CN109721689A - A kind of synthetic method of collapse protective poly-carboxylic acid water reducing agent - Google Patents
A kind of synthetic method of collapse protective poly-carboxylic acid water reducing agent Download PDFInfo
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- CN109721689A CN109721689A CN201910068505.4A CN201910068505A CN109721689A CN 109721689 A CN109721689 A CN 109721689A CN 201910068505 A CN201910068505 A CN 201910068505A CN 109721689 A CN109721689 A CN 109721689A
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Abstract
The invention belongs to cement water reducing agent preparation technical fields, disclose a kind of synthetic method of collapse protective poly-carboxylic acid water reducing agent, the following steps are included: polymeric monomer, a small amount of acrylamide, function monomer and deionized water are added into four-hole boiling flask, be heated to 25 ~ 45 DEG C be completely dissolved after, initiator is added, stirring to abundant dissolution obtains solution A；Function monomer, acrylic acid, maleic anhydride, remaining acrylamide, chain-transferring agent and reducing agent are mixed into solution B, solution B is added dropwise into solution A, time for adding is 2.5 ~ 3.5h, and temperature is controlled in 20 DEG C ~ 40 DEG C progress Raolical polymerizables；After being added dropwise to complete, continue 0.5 ~ 1h of stirring, NaOH solution is added and adjusts pH value to 7, is cooled to room temperature, obtains polycarboxylate water-reducer.The water-reducing agent that the present invention synthesizes is better than commercially available water-reducing agent in indexs such as water-reducing rate, initial slump and slump 1h ongoing change amounts, while concrete crushing strength, air-void spacing factor etc. are able to satisfy design requirement.
Description
Technical field
The invention belongs to cement water reducing agent preparation technical fields, are related to a kind of synthesis side of collapse protective poly-carboxylic acid water reducing agent
Method.
Background technique
Poly carboxylic acid series water reducer is widely used in the construction projects high performance concrete such as railway, highway, bridge, skyscraper
Preparation in.Document points out that poly carboxylic acid series water reducer (20% mother liquor) yield in 2015 up to 62,190,000 tons, accounts for efficient diminishing
Agent market yield close to 80%.However, main problem existing for polycarboxylate water-reducer is that polymeric monomer homogeneity is excessively serious, it is
Columnization, functionalization require relatively prominent；The early strength of concrete and slump-loss of preparation often conflict；To sand material, especially
It is clay content Indexes Comparison sensitivity etc..
The molecular structure of polycarboxylate water-reducer is designed for the cement mechanism of action, has that ultra-dispersed property, volume be low, slump retaining
Can be good the advantages that.It is in recent years, domestic unprecedentedly active to the research of water-reducing agent because of the significant economic benefit of polycarboxylate water-reducer,
And there is certain improvement in its preparation process.But it is poor to still remain polycarboxylate water-reducer comprehensive performance, and slump retaining is insufficient
The problem of.
Summary of the invention
The purpose of the present invention is to provide a kind of synthetic method of collapse protective poly-carboxylic acid water reducing agent, the water-reducing agent of synthesis is subtracting
The indexs such as water rate, initial slump and slump 1h ongoing change amount are better than commercially available water-reducing agent.
To achieve the above object, the invention adopts the following technical scheme:
The present invention provides a kind of synthetic method of collapse protective poly-carboxylic acid water reducing agent, comprising the following steps:
Step 1: polymeric monomer methacrylic polyoxy second being added into the four-hole boiling flask equipped with blender, thermometer and Dropping feeder
Alkene ether, a small amount of acrylamide, function monomer and deionized water, be heated to 25~45 DEG C be completely dissolved after, be added initiator dioxygen
Water, stirring to abundant dissolution obtain solution A；
Step 2: by function monomer, acrylic acid, maleic anhydride, remaining acrylamide, chain-transferring agent thioacetic acid and reducing agent
L-AA is mixed into solution B, and solution B is added dropwise into solution A, and time for adding is 2.5~3.5h, temperature control 20 DEG C~
40 DEG C of progress Raolical polymerizables；
Step 3: after being added dropwise to complete, continuing 0.5~1h of stirring, NaOH solution is added and adjusts pH value to 7, is cooled to room temperature, obtains
The polycarboxylate water-reducer that solid content is 35%~40%.
