CN110407506B - Synthetic method of polycarboxylic acid type high slump loss resistant water reducer - Google Patents
Synthetic method of polycarboxylic acid type high slump loss resistant water reducer Download PDFInfo
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- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
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- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
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Abstract
The invention discloses a method for synthesizing a polycarboxylic acid type high slump loss resistant water reducing agent, which belongs to the field of concrete preparation, and comprises the steps of preparing treated water, a large monomer solution, a small monomer solution and an alkali solution, promoting the reaction of a polymerization reaction under the initiation of an initiator solution, changing the traditional initiation condition by optimizing a synthesis process while reducing the cost of raw materials, adopting an oxidation-reduction system to autonomously release heat to promote the polymerization reaction, adding an oxidant and a reducing agent through a self-sustained release device, having the function of autonomously adjusting the oxidation-reduction reaction according to the environmental temperature, remarkably improving the stability and the sufficiency of the polymerization reaction, further improving the performance of a finished water reducing agent product, reducing the water-cement ratio of concrete to the minimum, simultaneously maximizing the fluidity, and efficiently reducing water, Improve concrete gas pore structure and closely knit degree, control concrete slump loss that can also be better.
Description
Technical Field
The invention relates to the field of concrete preparation, in particular to a method for synthesizing a polycarboxylic acid type high slump loss resistant water reducer.
Background
In recent years, with the increasing demand of building concrete, the requirement on the admixture which must be added into the concrete is very high, and especially in recent years, the proposal of the high-strength self-compacting environment-friendly concrete promotes the development of the concrete admixture towards the directions of environmental protection, high water reduction, high slump loss resistance and better adaptability to concrete floor materials. The polycarboxylate superplasticizer is widely applied due to the advantages of low mixing amount, high water reducing rate, low concrete shrinkage, environmental protection and the like, and is called as a third-generation high-performance water reducing agent. With the continuous and vigorous development of the infrastructure of the country and the higher and higher requirements on concrete, the polycarboxylic acid water reducer has larger and larger market share, high water reducing rate and higher slump retaining performance, and has more favorable market competitiveness.
The production process of the polycarboxylic acid water reducing agent at present mainly comprises two types, one type is ester type, MPEG is taken as a raw material, and the polycarboxylic acid water reducing agent is prepared by esterification and synthesis, although the raw material is low in price, the process is complex, long in time consumption, difficult to control quality, and high in temperature required by esterification, so that the energy consumption cost and the labor cost are high; the other is polyether type, unsaturated polyoxyethylene ether, unsaturated carboxylic acid and other monomers are directly polymerized under the action of an initiator, and the process is simpler than an ester type process, consumes less time, has high productivity and is low in energy consumption and labor cost, but the slump retaining capacity of the current polyether type product needs to be further improved.
In order to solve the problems, the Chinese invention application No. CN201310097839.7 discloses a method for synthesizing a polycarboxylic acid type high slump loss resistant water reducing agent, which comprises the following steps: 1. adding a water treatment agent acrylic acid-maleic anhydride copolymer into tap water to 3-8mg/L to obtain treated water; 2. adding a base material consisting of unsaturated polyoxyethylene ether, maleic anhydride, functional small monomers and processing water into a polymerization reaction kettle, heating to 40 ℃, stirring until the base material is completely dissolved, adjusting the pH value by using a NaOH solution, adding a proper amount of hydrogen peroxide, dropwise adding a mixed solution prepared in advance and consisting of acrylic acid, ammonium ferrous sulfate, a cross-linking agent, a chain transfer agent and the processing water, continuously preserving heat for 0.5-1.5h after dropwise adding for 2.5-4h, and neutralizing to the pH value of 5-6 by using a NaOH solution to obtain the product.
However, in the above scheme, the initiation of the polymerization reaction is not sufficient, it is difficult to artificially control the initiation conditions, the polymerization reaction is not stable and uniform enough, the duration is long, the synthesis efficiency is reduced, and the performance of the finished water reducer is reduced while the raw material conversion rate is low and the cost is increased due to the limitation of the polymerization reaction.
Disclosure of Invention
1. Technical problem to be solved
Aiming at the problems in the prior art, the invention aims to provide a method for synthesizing a polycarboxylic acid type high slump loss resistant water reducer, which can reduce the cost of raw materials, simultaneously optimize a synthesis process, change the traditional initiation conditions, adopt an oxidation-reduction system to independently release heat to promote the polymerization reaction, add an oxidant and a reducing agent through a self-sustained release device, simultaneously have the function of automatically adjusting the oxidation-reduction reaction according to the environmental temperature, obviously improve the stability and the sufficiency of the polymerization reaction, further improve the performance of a finished water reducer product, reduce the water-cement ratio of concrete to the minimum, simultaneously achieve the maximum fluidity, have the effects of efficiently reducing water, improving the air pore structure and the compactness degree of the concrete and better control the slump loss of the concrete.
