阅读说明：本技术 一种混凝土泵送调节剂及其制备方法 (Concrete pumping regulator and preparation method thereof ) 是由 郭诚 樊伟 冯宁宁 王雪敏 刘伟 张孝伍 于 2020-04-17 设计创作，主要内容包括：本发明提供了一种混凝土泵送调节剂及其制备方法。其制备方法包括：在氮气保护下,将聚苯乙烯加热至预设第一温度融化；加入马来酸酐,维持预设第二温度并不断搅拌,保持预设第一时长；降温至预设第三温度,在预设第二时长内均匀加入氨水,然后保持预设第三时长；升温至预设第四温度,并抽真空进行减压蒸馏,保持预设第四时长；降温并加入水,搅拌均匀,配制成溶液。应用本发明可以解决现有技术中由于使用人工砂而带来的混凝土离析、泌水、包裹性差的问题。(The invention provides a concrete pumping regulator and a preparation method thereof. The preparation method comprises the following steps: under the protection of nitrogen, heating polystyrene to a preset first temperature to melt; adding maleic anhydride, maintaining a preset second temperature and continuously stirring, and keeping a preset first time length; cooling to a preset third temperature, uniformly adding ammonia water within a preset second time period, and then keeping the preset third time period; heating to a preset fourth temperature, vacuumizing, and carrying out reduced pressure distillation for a preset fourth time; cooling, adding water, stirring, and making into solution. The invention can solve the problems of concrete segregation, bleeding and poor wrapping property caused by using artificial sand in the prior art.)

1. A preparation method of a concrete pumping regulator is characterized by comprising the following steps:

under the protection of nitrogen, heating polystyrene to a preset first temperature to melt;

adding maleic anhydride, maintaining a preset second temperature and continuously stirring, and keeping a preset first time length;

cooling to a preset third temperature, uniformly adding ammonia water within a preset second time period, and then keeping the preset third time period;

heating to a preset fourth temperature, vacuumizing, and carrying out reduced pressure distillation for a preset fourth time;

cooling, adding water, stirring, and making into solution.

2. The method of claim 1, wherein prior to melting the polystyrene by heating it to the predetermined first temperature, the method further comprises:

polystyrene is pretreated.

3. The method of claim 1, further comprising, prior to adding the maleic anhydride:

maleic anhydride was previously melted.

4. The method of claim 1, wherein:

the addition amount of the maleic anhydride is not less than 50% of the mass of the polystyrene;

the concentration of the ammonia water is not lower than 20%; the adding amount of the ammonia water is not less than 80 percent of the mass of the maleic anhydride.

5. The method of claim 4, wherein:

the addition amount of the maleic anhydride is 85-90% of the mass of the polystyrene;

the adding amount of the ammonia water is 100-120% of the mass of the maleic anhydride.

6. The method of claim 1, wherein:

the first temperature and the second temperature are 150-160 ℃;

the preset third temperature is 100-110 ℃;

the fourth temperature is 120-140 ℃;

the first time is 8-14 hours;

the second time period is not less than 3 hours;

the third time is not less than 5 hours;

the fourth time is not less than 3 hours.

7. The method of claim 1, wherein:

the second time is 5-8 hours;

the third time is 6-10 hours;

the fourth time is 6-10 hours.

8. The method of claim 1, wherein:

when distillation is carried out under reduced pressure, the degree of vacuum is 95% or more.

9. The method of claim 1, wherein:

under the protection of nitrogen, the nitrogen accounts for more than 95 percent of the total gas fraction.

10. The concrete pumping regulator prepared by the preparation method of any one of claims 1 to 9, wherein the molecular structural formula of the effective components of the concrete pumping regulator is as follows:

Technical Field

The application relates to the technical field of concrete regulators, in particular to a concrete pumping regulator and a preparation method thereof.

Background

With the continuous progress of the basic construction of China, the natural concrete aggregate is gradually exhausted. Therefore, in recent years, the use of artificial aggregates such as machine-made sand, tailing sand, and construction solid waste has been becoming widespread. The artificial aggregate is a product produced by changing the original state of a solid substance through mechanical force, and has the characteristics of large difference of gradation compared with natural river sand, serious fault phenomenon and large proportion of needle-shaped particle types. Therefore, after artificial sand is used for replacing natural river sand, concrete with strength grade of C30 or below has a bleeding phenomenon more commonly.