Preferably, the function monomer is hydroxy-ethyl acrylate.
Preferably, the molar ratio of the acrylic acid and maleic anhydride is (1~3): (0.5~2.5).
Preferably, the ratio between additional amount of acrylamide is 6:4 in acrylamide and step 2 in the step 1.
Preferably, the molar ratio of the acrylic acid and chain-transferring agent thioacetic acid is 1:(0.01~0.05).
Compared with prior art, the beneficial effects of the present invention are:
The redox system that the present invention is formed with L-AA using hydrogen peroxide synthesizes, mainly from monomer mole ratio,
The synthesis technology of the Discussion of factors polycarboxylate water-reducer such as initiator, chain-transferring agent, the water-reducing agent of synthesis is in water-reducing rate, initial slump
The indexs such as degree and slump 1h ongoing change amount are better than commercially available water-reducing agent, while concrete crushing strength, air-void spacing factor
Etc. being able to satisfy design requirement.
Detailed description of the invention
Fig. 1 is the influence of acrylic acid and maleic anhydride dosage to flowing degree of net paste of cement in the embodiment of the present invention 2.
Fig. 2 is influence of the TPEG dosage to flowing degree of net paste of cement in the embodiment of the present invention 3.
Fig. 3 is influence of the initiator amount to flowing degree of net paste of cement in the embodiment of the present invention 4.
Fig. 4 is influence of the 5 Chain transfer agent dosage of the embodiment of the present invention to flowing degree of net paste of cement.
Fig. 5 is influence of the reaction temperature to flowing degree of net paste of cement in the embodiment of the present invention 6.
Specific embodiment
The following examples are intended to illustrate the invention, but is not used to limit the scope of protection of the present invention.Unless otherwise specified, real
Apply the conventional means that technological means used in example is well known to those skilled in the art.Test method in following embodiments, such as
It is conventional method without special instruction.
According to GB/T 8077-2012, " concrete admixture is homogeneous for flowing degree of net paste of cement test in the embodiment of the present invention
Property test method " carry out, the ratio of mud 0.29；Concrete mix working performance (slump, 1h ongoing change amount) test according to
It is carried out according to GB/T 50081-2016 " Standard for test methods of properties of ordinary concrete mixture standard "；Concrete crushing strength according to
GB/T 50081-2002 " standard for test methods of mechanical properties of ordinary concrete " is carried out；Concrete air-void spacing factor according to
TB/T 3275-2011 " railway concrete " is carried out.
Embodiment one
1mol polymeric monomer methacrylic polyoxyethylene is added into the four-hole boiling flask equipped with blender, thermometer and Dropping feeder
Ether (TPEG), 0.6mol acrylamide, 1mol function monomer and deionized water, be heated to 25~45 DEG C be completely dissolved after, be added
0.04mol causes agent hydrogen peroxide, and stirring to abundant dissolution obtains solution A.
By 1mol function monomer hydroxy-ethyl acrylate, 1mol acrylic acid, 2.5mol maleic anhydride, 0.4mol acrylamide,
0.05mol chain-transferring agent thioacetic acid and reducing agent L-AA are mixed into solution B, and solution B is added dropwise to solution A, are added dropwise
Time is 2.5~3.5h, and temperature is controlled in 20 DEG C of progress Raolical polymerizables.
After being added dropwise to complete, continuing 0.5~1h of stirring, addition NaOH solution adjusting pH value to 7 is cooled to room temperature, consolidate
The polycarboxylate water-reducer that content is 35%~40%.
Embodiment two
The present embodiment is basically the same as the first embodiment, the difference is that: the molar ratio of acrylic acid (AA) and maleic anhydride (MAH)
Respectively 1:2.5,1.5:2,2:1.5,2.5:1 and 3:0.5 measure acrylic acid and maleic anhydride dosage to flowing degree of net paste of cement
Influence, as shown in Figure 1.It will be seen from figure 1 that AA is easier to be adsorbed in hydrated cementitious particle surface relative to MAH, MAH is then
There is certain wholesome effect to the retentivity of flowing degree of net paste of cement.