2. Technical scheme
In order to solve the above problems, the present invention adopts the following technical solutions.
A synthetic method of a polycarboxylic acid type high slump loss resistant water reducer comprises the following steps:
s1, preparing treated water: adding a water treatment agent acrylic acid-maleic anhydride copolymer into tap water until the content of the acrylic acid-maleic anhydride copolymer is 3-8mg/L to obtain treated water for later use.
S2, preparing a macromonomer solution: weighing the macromonomer and the treated water according to the weight part ratio, placing the macromonomer and the treated water in a reaction kettle of a stirrer to be dissolved and mixed, uniformly stirring, and preparing a macromonomer solution for later use.
S3, preparing a small monomer solution: weighing the functional monomer, the anti-mud agent, the anti-mud retarder, the slump retaining agent and the acrylic acid according to the weight part ratio, sequentially putting into treated water for dissolving and mixing, uniformly stirring, and preparing a small monomer solution for later use.
S4, preparing an alkali solution: weighing sodium hydroxide powder, adding the sodium hydroxide powder into the treated water for dissolving and mixing, uniformly stirring, and preparing an alkali solution for later use.
S5, synthesizing a water reducing agent sample: and (3) dropwise adding the small monomer solution and the chain transfer agent into the large monomer solution in the reaction kettle in the S2 at the flow speed controlled by a constant flow pump, simultaneously adding the initiator solution through a slow release device, and continuously stirring and preserving heat for 1-2h after the reaction is finished to obtain the water reducer sample.
S6, checking the net slurry fluidity of the sample: and (4) extracting a small amount of water reducing agent samples to carry out clean slurry fluidity detection, returning to the step S5 to continue stirring and heat preservation if the water reducing agent samples are unqualified, and continuing to the next step if the water reducing agent samples are qualified.
S7, discharging of the finished water reducer: stopping the reaction, and adding a proper amount of alkali solution to adjust the pH value of the water reducer sample to 6-8 to obtain the finished water reducer.
Further, the molecular weight of the acrylic acid-maleic anhydride copolymer is 2000-5000, and the acrylic acid: the molar ratio of the maleic anhydride is 1.2-1.5: 1.
Further, the macromonomer is a mixture of more than one of allyl polyoxyethylene ether, methallyl polyoxyethylene ether, butenyl polyoxyethylene ether, methyl butenyl polyoxyethylene ether, vinyl polyoxyethylene ether and hydroxybutyl vinyl polyoxyethylene ether mixed in any proportion, and the weight ratio of the macromonomer to the treated water is 1: 0.8-1.5.
Further, the functional monomer is selected from one or more of fumaric acid, vinyl acetate, methacryloyloxyethyl phosphate, multifunctional acidic acrylate, ethylene glycol methacrylate phosphate and acrylamide which are mixed in any proportion, the molar ratio between the functional monomer and the macromonomer is 0.5-1:1, the weight of the anti-mud agent accounts for 1-5% of the small monomer solution, the weight of the anti-mud type retarder accounts for 0.5-2% of the small monomer solution, the weight of the slump retaining agent accounts for 2-5% of the small monomer solution, and the acrylic acid accounts for 30-50% of the small monomer solution.
Furthermore, the step S2, the step S3 and the step S4 may be performed in any order or simultaneously, so that the technician may select the steps according to the actual situation and schedule the steps more reasonably and effectively.
Further, the initiator solution comprises an oxidant and a reducing agent in a ratio of 1:1, the oxidant is a hydrogen peroxide solution with a mass fraction of 30-35%, the reducing agent is any one of L ascorbic acid, D erythorbic acid, sodium L ascorbate and sodium D erythorbate, and a redox system is adopted to release heat at normal temperature in a large amount to promote polymerization reaction.