Concrete bleeding not only adversely affects the appearance quality of the concrete structure (e.g., such as sand lines, water marks, etc.), but also adversely affects the durability of the concrete. The process that the inside moisture content of concrete is migrated to the surface and is exuded can form corresponding passageway in concrete inside for inside this passageway entering concrete of harmful medium can corrode the inside reinforcing bar of concrete. Meanwhile, the secreted water is gathered on the surface of the concrete, so that the water-cement ratio of the surface of the concrete is increased, the surface strength is reduced, and the surface of the hardened concrete is easy to generate ash. Therefore, how to prevent concrete bleeding has become a hot spot of industrial research.

Disclosure of Invention

In view of the above, the invention provides a concrete pumping regulator and a preparation method thereof, so that the problems of concrete segregation, bleeding and poor wrapping property caused by the use of artificial sand in the prior art can be solved.

The technical scheme of the invention is realized as follows:

a preparation method of concrete pumping regulator comprises the following steps:

under the protection of nitrogen, heating polystyrene to a preset first temperature to melt;

adding maleic anhydride, maintaining a preset second temperature and continuously stirring, and keeping a preset first time length;

cooling to a preset third temperature, uniformly adding ammonia water within a preset second time period, and then keeping the preset third time period;

heating to a preset fourth temperature, vacuumizing, and carrying out reduced pressure distillation for a preset fourth time;

cooling, adding water, stirring, and making into solution.

Optionally, before heating the polystyrene to the preset first temperature to melt, the method further includes:

polystyrene is pretreated.

Optionally, prior to adding the maleic anhydride, the method further comprises:

maleic anhydride was previously melted.

Optionally, the addition amount of the maleic anhydride is not less than 50% of the mass of the polystyrene;

the concentration of the ammonia water is not lower than 20%; the adding amount of the ammonia water is not less than 80 percent of the mass of the maleic anhydride.

Optionally, the adding amount of the maleic anhydride is 85-90% of the mass of the polystyrene;

the adding amount of the ammonia water is 100-120% of the mass of the maleic anhydride.

Optionally, the first temperature and the second temperature are 150-160 ℃;

the preset third temperature is 100-110 ℃;

the fourth temperature is 120-140 ℃;

the first time is 8-14 hours;

the second time period is not less than 3 hours;

the third time is not less than 5 hours;

the fourth time is not less than 3 hours.

Optionally, the second time period is 5-8 hours;

the third time is 6-10 hours;

the fourth time is 6-10 hours.

Optionally, the vacuum degree is 95% or more when the reduced pressure distillation is performed.

Optionally, the nitrogen accounts for more than 95% of the total gas fraction under the protection of nitrogen.

The invention also provides a concrete pumping regulator prepared by any one of the preparation methods, and the molecular structural formula of the effective components of the concrete pumping regulator is as follows:

as can be seen from the above, in the concrete pumping regulator and the preparation method thereof of the present invention, recycled waste polystyrene can be used to melt polystyrene, and the melted polystyrene and maleic anhydride undergo an alder-dicke reaction, and then ammonia water is added to undergo an amidation reaction, so that polystyrene forms a super absorbent resin. Therefore, the concrete pumping regulator provided by the invention which is finally prepared has an obvious water retention effect on concrete, so that the problems of concrete segregation, bleeding and poor wrapping property caused by the use of artificial sand in the prior art can be effectively solved.

Drawings

Fig. 1 is a flowchart of a method for preparing a concrete pumping regulator in an embodiment of the present invention.

Detailed Description

In order to make the technical scheme and advantages of the invention more apparent, the invention is further described in detail with reference to the accompanying drawings and specific embodiments.

Fig. 1 is a flowchart of a method for preparing a concrete pumping regulator in an embodiment of the present invention.

As shown in fig. 1, the preparation method of the concrete pumping regulator for the construction site in the embodiment of the present invention includes the following steps:

and 11, heating the polystyrene to a preset first temperature to melt under the protection of nitrogen.