Embodiment three
The present embodiment is basically the same as the first embodiment, the difference is that: acrylic acid (AA), maleic anhydride (MAH) are with TPEG's
Molar ratio be respectively 2.5:1:0.5,2.5:1:1,2.5:1:1.5 and 2.5:1:2, measure TPEG dosage to pulp flowage
The influence of degree, as shown in Figure 2.Figure it is seen that cement paste is initial when the ratio of AA, MAH, TPEG are 2.5: 1: 1
Flowing angle value is larger after flowing angle value and 1h, and respectively 315mm, 280mm, paste flowing degree retentivity are preferable.This is because carboxylic
The obvious absorption behavior for influencing polycarboxylate water-reducer of the density of base, is integrally presented the trend fallen after rising, when density is smaller
When, absorption is slower, and cement paste initial flow degree is smaller, when density is larger, influences the space steric effect of polymeric monomer, only
Slurry fluidity decreases.
Example IV
The present embodiment is basically the same as the first embodiment, the difference is that: acrylic acid (AA) and the molar ratio for causing agent hydrogen peroxide
For 1:0.03,1:0.04,1:0.05 and 1:0.06, influence of the initiator amount to flowing degree of net paste of cement is measured, such as Fig. 3 institute
Show.From figure 3, it can be seen that the dispersibility of polycarboxylate water-reducer is first improved and is reduced afterwards with the increase of initiator amount.When AA with
When the molar ratio for causing agent hydrogen peroxide is 0.04, flowing angle value is larger after cement paste initial flow angle value and 1h, i.e. polycarboxylic acids
The dispersibility and dispersion retentivity of water-reducing agent are good.Gather this is because initiator not only adjusts control in water-reducing agent polymerization process
Rate is closed, and has apparent influence to the molecular weight of polymer.In radical polymerization process, kinetic chain length is dense with initiator
The square root of degree is inversely proportional, and with the increase of initiator amount, reaction rate reduces the molecular weight of reactant while increase.
With the increase of initiator, water-reducing agent molecular mass is close to optimum weight range, and when initiator is excessive, polycarboxylic acids diminishing
The molecular weight reduction of agent is more, and backbone length reduces, and influences the overall space steric hindrance of comb-type structure, and then show as water-reducing agent
The reduction of water-reducing rate.
Embodiment five
The present embodiment is basically the same as the first embodiment, the difference is that: acrylic acid (AA) rubs with chain-transferring agent thioacetic acid
You measure influence of the chain-transferring agent dosage to flowing degree of net paste of cement, as shown in Figure 4 than being 1:0.01,1:0.02 and 1:0.03.
From fig. 4, it can be seen that flowing degree of net paste of cement value is maximum, it may be assumed that water-reducing agent when the molar ratio of AA and chain-transferring agent is 1:0.02
With appropriate molecular weight and molecualr weight distribution.
Embodiment six
The present embodiment is basically the same as the first embodiment, the difference is that: the reaction temperature of Raolical polymerizable is set separately
It is 25 DEG C, 30 DEG C, 35 DEG C and 40 DEG C, measures influence of the reaction temperature to flowing degree of net paste of cement, as shown in Figure 5.It can be with from Fig. 5
Find out, when temperature is 40 DEG C, flowing degree of net paste of cement value is larger.This is because the too low decomposition for influencing whether free radical of temperature
Rate, excessively slow decomposition rate makes polymerization efficiency poor, and temperature is excessively high, and rate of polymerization is not easy to control, water-reducing agent molecular weight
Unevenly, the active constituent content of water-reducing agent decreases.
The present invention use certain high-speed rail precast beam field match ratio, be shown in Table 1, by AA, MAH of the present invention, TPEG, function monomer ratio
Example is 2.5:1:1:2, and 40 DEG C of reaction temperature, for other conditions with embodiment 1, the collapse protective poly-carboxylic acid water reducing agent of synthesis is commercially available with certain
ZGPCA slow-setting polycarboxylic acid water reducing agent compares test, and concrete outcome is shown in Table 2.