Furthermore, the self-sustained release device comprises a pair of liquid storage semi-rings which are symmetrically combined into a whole ring, a liquid storage cavity is drilled in the liquid storage semi-rings, a plurality of liquid outlet holes communicated with the liquid storage cavity are further drilled at the inner ends of the liquid storage semi-rings, a semi-annular shunt pipe is arranged at the upper side of the liquid storage semi-rings, a plurality of communicating pipes are fixedly connected between the semi-annular shunt pipe and the liquid storage semi-rings, and a liquid inlet pipe is fixedly connected to the outer ends of the semi-annular shunt pipes, compared with the traditional method that a large monomer solution and hydrogen peroxide are mixed in a reaction kettle firstly and then a reducing agent is dripped to initiate a polymerization reaction, the self-sustained release device can enable the hydrogen peroxide and the reducing agent to be fully mixed according to the proportion of 1:1, is mild and uniform, has high safety, avoids the phenomenon that the reaction is too violent and even explosion due to the mixing of a large amount of the hydrogen peroxide and the reducing agent, and can release heat in the overall range of the mixed solution, promote the polymerization reaction to proceed rapidly and completely.
Further, the inner end of the liquid outlet hole is fixedly connected with a deformable water retaining ring, the inner end of the deformable water retaining ring is fixedly connected with a temperature-sensitive deformable metal ring, the temperature-sensitive deformable metal ring is made of memory alloy with two-way memory effect, the balance temperature of the temperature-sensitive deformable metal ring is 45 ℃, the temperature of the temperature-sensitive deformable metal ring is 45 ℃ and is recovered to a high-temperature phase shape, the temperature of the temperature-sensitive deformable metal ring is lower than 45 ℃, the low-temperature phase shape is recovered, the flux is automatically changed along with the change of the environmental temperature through the temperature memory function of the temperature-sensitive deformable metal ring, the temperature-sensitive deformable metal ring is recovered to the low-temperature phase shape, namely, the circular shape when the environmental temperature is lower, the amount of the solution of the initiator which can pass is increased, the heat is further released after the oxidation-reduction reaction is enhanced, the environmental temperature is increased and the polymerization reaction is carried out, and the temperature-sensitive deformable metal ring is recovered to the high-temperature phase shape, namely, the inward shrinkage shape when the environmental temperature reaches 45 ℃, the content of the initiator solution is reduced, the redox reaction is weakened, the phenomenon that the reaction is too violent and even explosion is caused is avoided, the degree of the redox reaction can be self-regulated, and the polymerization reaction is promoted to be carried out under the stable and sufficient initiating condition.
Further, the low temperature looks shape of temperature sensing deformation becket is circular, the high temperature looks shape of temperature sensing deformation becket contracts the shape for interior, and the diameter of circular temperature sensing deformation becket is 0.8mm, the diameter of going out the liquid hole is 1 mm.
Further, in the step S5, the small monomer solution is dripped within 1-2h, the residual chain transfer agent is dripped within 20min, the initiator solution is stopped from being added, and the mixture is taken out from the slow release device.
3. Advantageous effects
Compared with the prior art, the invention has the advantages that:
(1) this scheme can realize when reducing the raw materials cost, through optimizing synthesis technology, change traditional initiation condition, adopt the redox system to come independently exothermic, make the polyreaction go on, and through adding oxidant and reductant from slow release device, the function of independently adjusting redox reaction according to ambient temperature has simultaneously, show stability and the sufficiency that improves the polyreaction, and then improve the off-the-shelf performance of water-reducing agent, the water-cement ratio that enables the concrete is dropped to minimumly, mobility reaches the biggest simultaneously, have high-efficient water reducing, improve concrete pore structure and closely knit degree, control concrete slump loss that can also be better.
(2) The molecular weight of the acrylic acid-maleic anhydride copolymer is 2000-: the molar ratio of the maleic anhydride is 1.2-1.5: 1.
(3) The macromonomer is a mixture of more than one of allyl polyoxyethylene ether, methyl allyl polyoxyethylene ether, butenyl polyoxyethylene ether, methyl butenyl polyoxyethylene ether, vinyl polyoxyethylene ether and hydroxybutyl vinyl polyoxyethylene ether mixed in any proportion, and the weight ratio of the macromonomer to the treated water is 1: 0.8-1.5.
(4) The functional monomer is selected from one or more of fumaric acid, vinyl acetate, methacryloxyethyl phosphate, multifunctional acidic acrylate, ethylene glycol methacrylate phosphate and acrylamide which are mixed in any proportion, the molar ratio of the functional monomer to the macromonomer is 0.5-1:1, the weight of the anti-mud agent accounts for 1-5% of the small monomer solution, the weight of the anti-mud type retarder accounts for 0.5-2% of the small monomer solution, the weight of the slump retaining agent accounts for 2-5% of the small monomer solution, and the weight of acrylic acid accounts for 30-50% of the small monomer solution.
(5) The steps of S2, S3, and S4 may be performed in any order or simultaneously, and technicians may select the steps according to actual situations, so as to perform scheduling more reasonably and effectively.
