substituted or unsubstituted C2-C30alkenyl, a substituted or unsubstituted C2-C30alkynyl, a substituted or unsubstituted C1-C30alkoxy, a substituted or unsubstituted C3-30cycloalkyl, a substituted or unsubstituted C6-C30aryl, a substituted or unsubstituted 3-30 membered heterocyclyl, a substituted or unsubstituted 5-30 membered heteroaryl; X1, X2, X3are each independently selected from CH or N; L1, L2, L3are each independently selected from the group comprising and groups; R 11 , R 21 , R 31 are each independently selected from groups comprising polyether segments.

2. The concrete freeze-resistant water-reducing agent according to claim 1, characterized by, The concrete antifreeze water reducing agent satisfies at least one of the following conditions: (1) the organic acid is selected from citric acid, lactic acid, tartaric acid, salicylic acid, gallic acid, succinic acid or malic acid; (2) the fiber is selected from polypropylene fiber or its modified product, polyvinyl alcohol fiber or its modified product, glass fiber or its modified product, hydroxypropyl cellulose or its modified product, hydroxyethyl cellulose or its modified product, brucite fiber or its modified product, wollastonite fiber or its modified product; (3) in solvent D, the mass ratio of water and organic solvent is selected from 1:(0.25-0.75); the organic solvent is selected from at least one of the following: ethanol, n-propanol, diethyl ether, dimethyl ether, acetone.

3. The concrete freeze-resistant water-reducing agent according to claim 2, characterized by, The fiber is selected from maleic anhydride modified polypropylene fiber; the maleic anhydride modified polypropylene fiber is prepared by the following steps: Step 1-a: polypropylene fiber, maleic anhydride, BPO, dimethylbenzene are added to a reaction container, then nitrogen is introduced for protection, then the temperature is raised to 50-55℃ and maintained for 30-60min to complete swelling; Step 2-a: the temperature is raised to 80-90℃ and reacted for 3-6h; Step 3-a: the reaction product is extracted with acetone in a Soxhlet extractor for 10-20h, and the maleic anhydride modified polypropylene fiber is obtained after drying.

4. The concrete freeze-resistant water-reducing agent according to claim 1, characterized by, R1is selected from any one of the following groups: 。 5. The concrete freeze-resistant water-reducing agent according to claim 4, characterized by, Compound A is selected from the group consisting of compounds represented by the following structural formula I-2: ; wherein L1is selected from the group consisting of the following formula III-1: ; wherein, T4and T5are each independently selected from a direct bond, substituted or unsubstituted C1-C10alkyl, substituted or unsubstituted C2-C10alkenyl, substituted or unsubstituted C2-C10alkynyl, substituted or unsubstituted C1-C10alkoxy, substituted or unsubstituted C3-8cycloalkyl; R 11 is selected from groups comprising polyether segments.

6. The concrete freeze-resistant water-reducing agent according to claim 5, characterized by, L1 is: .

7. The concrete freeze-resistant water-reducing agent according to claim 5, characterized by, R 11 comprises a polyethylene glycol segment.

8. The concrete freeze-resistant water-reducing agent according to claim 5, characterized by, R 11 selected from any one of the following groups: ; wherein i is selected from 13, 14, 15, or 16.

9. A method of preparing the concrete antifreeze water reducer according to any one of claims 1 to 8, characterized in that, The method comprises the following steps: Step 1: preparing maleic anhydride modified polypropylene fiber; Step 2: preparing compound A; Step 3: compound A and component B are added to a stirring tank, mechanical stirring is maintained, then solvent D is slowly added, stirring is continued for 60-90min, then component C comprising the maleic anhydride modified polypropylene fiber is added, and stirring is continued for 5-10min; the concrete antifreeze water reducing agent is obtained.

10. Use of the concrete antifreeze water reducing agent according to any one of claims 1-8, and / or the concrete antifreeze water reducing agent prepared by the method according to claim 9 in preparing a concrete-based material.

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