1 concrete mix of table
2 testing concrete performance result of table
As can be seen that under the conditions of certain ready-mixed concrete cooperates when certain high-speed rail precast beam field match ratio, the water-reducing agent of synthesis
Commercially available water-reducing agent, while concrete anti-compression are better than in indexs such as water-reducing rate, initial slump and slump 1h ongoing change amounts
Intensity, air-void spacing factor etc. are able to satisfy design requirement.
The embodiment of the above, only presently preferred embodiments of the present invention, is only used to explain the present invention, not limit
The scope of the present invention processed to those of ordinary skill in the art certainly can be according to skill disclosed in this specification
Art content makes other embodiments easily by way of replacing or changing, therefore all made in the principle of the present invention
Changes and improvements etc., should be included in scope of the present invention patent.
Claims (5)
1. a kind of synthetic method of collapse protective poly-carboxylic acid water reducing agent, which comprises the following steps:
Step 1: polymeric monomer methacrylic polyoxy second being added into the four-hole boiling flask equipped with blender, thermometer and Dropping feeder
Alkene ether, a small amount of acrylamide, function monomer and deionized water, be heated to 25 ~ 45 DEG C be completely dissolved after, be added initiator dioxygen
Water, stirring to abundant dissolution obtain solution A；
Step 2: by function monomer, acrylic acid, maleic anhydride, remaining acrylamide, chain-transferring agent thioacetic acid and reducing agent
L-AA is mixed into solution B, and solution B is added dropwise into solution A, and time for adding is 2.5 ~ 3.5h, and temperature is controlled 20 DEG C ~ 40
DEG C carry out Raolical polymerizable；
Step 3: after being added dropwise to complete, continue 0.5 ~ 1h of stirring, addition NaOH solution adjusting pH value to 7 is cooled to room temperature, consolidate
The polycarboxylate water-reducer that content is 35% ~ 40%.
2. a kind of synthetic method of collapse protective poly-carboxylic acid water reducing agent according to claim 1, which is characterized in that the function
Monomer is hydroxy-ethyl acrylate.
3. a kind of synthetic method of collapse protective poly-carboxylic acid water reducing agent according to claim 1, which is characterized in that the propylene
The molar ratio of acid and maleic anhydride is (1 ~ 3): (0.5 ~ 2.5).
4. a kind of synthetic method of collapse protective poly-carboxylic acid water reducing agent according to claim 1, which is characterized in that the step
The ratio between additional amount of acrylamide is 6:4 in acrylamide and step 2 in 1.
5. a kind of synthetic method of collapse protective poly-carboxylic acid water reducing agent according to claim 1, which is characterized in that the propylene
The molar ratio of acid and chain-transferring agent thioacetic acid is 1:(0.01 ~ 0.05).
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110713573A (en) * | 2019-09-18 | 2020-01-21 | 山东申鑫建材科技有限公司 | Method for synthesizing polycarboxylate superplasticizer slump-retaining mother liquor |
| CN113214438A (en) * | 2021-06-29 | 2021-08-06 | 安徽海螺新材料科技有限公司 | Polycarboxylic acid water reducing agent containing maleic anhydride and preparation method thereof |
| CN114524634A (en) * | 2022-02-16 | 2022-05-24 | 湖南先锋建材有限公司 | High-dispersion polycarboxylate superplasticizer |
-
2019
- 2019-01-24 CN CN201910068505.4A patent/CN109721689A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110713573A (en) * | 2019-09-18 | 2020-01-21 | 山东申鑫建材科技有限公司 | Method for synthesizing polycarboxylate superplasticizer slump-retaining mother liquor |
| CN113214438A (en) * | 2021-06-29 | 2021-08-06 | 安徽海螺新材料科技有限公司 | Polycarboxylic acid water reducing agent containing maleic anhydride and preparation method thereof |
| CN114524634A (en) * | 2022-02-16 | 2022-05-24 | 湖南先锋建材有限公司 | High-dispersion polycarboxylate superplasticizer |
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