(6) The initiator solution comprises an oxidant and a reducing agent in a ratio of 1:1, the oxidant is a hydrogen peroxide solution with a mass fraction of 30-35%, the reducing agent is any one of L ascorbic acid, D erythorbic acid, L sodium ascorbate and D sodium erythorbate, and a redox system is adopted to release heat in a large amount at normal temperature to promote polymerization reaction.
(7) The self-sustained release device comprises a pair of liquid storage semi-rings, the liquid storage semi-rings are symmetrically combined into a whole ring, a liquid storage cavity is drilled in each liquid storage semi-ring, a plurality of liquid outlet holes communicated with the liquid storage cavity are further drilled in the inner ends of the liquid storage semi-rings, a semi-annular shunt pipe is arranged on the upper side of each liquid storage semi-ring, a plurality of communicating pipes are fixedly connected between the semi-annular shunt pipe and the liquid storage semi-rings, and a liquid inlet pipe is fixedly connected to the outer end of each semi-annular shunt pipe, compared with the traditional method that a large monomer solution and hydrogen peroxide are mixed in a reaction kettle firstly and then a reducing agent is dripped to initiate polymerization reaction, the self-sustained release device can enable the hydrogen peroxide and the reducing agent to be fully mixed and reacted according to the proportion of 1:1, is mild, uniform and high in safety, the phenomenon that the reaction is too violent and even explosion is caused due to the large amount of mixed liquid and the mixed liquid is avoided, and heat release can be carried out in the whole range of the mixed solution at the same time, promote the polymerization reaction to proceed rapidly and completely.
(8) The inner end of the liquid outlet hole is fixedly connected with a deformable water retaining ring, the inner end of the deformable water retaining ring is fixedly connected with a temperature-sensitive deformable metal ring, the temperature-sensitive deformable metal ring is made of memory alloy with two-way memory effect, the equilibrium temperature of the temperature-sensitive deformable metal ring is 45 ℃, the temperature of the temperature-sensitive deformable metal ring is 45 ℃ and recovers to the shape of a high-temperature phase, the temperature of the temperature-sensitive deformable metal ring is lower than 45 ℃, the shape of the low-temperature phase is recovered, the flux is automatically changed along with the change of the environmental temperature through the temperature memory function of the temperature-sensitive deformable metal ring, the shape of the low-temperature phase is recovered to be circular when the environmental temperature is lower, the amount of the solution of the initiator which can pass at the moment is increased, the heat is further released after the oxidation reduction reaction is strengthened, the environmental temperature is increased and the polymerization reaction is carried out, and the temperature-sensitive deformable metal ring recovers to the shape of the high-temperature phase, namely, the shape is retracted when the environmental temperature reaches 45 ℃, the content of the initiator solution is reduced, the redox reaction is weakened, the phenomenon that the reaction is too violent and even explosion is caused is avoided, the degree of the redox reaction can be self-regulated, and the polymerization reaction is promoted to be carried out under the stable and sufficient initiating condition.
(9) The low-temperature phase of the temperature-sensitive deformation metal ring is circular, the high-temperature phase of the temperature-sensitive deformation metal ring is in an inward shrinkage shape, the diameter of the circular temperature-sensitive deformation metal ring is 0.8mm, and the diameter of the liquid outlet hole is 1 mm.
(10) In the step S5, the small monomer solution is dripped within 1-2h, the residual chain transfer agent is dripped within 20min, the initiator solution is stopped from being added, and the mixture is taken out from the slow release device.
Drawings
FIG. 1 is a process flow diagram of the present invention;
FIG. 2 is a schematic structural diagram of a self-sustained release apparatus according to the present invention;
FIG. 3 is a schematic structural view of a temperature-sensitive deformable metal ring in a discharge hole in a high-temperature phase state according to the present invention;
FIG. 4 is a schematic structural view of a temperature-sensitive deformable metal ring in a discharge hole of the present invention in a low-temperature phase state.
The reference numbers in the figures illustrate:
1 stock solution semi-ring, 2 play liquid holes, 3 communicating pipes, 4 semicircular shunt tubes, 5 feed liquor pipes, 6 deformable water retaining rings, 7 temperature sensing deformation becket.
Detailed Description
The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention; it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and all other embodiments obtained by those skilled in the art without any inventive work are within the scope of the present invention.
In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top/bottom", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise specifically stated or limited, the terms "mounted," "disposed," "sleeved/connected," "connected," and the like are used in a broad sense, and for example, "connected" may be a fixed connection, a detachable connection, an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection through an intermediate medium, and a communication between two elements.