Since the organic compound group of the polymer is easily reacted with oxygen radicals in oxygen during synthesis, thereby reducing the quality of the final product, nitrogen is introduced to eliminate the interference of oxygen. Therefore, in this step, it is necessary to heat the polystyrene to melt under the protection of nitrogen (for example, in a nitrogen atmosphere, or in high-purity nitrogen, or in a vacuum, and then introducing nitrogen, etc.).

Additionally, in an alternative embodiment of the present invention, the polystyrene may be waste polystyrene. For example, the polystyrene may be: polystyrene or polystyrene waste with the mass fraction of the styrene monomer reaching more than 85 percent.

In addition, in an alternative embodiment of the present invention, the nitrogen gas accounts for more than 95% of the total gas fraction under the protection of nitrogen gas.

In addition, in an alternative embodiment of the present invention, the first temperature may be 150 to 160 ℃.

And step 12, adding maleic anhydride, maintaining the preset second temperature and continuously stirring, and keeping the preset first time.

In this step, maleic anhydride is added to the melted polystyrene, and the mixture is kept at the preset second temperature and continuously stirred for the preset first time period, so that the alder-dicke reaction occurs.

In addition, in an alternative embodiment of the present invention, the maleic anhydride is added in an amount of not less than 50% by mass of the polystyrene.

For example, optionally, the addition amount of the maleic anhydride is 85-90% of the mass of the polystyrene.

In addition, in an alternative embodiment of the present invention, the second temperature may be 150 to 160 ℃.

In addition, in an alternative embodiment of the present invention, the first time period may be 8 to 14 hours.

And step 13, cooling to a preset third temperature, uniformly adding ammonia water within a preset second time period, and then keeping the preset third time period.

In the step, the temperature is reduced to a preset third temperature, then ammonia water is slowly added dropwise, namely the ammonia water is uniformly added within a preset second time period, and after the ammonia water is added, the preset third time period is maintained, so that the ring-opening reaction of the anhydride is carried out.

In addition, in an alternative embodiment of the present invention, the preset third temperature may be 100 to 110 ℃.

In addition, in an alternative embodiment of the present invention, the second period of time is not less than 3 hours.

For example, optionally, the second time period may be 5 to 8 hours.

In addition, in an alternative embodiment of the present invention, the concentration of the aqueous ammonia is not less than 20%.

In addition, in an alternative embodiment of the present invention, the amount of the ammonia added is not less than 80% by mass of the maleic anhydride.

For example, optionally, the adding amount of the ammonia water is 100-120% of the mass of the maleic anhydride.

Additionally, in an alternative embodiment of the present invention, the third period of time is not less than 5 hours.

For example, optionally, the third time period may be 6 to 10 hours.

And step 14, heating to a preset fourth temperature, vacuumizing, and carrying out reduced pressure distillation for a preset fourth time.

In the step, the vacuum is pumped for reduced pressure distillation, the vacuum is heated to a preset fourth temperature, and the preset fourth time is kept for dehydration and amidation.

In addition, in an alternative embodiment of the present invention, the fourth temperature may be 120 to 140 ℃.

In addition, in an alternative embodiment of the present invention, the vacuum degree is not less than 85% when distillation under reduced pressure is carried out.

For example, optionally, the vacuum degree is 95% or more when distillation under reduced pressure is performed.

By the above-mentioned distillation under reduced pressure, it is possible to dehydrate and remove excess ammonia gas.

Additionally, in an alternative embodiment of the present invention, the fourth time period is not less than 3 hours.

For example, optionally, the fourth time period may be 6 to 10 hours.

And step 15, cooling, adding water, uniformly stirring, and preparing a solution.

In this step, the concrete pumping regulator of the present invention can be prepared by adding water (or adding the product of step 14) while reducing the temperature (for example, reducing the temperature below the boiling point of water to avoid boiling of the liquid), and then stirring uniformly to prepare a solution.

The concrete pumping regulator can be prepared through the steps 11-15.

In addition, in an alternative embodiment of the present invention, before step 11, the method may further include:

step 10, polystyrene is pretreated.

In addition, in an alternative embodiment of the present invention, the pre-treating the polystyrene may include: the polystyrene is subjected to washing, drying and pulverizing operations.

In the above pretreatment, the washing, drying and the like are performed in order to reduce the sum of the mass of nonpolymeric components such as dirt and impurity moisture in the polystyrene (or waste polystyrene) to 1% or less of the total mass. The purpose of the crushing operation is to facilitate the melting of the polystyrene.