Example 1:
referring to fig. 1, a method for synthesizing a polycarboxylic acid type high slump loss resistant water reducer includes the following steps:
s1, preparing treated water: adding a water treatment agent acrylic acid-maleic anhydride copolymer into tap water until the content of the acrylic acid-maleic anhydride copolymer is 3/L to obtain treated water for later use;
the molecular weight of the acrylic acid-maleic anhydride copolymer is 2000-: the molar ratio of maleic anhydride was 1.5: 1.
S2, preparing a macromonomer solution: weighing the macromonomer and the treated water according to the weight part ratio, placing the macromonomer and the treated water in a reaction kettle of a stirrer to be stirred for dissolving and mixing, and stirring uniformly to prepare a macromonomer solution for later use;
the macromonomer is a mixture of more than one of allyl polyoxyethylene ether, methyl allyl polyoxyethylene ether, butenyl polyoxyethylene ether, methyl butenyl polyoxyethylene ether, vinyl polyoxyethylene ether and hydroxybutyl vinyl polyoxyethylene ether mixed in any proportion, and the weight ratio of the macromonomer to the treated water is 1: 0.8.
S3, preparing a small monomer solution: weighing the functional monomer, the anti-mud agent, the anti-mud retarder, the slump retaining agent and the acrylic acid according to the weight part ratio, sequentially putting into treated water for dissolving and mixing, uniformly stirring, and preparing a small monomer solution for later use.
The functional monomer is selected from one or more of fumaric acid, vinyl acetate, methacryloxyethyl phosphate, multifunctional acidic acrylate, ethylene glycol methacrylate phosphate and acrylamide which are mixed in any proportion, the molar ratio of the functional monomer to the macromonomer is 0.5:1, the anti-mud agent accounts for 1% of the small monomer solution, the anti-mud type retarder accounts for 0.5% of the small monomer solution, the slump retaining agent accounts for 2% of the small monomer solution, and the acrylic acid accounts for 30% of the small monomer solution.
S4, preparing an alkali solution: weighing sodium hydroxide powder, adding the sodium hydroxide powder into the treated water for dissolving and mixing, uniformly stirring, and preparing an alkali solution for later use.
The steps of S2, S3, and S4 may be performed in any order or simultaneously, and technicians may select the steps according to actual situations, so as to perform scheduling more reasonably and effectively.
S5, synthesizing a water reducing agent sample: and (3) dropwise adding the small monomer solution and the chain transfer agent into the large monomer solution in the reaction kettle in the S2 at the flow speed controlled by a constant flow pump, simultaneously adding the initiator solution through a slow release device, and continuously stirring and preserving heat for 1h after the reaction is finished to obtain the water reducer sample.
In the step S5, the small monomer solution is dripped within 1h, the residual chain transfer agent is dripped within 20min, the initiator solution is stopped from being added, and the solution is taken out from the slow release device.
S6, checking the net slurry fluidity of the sample: extracting a small amount of water reducing agent samples to carry out clean slurry fluidity detection, returning to the step S5 to continue stirring and heat preservation if the water reducing agent samples are unqualified, and continuing the next step if the water reducing agent samples are qualified;
the specific operation is as follows: adding a certain amount of cement, a water reducing agent sample and water into a cement paste mixer for mixing, injecting the mixed paste into a truncated cone circular mold, lifting the truncated cone circular mold, and measuring the maximum diameter of the free flowing of the cement paste on a glass plane.
S7, discharging of the finished water reducer: stopping the reaction, adding a proper amount of alkali solution to adjust the pH value of a water reducer sample to be 7, namely the water reducer is finally neutral and cannot generate acidic or alkaline influence on cement, so that the influence of the water reducer on the service life of the cement can be basically ignored, and the finished water reducer is obtained.
The initiator solution comprises an oxidant and a reducing agent in a ratio of 1:1, the oxidant is a hydrogen peroxide solution with a mass fraction of 30-35%, the reducing agent is any one of L ascorbic acid, D erythorbic acid, L sodium ascorbate and D sodium erythorbate, and a redox system is adopted to release heat in a large amount at normal temperature to promote polymerization reaction.