In addition, in an alternative embodiment of the present invention, before step 12, the method may further include:

and 20, pre-melting maleic anhydride.

In addition, in an alternative embodiment of the present invention, the temperature for melting the maleic anhydride may be 90 to 150 ℃.

In addition, in the technical scheme of the invention, the concrete pumping regulator prepared by the preparation method is provided, and the molecular structural formula of the effective components of the concrete pumping regulator is as follows:

in addition, in the technical scheme of the invention, the effective components of the concrete pumping regulator are mixed with water to prepare an aqueous solution with the percentage concentration of 1-50%, so that the concrete pumping regulator can be obtained.

The technical solution of the present invention will be described in detail below by taking several specific implementation modes as examples.

Example one：

In this example, 2 tons (t) of clean and dry waste polystyrene was melted by heating to 150 ℃ under nitrogen protection, and 1.7 tons of maleic anhydride was added while stirring, and the mixture was kept at 150 to 160 ℃ for 8 hours while stirring. The temperature is reduced to 100 ℃, and 1t of ammonia water with the concentration of 20 percent is slowly dropped. The ammonia was added uniformly over a period of 5 hours and then held for 10 hours. Heating to 130 ℃, vacuumizing, and keeping for 7 hours when the vacuum degree reaches 95 MPa. Feeding materials while cooling, adding the materials into 20t of water, uniformly stirring, and preparing into a solution to obtain the concrete pumping regulator.

Example two：

In this example, 2t of clean and dry waste polystyrene was heated to 150 ℃ to melt under nitrogen protection, 1.5t of maleic anhydride was added while stirring, and the mixture was kept at 150 to 160 ℃ for 12 hours while stirring. The temperature is reduced to 100 ℃, and 1t of ammonia water with the concentration of 20 percent is slowly dropped. The ammonia was added uniformly over a period of 5 hours and then held for 10 hours. Heating to 130 ℃, vacuumizing, and keeping for 7 hours when the vacuum degree reaches 95 MPa. Feeding materials while cooling, adding the materials into 20t of water, uniformly stirring, and preparing into a solution to obtain the concrete pumping regulator.

EXAMPLE III：

In this example, 2t of clean and dry waste polystyrene was heated to 150 ℃ to melt under nitrogen protection, 1.9t of maleic anhydride was added while stirring, and the mixture was kept at 150 to 160 ℃ for 7 hours while stirring. The temperature is reduced to 110 ℃, and 1.2t of ammonia water with the concentration of 20 percent is slowly dropped. The ammonia was added uniformly over a period of 8 hours and then held for 6 hours. Heating to 130 ℃, vacuumizing, and keeping for 7 hours when the vacuum degree reaches 95 MPa. Feeding materials while cooling, adding the materials into 20t of water, uniformly stirring, and preparing into a solution to obtain the concrete pumping regulator.

Product performance comparison:

in the technical scheme of the invention, concrete pumping regulators in the first to third examples can be compared with some concrete water-retaining agent samples in the prior art. In the comparative experiments, the respective samples used for comparison had the same concentration and the conditions of the added concrete were the same.

The results of the comparative experiments are shown in the following table:

wherein the dosage in the above table refers to the ratio of the amount of incorporation to the mass of cement.

According to the results of the comparative experiments, compared with the comparative products in the prior art, the concrete pumping regulator has small difference in the initial fluidity of concrete, and the retention time of the concrete pumping regulator is obviously superior to that of domestic comparative samples; meanwhile, the bleeding rate is obviously lower than that of a domestic comparison sample, which shows that the concrete pumping regulator has excellent water retention effect.

In summary, in the technical scheme of the present invention, the recycled waste polystyrene can be used to melt polystyrene, and the melted polystyrene and maleic anhydride are subjected to an alder-dicke reaction, and then ammonia water is added to perform an amidation reaction, so that the polystyrene forms the super absorbent resin. Therefore, the concrete pumping regulator has obvious water retention effect on concrete by controlling the carboxylation degree and the amidation degree, so that the problems of concrete segregation, bleeding and poor wrapping property caused by the use of artificial sand in the prior art can be effectively solved.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.