Referring to fig. 2, the self-sustained release device includes a pair of liquid storage half rings 1, the liquid storage half rings 1 are symmetrically combined into a whole ring, the pair of liquid storage half rings 1 respectively store an oxidant and a reducing agent, a liquid storage cavity is drilled in the liquid storage half rings 1, a plurality of liquid outlet holes 2 communicated with the liquid storage cavity are further drilled at the inner ends of the liquid storage half rings 1, the pair of liquid storage half rings 1 can uniformly and comprehensively add the oxidant and the reducing agent into a reaction kettle through the plurality of liquid outlet holes 2, the mutual symmetrical addition and contact are more sufficient, the reaction is more rapid and sufficient, a semi-annular shunt pipe 4 is arranged at the upper side of the liquid storage half rings 1, a plurality of communicating pipes 3 are fixedly connected between the semi-annular shunt pipe 4 and the liquid storage half rings 1, and a liquid inlet pipe 5 is fixedly connected at the outer end of the semi-annular shunt pipe 4, compared with the conventional method that a large monomer solution and hydrogen peroxide solution are firstly mixed in the reaction kettle and then the reducing agent is added to initiate a polymerization reaction, the self-sustained release device can ensure that hydrogen peroxide and the reducing agent are fully mixed and react according to the proportion of 1:1, is mild and uniform, has higher safety, avoids the phenomenon of over violent reaction and even explosion caused by mixing a large amount of hydrogen peroxide and the reducing agent together, and can release heat in the global range of the mixed solution to promote the rapid and comprehensive polymerization reaction.
Referring to fig. 3-4, the inner end of the liquid outlet hole 2 is fixedly connected with a deformable water retaining ring 6, the inner end of the deformable water retaining ring 6 is fixedly connected with a temperature-sensitive deformable metal ring 7, the temperature-sensitive deformable metal ring 7 is made of a memory alloy with a two-way memory effect, the equilibrium temperature of the temperature-sensitive deformable metal ring 7 is 45 ℃, the temperature-sensitive deformable metal ring 7 recovers a high-temperature phase shape when reaching 45 ℃, the temperature-sensitive deformable metal ring 7 recovers a low-temperature phase shape when reaching less than 45 ℃, the flux is autonomously changed along with the change of the environmental temperature through the temperature memory function of the temperature-sensitive deformable metal ring 7, the temperature-sensitive deformable metal ring 7 recovers a low-temperature phase shape, namely, a round shape when the environmental temperature is lower, the amount of the solution which can pass through the initiator is increased, the heat is further released after the redox reaction is enhanced, the environmental temperature is increased and the polymerization reaction is carried out, and the temperature-sensitive deformable metal ring 7 recovers a high-temperature, namely, the shape is retracted shape when the environmental temperature reaches 45 ℃, the content of the initiator solution is reduced, the redox reaction is weakened, the reaction is avoided being too violent, even explosion is caused, the degree of self-regulation of the redox reaction can be realized, the polymerization reaction is promoted to be carried out under the stable and sufficient initiating condition, the low-temperature phase shape of the temperature-sensitive deformation metal ring 7 is circular, the high-temperature phase shape of the temperature-sensitive deformation metal ring 7 is in an inner shrinkage shape, the diameter of the circular temperature-sensitive deformation metal ring 7 is 0.8mm, and the diameter of the liquid outlet hole 2 is 1 mm.
Example 2:
referring to fig. 1, a method for synthesizing a polycarboxylic acid type high slump loss resistant water reducer comprises the following steps:
s1, preparing treated water: adding a water treatment agent acrylic acid-maleic anhydride copolymer into tap water until the content of the acrylic acid-maleic anhydride copolymer is 8mg/L to obtain treated water for later use.
The molecular weight of the acrylic acid-maleic anhydride copolymer is 2000-: the molar ratio of maleic anhydride was 1.2: 1.
S2, preparing a macromonomer solution: weighing the macromonomer and the treated water according to the weight part ratio, placing the macromonomer and the treated water in a reaction kettle of a stirrer to be dissolved and mixed, uniformly stirring, and preparing a macromonomer solution for later use.
The macromonomer is a mixture of more than one of allyl polyoxyethylene ether, methyl allyl polyoxyethylene ether, butenyl polyoxyethylene ether, methyl butenyl polyoxyethylene ether, vinyl polyoxyethylene ether and hydroxybutyl vinyl polyoxyethylene ether mixed in any proportion, and the weight ratio of the macromonomer to the treated water is 1: 1.5.
S3, preparing a small monomer solution: weighing the functional monomer, the anti-mud agent, the anti-mud retarder, the slump retaining agent and the acrylic acid according to the weight part ratio, sequentially putting into treated water for dissolving and mixing, uniformly stirring, and preparing a small monomer solution for later use.
The functional monomer is selected from one or more of fumaric acid, vinyl acetate, methacryloxyethyl phosphate, multifunctional acidic acrylate, ethylene glycol methacrylate phosphate and acrylamide which are mixed in any proportion, the molar ratio of the functional monomer to the large monomer is 1:1, the mud-resistant agent accounts for 5% of the small monomer solution, the mud-resistant retarder accounts for 2% of the small monomer solution, the slump retaining agent accounts for 5% of the small monomer solution, and the acrylic acid accounts for 50% of the small monomer solution.
S4, preparing an alkali solution: weighing sodium hydroxide powder, adding the sodium hydroxide powder into the treated water for dissolving and mixing, uniformly stirring, and preparing an alkali solution for later use.
The steps of S2, S3, and S4 may be performed in any order or simultaneously, and technicians may select the steps according to actual situations, so as to perform scheduling more reasonably and effectively.
S5, synthesizing a water reducing agent sample: and (3) dropwise adding the small monomer solution and the chain transfer agent into the large monomer solution in the reaction kettle in the S2 at the flow speed controlled by a constant flow pump, simultaneously adding the initiator solution through a slow release device, and continuously stirring and preserving heat for 2 hours after the reaction is finished to obtain the water reducer sample.
The step S5 is to drop the small monomer solution within 2h, drop the rest chain transfer agent within 20min, stop adding the initiator solution and take out from the slow release device.
S6, checking the net slurry fluidity of the sample: extracting a small amount of water reducing agent samples to carry out clean slurry fluidity detection, returning to the step S5 to continue stirring and heat preservation if the water reducing agent samples are unqualified, and continuing the next step if the water reducing agent samples are qualified;
the specific operation is as follows: adding a certain amount of cement, a water reducing agent sample and water into a cement paste mixer for mixing, injecting the mixed paste into a truncated cone circular mold, lifting the truncated cone circular mold, and measuring the maximum diameter of the free flowing of the cement paste on a glass plane.
S7, discharging of the finished water reducer: stopping the reaction, adding a proper amount of alkali solution to adjust the pH value of a water reducer sample to be 7, namely the water reducer is finally neutral and cannot generate acidic or alkaline influence on cement, so that the influence of the water reducer on the service life of the cement can be basically ignored, and the finished water reducer is obtained.
The initiator solution comprises an oxidant and a reducing agent in a ratio of 1:1, the oxidant is 35% of hydrogen peroxide solution by mass, the reducing agent is any one of L ascorbic acid, D erythorbic acid, L sodium ascorbate and D sodium erythorbate, and a redox system is adopted to release heat in a large amount at normal temperature to promote polymerization reaction.
The invention can reduce the cost of raw materials, simultaneously change the traditional initiation condition by optimizing the synthesis process, independently release heat by adopting an oxidation-reduction system, promote the polymerization reaction to be carried out, add an oxidant and a reducing agent by a self-sustained release device, simultaneously have the function of automatically adjusting the oxidation-reduction reaction according to the environmental temperature, obviously improve the stability and the sufficiency of the polymerization reaction, further improve the performance of the finished product of the water reducing agent, reduce the water-cement ratio of concrete to the minimum, simultaneously achieve the maximum fluidity, have high-efficiency water reduction, improve the air pore structure and the compaction degree of the concrete, and better control the slump loss of the concrete.
The foregoing is only a preferred embodiment of the present invention; the scope of the invention is not limited thereto. Any person skilled in the art should be able to cover the technical scope of the present invention by equivalent or modified solutions and modifications within the technical scope of the present invention.
Claims (4)
1. A method for synthesizing a polycarboxylic acid type high slump loss resistant water reducing agent is characterized by comprising the following steps: the synthesis method comprises the following steps:
s1, preparing treated water: adding a water treatment agent acrylic acid-maleic anhydride copolymer into tap water until the content of the acrylic acid-maleic anhydride copolymer is 3-8mg/L to obtain treated water for later use;
s2, preparing a macromonomer solution: weighing the macromonomer and the treated water according to the weight part ratio, placing the macromonomer and the treated water in a reaction kettle of a stirrer to be stirred for dissolving and mixing, and stirring uniformly to prepare a macromonomer solution for later use;
s3, preparing a small monomer solution: weighing functional monomers, an anti-mud agent, an anti-mud retarder, a slump retaining agent and acrylic acid according to the weight part ratio, sequentially adding the functional monomers, the anti-mud agent, the anti-mud retarder, the slump retaining agent and the acrylic acid into treated water for dissolving and mixing, and uniformly stirring to prepare a small monomer solution for later use;
s4, preparing an alkali solution: weighing sodium hydroxide powder, adding the sodium hydroxide powder into treated water for dissolving and mixing, uniformly stirring, and preparing an alkali solution for later use;
s5, synthesizing a water reducing agent sample: dropwise adding a small monomer solution and a chain transfer agent into a large monomer solution in a reaction kettle in S2 at a flow rate controlled by a constant flow pump, simultaneously adding an initiator solution through a self-sustained release device, and continuously stirring and preserving heat for 1-2 hours after the reaction is finished to obtain a water reducer sample;
s6, checking the net slurry fluidity of the sample: extracting a small amount of water reducing agent samples to carry out clean slurry fluidity detection, returning to the step S5 to continue stirring and heat preservation if the water reducing agent samples are unqualified, and continuing the next step if the water reducing agent samples are qualified;
s7, discharging of the finished water reducer: stopping the reaction, and adding a proper amount of alkali solution to adjust the pH value of a water reducer sample to 6-8 to obtain a finished water reducer;
the molecular weight of the acrylic acid-maleic anhydride copolymer is 2000-5000, and the weight ratio of acrylic acid in the acrylic acid-maleic anhydride copolymer is as follows: the molar ratio of the maleic anhydride is 1.2-1.5: 1;
the functional monomer is selected from one or more of fumaric acid, vinyl acetate, methacryloyloxyethyl phosphate, multifunctional acidic acrylate, ethylene glycol methacrylate phosphate and acrylamide which are mixed in any proportion, the molar ratio of the functional monomer to the macromonomer is 0.5-1:1, the weight of the mud-resistant agent accounts for 1-5% of the small monomer solution, the weight of the mud-resistant retarder accounts for 0.5-2% of the small monomer solution, the weight of the slump retaining agent accounts for 2-5% of the small monomer solution, and the weight of the acrylic acid accounts for 30-50% of the small monomer solution;
the initiator solution comprises an oxidant and a reducing agent in a ratio of 1:1, wherein the oxidant is a hydrogen peroxide solution with a mass fraction of 30-35%, and the reducing agent is selected from any one of L ascorbic acid, D isoascorbic acid, L sodium ascorbate and D sodium erythorbate;
in the step S5, dripping small monomer solution within 1-2h, dripping the residual chain transfer agent within 20min, stopping adding the initiator solution, and taking out from the slow release device;
the self-sustained release device comprises a pair of liquid storage semi-rings (1), the liquid storage semi-rings (1) are mutually and symmetrically combined into a whole ring, a liquid storage cavity is formed in each liquid storage semi-ring (1), a plurality of liquid outlet holes (2) communicated with the liquid storage cavity are further formed in the inner end of each liquid storage semi-ring (1), a semi-annular shunt pipe (4) is arranged on the upper side of each liquid storage semi-ring (1), a plurality of communicating pipes (3) are fixedly connected between each semi-annular shunt pipe (4) and each liquid storage semi-ring (1), and a liquid inlet pipe (5) is fixedly connected at the outer end of each semi-annular shunt pipe (4);
go out liquid hole (2) inner fixedly connected with deformable water retaining ring (6), inner fixedly connected with temperature sensing deformation becket (7) of deformable water retaining ring (6), temperature sensing deformation becket (7) adopts the memory alloy of two-way memory effect to make, and the equilibrium temperature of temperature sensing deformation becket (7) is 45 ℃, temperature sensing deformation becket (7) temperature reachs 45 ℃ and resumes high temperature looks shape, temperature sensing deformation becket (7) temperature resumes low temperature looks shape when being less than 45 ℃.
2. The method for synthesizing the polycarboxylic acid type high slump loss resistant water reducer according to claim 1, characterized in that: the macromonomer is a mixture of more than one of allyl polyoxyethylene ether, methyl allyl polyoxyethylene ether, butenyl polyoxyethylene ether, methyl butenyl polyoxyethylene ether, vinyl polyoxyethylene ether and hydroxybutyl vinyl polyoxyethylene ether mixed in any proportion, and the weight ratio of the macromonomer to the treated water is 1: 0.8-1.5.
3. The method for synthesizing the polycarboxylic acid type high slump loss resistant water reducer according to claim 1, characterized in that: the step S2, the step S3 and the step S4 are performed in any order or in synchronization.
4. The method for synthesizing the polycarboxylic acid type high slump loss resistant water reducer according to claim 1, characterized in that: the low temperature looks shape of thalposis deformation becket (7) is circular, the high temperature looks shape of thalposis deformation becket (7) is the shape of internal contraction, and the diameter of circular shape thalposis deformation becket (7) is 0.8mm, the diameter of going out liquid hole (2) is 1 mm.
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